Fixed FM demod and http server.

Conflicts:
	src/autocast.hh
	src/baseband.hh
	src/freqshift.hh
	src/rtlsource.hh
	src/utils.hh

CMakeLists.txt

@@ -3,9 +3,11 @@ project(libsdr)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/cmake)
 include(InstallHeadersWithDirectory)
+include(LinkResources)
 
 OPTION(BUILD_EXAMPLES "Build examples" OFF)
 OPTION(BUILD_UNIT_TESTS "Build unit tests" OFF)
+OPTION(BUILD_COMMANDLINETOOL "Build command line tool" ON)
 
 SET(libsdr_VERSION_MAJOR "0")
 SET(libsdr_VERSION_MINOR "1")
@@ -19,6 +21,7 @@ find_package(RTLSDR)
 INCLUDE_DIRECTORIES(${PROJECT_SOURCE_DIR}/src)
 INCLUDE_DIRECTORIES(${PROJECT_BINARY_DIR}/src)
 INCLUDE_DIRECTORIES(${PORTAUDIO_INCLUDE_DIRS})
+INCLUDE_DIRECTORIES(${GETOPT_INCLUDE_DIRS})
 
 # Set some variables for the configuration file
 IF(FFTW_FOUND)
@@ -41,7 +44,8 @@ ELSE(TRLSDR_FOUND)
 ENDIF(RTLSDR_FOUND)
 
 
-set(LIBS ${FFTW_LIBRARIES} ${FFTWSingle_LIBRARIES} ${PORTAUDIO_LIBRARIES} ${RTLSDR_LIBRARIES} "pthread")
+set(LIBS ${FFTW_LIBRARIES} ${FFTWSingle_LIBRARIES} ${PORTAUDIO_LIBRARIES} ${RTLSDR_LIBRARIES}
+         "pthread")
 
 # Set compiler flags
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -fPIC")
@@ -82,13 +86,19 @@ ENDIF(UNIX AND APPLE)
 
 # Add core library, and unit tests
 add_subdirectory(src)
+
 IF(BUILD_UNIT_TESTS)
  add_subdirectory(test)
 ENDIF(BUILD_UNIT_TESTS)
+
 IF(BUILD_EXAMPLES)
  add_subdirectory(examples)
 ENDIF(BUILD_EXAMPLES)
 
+IF(BUILD_COMMANDLINETOOL)
+ add_subdirectory(cmd)
+endif(BUILD_COMMANDLINETOOL)
+
 # Source distribution packages:
 set(CPACK_PACKAGE_VERSION_MAJOR ${libsdr_VERSION_MAJOR})
 set(CPACK_PACKAGE_VERSION_MINOR ${libsdr_VERSION_MINOR})

README.md

@@ -1,22 +1,34 @@
 # libsdr - A simple software defined radio (SDR) library
 
-**First of all:** I  assembled this library for my one entertainment and to learn something about software defined radio. If you are interested into a full-featured, performant SDR framework, consider using GNU radio (http://gnuradio.org). 
+**First of all:** I  assembled this library for my one entertainment and to learn something about
+software defined radio. If you are interested into a full-featured, performant SDR framework,
+consider using GNU radio (http://gnuradio.org).
 
-<a href="http://de.tinypic.com?ref=2jb2qfb" target="_blank"><img src="http://i61.tinypic.com/2jb2qfb.png" border="0" alt="SRD-RX"></a>
+<a href="http://de.tinypic.com?ref=2jb2qfb" target="_blank">
+ <img src="http://i61.tinypic.com/2jb2qfb.png" border="0" alt="SRD-RX">
+</a>
 
-Although being simple, libsdr is sufficient to write a simple SDR receiver application (http://github.com/hmatuschek/sdr-rx, above). This RX application supports several input sources (i.e. sound card, files, RTL2382 dongles etc.) and modes (i.e. AM, FM, SSB, CW, etc.).
+Although being simple, libsdr is sufficient to write a simple SDR receiver application
+(http://github.com/hmatuschek/sdr-rx, above). This RX application supports several input sources
+(i.e. sound card, files, RTL2382 dongles etc.) and modes (i.e. AM, FM, SSB, CW, etc.).
 
 
 ## Build
 
-The only required run-time dependency of `libsdr` is `libpthread`, which is available on all Unix-like OSs like Linux and MacOS X. It is also available for windows if `mingw` is used (http://www.mingw.org) of compilation. There are also some optional dependencies, which allow for the usage of some additional features of the library. 
+The only required run-time dependency of `libsdr` is `libpthread`, which is available on all
+Unix-like OSs like Linux and MacOS X. It is also available for windows if `mingw` is used
+(http://www.mingw.org) of compilation. There are also some optional dependencies, which allow for
+the usage of some additional features of the library.
 
-* `Qt5` (http://qt-project.org) - Enables the `libsdr-gui` library implementing some graphical user interface elements like a spectrum view.
-* `fftw3` (http://www.fftw.org) - Also required by the GUI library and allows for FFT-convolution filters.
+* `Qt5` (http://qt-project.org) - Enables the `libsdr-gui` library implementing some graphical user
+   interface elements like a spectrum view.
+* `fftw3` (http://www.fftw.org) - Also required by the GUI library and allows for FFT-convolution
+   filters.
 * `PortAudio` (http://www.portaudio.com) - Allows for sound-card input and output.
 * `librtlsdr` (http://rtlsdr.org) - Allows to interface RTL2382U based USB dongles.
 
-For the compilation of the library, `cmake` (http://www.cmake.org) is also required (as well as a compiler like gcc or clang of cause).
+For the compilation of the library, `cmake` (http://www.cmake.org) is also required (as well as a
+compiler like gcc or clang of cause).
 
 Compiling the library is the canonical cmake path:
 

cmake/LinkResources.cmake

@@ -0,0 +1,7 @@
+macro(link_resources HEADER_NAME)
+  #create_resources("${CMAKE_CURRENT_BINARY_DIR}/${HEADER_NAME}.hh" ${ARGN})
+  add_custom_target(${HEADER_NAME} ALL
+   COMMAND ${CMAKE_COMMAND} -DOUTPUT="${CMAKE_CURRENT_BINARY_DIR}/${HEADER_NAME}.hh" -DRESOURCE_PATH="${CMAKE_CURRENT_SOURCE_DIR}" -DFILES="${ARGN}" -P "${PROJECT_SOURCE_DIR}/cmake/create_resources.cmake"
+   DEPENDS ${ARGN} SOURCES ${ARGN})
+endmacro(link_resources)
+

cmake/create_resources.cmake

@@ -0,0 +1,22 @@
+#
+# Implements the packing of resource files into a header file
+#
+get_filename_component(OUTPUT_FILE ${OUTPUT} NAME)
+message(STATUS "Generate resource file '${OUTPUT_FILE}' from: ${FILES}")
+# Create empty file
+file(WRITE ${OUTPUT} "")
+# For each resource file
+foreach(file ${FILES})
+  # Normalize filename
+  string(REGEX MATCH "([^/]+)$" filename ${file})
+  string(REGEX REPLACE "\\.| " "_" filename ${filename})
+  # Read and convert file content
+  file(READ "${RESOURCE_PATH}/${file}" filedata HEX)
+  string(REGEX REPLACE "([0-9a-fA-F][0-9a-fA-F])" "0x\\1," filedata ${filedata})
+  # Update output file
+  file(APPEND ${OUTPUT}
+       "extern \"C\" {\n"
+       "  static char ${filename}[] = {${filedata}};\n"
+       "  static unsigned ${filename}_size = sizeof(${filename});\n"
+       "}\n")
+endforeach()

cmd/CMakeLists.txt

@@ -0,0 +1,8 @@
+
+# Creates a header file including the shared resources
+INCLUDE_DIRECTORIES(${CMAKE_CURRENT_BINARY_DIR})
+link_resources(sdr_cmd_resources shared/index.html)
+
+add_executable(sdr_cmd main.cc aprsapplication.cc)
+add_dependencies(sdr_cmd sdr_cmd_resources)
+target_link_libraries(sdr_cmd ${LIBS} libsdr )

cmd/aprsapplication.cc

@@ -0,0 +1,87 @@
+#include "aprsapplication.hh"
+
+// This file will be generated at build time
+// and contains the static content served.
+#include "sdr_cmd_resources.hh"
+
+
+using namespace sdr;
+
+APRSApplication::APRSApplication(http::Server &server)
+  : APRS(), _server(server), _messages()
+{
+  // Register callbacks
+  server.addStatic("/", std::string(index_html, index_html_size), "text/html");
+  server.addJSON("/spots", this, &APRSApplication::spots);
+  server.addHandler("/update", this, &APRSApplication::update);
+}
+
+APRSApplication::~APRSApplication() {
+  // pass...
+}
+
+
+bool
+APRSApplication::spots(const http::JSON &request, http::JSON &response) {
+  std::list<http::JSON> msg_list;
+  for (std::list<Message>::iterator msg = _messages.begin(); msg != _messages.end(); msg++) {
+    std::map<std::string, http::JSON> message;
+    message["call"] = http::JSON(msg->from().call());
+    if (msg->hasLocation()) {
+      message["lat"] = http::JSON(msg->latitude());
+      message["lon"] = http::JSON(msg->longitude());
+    }
+    time_t time = msg->time();
+    message["time"] = http::JSON(ctime(&time));
+    msg_list.push_back(message);
+  }
+  response = http::JSON(msg_list);
+  return true;
+}
+
+void
+APRSApplication::handleAPRSMessage(const Message &message) {
+  _messages.push_back(message);
+  // Serialize JSON message
+  std::string json_text;
+  if (_clients.size()) {
+    std::map<std::string, http::JSON> msg;
+    msg["call"] = http::JSON(message.from().call());
+    if (message.hasLocation()) {
+      msg["lat"] = http::JSON(message.latitude());
+      msg["lon"] = http::JSON(message.longitude());
+    }
+    time_t time = message.time();
+    msg["time"] = http::JSON(ctime(&time));
+    http::JSON(msg).serialize(json_text);
+  }
+  // a list collecting the closed
+  // signal all clients connected
+  std::list<http::Connection>::iterator client = _clients.begin();
+  while (client != _clients.end()) {
+    if (client->isClosed()) {
+      // remove client from list
+      client = _clients.erase(client);
+    } else {
+      // send event
+      client->send("data: ");
+      client->send(json_text);
+      client->send("\n\n");
+    }
+  }
+}
+
+void
+APRSApplication::update(const http::Request &request, http::Response &response) {
+  // This call back implements a server side event stream, means the response will
+  // be blocked until the connection is closed
+  response.setHeader("Content-Type", "text/event-stream");
+  response.setHeader("Cache-Control", "no-cache");
+  response.setStatus(http::Response::STATUS_OK);
+  response.sendHeaders();
+  // Signal connection thread to exit without closing the connection
+  response.connection().setProtocolUpgrade();
+  // Store connection
+  _clients.push_back(response.connection());
+}
+

cmd/aprsapplication.hh

@@ -0,0 +1,29 @@
+#ifndef __SDR_APRS_APRSAPPLICATION_HH__
+#define __SDR_APRS_APRSAPPLICATION_HH__
+
+#include "http.hh"
+#include "aprs.hh"
+
+
+namespace sdr {
+
+class APRSApplication: public APRS
+{
+public:
+  APRSApplication(http::Server &server);
+  ~APRSApplication();
+
+  bool spots(const http::JSON &request, http::JSON &response);
+  void update(const http::Request &request, http::Response &response);
+
+  void handleAPRSMessage(const Message &message);
+
+protected:
+  http::Server      &_server;
+  std::list<Message> _messages;
+  std::list<http::Connection> _clients;
+};
+
+}
+
+#endif // APRSAPPLICATION_HH

cmd/main.cc

@@ -0,0 +1,36 @@
+#include <stdio.h>
+
+#include "queue.hh"
+#include "logger.hh"
+
+#include <iostream>
+#include <csignal>
+
+#include "aprsapplication.hh"
+
+using namespace sdr;
+
+
+static http::Server *server = 0;
+
+static void __sigint_handler(int signo) {
+  if (server) { server->stop(true); }
+}
+
+
+int main(int argc, char *argv[]) {
+  server = new http::Server(8080);
+  APRSApplication app(*server);
+
+  // Install log handler
+  sdr::Logger::get().addHandler(
+        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+
+  // Register signal handler:
+  signal(SIGINT, __sigint_handler);
+
+  // start server
+  server->start(true);
+
+  return 0;
+}

cmd/shared/index.html

@@ -0,0 +1,74 @@
+<html>
+ <head>
+  <title>sdr-aprs &mdash; An APRS receiver using libsdr.</title>
+  <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
+  <meta charset="utf-8">
+  <style>
+    html, body, #map-canvas {
+      height: 100%;
+      margin: 0px;
+      padding: 0px
+    }
+  </style>
+  <script src="https://maps.googleapis.com/maps/api/js?v=3.exp"></script>
+
+  <script>
+var map = null;
+var spots = {};
+var source = null;
+
+function onAddSpot (callsign, lon, lat) {
+  // Check if connection exists
+  if (callsign in spots) {
+    // If connection exists, update SNR
+    connections[spots].marker.setPosition(new google.maps.LatLng(lat, lon));
+  } else {
+    // otherwise, add marker at location with label callsign
+    var marker = new google.maps.Marker({
+       position: new google.maps.LatLng(lat, lon), title: callsign, map: map});
+    spots[callsign] = { marker: marker };
+  }
+}
+
+function updateHandler(e) {
+  var msg = JSON.parse(e.data);
+  console.log("RX: " + msg)
+  onAddSpot(msg.call, msg.lon, msg.lat);
+}
+
+function initialize() {
+  // Create Map object
+  map = new google.maps.Map(
+    document.getElementById('map-canvas'),
+    {zoom:2, center: new google.maps.LatLng(0,0), streetViewControl:false});
+
+  // Request all spots
+  var xmlhttp = new XMLHttpRequest();
+  var url = "spots";
+  xmlhttp.onreadystatechange = function() {
+    if (xmlhttp.readyState != 4 && xmlhttp.status != 200) { return; }
+    var spots = JSON.parse(xmlhttp.responseText);
+    for (spot in spots) { onAddSpot(spot); }
+  }
+  xmlhttp.open("GET", url, true);
+  xmlhttp.send();
+
+  // Now, connect to event source for updates
+  if (!!window.EventSource) {
+    source = new window.EventSource("update");
+    source.addEventListener('message', updateHandler);
+  } else {
+    alert("Your browser does not support the EventSource -> no live update.")
+  }
+}
+
+google.maps.event.addDomListener(window, 'load', initialize);
+  </script>
+ </head>
+ 
+ <body>
+  <div id="map-canvas">
+    <p>Can not load Google Maps view. Check your internet conenction!</p>
+  </div>
+ </body>
+</html>

dist/linux/debian/control

@@ -1,21 +1,25 @@
 Source: libsdr
 Priority: extra
 Maintainer: Hannes Matuschek <hmatuschek@gmail.com>
-Build-Depends: cdbs (>= 0.4.51), dh-exec, debhelper (>= 8.0.0), cmake, qtbase5-dev (>= 5.0), portaudio19-dev, librtlsdr-dev, fftw3-dev
-Standards-Version: 3.9.2
+Build-Depends: cdbs (>= 0.4.51), dh-exec, debhelper (>= 9.0.0), cmake, portaudio19-dev, librtlsdr-dev, fftw3-dev
+Standards-Version: 3.9.5
 Section: hamradio
 Homepage: http://github.com/hmatuschek/libsdr
 
-Package: libsdr
+Package: libsdr1
 Section: hamradio
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}
+Multi-Arch: same
+Pre-Depends: multiarch-support, ${misc:Pre-Depends}
+Depends: ${shlibs:Depends}, ${misc:Depends}, libportaudio2
 Description: libsdr
   A C++ library for software defined radio.
 
 Package: libsdr-dev
 Section: hamradio
 Architecture: any
-Depends: ${shlibs:Depends}, ${misc:Depends}, libsdr
+Multi-Arch: same
+Pre-Depends: multiarch-support, ${misc:Pre-Depends}
+Depends: libsdr1 (= ${binary:Version}), ${misc:Depends}, portaudio19-dev, librtlsdr-dev, fftw3-dev, libsdr1
 Description: libsdr
   A C++ library for software defined radio. Development files.

dist/linux/debian/libsdr-dev.install

@@ -1,4 +1,3 @@
 #! /usr/bin/dh-exec
-/usr/lib/${DEB_HOST_MULTIARCH}/libsdr.so
-/usr/lib/${DEB_HOST_MULTIARCH}/libsdr-gui.so
-/usr/include/*
+usr/lib/*/libsdr.so
+usr/include/*

dist/linux/debian/libsdr.install

@@ -1,3 +0,0 @@
-#! /usr/bin/dh-exec
-/usr/lib/${DEB_HOST_MULTIARCH}/libsdr.so.*
-/usr/lib/${DEB_HOST_MULTIARCH}/libsdr-gui.so.*

dist/linux/debian/libsdr1.install

@@ -0,0 +1,2 @@
+#! /usr/bin/dh-exec
+usr/lib/*/libsdr.so.*

examples/CMakeLists.txt

@@ -8,8 +8,15 @@ IF(SDR_WITH_PORTAUDIO)
  add_executable(sdr_rec sdr_rec.cc)
  target_link_libraries(sdr_rec ${LIBS} libsdr)
 
- add_executable(sdr_afsk1200 sdr_afsk1200.cc)
- target_link_libraries(sdr_afsk1200 ${LIBS} libsdr)
+ add_executable(sdr_rtty sdr_rtty.cc)
+ target_link_libraries(sdr_rtty ${LIBS} libsdr)
+
+ add_executable(sdr_pocsag sdr_pocsag.cc)
+ target_link_libraries(sdr_pocsag ${LIBS} libsdr)
+
+ add_executable(sdr_ax25 sdr_ax25.cc)
+ target_link_libraries(sdr_ax25 ${LIBS} libsdr)
+
 ENDIF(SDR_WITH_PORTAUDIO)
 
 

examples/sdr_afsk1200.cc

@@ -1,358 +0,0 @@
-#include "wavfile.hh"
-#include "autocast.hh"
-#include "interpolate.hh"
-
-using namespace sdr;
-
-static const uint16_t crc_ccitt_table[] = {
-    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
-    0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
-    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
-    0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
-    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
-    0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
-    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
-    0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
-    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
-    0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
-    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
-    0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
-    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
-    0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
-    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
-    0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
-    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
-    0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
-    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
-    0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
-    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
-    0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
-    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
-    0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
-    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
-    0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
-    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
-    0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
-    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
-    0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
-    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
-    0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
-};
-
-static inline bool check_crc_ccitt(const uint8_t *buf, int cnt)
-{
-    uint32_t crc = 0xffff;
-    for (; cnt > 0; cnt--, buf++) {
-        crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ (*buf)) & 0xff];
-    }
-    return (crc & 0xffff) == 0xf0b8;
-}
-
-
-class AFSK: public Sink<int16_t>, public Source {
-public:
-  AFSK(double baud=1200.0, double Fmark=1200.0, double Fspace=2200.0)
-    : Sink<int16_t>(), Source(), _baud(baud), _Fmark(Fmark), _Fspace(Fspace)
-  {
-    // pass...
-  }
-
-  virtual ~AFSK() {
-    // pass...
-  }
-
-  virtual void config(const Config &src_cfg) {
-    // Check if config is complete
-    if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
-
-    // Check if buffer type matches
-    if (Config::typeId<int16_t>() != src_cfg.type()) {
-      ConfigError err;
-      err << "Can not configure AFSK1200: Invalid type " << src_cfg.type()
-          << ", expected " << Config::typeId<int16_t>();
-      throw err;
-    }
-
-    // The input sample rate
-    _sampleRate = src_cfg.sampleRate();
-
-    // Samples per bit
-    _corrLen = int(_sampleRate/_baud);
-    // Compute symbol rate:
-    _symbolRate = std::min(10*_baud, _baud*_corrLen);
-
-    // Samples per symbol (fractional):
-    _mu = 0.0; _muIncr = _sampleRate/_symbolRate;
-    // Delayline for interpolating sub-sampler
-    _dl = Buffer<float>(2*8);
-    for (size_t i=0; i<(2*8); i++) { _dl[i] = 0; }
-    _dl_idx = 0;
-
-    // Assemble phase LUT:
-    _markLUT  = Buffer< std::complex<float> >(_corrLen);
-    _spaceLUT = Buffer< std::complex<float> >(_corrLen);
-
-    // Allocate ring-buffers for mark and space symbols
-    _markHist = Buffer< std::complex<float> >(_corrLen);
-    _spaceHist = Buffer< std::complex<float> >(_corrLen);
-
-    // Initialize LUTs and ring-buffers
-    double phiMark=0, phiSpace=0;
-    for (size_t i=0; i<_corrLen; i++) {
-      _markLUT[i] = std::exp(std::complex<float>(0.0, phiMark));
-      _spaceLUT[i] = std::exp(std::complex<float>(0.0, phiSpace));
-      phiMark  += (2.*M_PI*_Fmark)/_sampleRate;
-      phiSpace += (2.*M_PI*_Fspace)/_sampleRate;
-      _markHist[i] = 0; _spaceHist[i] = 0;
-    }
-    _lutIdx = 0;
-
-    // Get phase increment per symbol
-    _phase = 0; _omega = _baud/_symbolRate;
-    _omegaMin = _omega - 0.01*_omega;
-    _omegaMax = _omega + 0.01*_omega;
-    _gainOmega = 0.01;
-
-    // Allocate output buffer:
-    _buffer = Buffer<uint8_t>(src_cfg.bufferSize()/_corrLen + 1);
-
-    LogMessage msg(LOG_DEBUG);
-    msg << "Config AFSK1200 node: " << std::endl
-        << " input sample rate: " << _sampleRate << "Hz" << std::endl
-        << " samples per symbol: " << _muIncr << std::endl
-        << " symbols per bit: " << _corrLen << std::endl
-        << " symbol rate: " << _symbolRate << "Hz" << std::endl
-        << " Phase incr/symbol: " << float(_omega);
-
-    Logger::get().log(msg);
-
-    this->setConfig(Config(Traits<uint8_t>::scalarId, _baud, _buffer.size(), 1));
-  }
-
-
-  virtual void process(const Buffer<int16_t> &buffer, bool allow_overwrite) {
-    size_t i=0, o=0;
-    while (i<buffer.size()) {
-      // Update sub-sampler
-      while ((_mu>1) && (i<buffer.size())) {
-        _markHist[_lutIdx] = float(buffer[i])*_markLUT[_lutIdx];
-        _spaceHist[_lutIdx] = float(buffer[i])*_spaceLUT[_lutIdx];
-        // Modulo LUT length
-        _lutIdx++; if (_lutIdx==_corrLen) { _lutIdx=0; }
-        float symbol = _getSymbol();
-        // Put symbol into delay line
-        _dl[_dl_idx] = symbol; _dl[_dl_idx+8] = symbol;
-        _dl_idx = (_dl_idx+1)%8; _mu -= 1; i++;
-      }
-
-
-      if (i<buffer.size()) {
-        // Get interpolated symbol
-        float sample = interpolate(_dl.sub(_dl_idx, 8), _mu); _mu += _muIncr;
-        // Get symbol
-        _symbols <<= 1; _symbols |= (sample>0);
-        // Advance phase
-        _phase += _omega;
-
-        // Sample bit
-        if (_phase >= 1) {
-          // Modulo "2 pi"
-          _phase = fmodf(_phase, 1.0);
-          // Store bit
-          _lastBits <<= 1; _lastBits |= (_symbols & 1);
-          // Put decoded bit in output buffer
-          // transition -> 0; no transition -> 1
-          _buffer[o++] = ((_lastBits ^ (_lastBits >> 1) ^ 1) & 1);
-        }
-
-        // If transition
-        if ((_symbols ^ (_symbols >> 1)) & 1) {
-          // Phase correction
-          /*std::cerr << "Transition at phi=" << _phase << std::endl
-                    << "  update omega from " << _omega << " to "; */
-          if (_phase < 0.5) { _omega -= _gainOmega*(_phase); }
-          else { _omega += _gainOmega*(1-_phase); }
-          // Limit omega
-          _omega = std::min(_omegaMax, std::max(_omegaMin, _omega));
-          //std::cerr << _omega << std::endl;
-        }
-      }
-    }
-    this->send(_buffer.head(o));
-  }
-
-
-protected:
-  inline double _getSymbol() {
-    std::complex<double> markSum(0), spaceSum(0);
-    for (size_t i=0; i<_corrLen; i++) {
-      markSum += _markHist[i];
-      spaceSum += _spaceHist[i];
-    }
-    double f = markSum.real()*markSum.real() +
-        markSum.imag()*markSum.imag() -
-        spaceSum.real()*spaceSum.real() -
-        spaceSum.imag()*spaceSum.imag();
-    return f;
-  }
-
-
-protected:
-  float _sampleRate, _symbolRate;
-  float _baud;
-  float _Fmark, _Fspace;
-
-  uint32_t _corrLen;
-  uint32_t _lutIdx;
-  Buffer< std::complex<float> > _markLUT;
-  Buffer< std::complex<float> > _spaceLUT;
-
-  float _mu, _muIncr;
-  Buffer< float > _dl;
-  size_t _dl_idx;
-
-  Buffer< std::complex<float> > _markHist;
-  Buffer< std::complex<float> > _spaceHist;
-
-  uint32_t _symbols;
-  uint32_t _lastBits;
-  float _phase;
-  float _omega, _omegaMin, _omegaMax;
-  float _gainOmega;
-
-  static const uint32_t _phasePeriod = 0x10000u;
-  static const uint32_t _phaseMask   = 0x0ffffu;
-
-  /** Output buffer. */
-  Buffer<uint8_t> _buffer;
-};
-
-
-class AX25: public Sink<uint8_t>, public Source
-{
-public:
-  AX25()
-    : Sink<uint8_t>(), Source()
-  {
-    // pass...
-  }
-
-  virtual ~AX25() {
-    // pass...
-  }
-
-  virtual void config(const Config &src_cfg) {
-    if (! src_cfg.hasType()) { return; }
-    // Check if buffer type matches
-    if (Config::typeId<uint8_t>() != src_cfg.type()) {
-      ConfigError err;
-      err << "Can not configure AX25: Invalid type " << src_cfg.type()
-          << ", expected " << Config::typeId<uint8_t>();
-      throw err;
-    }
-
-    _bitstream = 0;
-    _bitbuffer = 0;
-    _state     = 0;
-    _ptr       = _rxbuffer;
-
-    // Allocate output buffer
-    _buffer = Buffer<uint8_t>(512);
-
-    // propergate config
-    this->setConfig(Config(Traits<uint8_t>::scalarId, 0, 512, 1));
-  }
-
-  virtual void process(const Buffer<uint8_t> &buffer, bool allow_overwrite) {
-    for (size_t i=0; i<buffer.size(); i++) {
-      // Store bit in stream
-      _bitstream <<= 1; _bitstream |= !!buffer[i];
-
-      // Check for sync byte
-      if ((_bitstream & 0xff) == 0x7e) {
-        if (_state && ((_ptr - _rxbuffer) > 2)) {
-          *_ptr = 0;
-          if (! check_crc_ccitt(_rxbuffer, _ptr-_rxbuffer)) {
-            std::cerr << "Got invalid buffer: " << _rxbuffer << std::endl;
-          } else {
-            std::cerr << "GOT: " << _rxbuffer << std::endl;
-            memcpy(_buffer.ptr(), _rxbuffer, _ptr-_rxbuffer);
-            this->send(_buffer.head(_ptr-_rxbuffer));
-          }
-
-        }
-        _state = 1;
-        _ptr = _rxbuffer;
-        _bitbuffer = 0x80;
-        continue;
-      }
-
-      // If 7 ones are received in a row -> error, wait or sync byte
-      if ((_bitstream & 0x7f) == 0x7f) { _state = 0; continue; }
-
-      // If state == wait for sync byte -> receive next bit
-      if (!_state) { continue; }
-
-      /* stuffed bit */
-      if ((_bitstream & 0x3f) == 0x3e) { continue; }
-
-      // prepend bit to bitbuffer
-      _bitbuffer |= ((_bitstream & 1) << 8);
-
-      // If 8 bits have been received (stored in b8-b1 of _bitbuffer)
-      if (_bitbuffer & 1) {
-        // Check for buffer overrun
-        if ((_ptr-_rxbuffer) >= 512) {
-          Logger::get().log(LogMessage(LOG_ERROR, "AX.25 packet too long."));
-          // Wait for next sync byte
-          _state = 0;
-          continue;
-        }
-
-        // Store received byte and ...
-        *_ptr++ = (_bitbuffer >> 1);
-        // reset bit buffer
-        _bitbuffer = 0x80;
-        continue;
-      }
-      // Shift bitbuffer one to the left
-      _bitbuffer >>= 1;
-    }
-  }
-
-protected:
-  uint32_t _bitstream;
-  uint32_t _bitbuffer;
-  uint32_t _state;
-
-  uint8_t _rxbuffer[512];
-  uint8_t *_ptr;
-
-  Buffer<uint8_t> _buffer;
-};
-
-
-int main(int argc, char *argv[]) {
-  if (2 > argc) { std::cout << "USAGE: sdr_afsk1200 FILENAME" << std::endl; return -1; }
-
-  sdr::Logger::get().addHandler(
-        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
-
-  WavSource src(argv[1], 1024);
-  if (! src.isOpen()) { std::cout << "Can not open file " << argv[1] << std::endl; return -1; }
-
-  AutoCast< int16_t > cast;
-  AFSK demod;
-  AX25     decode;
-
-  src.connect(&cast);
-  cast.connect(&demod);
-  demod.connect(&decode);
-
-  Queue::get().addIdle(&src, &WavSource::next);
-
-  Queue::get().start();
-  Queue::get().wait();
-
-  return 0;
-}

examples/sdr_ax25.cc

@@ -0,0 +1,192 @@
+/*
+ * sdr_ax25 -- A AX.25 and APRS receiver using libsdr.
+ *
+ * (c) 2015 Hannes Matuschek <hmatuschek at gmail dot com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "options.hh"
+#include "autocast.hh"
+#include "rtlsource.hh"
+#include "baseband.hh"
+#include "demod.hh"
+#include "portaudio.hh"
+#include "wavfile.hh"
+#include "fsk.hh"
+#include "utils.hh"
+#include "aprs.hh"
+
+#include <iostream>
+#include <cmath>
+#include <csignal>
+
+
+using namespace sdr;
+
+// On SIGINT -> stop queue properly
+static void __sigint_handler(int signo) {
+  Queue::get().stop();
+}
+
+// Command line options
+static Options::Definition options[] = {
+  {"frequency", 'F', Options::FLOAT,
+   "Selects a RTL2832 as the source and specifies the frequency in Hz."},
+  {"correction", 0, Options::FLOAT,
+   "Specifies the frequency correction for the RTL2832 device in parts-per-million (ppm)."},
+  {"audio", 'a', Options::FLAG, "Selects the system audio as the source."},
+  {"file", 'f', Options::ANY, "Selects a WAV file as the source."},
+  {"monitor", 'M', Options::FLAG, "Enable sound monitor."},
+  {"help", 0, Options::FLAG, "Prints this help message."},
+  {0,0,Options::FLAG,0}
+};
+
+
+void print_help() {
+  std::cerr << "USAGE: sdr_ax25 SOURCE [OPTIONS]" << std::endl << std::endl;
+  Options::print_help(std::cerr, options);
+}
+
+int main(int argc, char *argv[])
+{
+  // Install log handler
+  sdr::Logger::get().addHandler(
+        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+
+  // Register signal handler:
+  signal(SIGINT, __sigint_handler);
+
+  // Parse command line options.
+  Options opts;
+  if (! Options::parse(options, argc, argv, opts)) {
+    print_help(); return -1;
+  }
+
+  // If help flag is present -> print and done.
+  if (opts.has("help")) { print_help(); return 0; }
+
+  // If no source has been selected
+  if (! (opts.has("frequency")|opts.has("audio")|opts.has("file"))) {
+    print_help(); return -1;
+  }
+
+  // Init audio system
+  PortAudio::init();
+
+  // Get the global queue
+  Queue &queue = Queue::get();
+
+  // pointer to the selected source
+  Source *src = 0;
+
+  // nodes for WAV file input
+  WavSource *wav_src=0;
+  AutoCast<int16_t> *wav_cast=0;
+
+  // nodes for PortAudio input
+  PortSource<int16_t> *audio_src=0;
+
+  // nodes for RTL2832 input
+  RTLSource *rtl_source=0;
+  AutoCast< std::complex<int16_t> > *rtl_cast=0;
+  IQBaseBand<int16_t> *rtl_baseband=0;
+  FMDemod<int16_t> *rtl_demod=0;
+  FMDeemph<int16_t> *rtl_deemph=0;
+
+  if (opts.has("frequency")) {
+    // Assemble processing chain for the RTL2832 intput
+    rtl_source   = new RTLSource(opts.get("frequency").toFloat());
+    if (opts.has("correction")) {
+      // Apply specified frequency correction.
+      rtl_source->setFreqCorrection(opts.get("correction").toFloat());
+    }
+    rtl_cast     = new AutoCast< std::complex<int16_t> >();
+    rtl_baseband = new IQBaseBand<int16_t>(0, 15.0e3, 21, 0, 22050.0);
+    rtl_demod    = new FMDemod<int16_t>();
+    rtl_deemph   = new FMDeemph<int16_t>();
+    // Connect nodes
+    rtl_source->connect(rtl_cast);
+    rtl_cast->connect(rtl_baseband, true);
+    rtl_baseband->connect(rtl_demod);
+    rtl_demod->connect(rtl_deemph);
+    // FM deemph. is source for decoder
+    src = rtl_deemph;
+    // On queue start, start RTL source
+    Queue::get().addStart(rtl_source, &RTLSource::start);
+    // On queue stop, stop RTL source
+    Queue::get().addStop(rtl_source, &RTLSource::stop);
+  } else if (opts.has("audio")) {
+    // Configure audio source
+    audio_src = new PortSource<int16_t>(22010., 1024);
+    src = audio_src;
+    // On queue idle, read next chunk from audio source
+    Queue::get().addIdle(audio_src, &PortSource<int16_t>::next);
+  } else if (opts.has("file")) {
+    // Assemble processing chain for WAV file input
+    wav_src = new WavSource(opts.get("file").toString());
+    wav_cast = new AutoCast<int16_t>();
+    wav_src->connect(wav_cast);
+    src = wav_cast;
+    // On queue idle, read next chunk from file
+    Queue::get().addIdle(wav_src, &WavSource::next);
+    // On end of file, stop queue
+    wav_src->addEOS(&(Queue::get()), &Queue::stop);
+  }
+
+  /* Common demodulation nodes. */
+
+  // (A)FSK detector
+  FSKDetector detector(1200, 1200, 2200);
+  // Bit decoder
+  BitStream bits(1200, BitStream::TRANSITION);
+  // APRS decoder
+  APRS aprs;
+  // Audio sink for monitor
+  PortSink sink;
+
+  // connect source ASK detector
+  src->connect(&detector);
+  // detector to bit decoder
+  detector.connect(&bits);
+  // and bit decoder to APRS decoder and print
+  bits.connect(&aprs);
+
+  // If monitor is enabled -> connect to sink
+  if (opts.has("monitor")) {
+    src->connect(&sink);
+  }
+
+  // Start queue
+  queue.start();
+  // wait for queue to exit
+  queue.wait();
+
+  // Free allocated nodes
+  if (rtl_source) { delete rtl_source; }
+  if (rtl_cast) { delete rtl_cast; }
+  if (rtl_baseband) { delete rtl_baseband; }
+  if (rtl_demod) { delete rtl_demod; }
+  if (rtl_deemph) { delete rtl_deemph; }
+  if (audio_src) { delete audio_src; }
+  if (wav_src) { delete wav_src; }
+  if (wav_cast) { delete wav_cast; }
+
+  // terminate port audio system properly
+  PortAudio::terminate();
+
+  // quit.
+  return 0;
+}

examples/sdr_pocsag.cc

@@ -0,0 +1,191 @@
+/*
+ * sdr_pocsag -- A POCSAG receiver using libsdr.
+ *
+ * (c) 2015 Hannes Matuschek <hmatuschek at gmail dot com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "autocast.hh"
+#include "portaudio.hh"
+#include "wavfile.hh"
+#include "fsk.hh"
+#include "utils.hh"
+#include "pocsag.hh"
+#include "options.hh"
+#include "rtlsource.hh"
+#include "demod.hh"
+#include "baseband.hh"
+
+#include <iostream>
+#include <cmath>
+#include <csignal>
+
+using namespace sdr;
+
+// On SIGINT -> stop queue properly
+static void __sigint_handler(int signo) {
+  Queue::get().stop();
+}
+
+// Command line options
+static Options::Definition options[] = {
+  {"frequency", 'F', Options::FLOAT,
+   "Selects a RTL2832 as the source and specifies the frequency in Hz."},
+  {"correction", 0, Options::FLOAT,
+   "Specifies the frequency correction for the RTL2832 device in parts-per-million (ppm)."},
+  {"audio", 'a', Options::FLAG, "Selects the system audio as the source."},
+  {"file", 'f', Options::ANY, "Selects a WAV file as the source."},
+  {"monitor", 'M', Options::FLAG, "Enable sound monitor."},
+  {"invert", 0, Options::FLAG, "Inverts mark/space logic."},
+  {"help", 0, Options::FLAG, "Prints this help message."},
+  {0,0,Options::FLAG,0}
+};
+
+void print_help() {
+  std::cerr << "USAGE: sdr_pocsag SOURCE [OPTIONS]" << std::endl << std::endl;
+  Options::print_help(std::cerr, options);
+}
+
+
+int main(int argc, char *argv[])
+{
+  // Install log handler
+  sdr::Logger::get().addHandler(
+        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+
+  // Register signal handler:
+  signal(SIGINT, __sigint_handler);
+
+  // Parse command line options.
+  Options opts;
+  if (! Options::parse(options, argc, argv, opts)) {
+    print_help(); return -1;
+  }
+
+  if (opts.has("help")) {
+    print_help(); return 0;
+  }
+
+  // If no source has been selected
+  if (! (opts.has("frequency")|opts.has("audio")|opts.has("file"))) {
+    print_help(); return -1;
+  }
+
+  // Init audio system
+  PortAudio::init();
+
+  // Get the global queue
+  Queue &queue = Queue::get();
+
+  // pointer to the selected source
+  Source *src = 0;
+
+  // Nodes for WAV file input
+  WavSource *wav_src=0;
+  AutoCast<int16_t> *wav_cast=0;
+
+  // Nodes for PortAudio input
+  PortSource<int16_t> *audio_src=0;
+
+  // Nodes for RTL2832 input
+  RTLSource *rtl_source=0;
+  AutoCast< std::complex<int16_t> > *rtl_cast=0;
+  IQBaseBand<int16_t> *rtl_baseband=0;
+  FMDemod<int16_t> *rtl_demod=0;
+  FMDeemph<int16_t> *rtl_deemph=0;
+
+  if (opts.has("frequency")) {
+    // Assemble processing chain for the RTL2832 intput
+    rtl_source   = new RTLSource(opts.get("frequency").toFloat());
+    if (opts.has("correction")) {
+      rtl_source->setFreqCorrection(opts.get("correction").toFloat());
+    }
+    rtl_cast     = new AutoCast< std::complex<int16_t> >();
+    rtl_baseband = new IQBaseBand<int16_t>(0, 12.5e3, 21, 0, 22050.0);
+    rtl_demod    = new FMDemod<int16_t>();
+    rtl_deemph   = new FMDeemph<int16_t>();
+    rtl_source->connect(rtl_cast);
+    rtl_cast->connect(rtl_baseband, true);
+    rtl_baseband->connect(rtl_demod);
+    rtl_demod->connect(rtl_deemph);
+    // FM deemph. is source for decoder
+    src = rtl_deemph;
+    // On queue start, start RTL source
+    Queue::get().addStart(rtl_source, &RTLSource::start);
+    // On queue stop, stop RTL source
+    Queue::get().addStop(rtl_source, &RTLSource::stop);
+  } else if (opts.has("audio")) {
+    // Configure audio source
+    audio_src = new PortSource<int16_t>(22010., 1024);
+    src = audio_src;
+    // On queue idle, read next chunk from audio source
+    Queue::get().addIdle(audio_src, &PortSource<int16_t>::next);
+  } else if (opts.has("file")) {
+    // Assemble processing chain for WAV file input
+    wav_src = new WavSource(opts.get("file").toString());
+    wav_cast = new AutoCast<int16_t>();
+    wav_src->connect(wav_cast);
+    src = wav_cast;
+    // On queue idle, read next chunk from file
+    Queue::get().addIdle(wav_src, &WavSource::next);
+    // On end of file, stop queue
+    wav_src->addEOS(&(Queue::get()), &Queue::stop);
+  }
+
+  /* Common demodulation nodes. */
+  // amplitude detector
+  ASKDetector<int16_t> detector(opts.has("invert"));
+  // Bit decoder
+  BitStream bits(1200, BitStream::NORMAL);
+  // POCSAG decoder
+  POCSAGDump pocsag(std::cout);
+  // Audio sink for monitor
+  PortSink sink;
+
+
+  // connect source ASK detector
+  src->connect(&detector);
+  // detector to bit decoder
+  detector.connect(&bits);
+  // and bit decoder to POCSAG decoder and print
+  bits.connect(&pocsag);
+
+  // If monitor is enabled -> connect to sink
+  if (opts.has("monitor")) {
+    src->connect(&sink);
+  }
+
+  // Start queue
+  queue.start();
+  // wait for queue to exit
+  queue.wait();
+
+  // Free allocated nodes
+  if (rtl_source) { delete rtl_source; }
+  if (rtl_cast) { delete rtl_cast; }
+  if (rtl_baseband) { delete rtl_baseband; }
+  if (rtl_demod) { delete rtl_demod; }
+  if (rtl_deemph) { delete rtl_deemph; }
+  if (audio_src) { delete audio_src; }
+  if (wav_src) { delete wav_src; }
+  if (wav_cast) { delete wav_cast; }
+
+  // terminate port audio system properly
+  PortAudio::terminate();
+
+  // quit.
+  return 0;
+}

examples/sdr_psk31.cc

@@ -1,81 +0,0 @@
-#include "baseband.hh"
-#include "autocast.hh"
-#include "demod.hh"
-#include "portaudio.hh"
-#include "wavfile.hh"
-#include "gui/gui.hh"
-#include "psk31.hh"
-
-#include <iostream>
-#include <cmath>
-#include <csignal>
-
-#include <QApplication>
-#include <QMainWindow>
-#include <QThread>
-
-using namespace sdr;
-
-static void __sigint_handler(int signo) {
-  // On SIGINT -> stop queue properly
-  Queue::get().stop();
-}
-
-
-
-
-
-int main(int argc, char *argv[]) {
-  if (2 != argc) {
-    std::cerr << "Usage: sdr_psk31 FILENAME" << std::endl;
-    return -1;
-  }
-
-  sdr::Logger::get().addHandler(
-        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
-
-  // Register handler:
-  signal(SIGINT, __sigint_handler);
-
-  QApplication app(argc, argv);
-
-  QMainWindow       *win       = new QMainWindow();
-  gui::Spectrum     *spec      = new gui::Spectrum(2, 1024, 5);
-  gui::SpectrumView *spec_view = new gui::SpectrumView(spec);
-  spec_view->setMindB(-60);
-  win->setCentralWidget(spec_view);
-  win->setMinimumSize(640, 240);
-  win->show();
-
-  PortAudio::init();
-  Queue &queue = Queue::get();
-
-  WavSource src(argv[1]);
-  AutoCast< std::complex<int16_t> > cast;
-  IQBaseBand<int16_t> baseband(0, 2144., 200.0, 63, 1);
-  baseband.setCenterFrequency(2144.0);
-  BPSK31<int16_t> demod;
-  PortSink sink;
-  Varicode decode;
-  DebugDump<uint8_t> dump;
-
-  src.connect(&cast, true);
-  cast.connect(&baseband, true);
-  baseband.connect(spec);
-  baseband.connect(&sink);
-  baseband.connect(&demod);
-  demod.connect(&decode, true);
-  decode.connect(&dump, true);
-
-  queue.addIdle(&src, &WavSource::next);
-  //queue.addIdle(&src, &IQSigGen<double>::next);
-
-  queue.start();
-  app.exec();
-  queue.stop();
-  queue.wait();
-
-  PortAudio::terminate();
-
-  return 0;
-}

examples/sdr_rds.cc

@@ -1,82 +0,0 @@
-#include "sdr.hh"
-#include "rtlsource.hh"
-#include "baseband.hh"
-#include "autocast.hh"
-#include "gui/gui.hh"
-#include "logger.hh"
-#include <signal.h>
-
-#include <QApplication>
-#include <QMainWindow>
-#include <QThread>
-
-using namespace sdr;
-
-static void __sigint_handler(int signo) {
-  // On SIGINT -> stop queue properly
-  Queue::get().stop();
-}
-
-
-int main(int argc, char *argv[])
-{
-  if (argc < 2) {
-    std::cerr << "USAGE: sdr_rds FREQUENCY" << std::endl;
-    return -1;
-  }
-  double freq = atof(argv[1]);
-
-  PortAudio::init();
-  Queue &queue = Queue::get();
-
-  // Register handler:
-  signal(SIGINT, __sigint_handler);
-
-  QApplication app(argc, argv);
-
-  QMainWindow       *win       = new QMainWindow();
-  gui::Spectrum     *spec      = new gui::Spectrum(2, 1024, 5);
-  gui::SpectrumView *spec_view = new gui::SpectrumView(spec);
-  spec_view->setMindB(-200);
-  win->setCentralWidget(spec_view);
-  win->setMinimumSize(640, 240);
-
-  win->show();
-
-  sdr::Logger::get().addHandler(new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
-
-  // Assemble processing chain
-  //RTLSource src(freq, 1e6);
-  WavSource src(argv[1]);
-  AutoCast< std::complex<int16_t> > cast;
-  IQBaseBand<int16_t> baseband(0, 200e3, 16, 5);
-  FMDemod<int16_t, int16_t> demod;
-  BaseBand<int16_t> mono(0, 15e3, 16, 6);
-  BaseBand<int16_t> pilot(19e3, 5e2, 16, 84);
-  BaseBand<int16_t> rds(57e3, 3e3, 16, 84);
-  PortSink sink;
-
-  src.connect(&cast, true);
-  cast.connect(&baseband, true);
-  //src.connect(&baseband, true);
-  baseband.connect(&demod, true);
-  demod.connect(&mono);
-  demod.connect(&pilot);
-  demod.connect(&rds);
-
-  mono.connect(&sink);
-  mono.connect(spec);
-
-  //queue.addStart(&src, &RTLSource::start);
-  //queue.addStop(&src, &RTLSource::stop);
-  queue.addIdle(&src, &WavSource::next);
-
-  queue.start();
-  app.exec();
-  queue.stop();
-  queue.wait();
-
-  PortAudio::terminate();
-
-  return 0;
-}

examples/sdr_rtty.cc

@@ -0,0 +1,72 @@
+#include "autocast.hh"
+#include "portaudio.hh"
+#include "wavfile.hh"
+#include "fsk.hh"
+#include "baudot.hh"
+#include "utils.hh"
+
+#include <iostream>
+#include <cmath>
+#include <csignal>
+
+using namespace sdr;
+
+static void __sigint_handler(int signo) {
+  // On SIGINT -> stop queue properly
+  Queue::get().stop();
+}
+
+
+int main(int argc, char *argv[])
+{
+  if (2 != argc) {
+    std::cerr << "Usage: sdr_rtty FILENAME" << std::endl;
+    return -1;
+  }
+
+  sdr::Logger::get().addHandler(
+        new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+
+  // Register handler:
+  signal(SIGINT, __sigint_handler);
+
+  PortAudio::init();
+
+  Queue &queue = Queue::get();
+
+  WavSource src(argv[1]);
+  PortSink sink;
+  AutoCast<int16_t> cast;
+  FSKDetector fsk(90.90, 930., 1100.);
+  BitStream bits(90.90, BitStream::NORMAL);
+  Baudot decoder;
+  TextDump dump;
+
+  // Playback
+  src.connect(&sink);
+  // Cast to int16
+  src.connect(&cast);
+  // FSK demod
+  cast.connect(&fsk);
+  fsk.connect(&bits);
+  // Baudot decoder
+  bits.connect(&decoder);
+  // dump to std::cerr
+  decoder.connect(&dump);
+
+  // on idle -> read next buffer from input file
+  queue.addIdle(&src, &WavSource::next);
+  // on end-of-file -> stop queue
+  src.addEOS(&queue, &Queue::stop);
+
+  // Start queue
+  queue.start();
+  // wait for queue to exit
+  queue.wait();
+
+  // terminate port audio system properly
+  PortAudio::terminate();
+
+  // quit.
+  return 0;
+}

examples/sdr_spec.cc

@@ -1,64 +0,0 @@
-#include "sdr.hh"
-#include "rtlsource.hh"
-#include "baseband.hh"
-#include "utils.hh"
-#include "gui/gui.hh"
-#include <signal.h>
-#include "portaudio.hh"
-
-#include <QApplication>
-#include <QMainWindow>
-#include <QThread>
-
-using namespace sdr;
-
-static void __sigint_handler(int signo) {
-  // On SIGINT -> stop queue properly
-  Queue::get().stop();
-}
-
-
-int main(int argc, char *argv[])
-{
-  Queue &queue = Queue::get();
-
-  // Register handler:
-  signal(SIGINT, __sigint_handler);
-
-  PortAudio::init();
-
-  QApplication app(argc, argv);
-
-  QMainWindow       *win       = new QMainWindow();
-  gui::Spectrum     *spec      = new gui::Spectrum(2, 1024, 5);
-  gui::WaterFallView *spec_view = new gui::WaterFallView(spec);
-  win->setCentralWidget(spec_view);
-  win->setMinimumSize(640, 240);
-
-  win->show();
-
-  // Assemble processing chain
-  PortSource< int16_t > src(44100.0, 2048);
-  AGC<int16_t> agc;
-  //IQBaseBand<int16_t> baseband(0, 500e3, 8, 5);
-  //AMDemod<int16_t> demod;
-  PortSink sink;
-
-  src.connect(&agc, true);
-  agc.connect(&sink, true);
-  //baseband.connect(&demod);
-  //demod.connect(&sink, true);
-  src.connect(spec);
-
-  queue.addIdle(&src, &PortSource< int16_t >::next);
-
-  queue.start();
-  app.exec();
-
-  queue.stop();
-  queue.wait();
-
-  PortAudio::terminate();
-
-  return 0;
-}

src/CMakeLists.txt

@@ -1,13 +1,13 @@
 # Sources of libsdr
 set(LIBSDR_SOURCES
-    buffer.cc node.cc queue.cc traits.cc
-    portaudio.cc utils.cc wavfile.cc
-    exception.cc logger.cc psk31.cc options.cc)
+    buffer.cc node.cc queue.cc traits.cc portaudio.cc utils.cc wavfile.cc exception.cc logger.cc
+    psk31.cc options.cc fsk.cc ax25.cc aprs.cc baudot.cc pocsag.cc bch31_21.cc http.cc sha1.cc)
 set(LIBSDR_HEADERS sdr.hh math.hh
     buffer.hh node.hh queue.hh buffernode.hh filternode.hh traits.hh autocast.hh
     siggen.hh portaudio.hh utils.hh wavfile.hh demod.hh firfilter.hh
     fftplan.hh fftplan_native.hh exception.hh baseband.hh freqshift.hh subsample.hh
-    combine.hh logger.hh psk31.hh interpolate.hh operators.hh options.hh)
+    combine.hh logger.hh psk31.hh interpolate.hh operators.hh options.hh fsk.hh ax25.hh
+    aprs.hh baudot.hh pocsag.hh bch31_21.hh http.hh sha1.hh)
 
 if(SDR_WITH_PORTAUDIO)
   set(LIBSDR_SOURCES ${LIBSDR_SOURCES} portaudio.cc)

src/aprs.cc

@@ -0,0 +1,344 @@
+#include "aprs.hh"
+#include "logger.hh"
+
+using namespace sdr;
+
+
+
+/* ******************************************************************************************** *
+ * Implementation of APRS
+ * ******************************************************************************************** */
+APRS::APRS()
+  : AX25()
+{
+  // pass...
+}
+
+void
+APRS::handleAX25Message(const AX25::Message &message) {
+  // Skip non-UI frames
+  if (0x03 != uint8_t(message.payload()[0])) {
+    LogMessage msg(LOG_DEBUG);
+    msg << "APRS: Skip non-UI frame (type="
+        << std::hex << int(uint8_t(message.payload()[0]))
+        << std::dec << "): " << message;
+    Logger::get().log(msg);
+    return;
+  }
+  // Skip frames woth level-3 protocol
+  if (0xf0 != uint8_t(message.payload()[1])) {
+    LogMessage msg(LOG_DEBUG);
+    msg << "APRS: Skip invalid UI (pid="
+        << std::hex << int(uint8_t(message.payload()[1]))
+        << std::dec << "): " << message;
+    Logger::get().log(msg);
+    return;
+  }
+  // Construct APRS message
+  Message msg(message);
+  // Handle message
+  this->handleAPRSMessage(msg);
+}
+
+void
+APRS::handleAPRSMessage(const Message &message) {
+  std::cerr << message << std::endl;
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of APRS::Message
+ * ******************************************************************************************** */
+bool __is_number(char c) {
+  return (('0'<=c) && ('9'>=c));
+}
+
+APRS::Message::Symbol
+__toSymbol(char table, char sym) {
+  if ('/' == table) {
+    switch (sym) {
+    case 'P':
+    case '!': return APRS::Message::POLICE;
+    case '%':
+    case '&':
+    case '(':
+    case 'B':
+    case 'n':
+    case '#': return APRS::Message::DIGI;
+    case '[':
+    case 'e':
+    case '$': return APRS::Message::JOGGER;
+    case 'X':
+    case '^':
+    case 'g':
+    case '\'': return APRS::Message::AIRCRAFT;
+    case '-': return APRS::Message::HOUSE;
+    case 'b':
+    case '<': return APRS::Message::MOTORCYCLE;
+    case '=':
+    case '*':
+    case 'U':
+    case 'j':
+    case 'k':
+    case 'u':
+    case 'v':
+    case '>': return APRS::Message::CAR;
+    case 'Y':
+    case 's':
+    case 'C': return APRS::Message::BOAT;
+    case 'O': return APRS::Message::BALLOON;
+    case '_': return APRS::Message::WX;
+    default: break;
+    }
+  } else if ('\\' == table) {
+    switch (sym) {
+    default: break;
+    }
+  }
+  return APRS::Message::NONE;
+}
+
+
+APRS::Message::Message()
+  : AX25::Message(), _hasLocation(false), _latitude(0), _longitude(0), _symbol(NONE),
+    _hasTime(false), _time(::time(0))
+{
+  // pass...
+}
+
+APRS::Message::Message(const AX25::Message &msg)
+  : AX25::Message(msg),
+    _hasLocation(false), _latitude(0), _longitude(0), _symbol(NONE),
+    _hasTime(false), _time(::time(0))
+{
+  size_t offset = 2;
+  // Dispatch by message type
+  switch (_payload[offset]) {
+  case '=':
+  case '!':
+    _hasLocation = true;
+    offset++;
+    break;
+  case '/':
+  case '@':
+    _hasTime = true;
+    _hasLocation = true;
+    offset++;
+    break;
+  case ';':
+    _hasTime = true;
+    _hasLocation = true;
+    // Skip ';', 9 char of object identifier and delimiter ('*' or '_').
+    offset += 11;
+    break;
+  default:
+    // On unknown message type -> store complete message as comment
+    if (offset < _payload.size()) {
+      _comment = _payload.substr(offset);
+      offset += _comment.size();
+    }
+    return;
+  }
+
+  if (_hasTime && (! _readTime(offset))) { _hasTime = false; _hasLocation = false; return; }
+  if (_hasLocation && (! _readLocation(offset))) { _hasLocation = false; return; }
+  // Remaining text is comment
+  if (offset < _payload.size()) {
+    _comment = _payload.substr(offset);
+    offset += _comment.size();
+  }
+}
+
+APRS::Message::Message(const Message &msg)
+  : AX25::Message(msg), _hasLocation(msg._hasLocation), _latitude(msg._latitude),
+    _longitude(msg._longitude), _symbol(msg._symbol), _hasTime(msg._hasTime),
+    _time(msg._hasTime)
+{
+  // pass...
+}
+
+
+bool
+APRS::Message::_readLocation(size_t &offset) {
+  // Read latitude
+  if(! _readLatitude(offset)) { return false; }
+
+  // Read symbol table
+  char symbolTable = _payload[offset]; offset++;
+
+  // Read longitude
+  if (! _readLongitude(offset)) { return false; }
+
+  // Read symbol
+  _symbol = __toSymbol(symbolTable, _payload[offset]); offset++;
+
+  return true;
+}
+
+
+bool
+APRS::Message::_readLatitude(size_t &offset)
+{
+  // read degree
+  if (! __is_number(_payload[offset])) { return false; }
+  _latitude = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  _latitude = _latitude*10 + int(_payload[offset]-0x30); offset++;
+
+  // read mintues
+  if (! __is_number(_payload[offset])) { return false; }
+  double min = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  min = min*10 + int(_payload[offset]-0x30); offset++;
+
+  // check for '.'
+  if ('.' != _payload[offset]) { return false; } offset++;
+
+  // read minutes decimal
+  if (! __is_number(_payload[offset])) { return false; }
+  double mindec = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  mindec = mindec*10 + int(_payload[offset]-0x30); offset++;
+  min += mindec/100;
+
+  // Update degree
+  _latitude += min/60;
+
+  // Process north/south indicator
+  switch (_payload[offset]) {
+  case 'N': offset++; break;
+  case 'S': _latitude = -_latitude; offset++; break;
+  default: return false; // <- on invalid indicator.
+  }
+
+  // done.
+  return true;
+}
+
+
+bool
+APRS::Message::_readLongitude(size_t &offset) {
+  // read degree
+  if (! __is_number(_payload[offset])) { return false; }
+  _longitude = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  _longitude = _longitude*10 + int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  _longitude = _longitude*10 + int(_payload[offset]-0x30); offset++;
+
+  // read minutes
+  if (! __is_number(_payload[offset])) { return false; }
+  double min = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  min = min*10 + int(_payload[offset]-0x30); offset++;
+
+  // skip '.'
+  if ('.' != _payload[offset]) { return false; } offset++;
+
+  // Read minutes decimals
+  if (! __is_number(_payload[offset])) { return false; }
+  double mindec = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  mindec = mindec*10 + int(_payload[offset]-0x30); offset++;
+  min += mindec/100;
+
+  // Update longitude
+  _longitude += min/60;
+
+  // read east/west indicator
+  switch (_payload[offset]) {
+  case 'E': offset++; break;
+  case 'W': offset++; _longitude = -_longitude; break;
+  default: return false;
+  }
+
+  return true;
+}
+
+
+bool
+APRS::Message::_readTime(size_t &offset) {
+  if (! __is_number(_payload[offset])) { return false; }
+  int a = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  a = a*10 + int(_payload[offset]-0x30); offset++;
+
+  if (! __is_number(_payload[offset])) { return false; }
+  int b = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  b = b*10 + int(_payload[offset]-0x30); offset++;
+
+  if (! __is_number(_payload[offset])) { return false; }
+  int c = int(_payload[offset]-0x30); offset++;
+  if (! __is_number(_payload[offset])) { return false; }
+  c = c*10 + int(_payload[offset]-0x30); offset++;
+
+  // Determine type of date-time
+  if ('z' == _payload[offset]) {
+    // Alter current time in terms of UTC
+    struct tm timeStruct = *gmtime(&_time);
+    timeStruct.tm_mday = a;
+    timeStruct.tm_hour = b;
+    timeStruct.tm_min  = c;
+    // Update time-stamp
+    _time = mktime(&timeStruct);
+    offset++;
+  } else if ('/' == _payload[offset]) {
+    // Alter current time in terms of local time
+    struct tm timeStruct = *localtime(&_time);
+    timeStruct.tm_mday = a;
+    timeStruct.tm_hour = b;
+    timeStruct.tm_min  = c;
+    // Update time-stamp
+    _time = mktime(&timeStruct);
+    offset++;
+  } else if ('h' == _payload[offset]) {
+    // Alter current time in terms of local time
+    struct tm timeStruct = *localtime(&_time);
+    timeStruct.tm_hour = a;
+    timeStruct.tm_min  = b;
+    timeStruct.tm_sec  = c;
+    // Update time-stamp
+    _time = mktime(&timeStruct);
+    offset++;
+  } else if (('0' <= _payload[offset]) && (('9' >= _payload[offset]))) {
+    if (! __is_number(_payload[offset])) { return false; }
+    int d = int(_payload[offset]-0x30); offset++;
+    if (! __is_number(_payload[offset])) { return false; }
+    d = d*10 + int(_payload[offset]-0x30); offset++;
+    // Alter current time in terms of local time
+    struct tm timeStruct = *localtime(&_time);
+    timeStruct.tm_mon  = a;
+    timeStruct.tm_mday = b;
+    timeStruct.tm_hour = c;
+    timeStruct.tm_min  = d;
+    // Update time-stamp
+    _time = mktime(&timeStruct);
+  } else {
+    return false;
+  }
+
+  // done...
+  return true;
+}
+
+
+std::ostream &
+sdr::operator <<(std::ostream &stream, const APRS::Message &message) {
+  std::cerr << "APRS: " << message.from() << " > " << message.to();
+  if (message.via().size()) {
+    std::cerr << " via " << message.via()[0];
+    for (size_t i=1; i<message.via().size(); i++) {
+      std::cerr << ", " << message.via()[i];
+    }
+  }
+  std::cerr << std::endl << " time: " << asctime(localtime(&message.time()));
+  if (message.hasLocation()) {
+    std::cerr << " location: " << message.latitude() << ", " << message.longitude()
+              << std::endl << " symbol: " << message.symbol() << std::endl;
+  }
+  if (message.hasComment()) {
+    std::cerr << " comment: " << message.comment() << std::endl;
+  }
+  return stream;
+}

src/aprs.hh

@@ -0,0 +1,66 @@
+#ifndef __SDR_APRS_HH__
+#define __SDR_APRS_HH__
+
+#include "ax25.hh"
+#include <ctime>
+
+
+namespace sdr {
+
+class APRS: public AX25
+{
+public:
+  class Message: public AX25::Message
+  {
+  public:
+    /** A small selection of possible symbols to display the station. */
+    typedef enum {
+      NONE, POLICE, DIGI, PHONE, AIRCRAFT, HOUSE, MOTORCYCLE, CAR, BBS, BALLOON, BUS,
+      BOAT, JOGGER, WX
+    } Symbol;
+
+  public:
+    Message();
+    Message(const AX25::Message &msg);
+    Message(const Message &msg);
+
+    Message &operator=(const Message &other);
+
+    inline bool hasLocation() const { return _hasLocation; }
+    inline double latitude() const { return _latitude; }
+    inline double longitude() const { return _longitude; }
+    inline Symbol symbol() const { return _symbol; }
+
+    inline const time_t &time() const { return _time; }
+
+    inline bool hasComment() const { return (0 != _comment.size()); }
+    inline const std::string &comment() const { return _comment; }
+
+  protected:
+    bool _readLocation(size_t &offset);
+    bool _readLatitude(size_t &offset);
+    bool _readLongitude(size_t &offset);
+    bool _readTime(size_t &offset);
+
+  protected:
+    bool _hasLocation;
+    double _latitude;
+    double _longitude;
+    Symbol _symbol;
+    bool _hasTime;
+    time_t _time;
+    std::string _comment;
+  };
+
+public:
+  APRS();
+
+  void handleAX25Message(const AX25::Message &message);
+  virtual void handleAPRSMessage(const Message &message);
+};
+
+std::ostream& operator<<(std::ostream &stream, const APRS::Message &msg);
+
+}
+
+#endif // __SDR_APRS_HH__

src/autocast.hh

@@ -7,8 +7,9 @@
 
 namespace sdr {
 
-/** This class performs some automatic casts to a certain buffer type if possible specified by
- * the template argument. Currently only integer casts are supported. */
+/** This class performs some automatic casts to a certain buffer type (if possible) specified by
+ * the template argument. Currently only integer casts are supported.
+ * @ingroup datanodes */
 template <class Scalar>
 class AutoCast: public SinkBase, public Source
 {
@@ -28,9 +29,9 @@ public:
     // Check type cast combination
     if (Config::Type_s8 == Traits<Scalar>::scalarId) {
       switch (src_cfg.type()) {
-      case Config::Type_u8:
+      case Config::Type_u8: _cast = _uint8_int8; break;
       case Config::Type_s8: _cast = _identity; break;
-      case Config::Type_u16:
+      case Config::Type_u16: _cast = _uint16_int8; break;
       case Config::Type_s16: _cast = _int16_int8; break;
       default: break;
       }
@@ -38,17 +39,19 @@ public:
       switch (src_cfg.type()) {
       case Config::Type_u8: _cast = _uint8_cint8; break;
       case Config::Type_s8: _cast = _int8_cint8; break;
-      case Config::Type_cu8: _cast = _cuint8_cint8; break;
+      case Config::Type_cu8: _cast = _uint8_int8; break;
       case Config::Type_cs8: _cast = _identity; break;
-      case Config::Type_u16:
+      case Config::Type_u16: _cast = _uint16_cint8; break;
       case Config::Type_s16: _cast = _int16_cint8; break;
+      case Config::Type_cu16: _cast = _uint16_int8; break;
+      case Config::Type_cs16: _cast = _int16_int8; break;
       default: break;
       }
     } else if (Config::Type_s16 == Traits<Scalar>::scalarId) {
       switch (src_cfg.type()) {
-      case Config::Type_u8:
+      case Config::Type_u8: _cast = _uint8_int16; break;
       case Config::Type_s8: _cast = _int8_int16; break;
-      case Config::Type_u16:
+      case Config::Type_u16: _cast = _uint16_int16; break;
       case Config::Type_s16: _cast = _identity; break;
       default: break;
       }
@@ -56,11 +59,11 @@ public:
       switch (src_cfg.type()) {
       case Config::Type_u8: _cast = _uint8_cint16; break;
       case Config::Type_s8: _cast = _int8_cint16; break;
-      case Config::Type_cu8: _cast = _cuint8_cint16; break;
-      case Config::Type_cs8: _cast = _cint8_cint16; break;
+      case Config::Type_cu8: _cast = _uint8_int16; break;
+      case Config::Type_cs8: _cast = _int8_int16; break;
       case Config::Type_u16: _cast = _uint16_cint16; break;
       case Config::Type_s16: _cast = _int16_cint16; break;
-      case Config::Type_cu16:
+      case Config::Type_cu16: _cast = _uint16_int16; break;
       case Config::Type_cs16: _cast = _identity; break;
       default: break;
       }
@@ -110,11 +113,32 @@ protected:
     return in.bytesLen();
   }
 
+  /** uint8_t -> int8_t */
+  static size_t _uint8_int8(const RawBuffer &in, const RawBuffer &out) {
+    size_t N = in.bytesLen();
+    for (size_t i=0; i<N; i++) {
+      reinterpret_cast<int8_t *>(out.data())[i] =
+          int16_t(reinterpret_cast<uint8_t *>(in.data())[i]) - 127;
+    }
+    return N;
+  }
+
+  /** uint16 -> int8 */
+  static size_t _uint16_int8(const RawBuffer &in, const RawBuffer &out) {
+    size_t N = in.bytesLen()/2;
+    for (size_t i=0; i<N; i++) {
+      reinterpret_cast<int8_t *>(out.data())[i] =
+          int16_t(reinterpret_cast<uint16_t *>(in.data())[i]>>8) - 127;
+    }
+    return N;
+  }
+
   /** int16 -> int8 */
   static size_t _int16_int8(const RawBuffer &in, const RawBuffer &out) {
     size_t N = in.bytesLen()/2;
     for (size_t i=0; i<N; i++) {
-      reinterpret_cast<int8_t *>(out.data())[i] = reinterpret_cast<int16_t *>(in.data())[i]>>8;
+      reinterpret_cast<int8_t *>(out.data())[i] =
+          reinterpret_cast<int16_t *>(in.data())[i]>>8;
     }
     return N;
   }
@@ -134,18 +158,18 @@ protected:
   static size_t _int8_cint8(const RawBuffer &in, const RawBuffer &out) {
     size_t N = in.bytesLen();
     for (size_t i=0; i<N; i++) {
-      reinterpret_cast<std::complex<int8_t> *>(out.data())[i] = reinterpret_cast<int8_t *>(in.data())[i];
+      reinterpret_cast<std::complex<int8_t> *>(out.data())[i] =
+          reinterpret_cast<int8_t *>(in.data())[i];
     }
     return 2*N;
   }
 
-  /** std::complex<uint8_t> -> std::complex<int8_t>. */
-  static size_t _cuint8_cint8(const RawBuffer &in, const RawBuffer &out) {
+  /** uint16 -> complex int 8. */
+  static size_t _uint16_cint8(const RawBuffer &in, const RawBuffer &out) {
     size_t N = in.bytesLen()/2;
-    std::complex<uint8_t> *values = reinterpret_cast<std::complex<uint8_t> *>(in.data());
     for (size_t i=0; i<N; i++) {
-      reinterpret_cast<std::complex<int8_t> *>(out.data())[i] =
-          std::complex<int8_t>(int16_t(values[i].real())-127, int16_t(values[i].imag())-127);
+      reinterpret_cast<std::complex<int8_t> *>(out.data())[i]
+          = int32_t(reinterpret_cast<int16_t *>(in.data())[i]>>8)-((2<<15)-1);
     }
     return 2*N;
   }
@@ -159,12 +183,12 @@ protected:
     return 2*N;
   }
 
-  /** complex int16 -> complex int 8. */
-  static size_t _cint16_cint8(const RawBuffer &in, const RawBuffer &out) {
-    size_t N = in.bytesLen()/4;
-    std::complex<int16_t> *values = reinterpret_cast<std::complex<int16_t> *>(in.data());
+  /** uint8 -> int16. */
+  static size_t _uint8_int16(const RawBuffer &in, const RawBuffer &out) {
+    size_t N = in.bytesLen();
+    int8_t *values = reinterpret_cast<int8_t *>(in.data());
     for (size_t i=0; i<N; i++) {
-      reinterpret_cast<std::complex<int8_t> *>(out.data())[i] = std::complex<int8_t>(values[i].real()>>8, values[i].imag()>>8);
+      reinterpret_cast<int16_t *>(out.data())[i] = (int16_t(values[i])-127)<<8;
     }
     return 2*N;
   }
@@ -179,6 +203,16 @@ protected:
     return 2*N;
   }
 
+  /** uint16 -> int16. */
+  static size_t _uint16_int16(const RawBuffer &in, const RawBuffer &out) {
+    size_t N = in.bytesLen()/2;
+    uint16_t *values = reinterpret_cast<uint16_t *>(in.data());
+    for (size_t i=0; i<N; i++) {
+      reinterpret_cast<int16_t *>(out.data())[i] = int32_t(values[i])-((2<<15)-1);
+    }
+    return 2*N;
+  }
+
   /** unsinged int8 -> complex int16. */
   static size_t _uint8_cint16(const RawBuffer &in, const RawBuffer &out) {
     size_t N = in.bytesLen();
@@ -201,30 +235,6 @@ protected:
     return 4*N;
   }
 
-  /** complex unsigned int8 -> complex int16. */
-  static size_t _cuint8_cint16(const RawBuffer &in, const RawBuffer &out) {
-    size_t N = in.bytesLen()/2;
-    std::complex<uint8_t> *values = reinterpret_cast<std::complex<uint8_t> *>(in.data());
-    for (size_t i=0; i<N; i++) {
-      reinterpret_cast<std::complex<int16_t> *>(out.data())[i] =
-          std::complex<int16_t>((int16_t(values[i].real())-127)*(1<<8),
-                                (int16_t(values[i].imag())-127)*(1<<8));
-    }
-    return 4*N;
-  }
-
-  /** complex int8 -> complex int16. */
-  static size_t _cint8_cint16(const RawBuffer &in, const RawBuffer &out) {
-    size_t N = in.bytesLen()/2;
-    std::complex<int8_t> *values = reinterpret_cast<std::complex<int8_t> *>(in.data());
-    for (size_t i=0; i<N; i++) {
-      reinterpret_cast<std::complex<int16_t> *>(out.data())[i] =
-          std::complex<int16_t>(int16_t(values[i].real())*(1<<8),
-                                int16_t(values[i].imag())*(1<<8));
-    }
-    return 4*N;
-  }
-
   /** uint16 -> complex int16. */
   static size_t _uint16_cint16(const RawBuffer &in, const RawBuffer &out) {
     size_t N = in.bytesLen()/2;

src/ax25.cc

@@ -0,0 +1,277 @@
+#include "ax25.hh"
+#include "logger.hh"
+#include "traits.hh"
+#include <ctime>
+
+
+using namespace sdr;
+
+
+static const uint16_t crc_ccitt_table[] = {
+    0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
+    0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
+    0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
+    0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
+    0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+    0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
+    0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
+    0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
+    0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
+    0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
+    0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
+    0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
+    0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
+    0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+    0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
+    0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
+    0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
+    0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
+    0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
+    0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
+    0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
+    0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
+    0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+    0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
+    0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
+    0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
+    0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
+    0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
+    0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
+    0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
+    0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
+    0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
+};
+
+static inline bool check_crc_ccitt(const uint8_t *buf, int cnt)
+{
+    uint32_t crc = 0xffff;
+    for (; cnt > 0; cnt--, buf++) {
+        crc = (crc >> 8) ^ crc_ccitt_table[(crc ^ (*buf)) & 0xff];
+    }
+    return (crc & 0xffff) == 0xf0b8;
+}
+
+void
+unpackCall(const uint8_t *buffer, std::string &call, int &ssid, bool &addrExt) {
+  size_t length = 0; call.resize(6);
+  for (size_t i=0; i<6; i++) {
+    call.at(i) = char(buffer[i]>>1);
+    if (' ' != call.at(i)) { length++; }
+  }
+  call.resize(length);
+  ssid = int( (buffer[6] & 0x1f) >> 1);
+  addrExt = !bool(buffer[6] & 0x01);
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of AX25 decoder
+ * ******************************************************************************************** */
+AX25::AX25() : Sink<uint8_t>()
+{
+  // pass...
+}
+
+AX25::~AX25() {
+  // pass...
+}
+
+void
+AX25::config(const Config &src_cfg) {
+  if (! src_cfg.hasType()) { return; }
+  // Check if buffer type matches
+  if (Config::typeId<uint8_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure AX25: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<uint8_t>();
+    throw err;
+  }
+
+  _bitstream = 0;
+  _bitbuffer = 0;
+  _state     = 0;
+  _ptr       = _rxbuffer;
+
+  LogMessage msg(LOG_DEBUG);
+  msg << "Config AX.25 node.";
+  Logger::get().log(msg);
+}
+
+void
+AX25::process(const Buffer<uint8_t> &buffer, bool allow_overwrite)
+{
+  for (size_t i=0; i<buffer.size(); i++) {
+    // Store bit in stream
+    _bitstream = ((_bitstream << 1) | (buffer[i] & 0x01));
+
+    // Check for sync byte
+    if ((_bitstream & 0xff) == 0x7e) {
+      if ((1==_state) && ((_ptr - _rxbuffer) > 2)) {
+        *_ptr = 0;
+        if (! check_crc_ccitt(_rxbuffer, _ptr-_rxbuffer)) {
+          /*LogMessage msg(LOG_DEBUG);
+          msg << "AX.25: Received invalid buffer: " << _rxbuffer;
+          Logger::get().log(msg); */
+        } else {
+          // Assemble message
+          Message msg(_rxbuffer, _ptr-_rxbuffer-2);
+          this->handleAX25Message(msg);
+        }
+      }
+      // Receive data
+      _state = 1;
+      _ptr = _rxbuffer;
+      _bitbuffer = 0x80;
+      continue;
+    }
+
+    // If 7 ones are received in a row -> error, wait or sync byte
+    if ((_bitstream & 0x7f) == 0x7f) { _state = 0; continue; }
+
+    // If state == wait for sync byte -> receive next bit
+    if (!_state) { continue; }
+
+    /* stuffed bit */
+    if ((_bitstream & 0x3f) == 0x3e) { continue; }
+
+    // prepend bit to bitbuffer
+    /// @todo Double check this!!!
+    _bitbuffer |= ((_bitstream & 0x01) << 8);
+
+    // If 8 bits have been received (stored in b8-b1 of _bitbuffer)
+    if (_bitbuffer & 0x01) {
+      // Check for buffer overrun
+      if ((_ptr-_rxbuffer) >= 512) {
+        Logger::get().log(LogMessage(LOG_DEBUG, "AX.25 packet too long."));
+        // Wait for next sync byte
+        _state = 0;
+        continue;
+      }
+
+      // Store received byte and ...
+      *_ptr++ = (_bitbuffer >> 1);
+      // reset bit buffer
+      _bitbuffer = 0x80;
+      continue;
+    }
+
+    // Shift bitbuffer one to the left
+    _bitbuffer >>= 1;
+  }
+}
+
+void
+AX25::handleAX25Message(const Message &message) {
+  // pass...
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of AX25Dump
+ * ******************************************************************************************** */
+AX25Dump::AX25Dump(std::ostream &stream)
+  : AX25(), _stream(stream)
+{
+  // pass...
+}
+
+void
+AX25Dump::handleAX25Message(const Message &message) {
+  _stream << "AX25: " << message << std::endl;
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of AX25 Address
+ * ******************************************************************************************** */
+AX25::Address::Address()
+  : _call(), _ssid(0)
+{
+  // pass...
+}
+
+AX25::Address::Address(const std::string &call, size_t ssid)
+  : _call(call), _ssid(ssid)
+{
+  // pass...
+}
+
+AX25::Address::Address(const Address &other)
+  : _call(other._call), _ssid(other._ssid)
+{
+  // pass...
+}
+
+AX25::Address &
+AX25::Address::operator =(const Address &other) {
+  _call = other._call;
+  _ssid = other._ssid;
+  return *this;
+}
+
+std::ostream &
+sdr::operator <<(std::ostream &stream, const AX25::Address &addr) {
+  stream << addr.call() << "-" << addr.ssid();
+  return stream;
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of AX25 Message
+ * ******************************************************************************************** */
+AX25::Message::Message()
+  : _from(), _to(), _via(), _payload()
+{
+  // pass...
+}
+
+AX25::Message::Message(uint8_t *buffer, size_t length)
+  : _via(), _payload()
+{
+  std::string call; int ssid; bool addrExt;
+  // Get destination address
+  unpackCall(buffer, call, ssid, addrExt); buffer+=7; length -= 7;
+  _to   = Address(call, ssid);
+  // Get source address
+  unpackCall(buffer, call, ssid, addrExt); buffer+=7; length -= 7;
+  _from = Address(call, ssid);
+  while (addrExt) {
+    unpackCall(buffer, call, ssid, addrExt); buffer+=7; length -= 7;
+    _via.push_back(Address(call, ssid));
+  }
+  // Store payload
+  _payload.resize(length);
+  for (size_t i=0; i<length; i++) { _payload[i] = char(buffer[i]); }
+}
+
+AX25::Message::Message(const Message &other)
+  : _from(other._from), _to(other._to), _via(other._via),
+    _payload(other._payload)
+{
+  // pass...
+}
+
+AX25::Message &
+AX25::Message::operator =(const Message &other) {
+  _from = other._from;
+  _to   = other._to;
+  _via  = other._via;
+  _payload = other._payload;
+  return *this;
+}
+
+
+std::ostream &
+sdr::operator <<(std::ostream &stream, const AX25::Message &msg) {
+  stream << msg.from() << " > " << msg.to();
+  if (0 < msg.via().size()) {
+    stream << " via " << msg.via()[0];
+    for (size_t i=1; i<msg.via().size(); i++) {
+      stream << ", " << msg.via()[i];
+    }
+  }
+  stream << " N=" << msg.payload().size() << std::endl;
+  stream << msg.payload();
+  return stream;
+}
+

src/ax25.hh

@@ -0,0 +1,115 @@
+#ifndef __SDR_AX25_HH__
+#define __SDR_AX25_HH__
+
+#include "node.hh"
+
+namespace sdr {
+
+/** Decodes AX25 (PacketRadio) messages from a bit stream.
+ *
+ * In conjecture with the (A)FSK demodulator, the AX25 can be used to receive packet radio or APRS
+ * messages. AX25 is usually transmitted as FSK in transition mode, means the bits aren't
+ * encoded by mark & space tones but rather as a transition from mark to space or in reverse. Hence
+ * the FSK node needs to be configured in transition mode.
+ *
+ * The node does not process the actual AX.25 packages, it only checks the frame check sequence and
+ * forwards the AX.25 datagram to all connected sinks on success. The receiving node is responsible
+ * for unpacking and handling the received datagram.
+ * @ingroup datanodes */
+class AX25: public Sink<uint8_t>
+{
+public:
+  class Address
+  {
+  public:
+    Address();
+    Address(const std::string &call, size_t ssid);
+    Address(const Address &other);
+
+    Address &operator=(const Address &other);
+
+    inline bool isEmpty() const { return 0 == _call.size(); }
+    inline const std::string &call() const { return _call; }
+    inline size_t ssid() const { return _ssid; }
+
+  protected:
+    std::string _call;
+    size_t _ssid;
+  };
+
+  class Message
+  {
+  public:
+    Message();
+    Message(uint8_t *buffer, size_t length);
+    Message(const Message &other);
+
+    Message &operator=(const Message &other);
+
+    inline const Address &from() const { return _from; }
+    inline const Address &to() const { return _to; }
+    inline const std::vector<Address> &via() const { return _via; }
+
+    inline const std::string &payload() const { return _payload; }
+
+  protected:
+    Address _from;
+    Address _to;
+    std::vector<Address> _via;
+    std::string _payload;
+  };
+
+public:
+  /** Constructor. */
+  AX25();
+  /** Destructor. */
+  virtual ~AX25();
+
+  /** Configures the node. */
+  virtual void config(const Config &src_cfg);
+  /** Processes the bit stream. */
+  virtual void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
+
+  virtual void handleAX25Message(const Message &message);
+
+protected:
+  /** The last bits. */
+  uint32_t _bitstream;
+  /** A buffer of received bits. */
+  uint32_t _bitbuffer;
+  /** The current state. */
+  uint32_t _state;
+
+  /** Message buffer. */
+  uint8_t _rxbuffer[512];
+  /** Insert-pointer to the buffer. */
+  uint8_t *_ptr;
+};
+
+
+/** Prints received AX25 messages to the specified stream. */
+class AX25Dump: public AX25
+{
+public:
+  /** Constructor.
+   * @param stream The output stream. */
+  AX25Dump(std::ostream &stream);
+
+  /** Implements AX25 interface. */
+  void handleAX25Message(const Message &message);
+
+protected:
+  /** The output stream. */
+  std::ostream &_stream;
+};
+
+
+/** Serialization of AX25 address. */
+std::ostream& operator<<(std::ostream &stream, const sdr::AX25::Address &addr);
+/** Serialization of AX25 message. */
+std::ostream& operator<<(std::ostream &stream, const sdr::AX25::Message &msg);
+
+} // namespace sdr
+
+
+#endif // __SDR_AX25_HH__

src/baseband.hh

@@ -14,9 +14,10 @@ namespace sdr {
 /** This class performs several operations on the complex (integral) input stream, it first filters
  * out some part of the input stream using a FIR band pass (band pass is centerred around @c Ff
  * with width @c width) then shifts the center frequency @c Fc to 0 and finally sub-samples the
- * resulting stream. This node can be used to select a portion of the input stream and reduce the
- * rate of the stream, allowing for some more expensive operations to be performed on the output
- * stream. */
+ * resulting stream. This node can be used to select a portion of the input spectrum and for the
+ * reduction of the stream rate, allowing for some more expensive operations to be performed on the
+ * output stream.
+ * @ingroup filters */
 template <class Scalar>
 class IQBaseBand: public Sink< std::complex<Scalar> >, public Source, public FreqShiftBase<Scalar>
 {
@@ -298,7 +299,8 @@ protected:
 /** This class performs several operations on the real input stream,
  * It first filters out some part of the input stream using a FIR band pass filter
  * then shifts the center frequency to 0 and finally sub-samples the resulting stream such that
- * the selected base-band is well represented. */
+ * the selected base-band is well represented.
+ * @ingroup filters */
 template <class Scalar>
 class BaseBand: public Sink<Scalar>, public Source, public FreqShiftBase<Scalar>
 {

src/baudot.cc

@@ -0,0 +1,111 @@
+#include "baudot.hh"
+#include "traits.hh"
+#include "logger.hh"
+
+
+using namespace sdr;
+
+// Baudot code tables
+char Baudot::_letter[32] = {  0, 'E','\n', 'A', ' ', 'S', 'I', 'U','\n', 'D', 'R', 'J', 'N', 'F',
+                            'C', 'K', 'T', 'Z', 'L', 'W', 'H', 'Y', 'P', 'Q', 'O', 'B', 'G',   0,
+                            'M', 'X', 'V',  0};
+char Baudot::_figure[32] = {  0, '3','\n', '-', ' ','\a', '8', '7','\n', '?', '4','\'', ',', '!',
+                            ':', '(', '5', '"', ')', '2', '#', '6', '0', '1', '9', '?', '&',   0,
+                            '.', '/', ';',  0};
+
+// Some special codes
+#define CHAR_NUL 0
+#define CHAR_STF 27
+#define CHAR_STL 31
+#define CHAR_SPA 4
+
+
+Baudot::Baudot(StopBits stopBits)
+  : Sink<uint8_t>(), Source(), _mode(LETTERS)
+{
+  switch (stopBits) {
+  case STOP1:
+    // Pattern xx11 xxxx xxxx xx00
+    // Mask    0011 0000 0000 0011
+    _stopHBits     = 2;
+    _bitsPerSymbol = 14;
+    _pattern       = 0x3000;
+    _mask          = 0x3003;
+    break;
+  case STOP15:
+    // Pattern x11x xxxx xxxx x000
+    // Mask    0110 0000 0000 0111
+    _stopHBits     = 3;
+    _bitsPerSymbol = 15;
+    _pattern       = 0x6000;
+    _mask          = 0x6007;
+    break;
+  case STOP2:
+    // Pattern 11xx xxxx xxxx 0000
+    // Mask    1100 0000 0000 1111
+    _stopHBits     = 4;
+    _bitsPerSymbol = 16;
+    _pattern       = 0xC000;
+    _mask          = 0xC00F;
+    break;
+  }
+}
+
+void
+Baudot::config(const Config &src_cfg) {
+  if (! src_cfg.hasType()) { return; }
+  // Check if buffer type matches
+  if (Config::typeId<uint8_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure Baudot: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<uint8_t>();
+    throw err;
+  }
+
+  // Init (half) bit stream and counter
+  _bitstream = 0;
+  _bitcount  = 0;
+
+  // Compute buffer size.
+  size_t buffer_size = (src_cfg.bufferSize()/(2*_bitsPerSymbol))+1;
+  _buffer  = Buffer<uint8_t>(buffer_size);
+
+  LogMessage msg(LOG_DEBUG);
+  msg << "Config Baudot node: " << std::endl
+      << " input sample rate: " << src_cfg.sampleRate() << " half-bits/s" << std::endl
+      << " start bits: " << 1 << std::endl
+      << " stop bits: " << float(_stopHBits)/2 << std::endl;
+  Logger::get().log(msg);
+
+  // propergate config
+  this->setConfig(Config(Traits<uint8_t>::scalarId, 0, buffer_size, 1));
+}
+
+
+void
+Baudot::process(const Buffer<uint8_t> &buffer, bool allow_overwrite)
+{
+  size_t o=0;
+  for (size_t i=0; i<buffer.size(); i++) {
+    _bitstream = (_bitstream << 1) | (buffer[i] & 0x1); _bitcount++;
+    // Check if symbol as received:
+    if ((_bitsPerSymbol <= _bitcount) && (_pattern == (_bitstream & _mask))) {
+      _bitcount = 0;
+      // Unpack 5bit baudot code
+      uint8_t code = 0;
+      for (int j=0; j<5; j++) {
+        int shift = _stopHBits + 2*j;
+        code |= (((_bitstream>>shift)&0x01)<<j);
+      }
+      // Decode to ASCII
+      if (CHAR_STL == code) { _mode = LETTERS; }
+      else if (CHAR_STF == code) { _mode = FIGURES; }
+      else {
+        if (CHAR_SPA == code) { _mode = LETTERS; }
+        if (LETTERS == _mode) { _buffer[o++] = _letter[code]; }
+        else { _buffer[o++] = _figure[code]; }
+      }
+    }
+  }
+  if (0 < o) { this->send(_buffer.head(o)); }
+}

src/baudot.hh

@@ -0,0 +1,72 @@
+#ifndef __SDR_BAUDOT_HH__
+#define __SDR_BAUDOT_HH__
+
+#include "node.hh"
+#include <map>
+
+namespace sdr {
+
+/** Implements a Baudot decoder. Inconjecture with the (A)FSK demodulator, it enables the
+ * reception of radio teletype (RTTY) messages.
+ *
+ * Please note that a baudot encoded char is usually transmitted in a frame with one start bit and
+ * 1, 1.5 or 2 stop bits. Hence this node expects to receive two bits for one decoded bit in order
+ * to detect the 1.5 stop bits reliably.
+ *
+ * I.e. to receive a 45.45 baud RTTY signal, the (A)FSK demodulator need to be configured for
+ * 90.90 baud (= 2*45.45 baud).
+ * @ingroup datanodes */
+class Baudot: public Sink<uint8_t>, public Source
+{
+public:
+  /** Specifies the current code-tables. */
+  typedef enum {
+    LETTERS,   ///< Letters.
+    FIGURES    ///< Numbers, symbols etc.
+  } Mode;
+
+  /** Specifies the number of stop bits. */
+  typedef enum {
+    STOP1,   ///< 1 stop bit.
+    STOP15,  ///< 1.5 stop bits.
+    STOP2    ///< 2 stop bits.
+  } StopBits;
+
+public:
+  /** Constructor. */
+  Baudot(StopBits stopBits = STOP15);
+
+  /** Configures the node. */
+  virtual void config(const Config &src_cfg);
+  /** Processes the bit-stream. */
+  virtual void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
+
+protected:
+  /** Code table for letters. */
+  static char _letter[32];
+  /** Code table for symbols or figure (i.e. numbers). */
+  static char _figure[32];
+  /** The last bits received. */
+  uint16_t _bitstream;
+  /** The number of bits received. */
+  size_t   _bitcount;
+
+  /** The currently selected table. */
+  Mode     _mode;
+
+  /** Specifies the number of half bits per symbol. */
+  size_t   _bitsPerSymbol;
+  /** Specifies the frame pattern. */
+  uint16_t _pattern;
+  /** Specifies the frame mask. */
+  uint16_t _mask;
+  /** Number of half bits forming the stop bit. */
+  uint16_t _stopHBits;
+
+  /** The output buffer. */
+  Buffer<uint8_t> _buffer;
+};
+
+}
+
+#endif // BAUDOT_HH

src/bch31_21.cc

@@ -0,0 +1,213 @@
+#include "bch31_21.hh"
+#include "stdlib.h"
+#include "string.h"
+
+using namespace sdr;
+
+/*
+ * the code used by POCSAG is a (n=31,k=21) BCH Code with dmin=5,
+ * thus it could correct two bit errors in a 31-Bit codeword.
+ * It is a systematic code.
+ * The generator polynomial is:
+ *   g(x) = x^10+x^9+x^8+x^6+x^5+x^3+1
+ * The parity check polynomial is:
+ *   h(x) = x^21+x^20+x^18+x^16+x^14+x^13+x^12+x^11+x^8+x^5+x^3+1
+ * g(x) * h(x) = x^n+1
+ */
+#define BCH_POLY 03551 /* octal */
+#define BCH_N    31
+#define BCH_K    21
+
+static inline unsigned char even_parity(uint32_t data)
+{
+    unsigned int temp = data ^ (data >> 16);
+
+    temp = temp ^ (temp >> 8);
+    temp = temp ^ (temp >> 4);
+    temp = temp ^ (temp >> 2);
+    temp = temp ^ (temp >> 1);
+    return temp & 1;
+}
+
+static unsigned int
+pocsag_syndrome(uint32_t data)
+{
+    uint32_t shreg = data >> 1; /* throw away parity bit */
+    uint32_t mask = 1L << (BCH_N-1), coeff = BCH_POLY << (BCH_K-1);
+    int n = BCH_K;
+
+    for(; n > 0; mask >>= 1, coeff >>= 1, n--) {
+      if (shreg & mask) { shreg ^= coeff; }
+    }
+    if (even_parity(data)) {
+      shreg |= (1 << (BCH_N - BCH_K));
+    }
+    return shreg;
+}
+
+static void
+bitslice_syndrome(uint32_t *slices)
+{
+    const int firstBit = BCH_N - 1;
+    int i, n;
+    uint32_t paritymask = slices[0];
+
+    // do the parity and shift together
+    for (i = 1; i < 32; ++i) {
+        paritymask ^= slices[i];
+        slices[i-1] = slices[i];
+    }
+    slices[31] = 0;
+
+    // BCH_POLY << (BCH_K - 1) is
+    //                                                              20   21 22 23
+    //  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ONE, 0, 0, ONE,
+    //  24 25   26  27  28   29   30   31
+    //  0, ONE, ONE, 0, ONE, ONE, ONE, 0
+
+    for (n = 0; n < BCH_K; ++n) {
+        // one line here for every '1' bit in coeff (above)
+        const int bit = firstBit - n;
+        slices[20 - n] ^= slices[bit];
+        slices[23 - n] ^= slices[bit];
+        slices[25 - n] ^= slices[bit];
+        slices[26 - n] ^= slices[bit];
+        slices[28 - n] ^= slices[bit];
+        slices[29 - n] ^= slices[bit];
+        slices[30 - n] ^= slices[bit];
+        slices[31 - n] ^= slices[bit];
+    }
+
+    // apply the parity mask we built up
+    slices[BCH_N - BCH_K] |= paritymask;
+}
+
+static uint32_t
+transpose_n(int n, uint32_t *matrix)
+{
+  uint32_t out = 0;
+  int j;
+
+  for (j = 0; j < 32; ++j) {
+    if (matrix[j] & (1<<n)) {
+      out |= (1<<j);
+    }
+  }
+
+  return out;
+}
+
+static uint32_t *
+transpose_clone(uint32_t src, uint32_t *out)
+{
+  int i;
+  if (!out) { out = (uint32_t *)malloc(sizeof(uint32_t)*32); }
+  for (i = 0; i < 32; ++i) {
+    if (src & (1<<i)) {
+      out[i] = 0xffffffff;
+    } else {
+      out[i] = 0;
+    }
+  }
+
+  return out;
+}
+
+
+// This might not be elegant, yet effective!
+// Error correction via bruteforce ;)
+//
+// It's a pragmatic solution since this was much faster to implement
+// than understanding the math to solve it while being as effective.
+// Besides that the overhead is neglectable.
+int
+sdr::pocsag_repair(uint32_t &data)
+{
+  // Check if data is correct
+  if (0 == pocsag_syndrome(data)) { return 0; }
+
+  int i, n, b1, b2;
+  uint32_t res;
+  uint32_t *xpose = 0, *in = 0;
+
+  // check for single bit errors
+  xpose = (uint32_t *) malloc(sizeof(uint32_t)*32);
+  in = (uint32_t *) malloc(sizeof(uint32_t)*32);
+
+  transpose_clone(data, xpose);
+  for (i = 0; i < 32; ++i) { xpose[i] ^= (1<<i); }
+  bitslice_syndrome(xpose);
+
+  res = 0;
+  for (i = 0; i < 32; ++i) { res |= xpose[i]; }
+  res = ~res;
+
+  if (res) {
+    int n = 0;
+    while (res) { ++n; res >>= 1; }
+    --n;
+    data ^= (1<<n);
+    goto returnfree;
+  }
+
+  //check for two bit errors
+  n = 0;
+  transpose_clone(data, xpose);
+
+  for (b1 = 0; b1 < 32; ++b1) {
+    for (b2 = b1; b2 < 32; ++b2) {
+      xpose[b1] ^= (1<<n);
+      xpose[b2] ^= (1<<n);
+
+      if (++n == 32) {
+        memcpy(in, xpose, sizeof(uint32_t)*32);
+        bitslice_syndrome(xpose);
+        res = 0;
+        for (i = 0; i < 32; ++i) { res |= xpose[i]; }
+        res = ~res;
+        if (res) {
+          int n = 0;
+          while (res) { ++n; res >>= 1; }
+          --n;
+
+          data = transpose_n(n, in);
+          goto returnfree;
+        }
+
+        transpose_clone(data, xpose);
+        n = 0;
+      }
+    }
+  }
+
+  if (n > 0) {
+    memcpy(in, xpose, sizeof(uint32_t)*32);
+
+    bitslice_syndrome(xpose);
+
+    res = 0;
+    for (i = 0; i < 32; ++i) { res |= xpose[i]; }
+    res = ~res;
+
+    if (res) {
+      int n = 0;
+      while (res) { ++n; res >>= 1; }
+      --n;
+
+      data = transpose_n(n, in);
+      goto returnfree;
+    }
+  }
+
+  if (xpose) { free(xpose); }
+  if (in) { free(in); }
+  return 1;
+
+returnfree:
+  if (xpose)
+    free(xpose);
+  if (in)
+    free(in);
+  return 0;
+}
+

src/bch31_21.hh

@@ -0,0 +1,14 @@
+#ifndef __SDR_BCH31_21_HH__
+#define __SDR_BCH31_21_HH__
+
+#include <inttypes.h>
+
+namespace sdr {
+
+/** Checks and repairs a POCSAG message with its
+ * BCH(31,21) ECC. */
+int pocsag_repair(uint32_t &data);
+
+}
+
+#endif // __SDR_BCH31_21_HH__

src/buffer.cc

@@ -25,7 +25,9 @@ RawBuffer::RawBuffer(size_t N, BufferOwner *owner)
     _refcount((int *)malloc(sizeof(int))), _owner(owner)
 {
   // Check if data could be allocated
-  if ((0 == _ptr) && (0 != _refcount)) { free(_refcount); _refcount = 0;  _storage_size = 0; return; }
+  if ((0 == _ptr) && (0 != _refcount)) {
+    free(_refcount); _refcount = 0;  _storage_size = 0; return;
+  }
   // Set refcount, done...
   if (_refcount) { (*_refcount) = 1; }
 }
@@ -62,7 +64,7 @@ void RawBuffer::unref() {
   // If empty -> skip...
   if ((0 == _ptr) || (0 == _refcount)) { return; }
   // Decrement refcount
-  (*_refcount) -= 1;
+  (*_refcount)--;
   // If there is only one reference left and the buffer is owned -> notify owner, who holds the last
   // reference.
   if ((1 == (*_refcount)) && (_owner)) { _owner->bufferUnused(*this); }

src/buffer.hh

@@ -82,7 +82,7 @@ public:
   void unref();
   /** Returns the reference counter. */
   inline int refCount() const { if (0 == _refcount) { return 0; } return (*_refcount); }
-  /** We assume here that buffers are owned by some object: A buffer is therefore "unused" if the
+  /** We assume here that buffers are owned by one object: A buffer is therefore "unused" if the
    * owner holds the only reference to the buffer. */
   inline bool isUnused() const {
     if (0 == _refcount) { return true; }

src/buffernode.hh

@@ -12,7 +12,8 @@
 namespace sdr {
 
 /** A simple buffering node, that ensures a fixed buffer size. This node is useful, expecially in
- * front of a node that performs a FFT transform, which requires a certain buffer size. */
+ * front of a node that performs a FFT transform, which requires a certain buffer size.
+ * @ingroup datanodes */
 template <class Scalar>
 class BufferNode : public Sink<Scalar>, public Source
 {

src/combine.hh

@@ -12,7 +12,7 @@ namespace sdr {
 
 template <class Scalar> class Combine;
 
-/** A single sink of a Combine node. */
+/** A single sink of a Combine node. Do not use this node explicitly, consider using @c Combine. */
 template <class Scalar>
 class CombineSink: public Sink<Scalar>
 {
@@ -60,7 +60,8 @@ protected:
 };
 
 
-/** A combine node. This node allows to combine several streams into one. */
+/** A combine node. This node allows to combine several streams into one.
+ * @ingroup datanodes */
 template <class Scalar>
 class Combine
 {
@@ -78,9 +79,11 @@ public:
   virtual ~Combine() {
     // Unref all buffers and free sinks
     for (size_t i=0; i<_sinks.size(); i++) {
-      _buffers[i].unref(); delete _sinks[i];
+      delete _sinks[i];
+      _buffers[i].unref();
     }
-    _buffers.clear(); _sinks.clear();
+    _buffers.clear();
+    _sinks.clear();
   }
 
   /** Needs to be overridden. */
@@ -147,7 +150,8 @@ protected:
 };
 
 
-/** Interleaves several input streams. */
+/** Interleaves several input streams.
+ * @ingroup datanodes */
 template <class Scalar>
 class Interleave : public Combine<Scalar>, public Source
 {

src/demod.hh

@@ -12,7 +12,8 @@
 namespace sdr {
 
 
-/** Amplitude modulation (AM) demodulator from an I/Q signal. */
+/** Amplitude modulation (AM) demodulator from an I/Q signal.
+ * @ingroup demods */
 template <class Scalar>
 class AMDemod
     : public Sink< std::complex<Scalar> >, public Source
@@ -26,7 +27,8 @@ public:
 
   /** Destructor. */
   virtual ~AMDemod() {
-    // pass...
+    // free buffers
+    _buffer.unref();
   }
 
   /** Configures the AM demod. */
@@ -40,8 +42,11 @@ public:
           << ", expected " << Config::typeId< std::complex<Scalar> >();
       throw err;
     }
+
+    // Unreference previous buffer
+    _buffer.unref();
     // Allocate buffer
-    _buffer =  Buffer<Scalar>(src_cfg.bufferSize());
+    _buffer = Buffer<Scalar>(src_cfg.bufferSize());
 
     LogMessage msg(LOG_DEBUG);
     msg << "Configure AMDemod: " << this << std::endl
@@ -59,16 +64,6 @@ public:
   /** Handles the I/Q input buffer. */
   virtual void process(const Buffer<std::complex<Scalar> > &buffer, bool allow_overwrite)
   {
-    // Drop buffer if output buffer is still in use:
-    if (! _buffer.isUnused()) {
-#ifdef SDR_DEBUG
-      LogMessage msg(LOG_WARNING);
-      msg << __FILE__ << ": Output buffer still in use: Drop received buffer...";
-      Logger::get().log(msg);
-      return;
-#endif
-    }
-
     Buffer<Scalar> out_buffer;
     // If source allow to overwrite the buffer, use it otherwise rely on own buffer
     if (allow_overwrite) { out_buffer = Buffer<Scalar>(buffer); }
@@ -91,7 +86,8 @@ protected:
 };
 
 
-/** SSB upper side band (USB) demodulator from an I/Q signal. */
+/** SSB upper side band (USB) demodulator from an I/Q signal.
+ * @ingroup demods */
 template <class Scalar>
 class USBDemod
     : public Sink< std::complex<Scalar> >, public Source
@@ -111,7 +107,7 @@ public:
 
   /** Destructor. */
   virtual ~USBDemod() {
-    // pass...
+    _buffer.unref();
   }
 
   /** Configures the USB demodulator. */
@@ -125,6 +121,9 @@ public:
           << ", expected " << Config::typeId<CScalar>();
       throw err;
     }
+
+    // Unreference previous buffer
+    _buffer.unref();
     // Allocate buffer
     _buffer =  Buffer<Scalar>(src_cfg.bufferSize());
 
@@ -146,16 +145,9 @@ public:
     if (allow_overwrite) {
       // Process in-place
       _process(buffer, Buffer<Scalar>(buffer));
-    } else if (_buffer.isUnused()) {
+    } else {
       // Store result in buffer
       _process(buffer, _buffer);
-    } else {
-      // Drop buffer
-#ifdef SDR_DEBUG
-      LogMessage msg(LOG_WARNING);
-      msg << "SSBDemod: Drop buffer.";
-      Logger::get().log(msg);
-#endif
     }
   }
 
@@ -175,7 +167,10 @@ protected:
 
 
 
-/** Demodulates FM from an I/Q signal. */
+/** Demodulates FM from an I/Q signal.
+ * This node only implements the demodulation of the signal, the needed post-filtering (deemphasize)
+ * is implemented in a separate node, @c sdr::FMDeemph.
+ * @ingroup demods */
 template <class iScalar, class oScalar=iScalar>
 class FMDemod: public Sink< std::complex<iScalar> >, public Source
 {
@@ -193,7 +188,7 @@ public:
 
   /** Destructor. */
   virtual ~FMDemod() {
-    // pass...
+    _buffer.unref();
   }
 
   /** Configures the FM demodulator. */
@@ -237,14 +232,8 @@ public:
 
     if (allow_overwrite && _can_overwrite) {
       _process(buffer, Buffer<oScalar>(buffer));
-    } else if (_buffer.isUnused()) {
-      _process(buffer, _buffer);
     } else {
-#ifdef SDR_DEBUG
-      LogMessage msg(LOG_WARNING);
-      msg << "FMDemod: Drop buffer: Output buffer still in use.";
-      Logger::get().log(msg);
-#endif
+      _process(buffer, _buffer);
     }
   }
 
@@ -252,34 +241,14 @@ protected:
   /** The actual demodulation. */
   void _process(const Buffer< std::complex<iScalar> > &in, const Buffer<oScalar> &out)
   {
-    // The last input value
-    std::complex<iScalar> last_value = _last_value;
-    // calc first value
-    SScalar a = (SScalar(in[0].real())*SScalar(last_value.real()))/2
-        + (SScalar(in[0].imag())*SScalar(last_value.imag()))/2;
-    SScalar b = (SScalar(in[0].imag())*SScalar(last_value.real()))/2
-        - (SScalar(in[0].real())*SScalar(last_value.imag()))/2;
-    a >>= Traits<iScalar>::shift; b >>= Traits<iScalar>::shift;
-    // update last value
-    last_value = in[0];
-    // calc output (prob. overwriting the last value)
-    out[0] = fast_atan2<iScalar, oScalar>(a, b);
-    //out[0] = (1<<12)*(std::atan2(float(a),float(b))/M_PI);
-
     // Calc remaining values
     for (size_t i=1; i<in.size(); i++) {
-      a = (SScalar(in[i].real())*SScalar(last_value.real()))/2
-          + (SScalar(in[i].imag())*SScalar(last_value.imag()))/2;
-      b = (SScalar(in[i].imag())*SScalar(last_value.real()))/2
-          - (SScalar(in[i].real())*SScalar(last_value.imag()))/2;
-      a >>= Traits<iScalar>::shift; b >>= Traits<iScalar>::shift;
-      last_value = in[i];
-      out[i] = fast_atan2<iScalar,oScalar>(a, b);
-      //out[i] = (1<<12)*(std::atan2(float(a),float(b))/M_PI);
+      oScalar phi = fast_atan2<iScalar, oScalar>(in[i].real(), in[i].imag())/2;
+      // dphi
+      out[i] = (_last_value - phi);
+      _last_value = phi;
     }
 
-    // Store last value
-    _last_value = last_value;
     // propergate result
     this->send(out.head(in.size()));
   }
@@ -288,8 +257,8 @@ protected:
 protected:
   /** Output rescaling. */
   int _shift;
-  /** The last input value. */
-  std::complex<iScalar> _last_value;
+  /** The last angle. */
+  oScalar _last_value;
   /** If true, in-place demodulation is poissible. */
   bool _can_overwrite;
   /** The output buffer, unused if demodulation is performed in-place. */
@@ -297,7 +266,8 @@ protected:
 };
 
 
-/** A tiny node to de-emphasize the higher frequencies of a FM transmitted audio signal. */
+/** A tiny node to de-emphasize the higher frequencies of a FM transmitted audio signal.
+ * @ingroup filters */
 template <class Scalar>
 class FMDeemph: public Sink<Scalar>, public Source
 {
@@ -311,7 +281,7 @@ public:
 
   /** Destructor. */
   virtual ~FMDeemph() {
-    // pass...
+    _buffer.unref();
   }
 
   /** Returns true if the filter node is enabled. */
@@ -336,8 +306,17 @@ public:
           1.0/( (1.0-exp(-1.0/(src_cfg.sampleRate() * 75e-6) )) ) );
     // Reset average:
     _avg = 0;
+    // Unreference previous buffer
+    _buffer.unref();
     // Allocate buffer:
     _buffer = Buffer<Scalar>(src_cfg.bufferSize());
+
+    LogMessage msg(LOG_DEBUG);
+    msg << "Configured FMDDeemph node: " << this << std::endl
+        << " sample-rate: " << src_cfg.sampleRate() << std::endl
+        << " type: " << src_cfg.type();
+    Logger::get().log(msg);
+
     // Propergate config:
     this->setConfig(Config(src_cfg.type(), src_cfg.sampleRate(), src_cfg.bufferSize(), 1));
   }

src/filternode.hh

@@ -47,7 +47,10 @@ public:
   }
 
   /** Destructor. */
-  virtual ~FilterSink() { }
+  virtual ~FilterSink() {
+    _in_buffer.unref();
+    _out_buffer.unref();
+  }
 
   /** Configures the node. */
   virtual void config(const Config &src_cfg) {
@@ -223,7 +226,8 @@ protected:
 };
 
 
-/** A FFT filter bank node wich consists of several filters. */
+/** A FFT filter bank node wich consists of several filters.
+ * @ingroup filters */
 template <class Scalar>
 class FilterNode
 {

src/firfilter.hh

@@ -111,7 +111,8 @@ public:
 
 
 /** Generic FIR filter class. Use one of the specializations below for a low-, high- or band-pass
- * filter. */
+ * filter.
+ * @ingroup filters */
 template <class Scalar, class FilterCoeffs>
 class FIRFilter: public Sink<Scalar>, public Source
 {
@@ -269,7 +270,8 @@ protected:
 };
 
 
-/** Low-pass FIR filter specialization. */
+/** Low-pass FIR filter specialization.
+ * @ingroup filters */
 template <class Scalar>
 class FIRLowPass: public FIRFilter<Scalar, FIRLowPassCoeffs>
 {
@@ -285,7 +287,8 @@ public:
   inline void setFreq(double freq) { FIRFilter<Scalar, FIRLowPassCoeffs>::setUpperFreq(freq); }
 };
 
-/** High-pass FIR filter specialization. */
+/** High-pass FIR filter specialization.
+ * @ingroup filters */
 template <class Scalar>
 class FIRHighPass: public FIRFilter<Scalar, FIRHighPassCoeffs>
 {
@@ -302,7 +305,8 @@ public:
 };
 
 
-/** Band-pass FIR filter specialization. */
+/** Band-pass FIR filter specialization.
+ * @ingroup filters */
 template <class Scalar>
 class FIRBandPass: public FIRFilter<Scalar, FIRBandPassCoeffs>
 {
@@ -314,7 +318,8 @@ public:
   virtual ~FIRBandPass() { }
 };
 
-/** Band-stop FIR filter specialization. */
+/** Band-stop FIR filter specialization.
+ * @ingroup filters */
 template <class Scalar>
 class FIRBandStop: public FIRFilter<Scalar, FIRBandStopCoeffs>
 {

src/freqshift.hh

@@ -8,7 +8,8 @@
 
 namespace sdr {
 
-/** A performant implementation of a frequency shift operation on integer signals. */
+/** A performant implementation of a frequency-shift operation on integer signals.
+ * @ingroup filters */
 template <class Scalar>
 class FreqShiftBase
 {
@@ -60,12 +61,15 @@ public:
     if (0 == _lut_inc) { return value; }
     // Get index, idx = (_lut_count/256)
     size_t idx = (_lut_count>>8);
+    // Handle negative frequency shifts
     if (0 > _freq_shift) { idx = _lut_size - idx - 1; }
+    // Apply
     value = ((_lut[idx] * value) >> Traits<Scalar>::shift);
     // Incement _lut_count
     _lut_count += _lut_inc;
     // _lut_count modulo (_lut_size*256)
     while (_lut_count >= (_lut_size<<8)) { _lut_count -= (_lut_size<<8); }
+    // Done.
     return value;
   }
 
@@ -75,7 +79,7 @@ protected:
     // Every sample increments the LUT index by lut_inc/256.
     // The multiple is needed as ratio between the frequency shift _Fc and the sample rate _Fs
     // may not result in an integer increment. By simply flooring _lut_size*_Fc/_Fs, the actual
-    // down conversion may be much smaller than actual reuqired. Hence, the counter in therefore
+    // down conversion may be much smaller than actual reuqired. Hence, the counter is therefore
     // incremented by the integer (256*_lut_size*_Fc/_Fs) and the index is then obtained by
     // dividing _lut_count by 256 (right shift 8 bits).
     _lut_inc = (_lut_size*(1<<8)*std::abs(_freq_shift))/_Fs;

src/fsk.cc

@@ -0,0 +1,236 @@
+#include "fsk.hh"
+#include "logger.hh"
+#include "traits.hh"
+#include "interpolate.hh"
+
+using namespace sdr;
+
+
+/* ******************************************************************************************** *
+ * Implementation of FSKDetector
+ * ******************************************************************************************** */
+FSKDetector::FSKDetector(float baud, float Fmark, float Fspace)
+  : Sink<int16_t>(), Source(), _baud(baud), _corrLen(0), _Fmark(Fmark), _Fspace(Fspace)
+{
+  // pass...
+}
+
+void
+FSKDetector::config(const Config &src_cfg)
+{
+  // Check if config is complete
+  if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
+
+  // Check if buffer type matches
+  if (Config::typeId<int16_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure FSKBase: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<int16_t>();
+    throw err;
+  }
+
+  _corrLen   = int(src_cfg.sampleRate()/_baud);
+  _markLUT   = Buffer< std::complex<float> >(_corrLen);
+  _spaceLUT  = Buffer< std::complex<float> >(_corrLen);
+  _markHist  = Buffer< std::complex<float> >(_corrLen);
+  _spaceHist = Buffer< std::complex<float> >(_corrLen);
+
+  // Initialize LUTs and ring-buffers
+  double phiMark=0, phiSpace=0;
+  for (size_t i=0; i<_corrLen; i++) {
+    _markLUT[i] = std::exp(std::complex<float>(0.0, phiMark));
+    _spaceLUT[i] = std::exp(std::complex<float>(0.0, phiSpace));
+    phiMark  += (2.*M_PI*_Fmark)/src_cfg.sampleRate();
+    phiSpace += (2.*M_PI*_Fspace)/src_cfg.sampleRate();
+    // Apply Window functions
+    //_markLUT[i] *= (0.42 - 0.5*cos((2*M_PI*i)/_corrLen) + 0.08*cos((4*M_PI*i)/_corrLen));
+    //_spaceLUT[i] *= (0.42 - 0.5*cos((2*M_PI*i)/_corrLen) + 0.08*cos((4*M_PI*i)/_corrLen));
+    _markHist[i] = 0; _spaceHist[i] = 0;
+  }
+  // Ring buffer index
+  _lutIdx = 0;
+
+  // Allocate output buffer
+  _buffer = Buffer<int8_t>(src_cfg.bufferSize());
+
+  LogMessage msg(LOG_DEBUG);
+  msg << "Config FSKDetector node: " << std::endl
+      << " sample/symbol rate: " << src_cfg.sampleRate() << " Hz" << std::endl
+      << " target baud rate: " << _baud << std::endl
+      << " approx. samples per bit: " << _corrLen;
+  Logger::get().log(msg);
+
+  // Forward config.
+  this->setConfig(Config(Traits<uint8_t>::scalarId, src_cfg.sampleRate(), src_cfg.bufferSize(), 1));
+}
+
+
+uint8_t
+FSKDetector::_process(int16_t sample) {
+  _markHist[_lutIdx] = float(sample)*_markLUT[_lutIdx];
+  _spaceHist[_lutIdx] = float(sample)*_spaceLUT[_lutIdx];
+  // inc _lutIdx, modulo LUT length
+  _lutIdx++; if (_lutIdx==_corrLen) { _lutIdx=0; }
+
+  std::complex<float> markSum(0), spaceSum(0);
+  for (size_t i=0; i<_corrLen; i++) {
+    markSum += _markHist[i];
+    spaceSum += _spaceHist[i];
+  }
+
+  float f = markSum.real()*markSum.real() +
+      markSum.imag()*markSum.imag() -
+      spaceSum.real()*spaceSum.real() -
+      spaceSum.imag()*spaceSum.imag();
+
+  return (f>0);
+}
+
+void
+FSKDetector::process(const Buffer<int16_t> &buffer, bool allow_overwrite) {
+  for (size_t i=0; i<buffer.size(); i++) {
+    _buffer[i] = _process(buffer[i]);
+  }
+  this->send(_buffer.head(buffer.size()), false);
+}
+
+
+
+/* ******************************************************************************************** *
+ * Implementation of BitStream
+ * ******************************************************************************************** */
+BitStream::BitStream(float baud, Mode mode)
+  : Sink<uint8_t>(), Source(), _baud(baud), _mode(mode), _corrLen(0)
+{
+  // pass...
+}
+
+void
+BitStream::config(const Config &src_cfg) {
+  // Check if config is complete
+  if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
+
+  // Check if buffer type matches
+  if (Config::typeId<uint8_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure BitStream: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<int16_t>();
+    throw err;
+  }
+
+  // # of symbols for each bit
+  _corrLen = int(src_cfg.sampleRate()/_baud);
+
+  // Config PLL for bit detection
+  _phase    = 0;
+  // exact bits per sample (<< 1)
+  _omega   = _baud/src_cfg.sampleRate();
+  // PLL limits +/- 10% around _omega
+  _omegaMin = _omega - 0.005*_omega;
+  _omegaMax = _omega + 0.005*_omega;
+  // PLL gain
+  _pllGain = 0.0005;
+
+  // symbol moving average
+  _symbols = Buffer<int8_t>(_corrLen);
+  for (size_t i=0; i<_corrLen; i++) { _symbols[i] = 0; }
+  _symIdx = 0; _symSum  = 0; _lastSymSum = 0;
+
+  // Reset bit hist
+  _lastBits = 0;
+
+  // Allocate output buffer
+  _buffer = Buffer<uint8_t>(1+src_cfg.bufferSize()/_corrLen);
+
+  LogMessage msg(LOG_DEBUG);
+  msg << "Config BitStream node: " << std::endl
+      << " symbol rate: " << src_cfg.sampleRate() << " Hz" << std::endl
+      << " baud rate:   " << _baud << std::endl
+      << " symbols/bit: " << 1./_omega << std::endl
+      << " bit mode:    " << ( (NORMAL == _mode) ? "normal" : "transition" );
+  Logger::get().log(msg);
+
+  // Forward config.
+  this->setConfig(Config(Traits<uint8_t>::scalarId, _baud, _buffer.size(), 1));
+}
+
+void
+BitStream::process(const Buffer<uint8_t> &buffer, bool allow_overwrite)
+{
+  size_t o=0;
+  for (size_t i=0; i<buffer.size(); i++)
+  {
+    // store symbol & update _symSum and _lastSymSum
+    _lastSymSum = _symSum;
+    _symSum -= _symbols[_symIdx];
+    _symbols[_symIdx] = ( buffer[i] ? 1 : -1 );
+    _symSum += _symbols[_symIdx];
+    _symIdx = ((_symIdx+1) % _corrLen);
+
+    // Advance phase
+    _phase += _omega;
+
+    // Sample bit ...
+    if (_phase >= 1) {
+      // Modulo "2 pi", phase is defined on the interval [0,1)
+      while (_phase>=1) { _phase -= 1; }
+      // Estimate bit by majority vote on all symbols (_symSum)
+      _lastBits = ((_lastBits<<1) | (_symSum>0));
+      // Put decoded bit in output buffer
+      if (TRANSITION == _mode) {
+        // transition -> 0; no transition -> 1
+        _buffer[o++] = ((_lastBits ^ (_lastBits >> 1) ^ 0x1) & 0x1);
+      } else {
+        // mark -> 1, space -> 0
+        _buffer[o++] = _lastBits & 0x1;
+      }
+    }
+
+    // If there was a symbol transition
+    if (((_lastSymSum < 0) && (_symSum>=0)) || ((_lastSymSum >= 0) && (_symSum<0))) {
+      // Phase correction
+      // transition at [-pi,0] -> increase omega
+      if (_phase < 0.5) { _omega += _pllGain*(0.5-_phase); }
+      // transition at [0,pi]  -> decrease omega
+      else { _omega -= _pllGain*(_phase-0.5); }
+      // Limit omega
+      _omega = std::min(_omegaMax, std::max(_omegaMin, _omega));
+    }
+  }
+
+  if (o>0) { this->send(_buffer.head(o)); }
+}
+
+
+/* ******************************************************************************************** *
+ * Implementation of BitDump
+ * ******************************************************************************************** */
+BitDump::BitDump(std::ostream &stream)
+  : Sink<uint8_t>(), _stream(stream)
+{
+  // pass...
+}
+
+void
+BitDump::config(const Config &src_cfg) {
+  // Check if config is complete
+  if (!src_cfg.hasType()) { return; }
+
+  // Check if buffer type matches
+  if (Config::typeId<uint8_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure BitDump: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<int16_t>();
+    throw err;
+  }
+}
+
+void
+BitDump::process(const Buffer<uint8_t> &buffer, bool allow_overwrite) {
+  for (size_t i=0; i<buffer.size(); i++) {
+    _stream << int(buffer[i]) << " ";
+  }
+  _stream << std::endl;
+}
+
+

src/fsk.hh

@@ -0,0 +1,192 @@
+#ifndef __SDR_FSK_HH__
+#define __SDR_FSK_HH__
+
+#include "node.hh"
+#include "traits.hh"
+#include "logger.hh"
+
+
+namespace sdr {
+
+
+/** Implements the basic FSK/AFSK symbol detection.
+ * This node contains two FIR filters for the detection of the mark and space frequencies. The node
+ * returns a sequence of symbols (i.e. sub-bits) which need to be processed to obtain a sequenc of
+ * transmitted bits (i.e. by the @c BitStream node).
+ *
+ * @ingroup demods */
+class FSKDetector: public Sink<int16_t>, public Source
+{
+public:
+  /** Constructor.
+   * @param baud Specifies the baud-rate of the signal.
+   * @param Fmark Specifies the mark frequency in Hz.
+   * @param Fspace Specifies the space frequency in Hz. */
+  FSKDetector(float baud, float Fmark, float Fspace);
+
+  void config(const Config &src_cfg);
+  void process(const Buffer<int16_t> &buffer, bool allow_overwrite);
+
+protected:
+  /** Updates the mark/space FIR filter and returns the sampled symbol. */
+  uint8_t _process(int16_t sample);
+
+protected:
+  /** Baudrate of the transmission. Needed to compute the filter length of the FIR mark/space
+   * filters. */
+  float _baud;
+  /** The filter lenght. */
+  size_t  _corrLen;
+  /** The current FIR filter LUT index. */
+  size_t _lutIdx;
+  /** Mark "tone" frequency. */
+  float _Fmark;
+  /** Space "tone" frequency. */
+  float _Fspace;
+  /** Mark frequency FIR filter LUT. */
+  Buffer< std::complex<float> > _markLUT;
+  /** Space frequency FIR filter LUT. */
+  Buffer< std::complex<float> > _spaceLUT;
+  /** FIR filter buffer. */
+  Buffer< std::complex<float> > _markHist;
+  /** FIR filter buffer. */
+  Buffer< std::complex<float> > _spaceHist;
+  /** Output buffer. */
+  Buffer<int8_t> _buffer;
+};
+
+
+/** Rather trivial node to detect mark/space symbols by the amplitude.
+ * For low baud rates (i.e. <= 1200 baud) a FSK signal can be "demodulated" using a
+ * simple FM demodulator. The result will be a series of decaying exponentials. Hence the
+ * mark/space symbols can be determined by the means of the input amplitude (positive/negative).
+ *
+ * This node implements such a simple symbol detection by the means of the amplitude. The node
+ * returns a sequence of symbols (sub-bits) that need to be processed to obtain the sequence of
+ * received bits (i.e. @c BitStream).
+ *
+ * @ingroup demods */
+template <class Scalar>
+class ASKDetector: public Sink<Scalar>, public Source
+{
+public:
+  /** Constructor. */
+  ASKDetector(bool invert=false)
+    : Sink<Scalar>(), Source(), _invert(invert)
+  {
+    // pass...
+  }
+
+  void config(const Config &src_cfg) {
+    // Check if config is complete
+    if (!src_cfg.hasType() || !src_cfg.hasSampleRate()) { return; }
+
+    // Check if buffer type matches
+    if (Config::typeId<int16_t>() != src_cfg.type()) {
+      ConfigError err;
+      err << "Can not configure ASKDetector: Invalid type " << src_cfg.type()
+          << ", expected " << Config::typeId<int16_t>();
+      throw err;
+    }
+
+    // Allocate output buffer
+    _buffer = Buffer<uint8_t>(src_cfg.bufferSize());
+
+    LogMessage msg(LOG_DEBUG);
+    msg << "Config ASKDetector node: " << std::endl
+        << " threshold:   " << 0 << std::endl
+        << " invert:      " << ( _invert ? "yes" : "no" ) << std::endl
+        << " symbol rate: " << src_cfg.sampleRate() << " Hz";
+    Logger::get().log(msg);
+
+    // Forward config.
+    this->setConfig(Config(Traits<uint8_t>::scalarId, src_cfg.sampleRate(), _buffer.size(), 1));
+  }
+
+  void process(const Buffer<Scalar> &buffer, bool allow_overwrite) {
+    for (size_t i=0; i<buffer.size(); i++) {
+      _buffer[i] = ((buffer[i]>0)^_invert);
+    }
+    this->send(_buffer.head(buffer.size()), false);
+  }
+
+protected:
+  /** If true the symbol logic is inverted. */
+  bool _invert;
+  /** The output buffer. */
+  Buffer<uint8_t> _buffer;
+};
+
+
+/** Decodes a bitstream with the desired baud rate.
+ * This node implements a simple PLL to syncronize the bit sampling with the transitions
+ * of the input symbol sequence. */
+class BitStream: public Sink<uint8_t>, public Source
+{
+public:
+  /** Possible bit decoding modes. */
+  typedef enum {
+    NORMAL,      ///< Normal mode (i.e. mark -> 1, space -> 0).
+    TRANSITION   ///< Transition mode (i.e. transition -> 0, no transition -> 1).
+  } Mode;
+
+public:
+  /** Constructor.
+   * @param baud Specifies the baud-rate of the input signal.
+   * @param mode Specifies the bit detection mode. */
+  BitStream(float baud, Mode mode = TRANSITION);
+
+  void config(const Config &src_cfg);
+  void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
+
+protected:
+  /** The baud rate. */
+  float _baud;
+  /** The bit detection mode. */
+  Mode  _mode;
+  /** The approximative bit length in samples. */
+  size_t _corrLen;
+  /** Last received symbols. */
+  Buffer<int8_t> _symbols;
+  /** Insertion index for the next symbol. */
+  size_t _symIdx;
+  /** Sum over all received symbol (encoded as -1 & 1). */
+  int32_t _symSum;
+  /** Last sum over all received symbol (encoded as -1 & 1). */
+  int32_t _lastSymSum;
+  /** Current bit "phase". */
+  float _phase;
+  /** Phase velocity. */
+  float _omega;
+  /** Minimum phase velocity. */
+  float _omegaMin;
+  /** Maximum phase velocity. */
+  float _omegaMax;
+  /** PLL gain. */
+  float _pllGain;
+  /** The last decoded bits (needed for transition mode). */
+  uint8_t _lastBits;
+  /** Output buffer. */
+  Buffer<uint8_t> _buffer;
+};
+
+
+/** Trivial node to dump a bit-stream to a std::ostream.
+ * @ingroup sinks */
+class BitDump : public Sink<uint8_t>
+{
+public:
+  /** Constructor.
+   * @param stream Specifies the output stream. */
+  BitDump(std::ostream &stream);
+
+  void config(const Config &src_cfg);
+  void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
+
+protected:
+  /** The output stream. */
+  std::ostream &_stream;
+};
+
+}
+#endif // __SDR_FSK_HH__

src/http.hh

@@ -0,0 +1,627 @@
+/** @defgroup http A rather trivia HTTP daemon implementation.
+ *
+ * This module collects some classes allowing to implement a simple HTTP server to serve static
+ * and dynamic content. The central class is the @c Server class which dispatches incomming
+ * requests to the registered @c Handler instances.
+ *
+ * There are several specializations of the @c Handler class avaliable suited to perform specific
+ * tasks. I.e. the @c StaticHandler serves some static content (i.e. strings) while the
+ * @c DelegateJSONHandler allows to implement a REST api easily.
+ *
+ * An example of a server, serving a static index page and provides a trivial JSON echo method.
+ * \code
+ * #include "http.hh"
+ * #include "logger.hh"
+ *
+ * using namespace sdr;
+ *
+ * // Implements an application, a collection of methods being called by the http::Server.
+ * class Application {
+ * public:
+ *   // contstructor.
+ *   Application() {}
+ *
+ *   // The callback to handle the JSON echo api.
+ *   bool echo(const http::JSON &request, http::JSON &result) {
+ *     // just echo
+ *     result = request;
+ *     // signal success
+ *     return true;
+ *   }
+ * };
+ *
+ * // Static content
+ * const char *index_html = "<html> ... </html>";
+ *
+ *
+ * int main(int argc, char *argv[]) {
+ *   // install log handler
+ *   sdr::Logger::get().addHandler(
+ *      new sdr::StreamLogHandler(std::cerr, sdr::LOG_DEBUG));
+ *
+ *   // serve on port 8080
+ *   http::Server server(8080);
+ *
+ *   // Instantiate application
+ *   Application app;
+ *
+ *   // Register static content handlers
+ *   server.addStatic("/", index_html, "text/html");
+ *   // Register JSON echo method
+ *   server.addJSON("/echo", &app, &Application::echo);
+ *
+ *   // Start server
+ *   server.start(true);
+ *
+ *   return 0;
+ * }
+ * \endcode
+ */
+
+#ifndef __SDR_HTTPD_HH__
+#define __SDR_HTTPD_HH__
+
+#include <string>
+#include <sstream>
+#include <map>
+#include <set>
+#include <list>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+
+namespace sdr {
+namespace http {
+
+// Forward declarations
+class Server;
+
+
+/** Represents a JSON object.
+ * JSON is a popular means to implement remote procedure calls (RPCs) using java script. JSON is
+ * valid java script code and allows to transfer numbers, string, lists and objects.
+ * @ingroup http */
+class JSON
+{
+public:
+  /** Specifies the possible json types. */
+  typedef enum {
+    EMPTY,     ///< null.
+    BOOLEAN,   ///< A boolean value.
+    NUMBER,    ///< A number.
+    STRING,    ///< A string.
+    ARRAY,     ///< An array or list.
+    TABLE      ///< A table or object.
+  } Type;
+
+public:
+  /** Empty constructor (null). */
+  JSON();
+  /** Constructs a boolean value. */
+  JSON(bool value);
+  /** Constructs a number. */
+  JSON(double value);
+  /** Constructs a string. */
+  JSON(const std::string &value);
+  /** Constructs a list. */
+  JSON(const std::list<JSON> &list);
+  /** Constructs a table. */
+  JSON(const std::map<std::string, JSON> &table);
+  /** Copy constructor (deep copy). */
+  JSON(const JSON &other);
+  /** Destructor. */
+  ~JSON();
+  /** Assignment operator (deep copy). */
+  JSON &operator=(const JSON &other);
+
+  /** Retruns @c true for the null. */
+  inline bool isNull() const { return EMPTY == _type; }
+  /** Returns @c true if this is a boolean value. */
+  inline bool isBoolean() const { return BOOLEAN == _type; }
+  /** Returns the boolean value. */
+  inline const bool &asBoolean() const { return *_value.boolean; }
+  /** Returns @c true if this is a number. */
+  inline bool isNumber() const { return NUMBER == _type; }
+  /** Returns the number. */
+  inline const double &asNumber() const { return *_value.number; }
+  /** Returns @c true if this is a string. */
+  inline bool isString() const { return STRING == _type; }
+  /** Returns the string. */
+  inline const std::string &asString() const { return *_value.string; }
+  /** Returns @c true if this is an array. */
+  inline bool isArray() const { return ARRAY == _type; }
+  /** Retruns the array as a list. */
+  inline const std::list<JSON> &asArray() const { return *_value.list; }
+  /** Returns @c true if this is a table. */
+  inline bool isTable() const { return TABLE == _type; }
+  /** Returns the table. */
+  inline const std::map<std::string, JSON> &asTable() const { return *_value.table; }
+  /** Resets the JSON object to null. */
+  void clear();
+
+  /** Parses the given string. Retruns @c true on success. */
+  static bool parse(const std::string &text, JSON &obj);
+  /** Serializes the JSON object. */
+  void serialize(std::ostream &stream) const;
+  /** Serializes the JSON object. */
+  inline void serialize(std::string &text) const {
+    std::stringstream buffer; this->serialize(buffer);
+    text = buffer.str();
+  }
+
+protected:
+  /** The type of the object. */
+  Type _type;
+  /** Union of value pointers. */
+  union {
+    /** The boolean value. */
+    bool   *boolean;
+    /** The number. */
+    double *number;
+    /** The string. */
+    std::string *string;
+    /** The array. */
+    std::list<JSON> *list;
+    /** The table. */
+    std::map<std::string, JSON> *table;
+  } _value;
+};
+
+
+/** Lists the possible HTTP methods.
+ * @ingroup http */
+typedef enum {
+  HTTP_UNKNOWN,   ///< Unknown method. Results into an invalid request.
+  HTTP_GET,       ///< The get method.
+  HTTP_HEAD,      ///< The head method.
+  HTTP_POST       ///< The post method.
+} Method;
+
+/** Lists the possible HTTP versions.
+ * @ingroup http */
+typedef enum {
+  UNKNOWN_VERSION, ///< Unknown http version. Results into an invalid request.
+  HTTP_1_0,        ///< HTTP/1.0
+  HTTP_1_1         ///< HTTP/1.1
+} Version;
+
+
+/** Represents a URL.
+ * @ingroup http */
+class URL
+{
+public:
+  /** Empty constructor. */
+  URL();
+  /** Constructor from protocol, host and path. */
+  URL(const std::string &proto, const std::string &host, const std::string &path);
+  /** Copy constructor. */
+  URL(const URL &other);
+
+  /** Assignment operator. */
+  URL &operator=(const URL &other);
+
+  /** Parses a URL from the given string. */
+  static URL fromString(const std::string &url);
+  /** Serializes the URL into a string. */
+  std::string toString() const;
+
+  /** Encode a string. */
+  static std::string encode(const std::string &str);
+  /** Decodes a string. */
+  static std::string decode(const std::string &str);
+
+  /** Returns @c true if the URL specifies a protocol. */
+  inline bool hasProtocol() const { return (0 != _protocol.size()); }
+  /** Returns the protocol. */
+  inline const std::string protocol() const { return _protocol; }
+  /** Sets the protocol. */
+  inline void setProtocol(const std::string &proto) { _protocol = proto; }
+  /** Returns @c true if the URL specified a host name. */
+  inline bool hasHost() const { return (0 != _host.size()); }
+  /** Returns the host name. */
+  inline const std::string &host() const { return _host; }
+  /** Set the host name. */
+  inline void setHost(const std::string &host) { _host = host; }
+  /** Retruns the path of the URL. */
+  inline const std::string &path() const { return _path; }
+  /** Sets the path of the URL. */
+  inline void setPath(const std::string &path) { _path = path; }
+  /** Adds a query pair (key, value) to the URL. */
+  inline void addQuery(const std::string &name, const std::string &value) {
+    _query.push_back(std::pair<std::string, std::string>(name, value));
+  }
+  /** Returns the list of query (key, value) pairs. */
+  inline const std::list< std::pair<std::string, std::string> > &query() const {
+    return _query;
+  }
+
+protected:
+  /** Holds the protocol. */
+  std::string _protocol;
+  /** Holds the host name. */
+  std::string _host;
+  /** Holds the path. */
+  std::string _path;
+  /** Holds the query pairs. */
+  std::list< std::pair<std::string, std::string> > _query;
+};
+
+
+struct ConnectionObj
+{
+public:
+  ConnectionObj(Server *server, int cli_socket);
+  ~ConnectionObj();
+
+  ConnectionObj *ref();
+  void unref();
+
+public:
+  /** A weak reference to the server instance. */
+  Server *server;
+  /** The connection socket. */
+  int socket;
+  /** If @c true (i.e. set by a handler), the http parser thread will exit without closing
+   * the connection. This allows to "take-over" the tcp connection to the client by the request
+   * handler. */
+  bool protocol_upgrade;
+  /** Reference counter. */
+  size_t refcount;
+};
+
+
+/** Implements a HTTP connection to a client.
+ * @c ingroup http */
+class Connection
+{
+public:
+  /** Empty constructor. */
+  Connection();
+  /** Constructor. */
+  Connection(Server *server, int socket);
+  /** Copy constructor. Implements reference counting. */
+  Connection(const Connection &other);
+  /** Destructor. */
+  ~Connection();
+
+  Connection &operator=(const Connection &other);
+
+  /** Closes the connection.
+   * If @c wait is @c true, the method will wait until the thread listening for incomming
+   * request joined. */
+  void close(bool wait=false);
+  /** Returns @c true if the connection is closed. */
+  bool isClosed() const;
+
+  /** Sets the protocol-update flag. */
+  inline void setProtocolUpgrade() const { _object->protocol_upgrade = true; }
+  inline bool protocolUpgrade() const { return _object->protocol_upgrade; }
+
+  inline ssize_t write(const void *data, size_t n) const {
+    if (0 == _object) { return -1; }
+    return ::write(_object->socket, data, n);
+  }
+
+  inline ssize_t read(void *data, size_t n) const {
+    if (0 == _object) { return -1; }
+    return ::read(_object->socket, data, n);
+  }
+
+  bool send(const std::string &data) const;
+
+  /** Main loop for incomming requests. */
+  void main();
+
+protected:
+  ConnectionObj *_object;
+};
+
+
+/** Represents a HTTP request.
+ * @ingroup http */
+class Request
+{
+public:
+  /** Constructor. */
+  Request(const Connection &connection);
+
+  /** Parses the HTTP request header, returns @c true on success. */
+  bool parse();
+
+  /** Return the connection to the client. */
+  inline const Connection &connection() const { return _connection; }
+
+  /** Returns @c true if the connection to the client is kept alive after the response
+     * has been send. */
+  bool isKeepAlive() const;
+
+  /** Returns @c true if the given header is present. */
+  bool hasHeader(const std::string &name) const;
+  /** Returns the value of the given header. */
+  std::string header(const std::string &name) const;
+
+  /** Returns @c true if the Content-Length header is present. */
+  inline bool hasContentLength() const { return hasHeader("Content-Length"); }
+  /** Returns the value of the Content-Length header. */
+  size_t contentLength() const { return atol(header("Content-Length").c_str()); }
+
+  /** Retruns the request method. */
+  inline Method method() const { return _method; }
+  /** Returns the request URL. */
+  inline const URL &url() const { return _url; }
+  /** Reads the complete body (if Content-Length header is present).
+   * Retruns @c true on success.*/
+  bool readBody(std::string &body) const;
+
+protected:
+  /** The connection socket. */
+  Connection _connection;
+  /** The request method. */
+  Method _method;
+  /** The HTTP version. */
+  Version _version;
+  /** The request URL. */
+  URL _url;
+  /** The request headers. */
+  std::map<std::string, std::string> _headers;
+};
+
+
+/** Represents a HTTP response. */
+class Response
+{
+public:
+  /** Defines all possible responses. */
+  typedef enum {
+    STATUS_OK = 200,           ///< OK.
+    STATUS_BAD_REQUEST = 400,  ///< Your fault.
+    STATUS_NOT_FOUND = 404,    ///< Resource not found.
+    STATUS_SERVER_ERROR = 500  ///< My fault.
+  } Status;
+
+public:
+  /** Constructor. */
+  Response(const Connection &connnection);
+
+  /** Return the connection to the client. */
+  inline const Connection &connection() const { return _connection; }
+
+  /** Specifies the response code. */
+  void setStatus(Status status);
+  /** Returns @c true if the response has the given header. */
+  bool hasHeader(const std::string &name) const;
+  /** Returns the value of the header. */
+  std::string header(const std::string &name) const;
+  /** Sets the header. */
+  void setHeader(const std::string &name, const std::string &value);
+  /** Helper function to set the content length. */
+  void setContentLength(size_t length);
+
+  /** Sends the response code and all defined headers. */
+  bool sendHeaders() const;
+
+protected:
+  /** The socket over which the response will be send. */
+  Connection _connection;
+  /** The response code. */
+  Status _status;
+  /** The response headers. */
+  std::map<std::string, std::string> _headers;
+  /** If @c true, the connection will be closed after the response has been send. */
+  bool _close_connection;
+};
+
+
+/** Base class of all HTTP request handlers.
+ * @ingroup http */
+class Handler
+{
+protected:
+  /** Hidden constructor. */
+  Handler();
+
+public:
+  /** Destructor. */
+  virtual ~Handler();
+  /** Needs to be implemented to accept the given request.
+   * If this method returns @c true, the server will call the @c handle instance next
+   * in expectation that this instance will process the request. */
+  virtual bool match(const Request &request) = 0;
+  /** Needs to be implemented to process requests, which have been accepted by the @c match()
+   * method. */
+  virtual void handle(const Request &request, Response &response) = 0;
+};
+
+
+/** Serves some static content.
+ * @ingroup http */
+class StaticHandler: public Handler
+{
+public:
+  /** Constructor.
+   * @param url Specifies the URL (path) of the static content.
+   * @param text Speciefies the content.
+   * @param mimeType Speficies the mime-type of the content. */
+  StaticHandler(const std::string &url, const std::string &text,
+                const std::string mimeType="text/text");
+  /** Destructor. */
+  virtual ~StaticHandler();
+
+  bool match(const Request &request);
+  void handle(const Request &request, Response &response);
+
+protected:
+  /** Holds the URL (path) of the content. */
+  std::string _url;
+  /** Holds the mime-type of the content. */
+  std::string _mimeType;
+  /** Holds the content itself. */
+  std::string _text;
+};
+
+
+/** Utility class to provide a handler as a delegate.
+ * @ingroup http */
+template <class T>
+class DelegateHandler: public Handler
+{
+public:
+  /** Constructor.
+   * @param url Specifies the path of the handler.
+   * @param instance Specifies the instance of the delegate.
+   * @param func Specifies the method of the delegate instance being called. */
+  DelegateHandler(const std::string &url, T *instance, void (T::*func)(const Request &, Response &))
+    : Handler(), _url(url), _instance(instance), _callback(func)
+  {
+    // pass...
+  }
+
+  bool match(const Request &request) {
+    return this->_url == request.url().path();
+  }
+
+  void handle(const Request &request, Response &response) {
+    (this->_instance->*(this->_callback))(request, response);
+  }
+
+protected:
+  /** Holds the path of the handler. */
+  std::string _url;
+  /** Holds the instance of the delegate. */
+  T *_instance;
+  /** Holds the method of the instance being called. */
+  void (T::*_callback)(const Request &, Response &);
+};
+
+
+/** Implements a specialized handler to ease the processing of JSON REST-APIs.
+ * @ingroup http */
+class JSONHandler: public http::Handler
+{
+public:
+  /** Constructor.
+   * @param url Speficies the path of the method. */
+  JSONHandler(const std::string &url);
+
+  bool match(const http::Request &request);
+  void handle(const http::Request &request, http::Response &response);
+
+  /** Needs to be implemented to process the request and assemble the result.
+   * An error (400 BAD REQUEST) will be send if the function does not return @c true. */
+  virtual bool process(const JSON &request, JSON &result) = 0;
+
+protected:
+  /** The URL of the method. */
+  std::string _url;
+};
+
+
+/** A delegate JSON handler.
+ * @ingroup http */
+template <class T>
+class DelegateJSONHandler: public JSONHandler
+{
+public:
+  /** Constructor. */
+  DelegateJSONHandler(const std::string &url, T *instance,
+                      bool (T::*func)(const JSON &request, JSON &response))
+    : JSONHandler(url), _instance(instance), _callback(func)
+  {
+    // pass...
+  }
+
+  virtual bool process(const JSON &request, JSON &result) {
+    return (this->_instance->*(this->_callback))(request, result);
+  }
+
+protected:
+  /** The delegate instance. */
+  T *_instance;
+  /** The method to be called from the delegate instance. */
+  bool (T::*_callback)(const JSON &request, JSON &response);
+};
+
+
+/** Implements a trivial HTTP/1.1 server.
+ * @ingroup http */
+class Server
+{
+public:
+  /** Constructor.
+   * @param port Specifies the port number to listen on. */
+  Server(uint port);
+  /** Destructor. */
+  ~Server();
+
+  /** Starts the server.
+   * If @c wait is @c true, the call to this method will bock until the server thread stops. */
+  void start(bool wait=false);
+
+  /** Stops the server.
+   * If @c wait is @c true, the call will block until the server thread stopped. */
+  void stop(bool wait=false);
+
+  /** Wait for the server thread to join. */
+  void wait();
+
+  /** Adds a generic handler to the dispatcher. */
+  void addHandler(Handler *handler);
+  /** Adds a delegate to the dispatcher. */
+  template <class T>
+  void addHandler(const std::string &url,
+                  T *instance, void (T::*func)(const Request &, Response &)) {
+    addHandler(new DelegateHandler<T>(url, instance, func));
+  }
+  /** Adds a JSON delegate to the dispatcher. */
+  template <class T>
+  void addJSON(const std::string &url,
+               T *instance, bool (T::*func)(const JSON &request, JSON &result)) {
+    addHandler(new DelegateJSONHandler<T>(url, instance, func));
+  }
+  /** Adds some static content to the dispatcher. */
+  inline void addStatic(const std::string &url, const std::string &text) {
+    addHandler(new StaticHandler(url, text));
+  }
+  /** Adds a generic handler to the dispatcher. */
+  inline void addStatic(const std::string &url, const std::string &text, const std::string &mimeType) {
+    addHandler(new StaticHandler(url, text, mimeType));
+  }
+
+protected:
+  /** Dispatches a request. */
+  void dispatch(const Request &request, Response &response);
+  /** The thread waiting for incomming connections. */
+  static void *_listen_main(void *ctx);
+  /** The thread handling connections. */
+  static void *_connection_main(void *ctx);
+
+protected:
+  /** Port to bind to. */
+  uint _port;
+  /** The socket to listen on. */
+  int _socket;
+  /** While true, the server is listening on the port for incomming connections. */
+  bool _is_running;
+  /** The listen thread. */
+  pthread_t _thread;
+  /** All registered handler. */
+  std::list<Handler *> _handler;
+  /** The connection queue. */
+  std::list<Connection> _queue;
+  /** The queue lock. */
+  pthread_mutex_t _queue_lock;
+  /** The set of handler threads. */
+  std::set<pthread_t> _threads;
+
+  /* Allow Connection to access dispatch(). */
+  friend class Connection;
+};
+
+}
+
+}
+#endif // __SDR_HTTPD_HH__

src/logger.hh

@@ -8,16 +8,17 @@
 
 namespace sdr {
 
-/** Specifies the possible log-level. */
+/** Specifies the possible log levels. */
 typedef enum {
-  LOG_DEBUG,
-  LOG_INFO,
-  LOG_WARNING,
-  LOG_ERROR
+  LOG_DEBUG = 0,   ///< Every thing that may be of interest.
+  LOG_INFO,    ///< Messages about state changes.
+  LOG_WARNING, ///< Non critical errors (i.e. data loss).
+  LOG_ERROR    ///< Critical errors.
 } LogLevel;
 
 
-/** A log message. */
+/** A log message.
+ * Bundles a message with a level. */
 class LogMessage: public std::stringstream
 {
 public:
@@ -41,7 +42,7 @@ protected:
 };
 
 
-/** Base class of all log message handlers. */
+/** Base class of all log-message handlers. */
 class LogHandler
 {
 protected:
@@ -68,6 +69,7 @@ public:
   StreamLogHandler(std::ostream &stream, LogLevel level);
   /** Destructor. */
   virtual ~StreamLogHandler();
+
   /** Handles the message. */
   virtual void handle(const LogMessage &msg);
 
@@ -96,6 +98,7 @@ public:
 
   /** Logs a message. */
   void log(const LogMessage &message);
+
   /** Adds a message handler. The ownership of the hander is transferred to the logger
    *  instance. */
   void addHandler(LogHandler *handler);

src/math.hh

@@ -20,6 +20,7 @@ template <> inline int16_t fast_atan2<int8_t, int16_t>(int8_t a, int8_t b) {
   return (a >= 0) ? angle : -angle;
 }
 
+/** Implementation of atan2 approximation using integers. */
 template <> inline int16_t fast_atan2<uint8_t, int16_t>(uint8_t ua, uint8_t ub) {
   int8_t a = (int16_t(ua)-(1<<7));
   int8_t b = (int16_t(ub)-(1<<7));
@@ -28,7 +29,6 @@ template <> inline int16_t fast_atan2<uint8_t, int16_t>(uint8_t ua, uint8_t ub)
 
 /** Implementation of atan2 approximation using integers. */
 template <> inline int16_t fast_atan2<int16_t, int16_t>(int16_t a, int16_t b) {
-  //return (1<<15)*(std::atan2(float(a), float(b))/M_PI);
   const int32_t pi4 = (1<<12);
   const int32_t pi34 = 3*(1<<12);
   int32_t aabs, angle;

src/node.hh

@@ -1,3 +1,19 @@
+/** @defgroup sources Data sources.
+ * This module collects all data sources provided by libsdr.
+ *
+ * @defgroup sinks Data sinks.
+ * This module collects all data sinks provided by libsdr.
+ *
+ * @defgroup filters Filter and signal processing nodes.
+ * This group collects all filter and signal processing nodes provided by libsdr.
+ *
+ * @defgroup demods Demodulator nodes.
+ * This group collects all demodulation nodes.
+ *
+ * @defgroup datanodes Data handling nodes.
+ * This group collects all nodes related to data handling. I.e. type casts etc.
+ */
+
 #ifndef __SDR_NODE_HH__
 #define __SDR_NODE_HH__
 
@@ -294,7 +310,8 @@ private:
 };
 
 
-/** A NOP node. */
+/** A NOP node.
+ * @ingroup filters */
 class Proxy: public SinkBase, public Source
 {
 public:

src/pocsag.cc

@@ -0,0 +1,373 @@
+#include "pocsag.hh"
+#include "bch31_21.hh"
+#include "logger.hh"
+
+using namespace sdr;
+
+inline bool is_address(uint32_t word) {
+  return (0 == (0x80000000 & word));
+}
+
+
+/* ********************************************************************************************* *
+ * Implementation of POCSAG
+ * ********************************************************************************************* */
+POCSAG::POCSAG()
+  : Sink<uint8_t>()
+{
+  // pass...
+}
+
+void
+POCSAG::config(const Config &src_cfg) {
+  if (! src_cfg.hasType()) { return; }
+  // Check if buffer type matches
+  if (Config::typeId<uint8_t>() != src_cfg.type()) {
+    ConfigError err;
+    err << "Can not configure POCSAG: Invalid type " << src_cfg.type()
+        << ", expected " << Config::typeId<uint8_t>();
+    throw err;
+  }
+
+  LogMessage msg(LOG_DEBUG);
+  msg << "Config POCSAG node.";
+  Logger::get().log(msg);
+
+  _state = WAIT;
+  _bits  = 0;
+}
+
+void
+POCSAG::process(const Buffer<uint8_t> &buffer, bool allow_overwrite)
+{
+  for (size_t i=0; i<buffer.size(); i++)
+  {
+    // put bit into shift register
+    _bits = ( (_bits<<1) | (buffer[i] & 0x01) );
+
+    // Dispatch by state
+    if (WAIT == _state) {
+      // Wait for the sync word to appear
+      uint32_t word = (_bits & 0xffffffff);
+      if ( (0 == pocsag_repair(word)) && (0x7cd215d8 == word)) {
+        // init messages
+        _reset_message();
+        _state = RECEIVE; _bitcount = 0; _slot = 0;
+      }
+    } else if (RECEIVE == _state) {
+      // Receive 64 bit (2 words)
+      _bitcount++;
+      if (64 == _bitcount) {
+        _bitcount=0;
+
+        // get and check 1st word bits
+        uint32_t word = ( (_bits>>32) & 0xffffffff );
+        if (0 == pocsag_repair(word)) { _process_word(word); }
+
+        // get and check 2nd word bits
+        word = ( _bits & 0xffffffff );
+        if (0 == pocsag_repair(word)) { _process_word(word); }
+
+        // Advance slot counter
+        _slot++;
+        if (8 == _slot) {
+          // If all slots (8) has been processed -> wait for continuation
+          _state = CHECK_CONTINUE;
+        }
+      }
+    } else if (CHECK_CONTINUE == _state) {
+      // Wait for an immediate sync word
+      _bitcount++;
+      if (32 == _bitcount) {
+        uint32_t word = (_bits&0xffffffff);
+        if ( (0 == pocsag_repair(word)) && (0x7cd215d8 == word)) {
+          // If a sync word has been received -> continue with reception of slot 0
+          _state = RECEIVE; _slot = 0; _bitcount = 0;
+        } else {
+          // Otherwise -> end of transmission, wait for next sync
+          _finish_message(); _state = WAIT;
+          // Process received messages
+          this->handleMessages();
+        }
+      }
+    }
+  }
+}
+
+
+void
+POCSAG::_process_word(uint32_t word)
+{
+  /*std::cerr << "POCSAG: RX " << std::hex << word
+            << std::dec << " @ " << int(_slot) << std::endl; */
+
+
+  if (0x7A89C197 == word) {
+    // Skip
+    _finish_message();
+  } else if (is_address(word)) {
+    // If address word
+    _finish_message();
+    // Assemble address
+    uint32_t addr = ((((word>>13) & 0x03ffff)<<3) + _slot );
+    uint8_t  func = ((word>>11) & 0x03);
+    // init new message
+    _message = Message(addr, func);
+  } else {
+    // on data word
+    if (_message.isEmpty()) {
+      LogMessage msg(LOG_DEBUG);
+      msg << "POCSAG: Payload w/o address in slot " << int(_slot)
+          << " word: " << std::hex << word;
+      Logger::get().log(msg);
+    } else {
+      _message.addPayload(word);
+    }
+  }
+}
+
+
+void
+POCSAG::_reset_message() {
+  _message = Message();
+}
+
+void
+POCSAG::_finish_message() {
+  if (_message.isEmpty()) { return; }
+  _queue.push_back(_message);
+  _reset_message();
+}
+
+void
+POCSAG::handleMessages() {
+  // pass...
+}
+
+
+/* ********************************************************************************************* *
+ * Implementation of POCSAGDump
+ * ********************************************************************************************* */
+POCSAGDump::POCSAGDump(std::ostream &stream)
+  : POCSAG(), _stream(stream)
+{
+  // pass...
+}
+
+void
+POCSAGDump::handleMessages() {
+  // You may re-implement this virutal method to process the queued messages in _queue.
+  while (_queue.size()) {
+    Message msg = _queue.back(); _queue.pop_back();
+    std::cerr << "POCSAG: @" << msg.address()
+              << ", F=" << int(msg.function())
+              << ", bits=" << msg.bits();
+    if (0 == msg.bits()) {
+      std::cerr << " (alert)" << std::endl;
+    } else if (msg.estimateText() >= msg.estimateNumeric()) {
+      std::cerr << " (txt)" << std::endl << " " << msg.asText() << std::endl;
+    } else {
+      std::cerr << " (num)" << std::endl << " " << msg.asNumeric() << std::endl;
+    }
+  }
+}
+
+
+/* ********************************************************************************************* *
+ * Implementation of POCSAG::Message
+ * ********************************************************************************************* */
+std::string
+ascii2text(uint8_t byte) {
+  switch ( byte ) {
+  case  0: return "<NUL>";
+  case  1: return "<SOH>";
+  case  2: return "<STX>";
+  case  3: return "<ETX>";
+  case  4: return "<EOT>";
+  case  5: return "<ENQ>";
+  case  6: return "<ACK>";
+  case  7: return "<BEL>";
+  case  8: return "<BS>";
+  case  9: return "<HT>";
+  case 10: return "<LF>";
+  case 11: return "<VT>";
+  case 12: return "<FF>";
+  case 13: return "<CR>";
+  case 14: return "<SO>";
+  case 15: return "<SI>";
+  case 16: return "<DLE>";
+  case 17: return "<DC1>";
+  case 18: return "<DC2>";
+  case 19: return "<DC3>";
+  case 20: return "<DC4>";
+  case 21: return "<NAK>";
+  case 22: return "<SYN>";
+  case 23: return "<ETB>";
+  case 24: return "<CAN>";
+  case 25: return "<EM>";
+  case 26: return "<SUB>";
+  case 27: return "<ESC>";
+  case 28: return "<FS>";
+  case 29: return "<GS>";
+  case 30: return "<RS>";
+  case 31: return "<US>";
+  default: break;
+  }
+  std::string txt; txt.resize(1, char(byte));
+  return txt;
+}
+
+char
+bcd2text(uint8_t bcd) {
+  static const char *conv_table = "084 2.6]195-3U7[";
+  return conv_table[bcd&0xf];
+}
+
+int
+pocsag_text_weight(char c) {
+  if (c < 32 || c == 127) {
+    return -5; // Non printable characters are uncommon
+  }
+  if ( (c > 32 && c < 48)
+       || (c > 57 && c < 65)
+       || (c > 90 && c < 97)
+       || (c > 122 && c < 127) ) {
+    return -2; // Penalize special characters
+  }
+  return 1;
+}
+
+int
+pocsag_numeric_weight(char cp, size_t pos) {
+  if(cp == 'U')
+    return -10;
+  if(cp == '[' || cp == ']')
+    return -5;
+  if(cp == ' ' || cp == '.' || cp == '-')
+    return -2;
+  if(pos < 10) // Penalize long messages
+    return 5;
+  return 0;
+}
+
+
+POCSAG::Message::Message()
+  : _address(0), _function(0), _empty(true), _bits(0)
+{
+  // pass...
+}
+
+POCSAG::Message::Message(uint32_t addr, uint8_t func)
+  : _address(addr), _function(func), _empty(false), _bits(0)
+{
+  // pass...
+}
+
+POCSAG::Message::Message(const Message &other)
+  : _address(other._address), _function(other._function), _empty(other._empty),
+    _bits(other._bits), _payload(other._payload)
+{
+  // pass...
+}
+
+POCSAG::Message &
+POCSAG::Message::operator =(const Message &other) {
+  _address = other._address;
+  _function = other._function;
+  _empty = other._empty;
+  _bits = other._bits;
+  _payload = other._payload;
+  return *this;
+}
+
+void
+POCSAG::Message::addPayload(uint32_t word) {
+  // Add data bits from data to payload vector
+  uint32_t mask = 0x40000000;
+  for (int i=19; i>=0; i--) {
+    // on new byte -> add empty byte to payload
+    if (0 == (_bits % 8)) { _payload.push_back(0x00); }
+    // add bit to last byte of payload
+    _payload.back() = ((_payload.back()<<1) | ((word & mask)>>(i+11)));
+    // Increment bit counter and update mask
+    _bits++; mask = (mask>>1);
+  }
+}
+
+std::string
+POCSAG::Message::asText() const
+{
+  uint8_t byte = 0;
+  // Decode message
+  std::stringstream buffer;
+  for (size_t i=0; i<_bits; i++) {
+    size_t byteIdx = i/8;
+    size_t bitIdx  = (7-(i%8));
+    // add bit to byte (reverse order)
+    byte = ((byte>>1) | (((_payload[byteIdx]>>bitIdx) & 0x01) << 6));
+    if (6 == (i%7)) {
+      buffer << ascii2text(byte&0x7f);
+    }
+    //std::cerr << "byte " << byteIdx << " bit " << bitIdx << " ascii bit " << (i%7) << std::endl;
+  }
+  return buffer.str();
+}
+
+
+std::string
+POCSAG::Message::asNumeric() const
+{
+  // Get number of complete half-bytes in payload
+  size_t N = _bits/4;
+  // Decode message
+  std::stringstream buffer;
+  for (size_t i=0; i<(N/2); i++) {
+    buffer << bcd2text((_payload[i]>>4) & 0xf);
+    buffer << bcd2text((_payload[i]>>0) & 0xf);
+  }
+  if (N%2) {
+    buffer << bcd2text((_payload[N/2]>>0) & 0xf);
+  }
+  return buffer.str();
+}
+
+std::string
+POCSAG::Message::asHex() const {
+  std::stringstream buffer;
+  buffer << std::hex;
+  for (size_t i=0; i<_payload.size(); i++) {
+    buffer << int(_payload[i]);
+  }
+  return buffer.str();
+}
+
+int
+POCSAG::Message::estimateText() const {
+  int weight = 0;
+  uint8_t byte = 0;
+  for (size_t i=0; i<_bits; i++) {
+    size_t byteIdx = i/8;
+    size_t bitIdx  = (7-i%8);
+    // add bit to byte
+    byte = ((byte>>1) | (((_payload[byteIdx]>>bitIdx) & 0x01) << 6));
+    if (6 == i%7) {
+      weight += pocsag_text_weight(byte&0x7f);
+    }
+  }
+  return weight;
+}
+
+int
+POCSAG::Message::estimateNumeric() const {
+  int weight = 0;
+  // Get number of complete half-bytes in payload
+  size_t N = _bits/4;
+  for (size_t i=0; i<(N/2); i++) {
+    weight += pocsag_numeric_weight(bcd2text((_payload[i]>>4) & 0xf), i);
+    weight += pocsag_numeric_weight(bcd2text((_payload[i]>>0) & 0xf), i);
+  }
+  if (N%2) {
+    weight += pocsag_numeric_weight(bcd2text((_payload[N/2]>>0) & 0xf), N/2);
+  }
+  return weight;
+}

src/pocsag.hh

@@ -0,0 +1,154 @@
+#ifndef __SDR_POSAG_HH__
+#define __SDR_POSAG_HH__
+
+#include "node.hh"
+
+namespace sdr {
+
+/** Implements a POCSAG decoder.
+ * In conjecture with the @c FSKDetector or @c AFSDetector and the @c BitStream nodes, this node
+ * can be used to receive and process POCSAG (pages) messages.
+ *
+ * The POCSAG protocol is defined as followig:
+ *
+ *  1. at least 576 bits of alternating value (1 0 1 0 ...)
+ *  2. a 32-bit sync word (0x7CD215D8)
+ *  3. 2x8 data words (each 32 bit)
+ *  4. If data left to send -> continue with step 2
+ *
+ * Unused data words are send as 0x7A89C197. Each dataword is either a address word (bit 31 = 0)
+ * or message word (bit 31 = 1).
+ *
+ * In order to process the received message you need to override the @c handleMessages() method
+ * which gets called once a batch of messages has been received.
+ *
+ * @ingroup datanodes */
+class POCSAG: public Sink<uint8_t>
+{
+public:
+  /** A pocsag message.
+   * A pocsag message can be either a numeric message (i.e. phone numbers) or a text message.
+   * The transmitter knows which type a certain receiver expects, hence there is no information
+   * embedded into the actual message that determines the type. Hence a heuristic needs to be
+   * used in order to select the message type by the contents of the message. This is done using
+   * the @c estimateText and @c estimateNumeric functions. They return a weight in favor of one of
+   * the types. I.e. if estimateText() > estimateNumeric(), the message is likely to be a text
+   * message. Like any heuristic, this approach may fail.
+   * The message text is returned by @c asText() and the numeric data is returned by
+   * @c asNumeric(). Both methods return a @c std::string as the numeric message may also contain
+   * a very limited set of non-number symbols. */
+  class Message {
+  public:
+    /** Empty constructor. */
+    Message();
+    /** Constructor from address and function. */
+    Message(uint32_t addr, uint8_t func);
+    /** Copy constructor. */
+    Message(const Message &other);
+
+    /** Assignment operator. */
+    Message &operator=(const Message &other);
+
+    /** Retruns @c true if the message is empty (has no address). */
+    inline bool isEmpty() const { return _empty; }
+    /** Returns the address of the message. */
+    inline uint32_t address() const { return _address; }
+    /** Returns the function of the message. */
+    inline uint8_t function() const { return _function; }
+    /** Returns the number of data bits. */
+    inline uint32_t bits() const { return _bits; }
+
+    /** Adds some payload from the given POGSAC word. */
+    void addPayload(uint32_t word);
+
+    /** Retruns the "likelihood" that the message is a text message (actually a log-likelihood). */
+    int estimateText() const;
+    /** Retruns the "likelihood" that the message is a numeric message
+     * (actually a log-likelihood). */
+    int estimateNumeric() const;
+
+    /** Decodes the message as a text message. */
+    std::string asText() const;
+    /** Decodes the message as a numeric message. */
+    std::string asNumeric() const;
+    /** Dumps the payload. */
+    std::string asHex() const;
+
+  protected:
+    /** The address of the message. */
+    uint32_t             _address;
+    /** The function of the message. */
+    uint8_t              _function;
+    /** If @c true the message is empty. */
+    bool                 _empty;
+    /** The number of payload bits in the message. */
+    uint32_t             _bits;
+    /** The actual payload. */
+    std::vector<uint8_t> _payload;
+  };
+
+protected:
+  /** The possible states of the POGSAC receiver. */
+  typedef enum {
+    WAIT,           ///< Wait for a sync word.
+    RECEIVE,        ///< Receive data.
+    CHECK_CONTINUE  ///< Wait for the sync word for continuation.
+  } State;
+
+public:
+  /** Constructor. */
+  POCSAG();
+
+  void config(const Config &src_cfg);
+  void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
+
+  /** Can be overwritten by any other implementation to process the received messages
+   * stored in @c _queue. */
+  virtual void handleMessages();
+
+protected:
+  /** Process a POGSAC word. */
+  void _process_word(uint32_t word);
+  /** Clear the message. */
+  void _reset_message();
+  /** Add the (non-empty) message to the queue. */
+  void _finish_message();
+
+protected:
+  /** The current state. */
+  State    _state;
+  /** The last received bits. */
+  uint64_t _bits;
+  /** The number of received bits. */
+  uint8_t  _bitcount;
+  /** The current slot. */
+  uint8_t  _slot;
+  /** The current message. */
+  Message _message;
+  /** The completed messages. */
+  std::list<Message> _queue;
+};
+
+
+/** A simple extention of the @c POCSAG node that prints the received messages to a
+ * @c std::ostream.
+ * @ingroup datanodes */
+class POCSAGDump: public POCSAG
+{
+public:
+  /** Constructor.
+   * @param stream Specifies the stream, the received messages are serialized into. */
+  POCSAGDump(std::ostream &stream);
+
+  /** Dumps the received messages. */
+  void handleMessages();
+
+protected:
+  /** The output stream. */
+  std::ostream &_stream;
+};
+
+
+}
+
+#endif // __SDR_POSAG_HH__

src/portaudio.hh

@@ -33,7 +33,8 @@ public:
 };
 
 
-/** PortAudio playback node. */
+/** PortAudio playback node.
+ * @ingroup sinks */
 class PortSink: public SinkBase
 {
 public:
@@ -55,7 +56,8 @@ protected:
 };
 
 
-/** PortAudio input stream as a @c Source. */
+/** PortAudio input stream as a @c Source.
+ * @ingroup sources */
 template <class Scalar>
 class PortSource: public Source
 {
@@ -70,7 +72,12 @@ public:
   }
 
   /** Destructor. */
-  virtual ~PortSource() { if (0 != _stream) { Pa_CloseStream(_stream); } }
+  virtual ~PortSource() {
+    // close stream
+    if (0 != _stream) { Pa_CloseStream(_stream); }
+    // unref buffer
+    _buffer.unref();
+  }
 
   /** Reads (blocking) the next buffer from the PortAudio stream. This function can be
    * connected to the idle event of the @c Queue. */

src/psk31.hh

@@ -8,10 +8,11 @@
 
 namespace sdr {
 
-/** A simple BPSK31 "demodulator". This node consumes a complex input stream with a sample-rate of
- * at least 2000Hz and produces a bitstream with 31.25 Hz "sample-rate". Use the @c Varicode node
+/** A simple BPSK31 "demodulator". This node consumes a complex input stream with a sample rate of
+ * at least 2000Hz and produces a bitstream with 31.25 Hz "sample rate". Use the @c Varicode node
  * to decode this bitstream to ASCII chars. The BPSK31 signal should be centered around 0Hz. This
- * node uses a simple PLL to adjust for small detunings. */
+ * node uses a simple PLL to adjust for small detunings.
+ * @ingroup demods */
 template <class Scalar>
 class BPSK31: public Sink< std::complex<Scalar> >, public Source
 {
@@ -62,7 +63,10 @@ public:
 
   /** Destructor. */
   virtual ~BPSK31() {
-    // pass...
+    // unreference buffers
+    _dl.unref();
+    _hist.unref();
+    _buffer.unref();
   }
 
   virtual void config(const Config &src_cfg)
@@ -290,7 +294,8 @@ protected:
 
 /** Simple varicode (Huffman code) decoder node. It consumes a bit-stream (uint8_t)
  * and produces a uint8_t stream of ascii chars. Non-printable chars (except for new-line) are
- * ignored. The output stream has no samplerate! */
+ * ignored. The output stream has no samplerate!
+ * @ingroup datanodes */
 class Varicode: public Sink<uint8_t>, public Source
 {
 public:

src/rtlsource.cc

@@ -105,7 +105,7 @@ RTLSource::setGain(double gain) {
 
 void
 RTLSource::start() {
-  pthread_create(&_thread, 0, RTLSource::__rtl_srd_parallel_main, this);
+  pthread_create(&_thread, 0, RTLSource::__rtl_sdr_parallel_main, this);
 }
 
 void
@@ -131,7 +131,7 @@ RTLSource::deviceName(size_t idx) {
 
 
 void *
-RTLSource::__rtl_srd_parallel_main(void *ctx) {
+RTLSource::__rtl_sdr_parallel_main(void *ctx) {
   RTLSource *self = reinterpret_cast<RTLSource *>(ctx);
   rtlsdr_read_async(self->_device, &RTLSource::__rtl_sdr_callback, self,
                     15, self->_buffer_size*2);

src/rtlsource.hh

@@ -8,7 +8,11 @@
 
 namespace sdr {
 
-/** Implements a @c uint_8 I/Q source for RTL2832 based TV dongles. */
+/** Implements a @c uint_8 I/Q source for RTL2832 based TV dongles.
+ * This source runs in its own thread, hence the user does not need to trigger the reception of
+ * the next data chunk explicitly. The reception is started by calling the @c start method and
+ * stopped by calling the @c stop method.
+ * @ingroup sources */
 class RTLSource: public Source
 {
 public:
@@ -18,14 +22,15 @@ public:
    * @c enableAGC and @c setGain methods.
    *
    * @param frequency Specifies the tuner frequency.
-   * @param sample_rate Specifies the sample rate.
-   * @param device_idx Specifies the device to be used. */
+   * @param sample_rate Specifies the sample rate in Hz.
+   * @param device_idx Specifies the device to be used. The @c numDevices
+   *        and @c deviceName static method can be used to select the desired device index. */
   RTLSource(double frequency, double sample_rate=1e6, size_t device_idx=0);
 
   /** Destructor. */
   virtual ~RTLSource();
 
-  /** Returns the freuency of the tuner. */
+  /** Returns the tuner frequency. */
   inline double frequency() const { return _frequency; }
   /** (Re-) Sets the tuner frequency. */
   void setFrequency(double frequency);
@@ -64,8 +69,8 @@ public:
   static std::string deviceName(size_t idx);
 
 protected:
-  /** Prallel routine to receive some data from the device. */
-  static void *__rtl_srd_parallel_main(void *ctx);
+  /** Parallel routine to receive some data from the device. */
+  static void *__rtl_sdr_parallel_main(void *ctx);
   /** Callback to process received data. */
   static void __rtl_sdr_callback(unsigned char *buffer, uint32_t len, void *ctx);
 

src/sdr.hh

@@ -290,6 +290,10 @@
 
 #include "demod.hh"
 #include "psk31.hh"
+#include "fsk.hh"
+#include "baudot.hh"
+#include "ax25.hh"
+#include "pocsag.hh"
 
 #include "fftplan.hh"
 

src/sha1.cc

@@ -0,0 +1,189 @@
+/* This code is public-domain - it is based on libcrypt
+ * placed in the public domain by Wei Dai and other contributors.
+ */
+// gcc -Wall -DSHA1TEST -o sha1test sha1.c && ./sha1test
+
+#include "sha1.hh"
+#include <stdint.h>
+#include <string.h>
+
+using namespace sdr;
+
+#ifdef __BIG_ENDIAN__
+# define SHA_BIG_ENDIAN
+#elif defined __LITTLE_ENDIAN__
+/* override */
+#elif defined __BYTE_ORDER
+# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__
+# define SHA_BIG_ENDIAN
+# endif
+#else // ! defined __LITTLE_ENDIAN__
+# include <endian.h> // machine/endian.h
+# if __BYTE_ORDER__ ==  __ORDER_BIG_ENDIAN__
+#  define SHA_BIG_ENDIAN
+# endif
+#endif
+
+
+
+
+/* code */
+#define SHA1_K0  0x5a827999
+#define SHA1_K20 0x6ed9eba1
+#define SHA1_K40 0x8f1bbcdc
+#define SHA1_K60 0xca62c1d6
+
+void
+sdr::sha1_init(sha1 *s) {
+	s->state[0] = 0x67452301;
+	s->state[1] = 0xefcdab89;
+	s->state[2] = 0x98badcfe;
+	s->state[3] = 0x10325476;
+	s->state[4] = 0xc3d2e1f0;
+	s->byteCount = 0;
+	s->bufferOffset = 0;
+}
+
+uint32_t
+sha1_rol32(uint32_t number, uint8_t bits) {
+	return ((number << bits) | (number >> (32-bits)));
+}
+
+void
+sha1_hashBlock(sha1 *s) {
+	uint8_t i;
+	uint32_t a,b,c,d,e,t;
+
+	a=s->state[0];
+	b=s->state[1];
+	c=s->state[2];
+	d=s->state[3];
+	e=s->state[4];
+	for (i=0; i<80; i++) {
+		if (i>=16) {
+			t = s->buffer[(i+13)&15] ^ s->buffer[(i+8)&15] ^ s->buffer[(i+2)&15] ^ s->buffer[i&15];
+			s->buffer[i&15] = sha1_rol32(t,1);
+		}
+		if (i<20) {
+			t = (d ^ (b & (c ^ d))) + SHA1_K0;
+		} else if (i<40) {
+			t = (b ^ c ^ d) + SHA1_K20;
+		} else if (i<60) {
+			t = ((b & c) | (d & (b | c))) + SHA1_K40;
+		} else {
+			t = (b ^ c ^ d) + SHA1_K60;
+		}
+		t+=sha1_rol32(a,5) + e + s->buffer[i&15];
+		e=d;
+		d=c;
+		c=sha1_rol32(b,30);
+		b=a;
+		a=t;
+	}
+	s->state[0] += a;
+	s->state[1] += b;
+	s->state[2] += c;
+	s->state[3] += d;
+	s->state[4] += e;
+}
+
+void
+sha1_addUncounted(sha1 *s, uint8_t data) {
+	uint8_t * const b = (uint8_t*) s->buffer;
+#ifdef SHA_BIG_ENDIAN
+	b[s->bufferOffset] = data;
+#else
+	b[s->bufferOffset ^ 3] = data;
+#endif
+	s->bufferOffset++;
+  if (s->bufferOffset == SDR_SHA1_BLOCK_LENGTH) {
+		sha1_hashBlock(s);
+		s->bufferOffset = 0;
+	}
+}
+
+void
+sdr::sha1_writebyte(sha1 *s, uint8_t data) {
+	++s->byteCount;
+	sha1_addUncounted(s, data);
+}
+
+void
+sdr::sha1_write(sha1 *s, const char *data, size_t len) {
+	for (;len--;) sha1_writebyte(s, (uint8_t) *data++);
+}
+
+void
+sha1_pad(sha1 *s) {
+	// Implement SHA-1 padding (fips180-2 §5.1.1)
+
+	// Pad with 0x80 followed by 0x00 until the end of the block
+	sha1_addUncounted(s, 0x80);
+	while (s->bufferOffset != 56) sha1_addUncounted(s, 0x00);
+
+	// Append length in the last 8 bytes
+	sha1_addUncounted(s, 0); // We're only using 32 bit lengths
+	sha1_addUncounted(s, 0); // But SHA-1 supports 64 bit lengths
+	sha1_addUncounted(s, 0); // So zero pad the top bits
+	sha1_addUncounted(s, s->byteCount >> 29); // Shifting to multiply by 8
+	sha1_addUncounted(s, s->byteCount >> 21); // as SHA-1 supports bitstreams as well as
+	sha1_addUncounted(s, s->byteCount >> 13); // byte.
+	sha1_addUncounted(s, s->byteCount >> 5);
+	sha1_addUncounted(s, s->byteCount << 3);
+}
+
+uint8_t*
+sdr::sha1_result(sha1 *s) {
+	// Pad to complete the last block
+	sha1_pad(s);
+
+#ifndef SHA_BIG_ENDIAN
+	// Swap byte order back
+	int i;
+	for (i=0; i<5; i++) {
+		s->state[i]=
+			  (((s->state[i])<<24)& 0xff000000)
+			| (((s->state[i])<<8) & 0x00ff0000)
+			| (((s->state[i])>>8) & 0x0000ff00)
+			| (((s->state[i])>>24)& 0x000000ff);
+	}
+#endif
+
+	// Return pointer to hash (20 characters)
+	return (uint8_t*) s->state;
+}
+
+#define HMAC_IPAD 0x36
+#define HMAC_OPAD 0x5c
+
+void
+sdr::sha1_initHmac(sha1 *s, const uint8_t* key, int keyLength) {
+	uint8_t i;
+  memset(s->keyBuffer, 0,SDR_SHA1_BLOCK_LENGTH);
+  if (keyLength >SDR_SHA1_BLOCK_LENGTH) {
+		// Hash long keys
+		sha1_init(s);
+		for (;keyLength--;) sha1_writebyte(s, *key++);
+    memcpy(s->keyBuffer, sha1_result(s),SDR_SHA1_HASH_LENGTH);
+	} else {
+		// Block length keys are used as is
+		memcpy(s->keyBuffer, key, keyLength);
+	}
+	// Start inner hash
+	sha1_init(s);
+  for (i=0; i<SDR_SHA1_BLOCK_LENGTH; i++) {
+		sha1_writebyte(s, s->keyBuffer[i] ^ HMAC_IPAD);
+	}
+}
+
+uint8_t*
+sdr::sha1_resultHmac(sha1 *s) {
+	uint8_t i;
+	// Complete inner hash
+  memcpy(s->innerHash,sha1_result(s), SDR_SHA1_HASH_LENGTH);
+	// Calculate outer hash
+	sha1_init(s);
+  for (i=0; i<SDR_SHA1_BLOCK_LENGTH; i++) sha1_writebyte(s, s->keyBuffer[i] ^ HMAC_OPAD);
+  for (i=0; i<SDR_SHA1_HASH_LENGTH; i++) sha1_writebyte(s, s->innerHash[i]);
+	return sha1_result(s);
+}

src/sha1.hh

@@ -0,0 +1,44 @@
+#ifndef __SDR_SHA1_HH__
+#define __SDR_SHA1_HH__
+
+#include <memory.h>
+#include <inttypes.h>
+
+namespace sdr {
+
+/* header */
+
+#define SDR_SHA1_HASH_LENGTH 20
+#define SDR_SHA1_BLOCK_LENGTH 64
+
+typedef struct {
+  uint32_t buffer[SDR_SHA1_BLOCK_LENGTH/4];
+  uint32_t state[SDR_SHA1_HASH_LENGTH/4];
+  uint32_t byteCount;
+  uint8_t bufferOffset;
+  uint8_t keyBuffer[SDR_SHA1_BLOCK_LENGTH];
+  uint8_t innerHash[SDR_SHA1_HASH_LENGTH];
+} sha1;
+
+/**
+ */
+void sha1_init(sha1 *s);
+/**
+ */
+void sha1_writebyte(sha1 *s, uint8_t data);
+/**
+ */
+void sha1_write(sha1 *s, const char *data, size_t len);
+/**
+ */
+uint8_t* sha1_result(sha1 *s);
+/**
+ */
+void sha1_initHmac(sha1 *s, const uint8_t* key, int keyLength);
+/**
+ */
+uint8_t* sha1_resultHmac(sha1 *s);
+
+}
+
+#endif // __SDR_SHA1_HH__

src/siggen.hh

@@ -6,7 +6,8 @@
 
 namespace sdr {
 
-/** Arbitrary function generator. */
+/** Arbitrary function generator.
+ * @ingroup sources */
 template <class Scalar>
 class SigGen: public Source
 {
@@ -83,7 +84,8 @@ protected:
 
 
 
-/** Arbitrary function generator. */
+/** Arbitrary function generator.
+ * @ingroup sources */
 template <class Scalar>
 class IQSigGen: public Source
 {

src/subsample.hh

@@ -10,7 +10,8 @@
 
 namespace sdr {
 
-/** Simple averaging sub-sampler. */
+/** Simple averaging sub-sampler.
+ * @ingroup filters */
 template <class Scalar>
 class SubSample: public Sink<Scalar>, public Source
 {
@@ -188,7 +189,8 @@ protected:
 /** An interpolating sub-sampler. This node uses an 8-tap FIR filter to interpolate between
  * two values (given 8). Please do not use this node to subsample by a factor grater than 8,
  * as this may result into artifacts unless the signal was filtered accordingly before
- * subsampling it. */
+ * subsampling it.
+ * @ingroup filters */
 template <class iScalar, class oScalar = iScalar>
 class InpolSubSampler: public Sink<iScalar>, public Source
 {

src/utils.cc

@@ -185,3 +185,34 @@ SignedToUnsigned::_process_int16(const RawBuffer &in, const RawBuffer &out) {
   }
   this->send(RawBuffer(out, 0, num), true);
 }
+
+
+/* ********************************************************************************************* *
+ * Implementation of TextDump
+ * ********************************************************************************************* */
+TextDump::TextDump(std::ostream &stream)
+  : Sink<uint8_t>(), _stream(stream)
+{
+  // pass...
+}
+
+void
+TextDump::config(const Config &src_cfg) {
+  // Requires type
+  if (!src_cfg.hasType()) { return; }
+  if (src_cfg.type() != Traits<uint8_t>::scalarId) {
+    ConfigError err;
+    err << "Can not configure TextDump node: Invalid input type " << src_cfg.type()
+        << ", expected " << Config::Type_u8 << ".";
+    throw err;
+  }
+  // done
+}
+
+void
+TextDump::process(const Buffer<uint8_t> &buffer, bool allow_overwrite) {
+  for (size_t i=0; i<buffer.size(); i++) {
+    _stream << char(buffer[i]);
+  }
+}
+

src/utils.hh

@@ -11,7 +11,8 @@
 
 namespace sdr {
 
-/** Extracts the real or imaginary part of a complex valued data stream. */
+/** Extracts the real or imaginary part of a complex valued data stream.
+ * @ingroup datanodes */
 template <class Scalar>
 class RealImagPart: public Sink< std::complex<Scalar> >, public Source
 {
@@ -76,7 +77,8 @@ protected:
 };
 
 
-/** Selects the real part of a complex signal. */
+/** Selects the real part of a complex signal.
+ * @ingroup datanodes */
 template <class Scalar>
 class RealPart: public RealImagPart<Scalar>
 {
@@ -90,7 +92,8 @@ public:
 };
 
 
-/** Selects the imaginary part of a complex signal. */
+/** Selects the imaginary part of a complex signal.
+ * @ingroup datanodes */
 template <class Scalar>
 class ImagPart: public RealImagPart<Scalar>
 {
@@ -104,7 +107,8 @@ public:
 };
 
 
-/** A simple node, that allows to balance an IQ signal. */
+/** A simple node, that allows to balance an IQ signal.
+ * @ingroup filters */
 template <class Scalar>
 class IQBalance: public Sink< std::complex<Scalar> >, public Source
 {
@@ -201,7 +205,8 @@ protected:
 
 
 /** Tiny helper node to transform a real part into a complex, including
- * a possible type-cast*/
+ * a possible type-cast
+ * @ingroup datanodes */
 template <class iScalar, class oScalar=iScalar>
 class ToComplex: public Sink<iScalar>, public Source
 {
@@ -256,7 +261,8 @@ protected:
 
 
 
-/** Explicit type cast node. */
+/** Explicit type cast node.
+ * @ingroup datanodes */
 template <class iScalar, class oScalar>
 class Cast : public Sink<iScalar>, public Source
 {
@@ -361,7 +367,8 @@ protected:
 
 
 
-/** Performs a reinterprete cast from an unsinged value to a singed one. */
+/** Performs a reinterprete cast from an unsinged value to a singed one.
+ * @ingroup datanodes */
 class UnsignedToSigned: public SinkBase, public Source
 {
 public:
@@ -392,7 +399,8 @@ protected:
 
 
 
-/** Performs a reinterprete cast from an unsinged value to a singed one. */
+/** Performs a reinterprete cast from an unsinged value to a singed one.
+ * @ingroup datanodes */
 class SignedToUnsigned: public SinkBase, public Source
 {
 public:
@@ -423,7 +431,8 @@ protected:
 /** Performs a frequency shift on a complex input signal, by multiplying it with \f$e^{i\omega t}\f$.
  * Please note, this node performs not optimal in cases, where the input scalar is an integer, as
  * the computation is performed using double precision floating point numbers.
- * @deprecated Implement a more efficient variant using FreqShiftBase. */
+ * @deprecated Implement a more efficient variant using FreqShiftBase.
+ * @ingroup filters */
 template <class Scalar>
 class FreqShift: public Sink< std::complex<Scalar> >, public Source
 {
@@ -510,7 +519,8 @@ protected:
 };
 
 
-/** Reads raw samples from an imput stream, (ie a file). */
+/** Reads raw samples from an imput stream, (ie a file).
+ * @ingroup sources */
 template<class Scalar>
 class StreamSource: public Source
 {
@@ -541,7 +551,8 @@ protected:
 };
 
 
-/** Serializes the incomming buffers as raw data. */
+/** Serializes the incomming buffers as raw data.
+ * @ingroup sinks */
 template <class Scalar>
 class StreamSink: public Sink<Scalar>
 {
@@ -579,7 +590,8 @@ protected:
 
 
 
-/** Simple scaling node. */
+/** Simple scaling node.
+ * @ingroup filters */
 template <class Scalar>
 class Scale : public Sink<Scalar>, public Source
 {
@@ -640,7 +652,8 @@ protected:
 
 
 
-/** An automatic gain control node. */
+/** An automatic gain control node.
+ * @ingroup filters */
 template <class Scalar>
 class AGC: public Sink<Scalar>, public Source
 {
@@ -780,7 +793,8 @@ protected:
 };
 
 
-/** Keeps a copy of the last buffer received. */
+/** Keeps a copy of the last buffer received.
+ * @ingroup sinks */
 template <class Scalar>
 class DebugStore: public Sink<Scalar>
 {
@@ -827,7 +841,8 @@ public:
 };
 
 
-/** Dumps buffers in a human readable form. */
+/** Dumps buffers in a human readable form.
+ * @ingroup sinks*/
 template <class Scalar>
 class DebugDump: public Sink<Scalar>
 {
@@ -868,8 +883,26 @@ protected:
   std::ostream &_stream;
 };
 
+/** Dumps the received uin8_t byte-stream as (ASCII) text.
+ * @ingroup sink */
+class TextDump : public Sink<uint8_t>
+{
+public:
+  /** Constructor. @c stream specifies the ouput stream. */
+  TextDump(std::ostream &stream=std::cerr);
+  /** Configures the sink. */
+  virtual void config(const Config &src_cfg);
+  /** Processes the input stream. */
+  virtual void process(const Buffer<uint8_t> &buffer, bool allow_overwrite);
 
-/** A Gaussian White Noise source. */
+protected:
+  /** The output stream. */
+  std::ostream &_stream;
+};
+
+
+/** A Gaussian White Noise source.
+ * @ingroup sources */
 template <class Scalar>
 class GWNSource: public Source
 {

src/wavfile.cc

@@ -135,7 +135,7 @@ WavSource::open(const std::string &filename)
   _file.read((char *)&chunk_size, 4); // read frame count
 
   // Configure source
-  _frame_count = chunk_size/(2*n_chanels);
+  _frame_count = chunk_size/(n_chanels*(bits_per_sample/8));
   if ((1 == n_chanels) && (8 == bits_per_sample)) { _type = Config::Type_u8; }
   else if ((1==n_chanels) && (16 == bits_per_sample)) { _type = Config::Type_s16; }
   else if ((2==n_chanels) && ( 8 == bits_per_sample)) { _type = Config::Type_cu8; }
@@ -150,7 +150,7 @@ WavSource::open(const std::string &filename)
   LogMessage msg(LOG_DEBUG);
   msg << "Configured WavSource:" << std::endl
       << " file: " << filename << std::endl
-      << " type:"  << _type << std::endl
+      << " type: "  << _type << std::endl
       << " sample-rate: " << _sample_rate << std::endl
       << " frame-count: " << _frame_count << std::endl
       << " duration: " << _frame_count/_sample_rate << "s" << std::endl

src/wavfile.hh

@@ -6,7 +6,8 @@
 
 namespace sdr {
 
-/** Stores the received buffers into a WAV file. */
+/** Stores the received buffers into a WAV file.
+ * @ingroup sinks */
 template <class Scalar>
 class WavSink: public Sink<Scalar>
 {
@@ -127,7 +128,8 @@ protected:
 
 
 /** A simple imput source that reads from a wav file. Some data is read from the file on every call
- * to  @c next until the end of file is reached. */
+ * to  @c next until the end of file is reached.
+ * @ingroup sources */
 class WavSource: public Source
 {
 public: