Add device_fd argument

.gitignore

@@ -0,0 +1,3 @@
+cmake-build-debug/
+/.idea/
+/build/

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "airspy"]
+	path = airspy
+	url = https://github.com/airspy/airspyone_host

CMakeLists.txt

@@ -0,0 +1,25 @@
+project(adsbdec)
+
+cmake_minimum_required(VERSION 3.10)
+set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
+include(FindPackageHandleStandardArgs)
+
+add_library(
+        adsbdec-lib
+        demod.c
+        crc.c
+        output.c
+        air.c
+        valid.c
+)
+
+add_subdirectory(airspy)
+
+find_package(LIBUSB REQUIRED)
+
+include_directories(${LIBUSB_INCLUDE_DIR})
+include_directories(airspy/libairspy/src)
+
+add_executable(adsbdec main.c)
+target_link_libraries(adsbdec-lib m airspy-static ${LIBUSB_LIBRARIES})
+target_link_libraries(adsbdec adsbdec-lib)

air.c

@@ -23,12 +23,13 @@
 #include <string.h>
 #include <fcntl.h>
 #include <time.h>
-#include <libairspy/airspy.h>
+#include <airspy.h>
 #include "adsbdec.h"
 
 #define AIR_SAMPLE_RATE 20000000
 
 int gain = 18;
+int device_fd = -1;
 uint32_t ampbuff[APBUFFSZ];
 
 #define DECOFFSET (240*PULSEW)
@@ -94,7 +95,12 @@ int initAirspy(void)
 	struct timespec tp;
 
 	/* init airspy */
-	result = airspy_open(&device);
+    if (device_fd == -1) {
+        result = airspy_open(&device);
+    } else {
+        result = airspy_open_fd(&device, device_fd);
+    }
+
 	if (result != AIRSPY_SUCCESS) {
 		fprintf(stderr, "airspy_open() failed: %s (%d)\n", airspy_error_name(result),
 			result);

cmake/FindLIBUSB.cmake

@@ -0,0 +1,37 @@
+# - Try to find the freetype library
+# Once done this defines
+#
+#  LIBUSB_FOUND - system has libusb
+#  LIBUSB_INCLUDE_DIR - the libusb include directory
+#  LIBUSB_LIBRARIES - Link these to use libusb
+
+# Copyright (c) 2006, 2008  Laurent Montel, <montel@kde.org>
+#
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING-CMAKE-SCRIPTS file.
+
+
+if (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)
+
+  # in cache already
+  set(LIBUSB_FOUND TRUE)
+
+else (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)
+
+  find_package(PkgConfig)
+  if(PKG_CONFIG_FOUND)
+    pkg_check_modules(PC_LIBUSB libusb-1.0)
+  endif(PKG_CONFIG_FOUND)
+
+  FIND_PATH(LIBUSB_INCLUDE_DIR libusb.h
+    PATHS ${PC_LIBUSB_INCLUDEDIR} ${PC_LIBUSB_INCLUDE_DIRS})
+
+  FIND_LIBRARY(LIBUSB_LIBRARIES NAMES usb-1.0
+    PATHS ${PC_LIBUSB_LIBDIR} ${PC_LIBUSB_LIBRARY_DIRS})
+
+  include(FindPackageHandleStandardArgs)
+  FIND_PACKAGE_HANDLE_STANDARD_ARGS(LIBUSB DEFAULT_MSG LIBUSB_LIBRARIES LIBUSB_INCLUDE_DIR)
+
+  MARK_AS_ADVANCED(LIBUSB_INCLUDE_DIR LIBUSB_LIBRARIES)
+
+endif (LIBUSB_INCLUDE_DIR AND LIBUSB_LIBRARIES)

crc.c

@@ -18,7 +18,7 @@
  */
 #include <stddef.h>
 #include <inttypes.h>
-#include <crc.h>
+#include "crc.h"
 
 static const uint32_t error_table[112] = {
 	0x3935ea, 0x1c9af5, 0xf1b77e, 0x78dbbf, 0xc397db, 0x9e31e9, 0xb0e2f0, 0x587178,

main.c

@@ -27,6 +27,7 @@ extern int outmode;
 extern int outformat;
 extern char *filename;
 extern int gain;
+extern int device_fd;
 
 extern int df, errcorr;
 
@@ -37,7 +38,7 @@ extern void print_stats(void);
 static void usage(void)
 {
 	printf("adsbdec airspy ADSB decoder 1.0 Copyright (c) 2018 Thierry Leconte  \n\n");
-	printf("usage : adsbdec [-d] [-c] [-e] [-m] [-b] [-g 0-21 ] [-f filename] [-s addr[:port]] [-l addr[:port]]\n\n");
+	printf("usage : adsbdec [-d] [-c] [-e] [-m] [-b] [-g 0-21 ] [-f filename] [-s addr[:port]] [-l addr[:port]] [-D device]\n\n");
 	printf
 	    ("By default receive samples from airspy and output long adsb frames in raw avr format on stdout\n");
 	printf("Options :\n");
@@ -49,7 +50,7 @@ static void usage(void)
 	printf("\t-f : input from filename instead of airspy (raw signed 16 bits real format)\n");
 	printf ("\t-s addr[:port] : send ouput via TCP to server at address addr:port (default port : 30001)\n");
 	printf ("\t-l addr[:port] : listen to addr:port (default port : 30002) and accept a TCP connection where to send output \n");
-
+    printf("\t-D device : specify the device file descriptor to use\n");
 }
 
 int main(int argc, char **argv)
@@ -58,7 +59,7 @@ int main(int argc, char **argv)
 	struct sigaction sigact;
 
 
-	while ((c = getopt(argc, argv, "cf:s:l:g:demb")) != EOF) {
+	while ((c = getopt(argc, argv, "cf:s:l:g:dembD:")) != EOF) {
 		switch (c) {
 		case 'f':
 			filename = optarg;
@@ -86,6 +87,9 @@ int main(int argc, char **argv)
 		case 'b':
 			outformat = 2;
 			break;
+        case 'D':
+            device_fd = atoi(optarg);
+            break;
 		default:
 			usage();
 			return 1;