In apt-X stub library export symbols as weak

CMakeLists.txt

@@ -31,16 +31,20 @@ endif()
 if(WITH_SNDFILE)
 	find_package(PkgConfig REQUIRED)
 	pkg_check_modules(SNDFile REQUIRED IMPORTED_TARGET sndfile)
-	add_definitions(-DWITH_SNDFILE=1)
 endif()
 
-include(GNUInstallDirs)
+configure_file(
+	${CMAKE_CURRENT_SOURCE_DIR}/config.h.in
+	${CMAKE_CURRENT_BINARY_DIR}/config.h
+	@ONLY)
 
-add_definitions(-DPACKAGE_NAME="${PROJECT_NAME}")
-add_definitions(-DPACKAGE_VERSION="${PROJECT_VERSION}")
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
+add_definitions(-DHAVE_CONFIG_H=1)
 
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include)
 
+include(GNUInstallDirs)
+
 if(ENABLE_DOC)
 	add_subdirectory(doc)
 endif()

README.md

@@ -25,6 +25,15 @@ make && make install
 - `WITH_FFMPEG` - use FFmpeg as a back-end (otherwise, stub library will be built)
 - `WITH_SNDFILE` - read file formats supported by libsndfile (used by openaptx utils)
 
+In the apt-X stub library (build without FFmpeg back-end), all symbols are exported as
+[weak](https://en.wikipedia.org/wiki/Weak_symbol). As a consequence, it should be possible to
+overwrite them during runtime with other library which exports strong symbols. However, it might
+be required to define `LD_DYNAMIC_WEAK` environment variable - for more information consult
+`ld.so` manual.
+
+When reverse-engineered libraries were enabled, they will be automatically linked with the apt-X
+stub library (build without FFmpeg back-end). See previous paragraph for the meaning of this.
+
 ## Benchmark
 
 Below is the result of a small benchmark test performed with various apt-X encoding libraries.

config.h.in

@@ -0,0 +1,10 @@
+/* config.h - Generated from config.h.in by CMake */
+
+/* Define to 1 if FFmpeg is enabled. */
+#cmakedefine WITH_FFMPEG 1
+
+/* Define to 1 if SNDFile is enabled. */
+#cmakedefine WITH_SNDFILE 1
+
+#define PACKAGE_NAME "@PROJECT_NAME@"
+#define PACKAGE_VERSION "@PROJECT_VERSION@"

src/CMakeLists.txt

@@ -10,6 +10,34 @@ set_target_properties(aptxHD PROPERTIES
 	PUBLIC_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/../include/openaptx.h)
 target_compile_definitions(aptxHD PRIVATE -DAPTXHD=1)
 
+if(ENABLE_APTX422)
+	add_library(aptx-4.2.2 SHARED
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/encode.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/params.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/processor.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/qmf.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/quantizer.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/search.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/main.c)
+	set_target_properties(aptx-4.2.2 PROPERTIES
+		PRIVATE_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/../include/aptx422.h)
+	install(TARGETS aptx-4.2.2)
+endif()
+
+if(ENABLE_APTXHD100)
+	add_library(aptxHD-1.0.0 SHARED
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/encode.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/params.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/processor.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/qmf.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/quantizer.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/search.c
+		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/main.c)
+	set_target_properties(aptxHD-1.0.0 PROPERTIES
+		PRIVATE_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/../include/aptxHD100.h)
+	install(TARGETS aptxHD-1.0.0)
+endif()
+
 if(WITH_FFMPEG)
 
 	target_sources(aptx
@@ -37,6 +65,11 @@ else()
 		${CMAKE_CURRENT_BINARY_DIR}/sample-sonar.c
 		${CMAKE_CURRENT_SOURCE_DIR}/aptx-stub.c)
 
+	if(ENABLE_APTX422)
+		# use reverse-engineered library as an encoding backend
+		target_link_libraries(aptx aptx-4.2.2)
+	endif()
+
 	add_custom_command(
 		DEPENDS bin2array ${SAMPLE_SONAR_APTX_HD}
 		COMMAND bin2array sample_sonar_aptx_hd ${SAMPLE_SONAR_APTX_HD} > sample-sonar-hd.c
@@ -46,35 +79,12 @@ else()
 		${CMAKE_CURRENT_BINARY_DIR}/sample-sonar-hd.c
 		${CMAKE_CURRENT_SOURCE_DIR}/aptx-stub.c)
 
+	if(ENABLE_APTXHD100)
+		# use reverse-engineered library as an encoding backend
+		target_link_libraries(aptxHD PRIVATE aptxHD-1.0.0)
+	endif()
+
 endif()
 
 install(TARGETS aptx aptxHD
 	PUBLIC_HEADER DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
-
-if(ENABLE_APTX422)
-	add_library(aptx422 SHARED
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/encode.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/params.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/processor.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/qmf.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/quantizer.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/search.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptx422/main.c)
-	set_target_properties(aptx422 PROPERTIES
-		PRIVATE_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/../include/aptx422.h)
-	install(TARGETS aptx422)
-endif()
-
-if(ENABLE_APTXHD100)
-	add_library(aptxHD100 SHARED
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/encode.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/params.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/processor.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/qmf.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/quantizer.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/search.c
-		${CMAKE_CURRENT_SOURCE_DIR}/aptxhd100/main.c)
-	set_target_properties(aptxHD100 PROPERTIES
-		PRIVATE_HEADER ${CMAKE_CURRENT_SOURCE_DIR}/../include/aptxHD100.h)
-	install(TARGETS aptxHD100)
-endif()

src/aptx-stub.c

@@ -73,6 +73,7 @@ struct internal_ctx {
 	bool swap;
 };
 
+__attribute__ ((weak))
 int _aptxenc_init_(APTXENC enc, bool swap) {
 
 	static bool banner = true;
@@ -93,6 +94,7 @@ int _aptxenc_init_(APTXENC enc, bool swap) {
 	return 0;
 }
 
+__attribute__ ((weak))
 int _aptxdec_init_(APTXDEC dec, bool swap) {
 
 	static bool banner = true;
@@ -113,17 +115,21 @@ int _aptxdec_init_(APTXDEC dec, bool swap) {
 	return 0;
 }
 
+__attribute__ ((weak))
 void _aptxenc_destroy_(APTXENC enc) {
 	(void)enc;
 }
 
+__attribute__ ((weak))
 void _aptxdec_destroy_(APTXDEC dec) {
 	(void)dec;
 }
 
 #if APTXHD
+__attribute__ ((weak))
 int _aptxenc_encode_(APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint32_t code[2]) {
 #else
+__attribute__ ((weak))
 int _aptxenc_encode_(APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4], uint16_t code[2]) {
 #endif
 
@@ -155,8 +161,10 @@ int _aptxenc_encode_(APTXENC enc, const int32_t pcmL[4], const int32_t pcmR[4],
 }
 
 #if APTXHD
+__attribute__ ((weak))
 int _aptxdec_decode_(APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint32_t code[2]) {
 #else
+__attribute__ ((weak))
 int _aptxdec_decode_(APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint16_t code[2]) {
 #endif
 	(void)code;
@@ -172,30 +180,37 @@ int _aptxdec_decode_(APTXDEC dec, int32_t pcmL[4], int32_t pcmR[4], const uint16
 	return 0;
 }
 
+__attribute__ ((weak))
 const char *_aptxenc_build_(void) {
 	return PACKAGE_NAME "-stub-" PACKAGE_VERSION;
 }
 
+__attribute__ ((weak))
 const char *_aptxdec_build_(void) {
 	return PACKAGE_NAME "-stub-" PACKAGE_VERSION;
 }
 
+__attribute__ ((weak))
 const char *_aptxenc_version_(void) {
 	return PACKAGE_VERSION;
 }
 
+__attribute__ ((weak))
 const char *_aptxdec_version_(void) {
 	return PACKAGE_VERSION;
 }
 
+__attribute__ ((weak))
 size_t _aptxenc_size_(void) {
 	return sizeof(struct internal_ctx);
 }
 
+__attribute__ ((weak))
 size_t _aptxdec_size_(void) {
 	return sizeof(struct internal_ctx);
 }
 
+__attribute__ ((weak))
 APTXENC _aptxenc_new_(bool swap) {
 	static struct internal_ctx ctx;
 	if (_aptxenc_init_(&ctx, swap) != 0)

test/CMakeLists.txt

@@ -5,7 +5,7 @@ if(ENABLE_APTX422)
 
 	add_library(qualcomm_libaptx SHARED IMPORTED)
 	set_target_properties(qualcomm_libaptx PROPERTIES
-		IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/3rdparty/libbt-aptX-ARM-4.2.2.so)
+		IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/archive/armv7/libbt-aptX-ARM-4.2.2.so)
 
 	add_executable(heval422 EXCLUDE_FROM_ALL
 		${PROJECT_SOURCE_DIR}/src/aptx422/encode.c
@@ -25,7 +25,7 @@ if(ENABLE_APTXHD100)
 
 	add_library(qualcomm_libaptxHD SHARED IMPORTED)
 	set_target_properties(qualcomm_libaptxHD PROPERTIES
-		IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/3rdparty/libaptXHD_encoder.so)
+		IMPORTED_LOCATION ${PROJECT_SOURCE_DIR}/archive/armv7/libaptXHD-1.0.0-rel-Android21-ARMv7A.so)
 
 	add_executable(hevalhd100 EXCLUDE_FROM_ALL
 		${PROJECT_SOURCE_DIR}/src/aptxhd100/encode.c
@@ -37,6 +37,6 @@ if(ENABLE_APTXHD100)
 		${CMAKE_CURRENT_SOURCE_DIR}/inspect-hd100.c
 		${CMAKE_CURRENT_SOURCE_DIR}/inspect-utils.c
 		${CMAKE_CURRENT_SOURCE_DIR}/heval-hd100.c)
-	target_link_libraries(heval422 qualcomm_libaptxHD)
+	target_link_libraries(hevalhd100 qualcomm_libaptxHD)
 
 endif()