Add (empty) Android OpenSL ES backend

CMakeLists.txt

@@ -36,6 +36,7 @@ option(ENABLE_PULSEAUDIO "Enable PulseAudio backend" ON)
 option(ENABLE_ALSA "Enable ALSA backend" ON)
 option(ENABLE_COREAUDIO "Enable CoreAudio backend" ON)
 option(ENABLE_WASAPI "Enable WASAPI backend" ON)
+option(ENABLE_ANDROID "Enable Android OpenSL ES backend" ON)
 
 find_package(Threads)
 if(Threads_FOUND)
@@ -138,6 +139,21 @@ else()
     set(SOUNDIO_HAVE_WASAPI false)
 endif()
 
+if(ENABLE_ANDROID)
+    find_package(AndroidOpenSLES)
+    if(ANDROID_OPENSLES_FOUND)
+        set(STATUS_ANDROID "OK")
+        set(SOUNDIO_HAVE_ANDROID true)
+    else()
+        set(STATUS_ANDROID "not found")
+        set(SOUNDIO_HAVE_ANDROID false)
+        set(ANDROID_OPENSLES_LIBRARY "")
+    endif()
+else()
+    set(STATUS_ANDROID "disabled")
+    set(SOUNDIO_HAVE_ANDROID false)
+    set(ANDROID_OPENSLES_LIBRARY "")
+endif()
 
 set(LIBSOUNDIO_SOURCES
     "${libsoundio_SOURCE_DIR}/src/soundio.c"
@@ -179,6 +195,11 @@ if(SOUNDIO_HAVE_WASAPI)
         "${libsoundio_SOURCE_DIR}/src/wasapi.c"
     )
 endif()
+if(SOUNDIO_HAVE_ANDROID)
+    set(LIBSOUNDIO_SOURCES ${LIBSOUNDIO_SOURCES}
+        "${libsoundio_SOURCE_DIR}/src/android.c"
+    )
+endif()
 
 include_directories(
     ${libsoundio_SOURCE_DIR}
@@ -195,6 +216,7 @@ set(LIBSOUNDIO_LIBS
     ${COREFOUNDATION_LIBRARY}
     ${AUDIOUNIT_LIBRARY}
     ${CMAKE_THREAD_LIBS_INIT}
+    ${ANDROID_OPENSLES_LIBRARY}
 )
 
 if(MSVC)
@@ -380,9 +402,10 @@ message(
     "System Dependencies\n"
     "-------------------\n"
     "* threads                      : ${STATUS_THREADS}\n"
-    "* JACK       (optional)        : ${STATUS_JACK}\n"
+    "* JACK              (optional) : ${STATUS_JACK}\n"
-    "* PulseAudio (optional)        : ${STATUS_PULSEAUDIO}\n"
+    "* PulseAudio        (optional) : ${STATUS_PULSEAUDIO}\n"
-    "* ALSA       (optional)        : ${STATUS_ALSA}\n"
+    "* ALSA              (optional) : ${STATUS_ALSA}\n"
-    "* CoreAudio  (optional)        : ${STATUS_COREAUDIO}\n"
+    "* CoreAudio         (optional) : ${STATUS_COREAUDIO}\n"
-    "* WASAPI     (optional)        : ${STATUS_WASAPI}\n"
+    "* WASAPI            (optional) : ${STATUS_WASAPI}\n"
+    "* Android OpenSL ES (optional) : ${STATUS_ANDROID}\n"
 )

cmake/FindAndroidOpenSLES.cmake

@@ -0,0 +1,16 @@
+# Copyright (c) 2016 libsoundio
+# This file is MIT licensed.
+# See http://opensource.org/licenses/MIT
+
+# ANDROID_OPENSLES_FOUND
+# ANDROID_OPENSLES_INCLUDE_DIR
+# ANDROID_OPENSLES_LIBRARY
+
+find_path(ANDROID_OPENSLES_INCLUDE_DIR NAMES SLES/OpenSLES_Android.h)
+
+find_library(ANDROID_OPENSLES_LIBRARY NAMES OpenSLES)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(ANDROID_OPENSLES DEFAULT_MSG ANDROID_OPENSLES_LIBRARY ANDROID_OPENSLES_INCLUDE_DIR)
+
+mark_as_advanced(ANDROID_OPENSLES_INCLUDE_DIR ANDROID_OPENSLES_LIBRARY)

soundio/soundio.h

@@ -223,6 +223,7 @@ enum SoundIoBackend {
     SoundIoBackendAlsa,
     SoundIoBackendCoreAudio,
     SoundIoBackendWasapi,
+    SoundIoBackendAndroid
 };
 
 enum SoundIoDeviceAim {

src/android.c

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) 2016 libsoundio
+ *
+ * This file is part of libsoundio, which is MIT licensed.
+ * See http://opensource.org/licenses/MIT
+ */
+
+#include "android.h"
+#include "soundio_private.h"
+
+enum SoundIoError soundio_android_init(struct SoundIoPrivate *si) {
+    return SoundIoErrorInitAudioBackend;
+}

src/android.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2016 libsoundio
+ *
+ * This file is part of libsoundio, which is MIT licensed.
+ * See http://opensource.org/licenses/MIT
+ */
+
+#ifndef SOUNDIO_ANDROID_H
+#define SOUNDIO_ANDROID_H
+
+#include "soundio_internal.h"
+
+struct SoundIoPrivate;
+enum SoundIoError soundio_android_init(struct SoundIoPrivate *si);
+
+#endif

src/config.h.in

@@ -18,5 +18,6 @@
 #cmakedefine SOUNDIO_HAVE_ALSA
 #cmakedefine SOUNDIO_HAVE_COREAUDIO
 #cmakedefine SOUNDIO_HAVE_WASAPI
+#cmakedefine SOUNDIO_HAVE_ANDROID
 
 #endif

src/soundio.c

@@ -29,6 +29,9 @@ static const enum SoundIoBackend available_backends[] = {
 #endif
 #ifdef SOUNDIO_HAVE_WASAPI
     SoundIoBackendWasapi,
+#endif
+#ifdef SOUNDIO_HAVE_ANDROID
+    SoundIoBackendAndroid,
 #endif
     SoundIoBackendDummy,
 };
@@ -67,6 +70,12 @@ static backend_init_t backend_init_fns[] = {
     NULL,
 #endif
 
+#ifdef SOUNDIO_HAVE_ANDROID
+    soundio_android_init,
+#else
+    NULL,
+#endif
+
     &soundio_dummy_init,
 };
 
@@ -165,6 +174,7 @@ const char *soundio_backend_name(enum SoundIoBackend backend) {
         case SoundIoBackendAlsa: return "ALSA";
         case SoundIoBackendCoreAudio: return "CoreAudio";
         case SoundIoBackendWasapi: return "WASAPI";
+        case SoundIoBackendAndroid: return "Android OpenSL ES";
         case SoundIoBackendDummy: return "Dummy";
     }
     return "(invalid backend)";

src/soundio_private.h

@@ -32,6 +32,10 @@
 #include "wasapi.h"
 #endif
 
+#ifdef SOUNDIO_HAVE_ANDROID
+#include "android.h"
+#endif
+
 #include "dummy.h"
 
 union SoundIoBackendData {