lavd/avdevice: add device iterators

Signed-off-by: Lukasz Marek <lukasz.m.luki@gmail.com>

doc/APIchanges

@@ -15,6 +15,12 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2014-xx-xx - xxxxxx - lavd 55.11.100 - avdevice.h
+  Add av_input_audio_device_next().
+  Add av_input_video_device_next().
+  Add av_output_audio_device_next().
+  Add av_output_video_device_next().
+
 2014-xx-xx - xxxxxxx - lavu 53.05.0 - frame.h
   Add av_frame_copy() for copying the frame data.
 

libavdevice/avdevice.c

@@ -37,6 +37,52 @@ const char * avdevice_license(void)
     return LICENSE_PREFIX FFMPEG_LICENSE + sizeof(LICENSE_PREFIX) - 1;
 }
 
+static void *av_device_next(void *prev, int output,
+                            AVClassCategory c1, AVClassCategory c2)
+{
+    const AVClass *pc;
+    AVClassCategory category = AV_CLASS_CATEGORY_NA;
+    do {
+        if (output) {
+            if (!(prev = av_oformat_next(prev)))
+                break;
+            pc = ((AVOutputFormat *)prev)->priv_class;
+        } else {
+            if (!(prev = av_iformat_next(prev)))
+                break;
+            pc = ((AVInputFormat *)prev)->priv_class;
+        }
+        if (!pc)
+            continue;
+        category = pc->category;
+    } while (category != c1 && category != c2);
+    return prev;
+}
+
+AVInputFormat *av_input_audio_device_next(AVInputFormat  *d)
+{
+    return av_device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT,
+                          AV_CLASS_CATEGORY_DEVICE_INPUT);
+}
+
+AVInputFormat *av_input_video_device_next(AVInputFormat  *d)
+{
+    return av_device_next(d, 0, AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
+                          AV_CLASS_CATEGORY_DEVICE_INPUT);
+}
+
+AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d)
+{
+    return av_device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT,
+                          AV_CLASS_CATEGORY_DEVICE_OUTPUT);
+}
+
+AVOutputFormat *av_output_video_device_next(AVOutputFormat *d)
+{
+    return av_device_next(d, 1, AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT,
+                          AV_CLASS_CATEGORY_DEVICE_OUTPUT);
+}
+
 int avdevice_app_to_dev_control_message(struct AVFormatContext *s, enum AVAppToDevMessageType type,
                                         void *data, size_t data_size)
 {

libavdevice/avdevice.h

@@ -66,6 +66,42 @@ const char *avdevice_license(void);
  */
 void avdevice_register_all(void);
 
+/**
+ * Audio input devices iterator.
+ *
+ * If d is NULL, returns the first registered input audio/video device,
+ * if d is non-NULL, returns the next registered input audio/video device after d
+ * or NULL if d is the last one.
+ */
+AVInputFormat *av_input_audio_device_next(AVInputFormat  *d);
+
+/**
+ * Video input devices iterator.
+ *
+ * If d is NULL, returns the first registered input audio/video device,
+ * if d is non-NULL, returns the next registered input audio/video device after d
+ * or NULL if d is the last one.
+ */
+AVInputFormat *av_input_video_device_next(AVInputFormat  *d);
+
+/**
+ * Audio output devices iterator.
+ *
+ * If d is NULL, returns the first registered output audio/video device,
+ * if d is non-NULL, returns the next registered output audio/video device after d
+ * or NULL if d is the last one.
+ */
+AVOutputFormat *av_output_audio_device_next(AVOutputFormat *d);
+
+/**
+ * Video output devices iterator.
+ *
+ * If d is NULL, returns the first registered output audio/video device,
+ * if d is non-NULL, returns the next registered output audio/video device after d
+ * or NULL if d is the last one.
+ */
+AVOutputFormat *av_output_video_device_next(AVOutputFormat *d);
+
 typedef struct AVDeviceRect {
     int x;      /**< x coordinate of top left corner */
     int y;      /**< y coordinate of top left corner */

libavdevice/version.h

@@ -28,7 +28,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVDEVICE_VERSION_MAJOR  55
-#define LIBAVDEVICE_VERSION_MINOR  10
+#define LIBAVDEVICE_VERSION_MINOR  11
 #define LIBAVDEVICE_VERSION_MICRO 100
 
 #define LIBAVDEVICE_VERSION_INT AV_VERSION_INT(LIBAVDEVICE_VERSION_MAJOR, \