swresample: add swr_is_initialized()

Idea-from/based-on: 7e86c27b4ee9e5a3fbe6cf5249b9d918b2a5e731
Reviewed-by: ubitux
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

doc/APIchanges

@@ -15,6 +15,9 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2014-02-xx - xxxxxxx - lswr 0.18.100 - swresample.h
+  Add swr_is_initialized() for checking whether a resample context is initialized.
+
 2014-02-xx - xxxxxxx - lavr 1.2.0 - avresample.h
   Add avresample_is_open() for checking whether a resample context is open.
 

libswresample/swresample.c

@@ -733,6 +733,10 @@ static int swr_convert_internal(struct SwrContext *s, AudioData *out, int out_co
     return out_count;
 }
 
+int swr_is_initialized(struct SwrContext *s) {
+    return !!s->in_buffer.ch_count;
+}
+
 int swr_convert(struct SwrContext *s, uint8_t *out_arg[SWR_CH_MAX], int out_count,
                                 const uint8_t *in_arg [SWR_CH_MAX], int  in_count){
     AudioData * in= &s->in;

libswresample/swresample.h

@@ -165,6 +165,13 @@ struct SwrContext *swr_alloc(void);
  */
 int swr_init(struct SwrContext *s);
 
+/**
+ * Check whether an swr context has been initialized or not.
+ *
+ * @return positive if it has been initialized, 0 if not initialized
+ */
+int swr_is_initialized(struct SwrContext *s);
+
 /**
  * Allocate SwrContext if needed and set/reset common parameters.
  *

libswresample/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBSWRESAMPLE_VERSION_MAJOR 0
-#define LIBSWRESAMPLE_VERSION_MINOR 17
-#define LIBSWRESAMPLE_VERSION_MICRO 104
+#define LIBSWRESAMPLE_VERSION_MINOR 18
+#define LIBSWRESAMPLE_VERSION_MICRO 100
 
 #define LIBSWRESAMPLE_VERSION_INT  AV_VERSION_INT(LIBSWRESAMPLE_VERSION_MAJOR, \
                                                   LIBSWRESAMPLE_VERSION_MINOR, \