fifo: add av_fifo_grow()

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

3 files changed, 25 insertions, 1 deletions

diff --git a/libavutil/avutil.h b/libavutil/avutil.h
index 2491264e35..d80393bece 100644
--- a/libavutil/avutil.h
+++ b/libavutil/avutil.h
@@ -153,7 +153,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 51
-#define LIBAVUTIL_VERSION_MINOR 51
+#define LIBAVUTIL_VERSION_MINOR 52
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
diff --git a/libavutil/fifo.c b/libavutil/fifo.c
index d1d9ba8003..47328c4585 100644
--- a/libavutil/fifo.c
+++ b/libavutil/fifo.c
@@ -79,6 +79,19 @@ int av_fifo_realloc2(AVFifoBuffer *f, unsigned int new_size)
     return 0;
 }
 
+int av_fifo_grow(AVFifoBuffer *f, unsigned int size)
+{
+    unsigned int old_size = f->end - f->buffer;
+    if(size + (unsigned)av_fifo_size(f) < size)
+        return AVERROR(EINVAL);
+
+    size += av_fifo_size(f);
+
+    if (old_size < size)
+        return av_fifo_realloc2(f, FFMAX(size, 2*size));
+    return 0;
+}
+
 // src must NOT be const as it can be a context for func that may need updating (like a pointer or byte counter)
 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int))
 {
diff --git a/libavutil/fifo.h b/libavutil/fifo.h
index 22a9aa5d18..515f0980a7 100644
--- a/libavutil/fifo.h
+++ b/libavutil/fifo.h
@@ -103,6 +103,17 @@ int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void
 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
 
 /**
+ * Enlarge an AVFifoBuffer.
+ * In case of reallocation failure, the old FIFO is kept unchanged.
+ * The new fifo size may be larger than the requested size.
+ *
+ * @param f AVFifoBuffer to resize
+ * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
+ * @return <0 for failure, >=0 otherwise
+ */
+int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
+
+/**
  * Read and discard the specified amount of data from an AVFifoBuffer.
  * @param f AVFifoBuffer to read from
  * @param size amount of data to read in bytes