Add a av_grow_packet function, to be used by code that merges

palette and video data packets to get rid of PaletteControl.

Originally committed as revision 25776 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/avcodec.h

@@ -32,7 +32,7 @@
 #include "libavutil/cpu.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 52
-#define LIBAVCODEC_VERSION_MINOR 96
+#define LIBAVCODEC_VERSION_MINOR 97
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
@@ -3026,6 +3026,14 @@ int av_new_packet(AVPacket *pkt, int size);
  */
 void av_shrink_packet(AVPacket *pkt, int size);
 
+/**
+ * Increase packet size, correctly zeroing padding
+ *
+ * @param pkt packet
+ * @param grow_by number of bytes by which to increase the size of the packet
+ */
+int av_grow_packet(AVPacket *pkt, int grow_by);
+
 /**
  * @warning This is a hack - the packet memory allocation stuff is broken. The
  * packet is allocated if it was not really allocated.

libavcodec/avpacket.c

@@ -20,6 +20,7 @@
  */
 
 #include "avcodec.h"
+#include "libavutil/avassert.h"
 
 
 void av_destruct_packet_nofree(AVPacket *pkt)
@@ -71,6 +72,23 @@ void av_shrink_packet(AVPacket *pkt, int size)
     memset(pkt->data + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
 }
 
+int av_grow_packet(AVPacket *pkt, int grow_by)
+{
+    void *new_ptr;
+    av_assert0((unsigned)pkt->size <= INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE);
+    if (!pkt->size)
+        return av_new_packet(pkt, grow_by);
+    if ((unsigned)grow_by > INT_MAX - (pkt->size + FF_INPUT_BUFFER_PADDING_SIZE))
+        return -1;
+    new_ptr = av_realloc(pkt->data, pkt->size + grow_by + FF_INPUT_BUFFER_PADDING_SIZE);
+    if (!new_ptr)
+        return AVERROR(ENOMEM);
+    pkt->data = new_ptr;
+    pkt->size += grow_by;
+    memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
+    return 0;
+}
+
 int av_dup_packet(AVPacket *pkt)
 {
     if (((pkt->destruct == av_destruct_packet_nofree) || (pkt->destruct == NULL)) && pkt->data) {