From 1a3f48f427d5f5e03e6b306d2eb60daf9066ea6f Mon Sep 17 00:00:00 2001
From: Wim Taymans <wim.taymans@collabora.co.uk>
Date: Tue, 12 Jul 2011 14:07:57 +0200
Subject: [PATCH] buffer: fix resize function some more

Don't remove memory blocks from the buffer when we clip and resize, instead set
the memory offset and size to 0. This allows us to make the buffer larger again
later.
---
 gst/gstbuffer.c | 75 +++++++++++++++++++++++++------------------------
 1 file changed, 38 insertions(+), 37 deletions(-)

diff --git a/gst/gstbuffer.c b/gst/gstbuffer.c
index 95e28f88fa..60cbe91576 100644
--- a/gst/gstbuffer.c
+++ b/gst/gstbuffer.c
@@ -817,7 +817,7 @@ void
 gst_buffer_resize (GstBuffer * buffer, gssize offset, gsize size)
 {
   guint len;
-  guint si, di;
+  guint i;
   gsize bsize, bufsize, bufoffs, bufmax;
   GstMemory *mem;
 
@@ -842,46 +842,47 @@ gst_buffer_resize (GstBuffer * buffer, gssize offset, gsize size)
   len = GST_BUFFER_MEM_LEN (buffer);
 
   /* copy and trim */
-  for (di = si = 0; si < len; si++) {
-    mem = GST_BUFFER_MEM_PTR (buffer, si);
+  for (i = 0; i < len; i++) {
+    gsize left, noffs;
+
+    mem = GST_BUFFER_MEM_PTR (buffer, i);
     bsize = gst_memory_get_sizes (mem, NULL, NULL);
 
-    if ((gssize) bsize <= offset) {
-      /* remove buffer */
-      GST_CAT_LOG (GST_CAT_BUFFER, "remove memory %p", mem);
-      gst_memory_unref (mem);
-      offset -= bsize;
-    } else {
-      gsize left;
-
-      /* last buffer always gets resized to the remaining size */
-      if (si + 1 == len)
-        left = size;
-      else
-        left = MIN (bsize - offset, size);
-
-      if (offset != 0 || left != bsize) {
-        /* we need to clip something */
-        if (GST_MEMORY_IS_WRITABLE (mem)) {
-          gst_memory_resize (mem, offset, left);
-        } else {
-          GstMemory *tmp;
-
-          if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
-            tmp = gst_memory_copy (mem, offset, left);
-          else
-            tmp = gst_memory_share (mem, offset, left);
-
-          gst_memory_unref (mem);
-          mem = tmp;
-        }
-        offset = 0;
-      }
-      GST_BUFFER_MEM_PTR (buffer, di++) = mem;
-      size -= left;
+    noffs = 0;
+    /* last buffer always gets resized to the remaining size */
+    if (i + 1 == len)
+      left = size;
+    /* shrink buffers before the offset */
+    else if ((gssize) bsize <= offset) {
+      left = 0;
+      noffs = offset - bsize;
+      offset = 0;
     }
+    /* clip other buffers */
+    else
+      left = MIN (bsize - offset, size);
+
+    if (offset != 0 || left != bsize) {
+      /* we need to clip something */
+      if (GST_MEMORY_IS_WRITABLE (mem)) {
+        gst_memory_resize (mem, offset, left);
+      } else {
+        GstMemory *tmp;
+
+        if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
+          tmp = gst_memory_copy (mem, offset, left);
+        else
+          tmp = gst_memory_share (mem, offset, left);
+
+        gst_memory_unref (mem);
+        mem = tmp;
+      }
+    }
+    offset = noffs;
+    size -= left;
+
+    GST_BUFFER_MEM_PTR (buffer, i) = mem;
   }
-  GST_BUFFER_MEM_LEN (buffer) = di;
 }
 
 /**