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.

diff --git a/gst/gstbuffer.c b/gst/gstbuffer.c
index 95e28f8..60cbe91 100644 (file)
--- 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);
-    bsize = gst_memory_get_sizes (mem, NULL, NULL);
+  for (i = 0; i < len; i++) {
+    gsize left, noffs;
 
-    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;
+    mem = GST_BUFFER_MEM_PTR (buffer, i);
+    bsize = gst_memory_get_sizes (mem, NULL, NULL);
 
-      /* last buffer always gets resized to the remaining size */
-      if (si + 1 == len)
-        left = size;
-      else
-        left = MIN (bsize - offset, size);
+    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 (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);
+        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_memory_unref (mem);
+        mem = tmp;
       }
-      GST_BUFFER_MEM_PTR (buffer, di++) = mem;
-      size -= left;
     }
+    offset = noffs;
+    size -= left;
+
+    GST_BUFFER_MEM_PTR (buffer, i) = mem;
   }
-  GST_BUFFER_MEM_LEN (buffer) = di;
 }
 
 /**