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buffer: small optimizations

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shortcut heavy work when buffer_resize does nothing.
Avoid an extra _ref when mapping a buffer.
Add some G_LIKELY.
This commit is contained in:
Wim Taymans 2012-03-09 16:14:02 +01:00
parent ebd4863d21
commit 6ffba69d65
1 changed files with 30 additions and 16 deletions
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46
gst/gstbuffer.c
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@ -173,7 +173,7 @@ _span_memory (GstBuffer * buffer, gsize offset, gsize size, gboolean writable)
} }
static GstMemory * static GstMemory *
_get_merged_memory (GstBuffer * buffer) _get_merged_memory (GstBuffer * buffer, gboolean * merged)
{ {
guint len; guint len;
GstMemory *mem; GstMemory *mem;
@ -187,9 +187,11 @@ _get_merged_memory (GstBuffer * buffer)
/* we can take the first one */ /* we can take the first one */
mem = GST_BUFFER_MEM_PTR (buffer, 0); mem = GST_BUFFER_MEM_PTR (buffer, 0);
gst_memory_ref (mem); gst_memory_ref (mem);
*merged = FALSE;
} else { } else {
/* we need to span memory */ /* we need to span memory */
mem = _span_memory (buffer, 0, -1, FALSE); mem = _span_memory (buffer, 0, -1, FALSE);
*merged = TRUE;
} }
return mem; return mem;
} }
@ -722,13 +724,14 @@ GstMemory *
gst_buffer_get_memory (GstBuffer * buffer, gint idx) gst_buffer_get_memory (GstBuffer * buffer, gint idx)
{ {
GstMemory *mem; GstMemory *mem;
gboolean merged;
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL); g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
g_return_val_if_fail (idx == -1 || g_return_val_if_fail (idx == -1 ||
(idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)), NULL); (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)), NULL);
if (idx == -1) { if (idx == -1) {
mem = _get_merged_memory (buffer); mem = _get_merged_memory (buffer, &merged);
} else if ((mem = GST_BUFFER_MEM_PTR (buffer, idx))) { } else if ((mem = GST_BUFFER_MEM_PTR (buffer, idx))) {
gst_memory_ref (mem); gst_memory_ref (mem);
} }
@ -898,6 +901,10 @@ gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
} }
g_return_if_fail (bufmax >= bufoffs + offset + size); g_return_if_fail (bufmax >= bufoffs + offset + size);
/* no change */
if (offset == 0 && size == bufsize)
return;
len = GST_BUFFER_MEM_LEN (buffer); len = GST_BUFFER_MEM_LEN (buffer);
/* copy and trim */ /* copy and trim */
@ -961,14 +968,16 @@ gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
* When the buffer contains multiple memory blocks, the returned pointer will be * When the buffer contains multiple memory blocks, the returned pointer will be
* a concatenation of the memory blocks. * a concatenation of the memory blocks.
* *
* The memory in @info should be unmapped with gst_buffer_unmap() after usage.
*
* Returns: (transfer full): %TRUE if the map succeeded and @info contains valid * Returns: (transfer full): %TRUE if the map succeeded and @info contains valid
* data. * data.
*/ */
gboolean gboolean
gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags) gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
{ {
GstMemory *mem; GstMemory *mem, *nmem;
gboolean write, writable; gboolean write, writable, merged;
g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE); g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
g_return_val_if_fail (info != NULL, FALSE); g_return_val_if_fail (info != NULL, FALSE);
@ -980,25 +989,28 @@ gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
if (G_UNLIKELY (write && !writable)) if (G_UNLIKELY (write && !writable))
goto not_writable; goto not_writable;
mem = _get_merged_memory (buffer); mem = _get_merged_memory (buffer, &merged);
if (G_UNLIKELY (mem == NULL)) if (G_UNLIKELY (mem == NULL))
goto no_memory; goto no_memory;
/* now try to map */ /* now try to map */
mem = gst_memory_make_mapped (mem, info, flags); nmem = gst_memory_make_mapped (mem, info, flags);
if (G_UNLIKELY (mem == NULL)) if (G_UNLIKELY (nmem == NULL))
goto cannot_map; goto cannot_map;
/* if the buffer is writable, replace the memory */ /* if we merged or when the map returned a different memory, we try to replace
if (writable) { * the memory in the buffer */
_replace_all_memory (buffer, gst_memory_ref (mem)); if (G_UNLIKELY (merged || nmem != mem)) {
} else { /* if the buffer is writable, replace the memory */
if (GST_BUFFER_MEM_LEN (buffer) > 1) { if (writable) {
GST_CAT_DEBUG (GST_CAT_PERFORMANCE, _replace_all_memory (buffer, gst_memory_ref (nmem));
"temporary mapping for memory %p in buffer %p", mem, buffer); } else {
if (GST_BUFFER_MEM_LEN (buffer) > 1) {
GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
"temporary mapping for memory %p in buffer %p", nmem, buffer);
}
} }
} }
return TRUE; return TRUE;
/* ERROR */ /* ERROR */
@ -1038,7 +1050,9 @@ gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
g_return_if_fail (GST_IS_BUFFER (buffer)); g_return_if_fail (GST_IS_BUFFER (buffer));
g_return_if_fail (info != NULL); g_return_if_fail (info != NULL);
if (info->memory) { /* we need to check for NULL, it is possible that we tried to map a buffer
* without memory and we should be able to unmap that fine */
if (G_LIKELY (info->memory)) {
gst_memory_unmap (info->memory, info); gst_memory_unmap (info->memory, info);
gst_memory_unref (info->memory); gst_memory_unref (info->memory);
} }