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adapter: more optimisations

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Remove duplicate copy code (_peek_into and _copy) and make a unified
optimized copy function.
This commit is contained in:
Wim Taymans 2009-05-19 22:13:04 +02:00 committed by Wim Taymans
parent 198dbe545c
commit d6b21ba529
1 changed files with 60 additions and 73 deletions
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133
libs/gst/base/gstadapter.c
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@ -231,6 +231,45 @@ update_timestamp (GstAdapter * adapter, GstBuffer * buf)
}
}
/* copy data into @dest, skipping @skip bytes from the head buffers */
static void
copy_into_unchecked (GstAdapter * adapter, guint8 * dest, guint skip,
guint size)
{
GSList *g;
GstBuffer *buf;
guint bsize, csize;
/* first step, do skipping and copy partial first buffer, we don't have to
* check for valid list entries, we keep things consistent. */
g = adapter->buflist;
while (skip > 0) {
buf = g->data;
g = g_slist_next (g);
bsize = GST_BUFFER_SIZE (buf);
if (G_LIKELY (skip < bsize)) {
/* last bit */
csize = MIN (bsize - skip, size);
memcpy (dest, GST_BUFFER_DATA (buf) + skip, csize);
size -= csize;
dest += csize;
/* break out and move to next step */
break;
} else {
skip -= bsize;
}
}
/* second step, copy remainder */
while (size > 0) {
buf = g->data;
g = g_slist_next (g);
csize = MIN (GST_BUFFER_SIZE (buf), size);
memcpy (dest, GST_BUFFER_DATA (buf), csize);
size -= csize;
dest += csize;
}
}
/**
* gst_adapter_push:
* @adapter: a #GstAdapter
@ -252,6 +291,8 @@ gst_adapter_push (GstAdapter * adapter, GstBuffer * buf)
size = GST_BUFFER_SIZE (buf);
if (G_UNLIKELY (size == 0)) {
/* we can't have empty buffers, several parts in this file rely on it, this
* has some problems for the timestamp tracking. */
GST_LOG_OBJECT (adapter, "discarding empty buffer");
gst_buffer_unref (buf);
} else {
@ -272,34 +313,6 @@ gst_adapter_push (GstAdapter * adapter, GstBuffer * buf)
}
}
/* Internal function that copies data into the given buffer, size must be
* bigger than the first buffer */
static void
gst_adapter_peek_into (GstAdapter * adapter, guint8 * data, guint size)
{
GstBuffer *cur;
GSList *cur_list;
guint copied, to_copy;
/* The first buffer might be partly consumed, so need to handle
* 'skipped' bytes. */
cur = adapter->buflist->data;
copied = MIN (GST_BUFFER_SIZE (cur) - adapter->skip, size);
memcpy (data, GST_BUFFER_DATA (cur) + adapter->skip, copied);
data += copied;
cur_list = g_slist_next (adapter->buflist);
while (copied < size) {
g_assert (cur_list);
cur = cur_list->data;
cur_list = g_slist_next (cur_list);
to_copy = MIN (GST_BUFFER_SIZE (cur), size - copied);
memcpy (data, GST_BUFFER_DATA (cur), to_copy);
data += to_copy;
copied += to_copy;
}
}
/* Internal method only. Tries to merge buffers at the head of the queue
* to form a single larger buffer of size 'size'. Only merges buffers that
* where 'gst_buffer_is_span_fast' returns TRUE.
@ -369,6 +382,7 @@ const guint8 *
gst_adapter_peek (GstAdapter * adapter, guint size)
{
GstBuffer *cur;
guint skip;
g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
g_return_val_if_fail (size > 0, NULL);
@ -385,16 +399,17 @@ gst_adapter_peek (GstAdapter * adapter, guint size)
/* our head buffer has enough data left, return it */
cur = adapter->buflist->data;
if (GST_BUFFER_SIZE (cur) >= size + adapter->skip)
return GST_BUFFER_DATA (cur) + adapter->skip;
skip = adapter->skip;
if (GST_BUFFER_SIZE (cur) >= size + skip)
return GST_BUFFER_DATA (cur) + skip;
/* We may be able to efficiently merge buffers in our pool to
* gather a big enough chunk to return it from the head buffer directly */
if (gst_adapter_try_to_merge_up (adapter, size)) {
/* Merged something! Check if there's enough avail now */
cur = adapter->buflist->data;
if (GST_BUFFER_SIZE (cur) >= size + adapter->skip)
return GST_BUFFER_DATA (cur) + adapter->skip;
if (GST_BUFFER_SIZE (cur) >= size + skip)
return GST_BUFFER_DATA (cur) + skip;
}
/* Gonna need to copy stuff out */
@ -409,7 +424,7 @@ gst_adapter_peek (GstAdapter * adapter, guint size)
}
adapter->assembled_len = size;
gst_adapter_peek_into (adapter, adapter->assembled_data, size);
copy_into_unchecked (adapter, adapter->assembled_data, skip, size);
return adapter->assembled_data;
}
@ -433,37 +448,11 @@ gst_adapter_peek (GstAdapter * adapter, guint size)
void
gst_adapter_copy (GstAdapter * adapter, guint8 * dest, guint offset, guint size)
{
GSList *g;
int skip;
g_return_if_fail (GST_IS_ADAPTER (adapter));
g_return_if_fail (size > 0);
g_return_if_fail (offset + size <= adapter->size);
/* we don't have enough data, return. This is unlikely
* as one usually does an _available() first instead of copying a
* random size. */
if (G_UNLIKELY (offset + size > adapter->size))
return;
skip = adapter->skip;
for (g = adapter->buflist; g && size > 0; g = g_slist_next (g)) {
GstBuffer *buf;
buf = g->data;
if (offset < GST_BUFFER_SIZE (buf) - skip) {
int n;
n = MIN (GST_BUFFER_SIZE (buf) - skip - offset, size);
memcpy (dest, GST_BUFFER_DATA (buf) + skip + offset, n);
dest += n;
offset = 0;
size -= n;
} else {
offset -= GST_BUFFER_SIZE (buf) - skip;
}
skip = 0;
}
copy_into_unchecked (adapter, dest, offset + adapter->skip, size);
}
/**
@ -550,7 +539,7 @@ gst_adapter_take (GstAdapter * adapter, guint nbytes)
memcpy (data, adapter->assembled_data, nbytes);
} else {
GST_LOG_OBJECT (adapter, "taking %u bytes by collection", nbytes);
gst_adapter_peek_into (adapter, data, nbytes);
copy_into_unchecked (adapter, data, adapter->skip, nbytes);
}
gst_adapter_flush (adapter, nbytes);
@ -581,7 +570,7 @@ gst_adapter_take_buffer (GstAdapter * adapter, guint nbytes)
{
GstBuffer *buffer;
GstBuffer *cur;
guint hsize;
guint hsize, skip;
g_return_val_if_fail (GST_IS_ADAPTER (adapter), NULL);
g_return_val_if_fail (nbytes > 0, NULL);
@ -595,28 +584,29 @@ gst_adapter_take_buffer (GstAdapter * adapter, guint nbytes)
return NULL;
cur = adapter->buflist->data;
skip = adapter->skip;
hsize = GST_BUFFER_SIZE (cur);
/* our head buffer has enough data left, return it */
if (adapter->skip == 0 && hsize == nbytes) {
if (skip == 0 && hsize == nbytes) {
GST_LOG_OBJECT (adapter, "providing buffer of %d bytes as head buffer",
nbytes);
buffer = gst_buffer_ref (cur);
goto done;
} else if (hsize >= nbytes + adapter->skip) {
} else if (hsize >= nbytes + skip) {
GST_LOG_OBJECT (adapter, "providing buffer of %d bytes via sub-buffer",
nbytes);
buffer = gst_buffer_create_sub (cur, adapter->skip, nbytes);
buffer = gst_buffer_create_sub (cur, skip, nbytes);
goto done;
}
if (gst_adapter_try_to_merge_up (adapter, nbytes)) {
/* Merged something, let's try again for sub-buffering */
cur = adapter->buflist->data;
if (GST_BUFFER_SIZE (cur) >= nbytes + adapter->skip) {
if (GST_BUFFER_SIZE (cur) >= nbytes + skip) {
GST_LOG_OBJECT (adapter, "providing buffer of %d bytes via sub-buffer",
nbytes);
buffer = gst_buffer_create_sub (cur, adapter->skip, nbytes);
buffer = gst_buffer_create_sub (cur, skip, nbytes);
goto done;
}
}
@ -629,7 +619,7 @@ gst_adapter_take_buffer (GstAdapter * adapter, guint nbytes)
memcpy (GST_BUFFER_DATA (buffer), adapter->assembled_data, nbytes);
} else {
GST_LOG_OBJECT (adapter, "taking %u bytes by collection", nbytes);
gst_adapter_peek_into (adapter, GST_BUFFER_DATA (buffer), nbytes);
copy_into_unchecked (adapter, GST_BUFFER_DATA (buffer), skip, nbytes);
}
done:
@ -687,10 +677,7 @@ gst_adapter_available_fast (GstAdapter * adapter)
first = GST_BUFFER_CAST (adapter->buflist->data);
size = GST_BUFFER_SIZE (first);
/* we cannot have skipped more than the first buffer */
g_assert (size > adapter->skip);
/* we can quickly get the data of the first buffer */
/* we can quickly get the (remaining) data of the first buffer */
return size - adapter->skip;
}