adapter: optimize _take() a little more

When we have already assembled some data before, reuse this data and only copy
the part that is new.
This commit is contained in:
Wim Taymans 2010-09-17 13:57:39 +02:00
parent fc4caf55c9
commit 961e2029db

View file

@ -545,19 +545,38 @@ static guint8 *
gst_adapter_take_internal (GstAdapter * adapter, guint nbytes)
{
guint8 *data;
guint toreuse, tocopy;
/* we have enough assembled data, take from there */
if (adapter->assembled_len >= nbytes) {
GST_LOG_OBJECT (adapter, "taking %u bytes already assembled", nbytes);
/* see how much data we can reuse from the assembled memory and how much
* we need to copy */
toreuse = MIN (nbytes, adapter->assembled_len);
tocopy = nbytes - toreuse;
/* find memory to return */
if (adapter->assembled_size >= nbytes && toreuse > 0) {
/* we reuse already allocated memory but only when we're going to reuse
* something from it because else we are worse than the malloc and copy
* case below */
GST_LOG_OBJECT (adapter, "reusing %u bytes of assembled data", toreuse);
/* we have enough free space in the assembled array */
data = adapter->assembled_data;
/* allocate new data, assembled_len will be set to 0 in the flush later */
/* flush after this function should set the assembled_size to 0 */
adapter->assembled_data = g_malloc (adapter->assembled_size);
} else {
/* we need to allocate and copy. We could potentially copy bytes from the
* assembled data before doing the copy_into */
GST_LOG_OBJECT (adapter, "taking %u bytes by collection", nbytes);
GST_LOG_OBJECT (adapter, "allocating %u bytes", nbytes);
/* not enough bytes in the assembled array, just allocate new space */
data = g_malloc (nbytes);
copy_into_unchecked (adapter, data, adapter->skip, nbytes);
/* reuse what we can from the already assembled data */
if (toreuse) {
GST_LOG_OBJECT (adapter, "reusing %u bytes", toreuse);
memcpy (data, adapter->assembled_data, toreuse);
}
}
if (tocopy) {
/* copy the remaining data */
GST_LOG_OBJECT (adapter, "copying %u bytes", tocopy);
copy_into_unchecked (adapter, toreuse + data, toreuse + adapter->skip,
tocopy);
}
return data;
}