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baseparse: allow increasing min_size for current frame parsing only

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Also check that subclass actually either directs to skip bytes or
increases expected frame size to avoid going nowhere in bogus
indefinite looping.
This commit is contained in:
Mark Nauwelaerts 2011-01-06 11:41:44 +01:00
parent 18b69e9320
commit 829507b650
1 changed files with 42 additions and 9 deletions
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51
gst/audioparsers/gstbaseparse.c
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@ -82,7 +82,8 @@
* @framesize according to the detected frame size. If buffer didn't
* contain a valid frame, this call must return FALSE and optionally
* set the @skipsize value to inform base class that how many bytes
* it needs to skip in order to find a valid frame. The passed buffer
* it needs to skip in order to find a valid frame. @framesize can always
* indicate a new minimum for current frame parsing. The passed buffer
* is read-only. Note that @check_valid_frame might receive any small
* amount of input data when leftover data is being drained (e.g. at EOS).
* </para></listitem>
@ -1874,7 +1875,7 @@ gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
guint fsize = 0;
gint skip = -1;
const guint8 *data;
guint min_size, av;
guint old_min_size = 0, min_size, av;
GstClockTime timestamp;
parse = GST_BASE_PARSE (GST_OBJECT_PARENT (pad));
@ -1905,11 +1906,17 @@ gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
while (!parse->priv->flushing) {
tmpbuf = gst_buffer_new ();
old_min_size = 0;
/* Synchronization loop */
for (;;) {
min_size = parse->priv->min_frame_size;
min_size = MAX (parse->priv->min_frame_size, fsize);
av = gst_adapter_available (parse->adapter);
/* loop safety check */
if (G_UNLIKELY (old_min_size >= min_size))
goto invalid_min;
old_min_size = min_size;
if (G_UNLIKELY (parse->priv->drain)) {
min_size = av;
GST_DEBUG_OBJECT (parse, "draining, data left: %d", min_size);
@ -1975,10 +1982,11 @@ gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
if (!parse->priv->discont)
parse->priv->sync_offset = parse->priv->offset;
parse->priv->discont = TRUE;
/* something changed least; nullify loop check */
old_min_size = 0;
}
/* There is a possibility that subclass set the skip value to zero.
This means that it has probably found a frame but wants to ask
more data (by increasing the min_size) to be sure of this. */
/* skip == 0 should imply subclass set min_size to need more data;
* we check this shortly */
if ((ret = gst_base_parse_check_sync (parse)) != GST_FLOW_OK) {
gst_buffer_unref (tmpbuf);
goto done;
@ -2033,6 +2041,15 @@ gst_base_parse_chain (GstPad * pad, GstBuffer * buffer)
done:
GST_LOG_OBJECT (parse, "chain leaving");
return ret;
/* ERRORS */
invalid_min:
{
GST_ELEMENT_ERROR (parse, STREAM, FAILED, (NULL),
("min_size evolution %d -> %d; breaking to avoid looping",
old_min_size, min_size));
return GST_FLOW_ERROR;
}
}
/* pull @size bytes at current offset,
@ -2180,14 +2197,18 @@ gst_base_parse_scan_frame (GstBaseParse * parse, GstBaseParseClass * klass,
{
GstBuffer *buffer, *outbuf;
GstFlowReturn ret = GST_FLOW_OK;
guint fsize = 0, min_size;
guint fsize = 0, min_size, old_min_size = 0;
gint skip = 0;
g_return_val_if_fail (buf != NULL, GST_FLOW_ERROR);
while (TRUE) {
min_size = parse->priv->min_frame_size;
min_size = MAX (parse->priv->min_frame_size, fsize);
/* loop safety check */
if (G_UNLIKELY (old_min_size >= min_size))
goto invalid_min;
old_min_size = min_size;
ret = gst_base_parse_pull_range (parse, min_size, &buffer);
if (ret != GST_FLOW_OK)
@ -2227,8 +2248,11 @@ gst_base_parse_scan_frame (GstBaseParse * parse, GstBaseParseClass * klass,
if (!parse->priv->discont)
parse->priv->sync_offset = parse->priv->offset;
parse->priv->discont = TRUE;
/* something changed least; nullify loop check */
old_min_size = 0;
}
/* skip == 0 should imply subclass set min_size to need more data ... */
/* skip == 0 should imply subclass set min_size to need more data;
* we check this shortly */
GST_DEBUG_OBJECT (parse, "finding sync...");
gst_buffer_unref (buffer);
if ((ret = gst_base_parse_check_sync (parse)) != GST_FLOW_OK) {
@ -2264,6 +2288,15 @@ gst_base_parse_scan_frame (GstBaseParse * parse, GstBaseParseClass * klass,
done:
return ret;
/* ERRORS */
invalid_min:
{
GST_ELEMENT_ERROR (parse, STREAM, FAILED, (NULL),
("min_size evolution %d -> %d; breaking to avoid looping",
old_min_size, min_size));
return GST_FLOW_ERROR;
}
}
/**