/**
* gst_adapter_masked_scan_uint32:
* @adapter: a #GstAdapter
* @mask: mask to apply to data before matching against @pattern
* @pattern: pattern to match (after mask is applied)
* @offset: offset into the adapter data from which to start scanning, returns
* the last scanned position.
* @size: number of bytes to scan from offset
*
* Scan for pattern @pattern with applied mask @mask in the adapter data,
* starting from offset @offset.
*
* The bytes in @pattern and @mask are interpreted left-to-right, regardless
* of endianness. All four bytes of the pattern must be present in the
* adapter for it to match, even if the first or last bytes are masked out.
*
* It is an error to call this function without making sure that there is
* enough data (offset+size bytes) in the adapter.
*
* This function calls gst_adapter_masked_scan_uint32_peek() passing NULL
* for value.
*
* Returns: offset of the first match, or -1 if no match was found.
*
* Example:
* <programlisting>
* // Assume the adapter contains 0x00 0x01 0x02 ... 0xfe 0xff
*
* gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 0, 256);
* // -> returns 0
* gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 1, 255);
* // -> returns -1
* gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 1, 255);
* // -> returns 1
* gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0001, 0, 256);
* // -> returns -1
* gst_adapter_masked_scan_uint32 (adapter, 0xffff, 0x0203, 0, 256);
* // -> returns 0
* gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 256);
* // -> returns 2
* gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0x02030000, 0, 4);
* // -> returns -1
* </programlisting>
*
* Since: 0.10.24
*/
guint
gst_adapter_masked_scan_uint32 (GstAdapter * adapter, guint32 mask,
guint32 pattern, guint offset, guint size)
{
return gst_adapter_masked_scan_uint32_peek (adapter, mask, pattern, offset,
size, NULL);
}
/* returns image length in bytes if parsed successfully,
* otherwise 0 if more data needed,
* if < 0 the absolute value needs to be flushed */
static gint
gst_jpeg_parse_get_image_length (GstJpegParse * parse)
{
guint size;
gboolean resync;
GstAdapter *adapter = parse->priv->adapter;
gint offset, noffset;
size = gst_adapter_available (adapter);
/* we expect at least 4 bytes, first of which start marker */
if (gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0xffd80000, 0, 4))
return 0;
GST_DEBUG ("Parsing jpeg image data (%u bytes)", size);
GST_DEBUG ("Parse state: offset=%d, resync=%d, entropy len=%d",
parse->priv->last_offset, parse->priv->last_resync,
parse->priv->last_entropy_len);
/* offset is 2 less than actual offset;
* - adapter needs at least 4 bytes for scanning,
* - start and end marker ensure at least that much
*/
/* resume from state offset */
offset = parse->priv->last_offset;
while (1) {
guint frame_len;
guint32 value;
noffset =
gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00, 0x0000ff00,
offset, size - offset, &value);
/* lost sync if 0xff marker not where expected */
if ((resync = (noffset != offset))) {
GST_DEBUG ("Lost sync at 0x%08x, resyncing", offset + 2);
}
/* may have marker, but could have been resyncng */
resync = resync || parse->priv->last_resync;
/* Skip over extra 0xff */
while ((noffset >= 0) && ((value & 0xff) == 0xff)) {
noffset++;
noffset =
gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00, 0x0000ff00,
noffset, size - noffset, &value);
}
/* enough bytes left for marker? (we need 0xNN after the 0xff) */
if (noffset < 0) {
GST_DEBUG ("at end of input and no EOI marker found, need more data");
goto need_more_data;
}
/* now lock on the marker we found */
offset = noffset;
value = value & 0xff;
if (value == 0xd9) {
GST_DEBUG ("0x%08x: EOI marker", offset + 2);
/* clear parse state */
parse->priv->last_resync = FALSE;
parse->priv->last_offset = 0;
return (offset + 4);
} else if (value == 0xd8) {
/* Skip this frame if we found another SOI marker */
GST_DEBUG ("0x%08x: SOI marker before EOI, skipping", offset + 2);
/* clear parse state */
parse->priv->last_resync = FALSE;
parse->priv->last_offset = 0;
return -(offset + 2);
}
if (value >= 0xd0 && value <= 0xd7)
frame_len = 0;
else {
/* peek tag and subsequent length */
if (offset + 2 + 4 > size)
goto need_more_data;
else
gst_adapter_masked_scan_uint32_peek (adapter, 0x0, 0x0, offset + 2, 4,
&frame_len);
frame_len = frame_len & 0xffff;
}
GST_DEBUG ("0x%08x: tag %02x, frame_len=%u", offset + 2, value, frame_len);
/* the frame length includes the 2 bytes for the length; here we want at
* least 2 more bytes at the end for an end marker */
if (offset + 2 + 2 + frame_len + 2 > size) {
goto need_more_data;
}
if (gst_jpeg_parse_parse_tag_has_entropy_segment (value)) {
guint eseglen = parse->priv->last_entropy_len;
GST_DEBUG ("0x%08x: finding entropy segment length", offset + 2);
noffset = offset + 2 + frame_len + eseglen;
while (1) {
noffset = gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00,
0x0000ff00, noffset, size - noffset, &value);
if (noffset < 0) {
/* need more data */
parse->priv->last_entropy_len = size - offset - 4 - frame_len - 2;
goto need_more_data;
}
if ((value & 0xff) != 0x00) {
eseglen = noffset - offset - frame_len - 2;
break;
}
noffset++;
}
parse->priv->last_entropy_len = 0;
frame_len += eseglen;
GST_DEBUG ("entropy segment length=%u => frame_len=%u", eseglen,
frame_len);
}
if (resync) {
/* check if we will still be in sync if we interpret
* this as a sync point and skip this frame */
noffset = offset + frame_len + 2;
noffset = gst_adapter_masked_scan_uint32 (adapter, 0x0000ff00, 0x0000ff00,
noffset, 4);
if (noffset < 0) {
/* ignore and continue resyncing until we hit the end
* of our data or find a sync point that looks okay */
offset++;
continue;
}
GST_DEBUG ("found sync at 0x%x", offset + 2);
}
offset += frame_len + 2;
}
/* EXITS */
need_more_data:
{
parse->priv->last_offset = offset;
parse->priv->last_resync = resync;
return 0;
}
}
static GstFlowReturn
gst_jpeg_dec_parse (GstVideoDecoder * bdec, GstVideoCodecFrame * frame,
GstAdapter * adapter, gboolean at_eos)
{
guint size;
gint toadd = 0;
gboolean resync;
gint offset = 0, noffset;
GstJpegDec *dec = (GstJpegDec *) bdec;
/* FIXME : The overhead of using scan_uint32 is massive */
size = gst_adapter_available (adapter);
GST_DEBUG ("Parsing jpeg image data (%u bytes)", size);
if (at_eos) {
GST_DEBUG ("Flushing all data out");
toadd = size;
/* If we have leftover data, throw it away */
if (!dec->saw_header)
goto drop_frame;
goto have_full_frame;
}
if (size < 8)
goto need_more_data;
if (!dec->saw_header) {
gint ret;
/* we expect at least 4 bytes, first of which start marker */
ret =
gst_adapter_masked_scan_uint32 (adapter, 0xffff0000, 0xffd80000, 0,
size - 4);
GST_DEBUG ("ret:%d", ret);
if (ret < 0)
goto need_more_data;
if (ret) {
gst_adapter_flush (adapter, ret);
size -= ret;
}
dec->saw_header = TRUE;
}
while (1) {
guint frame_len;
guint32 value;
GST_DEBUG ("offset:%d, size:%d", offset, size);
noffset =
gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00, 0x0000ff00,
offset, size - offset, &value);
/* lost sync if 0xff marker not where expected */
if ((resync = (noffset != offset))) {
GST_DEBUG ("Lost sync at 0x%08x, resyncing", offset + 2);
}
/* may have marker, but could have been resyncng */
resync = resync || dec->parse_resync;
/* Skip over extra 0xff */
while ((noffset >= 0) && ((value & 0xff) == 0xff)) {
noffset++;
noffset =
gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00, 0x0000ff00,
noffset, size - noffset, &value);
}
/* enough bytes left for marker? (we need 0xNN after the 0xff) */
if (noffset < 0) {
GST_DEBUG ("at end of input and no EOI marker found, need more data");
goto need_more_data;
}
/* now lock on the marker we found */
offset = noffset;
value = value & 0xff;
if (value == 0xd9) {
GST_DEBUG ("0x%08x: EOI marker", offset + 2);
/* clear parse state */
dec->saw_header = FALSE;
dec->parse_resync = FALSE;
toadd = offset + 4;
goto have_full_frame;
}
if (value == 0xd8) {
/* Skip this frame if we found another SOI marker */
GST_DEBUG ("0x%08x: SOI marker before EOI, skipping", offset + 2);
dec->parse_resync = FALSE;
/* FIXME : Need to skip data */
toadd -= offset + 2;
goto have_full_frame;
}
if (value >= 0xd0 && value <= 0xd7)
frame_len = 0;
else {
/* peek tag and subsequent length */
if (offset + 2 + 4 > size)
goto need_more_data;
else
gst_adapter_masked_scan_uint32_peek (adapter, 0x0, 0x0, offset + 2, 4,
&frame_len);
frame_len = frame_len & 0xffff;
}
GST_DEBUG ("0x%08x: tag %02x, frame_len=%u", offset + 2, value, frame_len);
/* the frame length includes the 2 bytes for the length; here we want at
* least 2 more bytes at the end for an end marker */
if (offset + 2 + 2 + frame_len + 2 > size) {
goto need_more_data;
}
if (gst_jpeg_dec_parse_tag_has_entropy_segment (value)) {
guint eseglen = dec->parse_entropy_len;
GST_DEBUG ("0x%08x: finding entropy segment length (eseglen:%d)",
offset + 2, eseglen);
if (size < offset + 2 + frame_len + eseglen)
goto need_more_data;
noffset = offset + 2 + frame_len + dec->parse_entropy_len;
while (1) {
GST_DEBUG ("noffset:%d, size:%d, size - noffset:%d",
noffset, size, size - noffset);
noffset = gst_adapter_masked_scan_uint32_peek (adapter, 0x0000ff00,
0x0000ff00, noffset, size - noffset, &value);
if (noffset < 0) {
/* need more data */
dec->parse_entropy_len = size - offset - 4 - frame_len - 2;
goto need_more_data;
}
if ((value & 0xff) != 0x00) {
eseglen = noffset - offset - frame_len - 2;
break;
}
noffset++;
}
dec->parse_entropy_len = 0;
frame_len += eseglen;
GST_DEBUG ("entropy segment length=%u => frame_len=%u", eseglen,
frame_len);
}
if (resync) {
/* check if we will still be in sync if we interpret
* this as a sync point and skip this frame */
noffset = offset + frame_len + 2;
noffset = gst_adapter_masked_scan_uint32 (adapter, 0x0000ff00, 0x0000ff00,
noffset, 4);
if (noffset < 0) {
/* ignore and continue resyncing until we hit the end
* of our data or find a sync point that looks okay */
offset++;
continue;
}
GST_DEBUG ("found sync at 0x%x", offset + 2);
}
/* Add current data to output buffer */
toadd += frame_len + 2;
offset += frame_len + 2;
}
need_more_data:
if (toadd)
gst_video_decoder_add_to_frame (bdec, toadd);
return GST_VIDEO_DECODER_FLOW_NEED_DATA;
have_full_frame:
if (toadd)
gst_video_decoder_add_to_frame (bdec, toadd);
return gst_video_decoder_have_frame (bdec);
drop_frame:
gst_adapter_flush (adapter, size);
return GST_FLOW_OK;
}
