/*
* helper_find_peek:
* @data: helper data struct
* @off: stream offset
* @size: block size
*
* Get data pointer within a stream. Keeps a cache of read buffers (partly
* for performance reasons, but mostly because pointers returned by us need
* to stay valid until typefinding has finished)
*
* Returns: address of the data or %NULL if buffer does not cover the
* requested range.
*/
static guint8 *
helper_find_peek (gpointer data, gint64 offset, guint size)
{
GstTypeFindHelper *helper;
GstBuffer *buffer;
GstFlowReturn ret;
GSList *insert_pos = NULL;
guint buf_size;
guint64 buf_offset;
GstCaps *caps;
helper = (GstTypeFindHelper *) data;
GST_LOG_OBJECT (helper->obj, "'%s' called peek (%" G_GINT64_FORMAT
", %u)", GST_PLUGIN_FEATURE_NAME (helper->factory), offset, size);
if (size == 0)
return NULL;
if (offset < 0) {
if (helper->size == -1 || helper->size < -offset)
return NULL;
offset += helper->size;
}
/* see if we have a matching buffer already in our list */
if (size > 0 && offset <= helper->last_offset) {
GSList *walk;
for (walk = helper->buffers; walk; walk = walk->next) {
GstBuffer *buf = GST_BUFFER_CAST (walk->data);
guint64 buf_offset = GST_BUFFER_OFFSET (buf);
guint buf_size = GST_BUFFER_SIZE (buf);
/* buffers are kept sorted by end offset (highest first) in the list, so
* at this point we save the current position and stop searching if
* we're after the searched end offset */
if (buf_offset <= offset) {
if ((offset + size) < (buf_offset + buf_size)) {
return GST_BUFFER_DATA (buf) + (offset - buf_offset);
}
} else if (offset + size >= buf_offset + buf_size) {
insert_pos = walk;
break;
}
}
}
buffer = NULL;
/* some typefinders go in 1 byte steps over 1k of data and request
* small buffers. It is really inefficient to pull each time, and pulling
* a larger chunk is almost free. Trying to pull a larger chunk at the end
* of the file is also not a problem here, we'll just get a truncated buffer
* in that case (and we'll have to double-check the size we actually get
* anyway, see below) */
ret = helper->func (helper->obj, offset, MAX (size, 4096), &buffer);
if (ret != GST_FLOW_OK)
goto error;
caps = GST_BUFFER_CAPS (buffer);
if (caps && !gst_caps_is_empty (caps) && !gst_caps_is_any (caps)) {
GST_DEBUG ("buffer has caps %" GST_PTR_FORMAT ", suggest max probability",
caps);
gst_caps_replace (&helper->caps, caps);
helper->best_probability = GST_TYPE_FIND_MAXIMUM;
gst_buffer_unref (buffer);
return NULL;
}
/* getrange might silently return shortened buffers at the end of a file,
* we must, however, always return either the full requested data or NULL */
buf_offset = GST_BUFFER_OFFSET (buffer);
buf_size = GST_BUFFER_SIZE (buffer);
if ((buf_offset != -1 && buf_offset != offset) || buf_size < size) {
GST_DEBUG ("dropping short buffer: %" G_GUINT64_FORMAT "-%" G_GUINT64_FORMAT
" instead of %" G_GUINT64_FORMAT "-%" G_GUINT64_FORMAT,
buf_offset, buf_offset + buf_size - 1, offset, offset + size - 1);
gst_buffer_unref (buffer);
return NULL;
}
if (insert_pos) {
helper->buffers =
g_slist_insert_before (helper->buffers, insert_pos, buffer);
} else {
/* if insert_pos is not set, our offset is bigger than the largest offset
* we have so far; since we keep the list sorted with highest offsets
* first, we need to prepend the buffer to the list */
helper->last_offset = GST_BUFFER_OFFSET (buffer) + GST_BUFFER_SIZE (buffer);
helper->buffers = g_slist_prepend (helper->buffers, buffer);
}
return GST_BUFFER_DATA (buffer);
error:
{
GST_INFO ("typefind function returned: %s", gst_flow_get_name (ret));
return NULL;
}
}
/*
* helper_find_peek:
* @data: helper data struct
* @off: stream offset
* @size: block size
*
* Get data pointer within a stream. Keeps a cache of read buffers (partly
* for performance reasons, but mostly because pointers returned by us need
* to stay valid until typefinding has finished)
*
* Returns: (nullable): address of the data or %NULL if buffer does not cover
* the requested range.
*/
static const guint8 *
helper_find_peek (gpointer data, gint64 offset, guint size)
{
GstTypeFindHelper *helper;
GstBuffer *buffer;
GSList *insert_pos = NULL;
gsize buf_size;
guint64 buf_offset;
GstMappedBuffer *bmap;
#if 0
GstCaps *caps;
#endif
helper = (GstTypeFindHelper *) data;
GST_LOG_OBJECT (helper->obj, "'%s' called peek (%" G_GINT64_FORMAT
", %u)", GST_OBJECT_NAME (helper->factory), offset, size);
if (size == 0)
return NULL;
if (offset < 0) {
if (helper->size == -1 || helper->size < -offset)
return NULL;
offset += helper->size;
}
/* see if we have a matching buffer already in our list */
if (size > 0 && offset <= helper->last_offset) {
GSList *walk;
for (walk = helper->buffers; walk; walk = walk->next) {
GstMappedBuffer *bmp = (GstMappedBuffer *) walk->data;
GstBuffer *buf = GST_BUFFER_CAST (bmp->buffer);
buf_offset = GST_BUFFER_OFFSET (buf);
buf_size = bmp->map.size;
/* buffers are kept sorted by end offset (highest first) in the list, so
* at this point we save the current position and stop searching if
* we're after the searched end offset */
if (buf_offset <= offset) {
if ((offset + size) < (buf_offset + buf_size)) {
/* must already have been mapped before */
return (guint8 *) bmp->map.data + (offset - buf_offset);
}
} else if (offset + size >= buf_offset + buf_size) {
insert_pos = walk;
break;
}
}
}
buffer = NULL;
/* some typefinders go in 1 byte steps over 1k of data and request
* small buffers. It is really inefficient to pull each time, and pulling
* a larger chunk is almost free. Trying to pull a larger chunk at the end
* of the file is also not a problem here, we'll just get a truncated buffer
* in that case (and we'll have to double-check the size we actually get
* anyway, see below) */
helper->flow_ret =
helper->func (helper->obj, helper->parent, offset, MAX (size, 4096),
&buffer);
if (helper->flow_ret != GST_FLOW_OK)
goto error;
#if 0
caps = GST_BUFFER_CAPS (buffer);
if (caps && !gst_caps_is_empty (caps) && !gst_caps_is_any (caps)) {
GST_DEBUG ("buffer has caps %" GST_PTR_FORMAT ", suggest max probability",
caps);
gst_caps_replace (&helper->caps, caps);
helper->best_probability = GST_TYPE_FIND_MAXIMUM;
gst_buffer_unref (buffer);
return NULL;
}
#endif
/* getrange might silently return shortened buffers at the end of a file,
* we must, however, always return either the full requested data or %NULL */
buf_offset = GST_BUFFER_OFFSET (buffer);
buf_size = gst_buffer_get_size (buffer);
if (buf_size < size) {
GST_DEBUG ("dropping short buffer of size %" G_GSIZE_FORMAT ","
"requested size was %u", buf_size, size);
gst_buffer_unref (buffer);
return NULL;
}
if (buf_offset != -1 && buf_offset != offset) {
GST_DEBUG ("dropping buffer with unexpected offset %" G_GUINT64_FORMAT ", "
"expected offset was %" G_GUINT64_FORMAT, buf_offset, offset);
gst_buffer_unref (buffer);
return NULL;
}
bmap = g_slice_new0 (GstMappedBuffer);
if (!gst_buffer_map (buffer, &bmap->map, GST_MAP_READ))
goto map_failed;
bmap->buffer = buffer;
if (insert_pos) {
helper->buffers = g_slist_insert_before (helper->buffers, insert_pos, bmap);
} else {
/* if insert_pos is not set, our offset is bigger than the largest offset
* we have so far; since we keep the list sorted with highest offsets
* first, we need to prepend the buffer to the list */
helper->last_offset = GST_BUFFER_OFFSET (buffer) + buf_size;
helper->buffers = g_slist_prepend (helper->buffers, bmap);
}
return bmap->map.data;
error:
{
GST_INFO ("typefind function returned: %s",
gst_flow_get_name (helper->flow_ret));
return NULL;
}
map_failed:
{
GST_ERROR ("map failed");
gst_buffer_unref (buffer);
g_slice_free (GstMappedBuffer, bmap);
return NULL;
}
}
