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adapter: add _masked_scan_uint32
Add a reasonably optimized new gst_adapter_masked_scan_uint32() function to scan the adapter for a pattern after applying a mask. Add some unit tests. API: GstAdapter::gst_adapter_masked_scan_uint32() Fixes #583187
This commit is contained in:
Wim Taymans
Wim Taymans
parent
d6b21ba529
commit
270723c85c
3 changed files with 259 additions and 0 deletions
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@ -707,3 +707,80 @@ gst_adapter_prev_timestamp (GstAdapter * adapter, guint64 * distance)
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return adapter->priv->timestamp;
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}
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/**
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* gst_adapter_masked_scan_uint32:
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* @adapter: a #GstAdapter
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* @mask: mask to apply to data before matching against @pattern
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* @pattern: pattern to match (after mask is applied)
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* @offset: offset into the adapter data from which to start scanning, returns
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* the last scanned position.
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* @size: number of bytes to scan from offset
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*
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* Scan for pattern @pattern with applied mask @mask in the adapter data,
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* starting from offset @offset.
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*
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* It is an error to call this function without making sure that there is
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* enough data (offset+size bytes) in the adapter.
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*
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* Returns: offset of the first match, or -1 if no match was found.
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*
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* Since: 0.10.24
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*/
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guint
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gst_adapter_masked_scan_uint32 (GstAdapter * adapter, guint32 mask,
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guint32 pattern, guint offset, guint size)
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{
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GSList *g;
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guint skip, bsize, i;
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guint32 state;
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guint8 *bdata;
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g_return_val_if_fail (size > 0, -1);
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g_return_val_if_fail (offset + size <= adapter->size, -1);
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/* we can't find the pattern with less than 4 bytes */
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if (G_UNLIKELY (size < 4))
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return -1;
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skip = offset + adapter->skip;
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/* first step, do skipping and position on the first buffer */
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g = adapter->buflist;
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bsize = GST_BUFFER_SIZE (g->data);
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while (skip >= bsize) {
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skip -= bsize;
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g = g_slist_next (g);
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bsize = GST_BUFFER_SIZE (g->data);
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}
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/* get the data now */
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bsize -= skip;
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bdata = GST_BUFFER_DATA (g->data) + skip;
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/* set the state to something that does not match */
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state = ~pattern;
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/* now find data */
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while (size > 0) {
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bsize = MIN (bsize, size);
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for (i = bsize; i; i--) {
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state = ((state << 8) | *bdata++);
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if (G_UNLIKELY ((state & mask) == pattern)) {
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offset += (bsize - i) - 3;
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goto found;
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}
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}
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size -= bsize;
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if (size > 0) {
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/* nothing found yet, go to next buffer */
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offset += bsize;
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g = g_slist_next (g);
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bsize = GST_BUFFER_SIZE (g->data);
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bdata = GST_BUFFER_DATA (g->data);
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}
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}
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/* nothing found */
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offset = -1;
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found:
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return offset;
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}
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@ -95,6 +95,10 @@ guint gst_adapter_available_fast (GstAdapter *adapter);
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GstClockTime gst_adapter_prev_timestamp (GstAdapter *adapter, guint64 *distance);
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guint gst_adapter_masked_scan_uint32 (GstAdapter * adapter, guint32 mask,
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guint32 pattern, guint offset, guint size);
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G_END_DECLS
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#endif /* __GST_ADAPTER_H__ */
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@ -407,6 +407,183 @@ GST_START_TEST (test_timestamp)
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GST_END_TEST;
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GST_START_TEST (test_scan)
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{
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GstAdapter *adapter;
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GstBuffer *buffer;
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guint8 *data;
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guint offset;
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guint i;
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adapter = gst_adapter_new ();
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fail_unless (adapter != NULL);
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buffer = gst_buffer_new_and_alloc (100);
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data = GST_BUFFER_DATA (buffer);
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/* fill with pattern */
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for (i = 0; i < 100; i++)
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data[i] = i;
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gst_adapter_push (adapter, buffer);
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/* find first bytes */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x00010203, 0, 100);
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fail_unless (offset == 0);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 0, 100);
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fail_unless (offset == 1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 1, 99);
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fail_unless (offset == 1);
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/* offset is past the pattern start */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x01020304, 2, 98);
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fail_unless (offset == -1);
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/* not enough bytes to find the pattern */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x02030405, 2, 3);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x02030405, 2, 4);
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fail_unless (offset == 2);
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/* size does not include the last scanned byte */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x40414243, 0, 0x41);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x40414243, 0, 0x43);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x40414243, 0, 0x44);
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fail_unless (offset == 0x40);
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/* past the start */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x40414243, 65, 10);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x40414243, 64, 5);
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fail_unless (offset == 64);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x60616263, 65, 35);
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fail_unless (offset == 0x60);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x60616263, 0x60, 4);
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fail_unless (offset == 0x60);
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/* past the start */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x60616263, 0x61, 3);
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fail_unless (offset == -1);
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/* add another buffer */
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buffer = gst_buffer_new_and_alloc (100);
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data = GST_BUFFER_DATA (buffer);
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/* fill with pattern */
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for (i = 0; i < 100; i++)
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data[i] = i + 100;
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gst_adapter_push (adapter, buffer);
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/* past the start */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x60616263, 0x61, 6);
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fail_unless (offset == -1);
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/* this should work */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x61626364, 0x61, 4);
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fail_unless (offset == 0x61);
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/* not enough data */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x62636465, 0x61, 4);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x62636465, 0x61, 5);
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fail_unless (offset == 0x62);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x62636465, 0, 120);
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fail_unless (offset == 0x62);
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/* border conditions */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x62636465, 0, 200);
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fail_unless (offset == 0x62);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x63646566, 0, 200);
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fail_unless (offset == 0x63);
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/* we completely searched the first list */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x64656667, 0, 200);
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fail_unless (offset == 0x64);
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/* skip first buffer */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x64656667, 0x64,
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100);
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fail_unless (offset == 0x64);
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/* past the start */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x64656667, 0x65,
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10);
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fail_unless (offset == -1);
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/* not enough data to scan */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x64656667, 0x63, 4);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x64656667, 0x63, 5);
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fail_unless (offset == 0x64);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0, 199);
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fail_unless (offset == -1);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0x62,
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102);
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fail_unless (offset == 0xc4);
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/* different masks */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0x00ffffff, 0x00656667, 0x64,
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100);
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fail_unless (offset == 0x64);
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/* does not even exist */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0x00ffffff, 0xffffffff, 0x65,
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99);
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fail_unless (offset == -1);
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/* flush some bytes */
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gst_adapter_flush (adapter, 0x20);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x20212223, 0, 100);
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fail_unless (offset == 0);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0x20212223, 0, 4);
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fail_unless (offset == 0);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0x62,
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70);
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fail_unless (offset == 0xa4);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0, 168);
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fail_unless (offset == 0xa4);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 164, 4);
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fail_unless (offset == 0xa4);
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0x44,
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100);
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fail_unless (offset == 0xa4);
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/* not enough bytes */
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offset =
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gst_adapter_masked_scan_uint32 (adapter, 0xffffffff, 0xc4c5c6c7, 0x44,
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99);
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fail_unless (offset == -1);
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g_object_unref (adapter);
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}
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GST_END_TEST;
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static Suite *
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gst_adapter_suite (void)
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{
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@ -423,6 +600,7 @@ gst_adapter_suite (void)
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tcase_add_test (tc_chain, test_take_order);
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tcase_add_test (tc_chain, test_take_buf_order);
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tcase_add_test (tc_chain, test_timestamp);
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tcase_add_test (tc_chain, test_scan);
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return s;
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}
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