| /* GStreamer |
| * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu> |
| * Copyright (C) 2004,2006 Thomas Vander Stichele <thomas at apestaart dot org> |
| * Copyright (C) 2014 Tim-Philipp Müller <tim centricular com> |
| * |
| * dataprotocol.c: Functions implementing the GStreamer Data Protocol |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public |
| * License along with this library; if not, write to the |
| * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| */ |
| |
| /** |
| * SECTION:gstdataprotocol |
| * @short_description: Serialization of caps, buffers and events. |
| * @see_also: #GstCaps, #GstEvent, #GstBuffer |
| * |
| * This helper library provides serialization of GstBuffer, GstCaps and |
| * GstEvent structures. |
| * |
| * This serialization is useful when GStreamer needs to interface with |
| * the outside world to transport data between distinct GStreamer pipelines. |
| * The connections with the outside world generally don't have mechanisms |
| * to transport properties of these structures. |
| * |
| * For example, transporting buffers across named pipes or network connections |
| * doesn't maintain the buffer size and separation. |
| * |
| * This data protocol assumes a reliable connection-oriented transport, such as |
| * TCP, a pipe, or a file. The protocol does not serialize the caps for |
| * each buffer; instead, it transport the caps only when they change in the |
| * stream. This implies that there will always be a caps packet before any |
| * buffer packets. |
| * |
| * The versioning of the protocol is independent of GStreamer's version. |
| * The major number gets incremented, and the minor reset, for incompatible |
| * changes. The minor number gets incremented for compatible changes that |
| * allow clients who do not completely understand the newer protocol version |
| * to still decode what they do understand. |
| * |
| * Version 0.2 serializes only a small subset of all events, with a custom |
| * payload for each type. Also, all GDP streams start with the initial caps |
| * packet. |
| * |
| * Version 1.0 serializes all events by taking the string representation of |
| * the event as the payload. In addition, GDP streams can now start with |
| * events as well, as required by the new data stream model in GStreamer 0.10. |
| * |
| * Converting buffers, caps and events to GDP buffers is done using the |
| * appropriate functions. |
| * |
| * For reference, this image shows the byte layout of the GDP header: |
| * |
| * <inlinegraphic format="PNG" fileref="gdp-header.png"></inlinegraphic> |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include <gst/gst.h> |
| #include "dataprotocol.h" |
| #include <glib/gprintf.h> /* g_sprintf */ |
| #include <string.h> /* strlen */ |
| #include "dp-private.h" |
| |
| /* debug category */ |
| GST_DEBUG_CATEGORY_STATIC (data_protocol_debug); |
| #ifndef GST_CAT_DEFAULT |
| #define GST_CAT_DEFAULT data_protocol_debug |
| #endif |
| |
| /* The version of the GDP protocol being used */ |
| typedef enum |
| { |
| GST_DP_VERSION_0_2 = 1, |
| GST_DP_VERSION_1_0, |
| } GstDPVersion; |
| |
| /* helper macros */ |
| |
| /* write first 6 bytes of header */ |
| #define GST_DP_INIT_HEADER(h, version, flags, type) \ |
| G_STMT_START { \ |
| gint maj = 0, min = 0; \ |
| switch (version) { \ |
| case GST_DP_VERSION_0_2: maj = 0; min = 2; break; \ |
| case GST_DP_VERSION_1_0: maj = 1; min = 0; break; \ |
| } \ |
| h[0] = (guint8) maj; \ |
| h[1] = (guint8) min; \ |
| h[2] = (guint8) flags; \ |
| h[3] = 0; /* padding byte */ \ |
| GST_WRITE_UINT16_BE (h + 4, type); \ |
| } G_STMT_END |
| |
| #define GST_DP_SET_CRC(h, flags, payload, length); \ |
| G_STMT_START { \ |
| guint16 crc = 0; \ |
| if (flags & GST_DP_HEADER_FLAG_CRC_HEADER) \ |
| /* we don't crc the last four bytes since they are crc's */ \ |
| crc = gst_dp_crc (h, 58); \ |
| GST_WRITE_UINT16_BE (h + 58, crc); \ |
| \ |
| crc = 0; \ |
| if (length && (flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD)) \ |
| crc = gst_dp_crc (payload, length); \ |
| GST_WRITE_UINT16_BE (h + 60, crc); \ |
| } G_STMT_END |
| |
| /* calculate a CCITT 16 bit CRC check value for a given byte array */ |
| /* |
| * this code snippet is adapted from a web page I found |
| * it is identical except for cleanups, and a final XOR with 0xffff |
| * as outlined in the uecp spec |
| * |
| * XMODEM x^16 + x^12 + x^5 + 1 |
| */ |
| |
| #define POLY 0x1021 |
| #define CRC_INIT 0xFFFF |
| |
| static guint16 gst_dp_crc (const guint8 * buffer, guint length); |
| static guint16 gst_dp_crc_from_memory_maps (const GstMapInfo * maps, |
| guint n_maps); |
| |
| /* payloading functions */ |
| |
| GstBuffer * |
| gst_dp_payload_buffer (GstBuffer * buffer, GstDPHeaderFlag flags) |
| { |
| GstBuffer *ret_buf; |
| GstMapInfo map; |
| GstMemory *mem; |
| guint8 *h; |
| guint16 flags_mask; |
| guint16 header_crc = 0, crc = 0; |
| gsize buffer_size; |
| |
| mem = gst_allocator_alloc (NULL, GST_DP_HEADER_LENGTH, NULL); |
| gst_memory_map (mem, &map, GST_MAP_READWRITE); |
| h = memset (map.data, 0, map.size); |
| |
| /* version, flags, type */ |
| GST_DP_INIT_HEADER (h, GST_DP_VERSION_1_0, flags, GST_DP_PAYLOAD_BUFFER); |
| |
| if ((flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD)) { |
| GstMapInfo *maps; |
| guint n_maps, i; |
| |
| buffer_size = 0; |
| |
| n_maps = gst_buffer_n_memory (buffer); |
| if (n_maps > 0) { |
| maps = g_newa (GstMapInfo, n_maps); |
| |
| for (i = 0; i < n_maps; ++i) { |
| GstMemory *mem; |
| |
| mem = gst_buffer_peek_memory (buffer, i); |
| gst_memory_map (mem, &maps[i], GST_MAP_READ); |
| buffer_size += maps[i].size; |
| } |
| |
| crc = gst_dp_crc_from_memory_maps (maps, n_maps); |
| |
| for (i = 0; i < n_maps; ++i) |
| gst_memory_unmap (maps[i].memory, &maps[i]); |
| } |
| } else { |
| buffer_size = gst_buffer_get_size (buffer); |
| } |
| |
| /* buffer properties */ |
| GST_WRITE_UINT32_BE (h + 6, buffer_size); |
| GST_WRITE_UINT64_BE (h + 10, GST_BUFFER_TIMESTAMP (buffer)); |
| GST_WRITE_UINT64_BE (h + 18, GST_BUFFER_DURATION (buffer)); |
| GST_WRITE_UINT64_BE (h + 26, GST_BUFFER_OFFSET (buffer)); |
| GST_WRITE_UINT64_BE (h + 34, GST_BUFFER_OFFSET_END (buffer)); |
| |
| /* data flags; eats two bytes from the ABI area */ |
| /* we copy everything but the read-only flags */ |
| flags_mask = GST_BUFFER_FLAG_LIVE | GST_BUFFER_FLAG_DISCONT | |
| GST_BUFFER_FLAG_HEADER | GST_BUFFER_FLAG_GAP | GST_BUFFER_FLAG_DELTA_UNIT; |
| |
| GST_WRITE_UINT16_BE (h + 42, GST_BUFFER_FLAGS (buffer) & flags_mask); |
| |
| /* from gstreamer 1.x, buffers also have the DTS */ |
| GST_WRITE_UINT64_BE (h + 44, GST_BUFFER_DTS (buffer)); |
| |
| /* header CRC */ |
| if ((flags & GST_DP_HEADER_FLAG_CRC_HEADER)) |
| /* we don't crc the last four bytes since they are crc's */ |
| header_crc = gst_dp_crc (h, 58); |
| else |
| header_crc = 0; |
| |
| GST_WRITE_UINT16_BE (h + 58, header_crc); |
| |
| /* payload CRC */ |
| GST_WRITE_UINT16_BE (h + 60, crc); |
| |
| GST_MEMDUMP ("payload header for buffer", h, GST_DP_HEADER_LENGTH); |
| gst_memory_unmap (mem, &map); |
| |
| ret_buf = gst_buffer_new (); |
| |
| /* header */ |
| gst_buffer_append_memory (ret_buf, mem); |
| |
| /* buffer data */ |
| return gst_buffer_append (ret_buf, gst_buffer_ref (buffer)); |
| } |
| |
| GstBuffer * |
| gst_dp_payload_caps (const GstCaps * caps, GstDPHeaderFlag flags) |
| { |
| GstBuffer *buf; |
| GstMapInfo map; |
| GstMemory *mem; |
| guint8 *h; |
| guchar *string; |
| guint payload_length; |
| |
| g_assert (GST_IS_CAPS (caps)); |
| |
| buf = gst_buffer_new (); |
| |
| mem = gst_allocator_alloc (NULL, GST_DP_HEADER_LENGTH, NULL); |
| gst_memory_map (mem, &map, GST_MAP_READWRITE); |
| h = memset (map.data, 0, map.size); |
| |
| string = (guchar *) gst_caps_to_string (caps); |
| payload_length = strlen ((gchar *) string) + 1; /* include trailing 0 */ |
| |
| /* version, flags, type */ |
| GST_DP_INIT_HEADER (h, GST_DP_VERSION_1_0, flags, GST_DP_PAYLOAD_CAPS); |
| |
| /* buffer properties */ |
| GST_WRITE_UINT32_BE (h + 6, payload_length); |
| GST_WRITE_UINT64_BE (h + 10, (guint64) 0); |
| GST_WRITE_UINT64_BE (h + 18, (guint64) 0); |
| GST_WRITE_UINT64_BE (h + 26, (guint64) 0); |
| GST_WRITE_UINT64_BE (h + 34, (guint64) 0); |
| |
| GST_DP_SET_CRC (h, flags, string, payload_length); |
| |
| GST_MEMDUMP ("payload header for caps", h, GST_DP_HEADER_LENGTH); |
| gst_memory_unmap (mem, &map); |
| |
| /* header */ |
| gst_buffer_append_memory (buf, mem); |
| |
| /* caps string */ |
| gst_buffer_append_memory (buf, |
| gst_memory_new_wrapped (0, string, payload_length, 0, payload_length, |
| string, g_free)); |
| |
| return buf; |
| } |
| |
| GstBuffer * |
| gst_dp_payload_event (const GstEvent * event, GstDPHeaderFlag flags) |
| { |
| GstBuffer *buf; |
| GstMapInfo map; |
| GstMemory *mem; |
| guint8 *h; |
| guint32 pl_length; /* length of payload */ |
| guchar *string = NULL; |
| const GstStructure *structure; |
| |
| g_assert (GST_IS_EVENT (event)); |
| |
| buf = gst_buffer_new (); |
| |
| mem = gst_allocator_alloc (NULL, GST_DP_HEADER_LENGTH, NULL); |
| gst_memory_map (mem, &map, GST_MAP_READWRITE); |
| h = memset (map.data, 0, map.size); |
| |
| structure = gst_event_get_structure ((GstEvent *) event); |
| if (structure) { |
| string = (guchar *) gst_structure_to_string (structure); |
| GST_LOG ("event %p has structure, string %s", event, string); |
| pl_length = strlen ((gchar *) string) + 1; /* include trailing 0 */ |
| } else { |
| GST_LOG ("event %p has no structure", event); |
| pl_length = 0; |
| } |
| |
| /* version, flags, type */ |
| GST_DP_INIT_HEADER (h, GST_DP_VERSION_1_0, flags, |
| GST_DP_PAYLOAD_EVENT_NONE + GST_EVENT_TYPE (event)); |
| |
| /* length */ |
| GST_WRITE_UINT32_BE (h + 6, pl_length); |
| /* timestamp */ |
| GST_WRITE_UINT64_BE (h + 10, GST_EVENT_TIMESTAMP (event)); |
| |
| GST_DP_SET_CRC (h, flags, string, pl_length); |
| |
| GST_MEMDUMP ("payload header for event", h, GST_DP_HEADER_LENGTH); |
| gst_memory_unmap (mem, &map); |
| |
| /* header */ |
| gst_buffer_append_memory (buf, mem); |
| |
| /* event string */ |
| if (pl_length > 0) { |
| gst_buffer_append_memory (buf, |
| gst_memory_new_wrapped (0, string, pl_length, 0, pl_length, |
| string, g_free)); |
| } |
| |
| return buf; |
| } |
| |
| /*** PUBLIC FUNCTIONS ***/ |
| |
| static const guint16 gst_dp_crc_table[256] = { |
| 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, |
| 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, |
| 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, |
| 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, |
| 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, |
| 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, |
| 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, |
| 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, |
| 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, |
| 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, |
| 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, |
| 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, |
| 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, |
| 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, |
| 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, |
| 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, |
| 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, |
| 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, |
| 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, |
| 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, |
| 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, |
| 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, |
| 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, |
| 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, |
| 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, |
| 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, |
| 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, |
| 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, |
| 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, |
| 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, |
| 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, |
| 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0 |
| }; |
| |
| /** |
| * gst_dp_crc: |
| * @buffer: array of bytes |
| * @length: the length of @buffer |
| * |
| * Calculate a CRC for the given buffer over the given number of bytes. |
| * This is only provided for verification purposes; typical GDP users |
| * will not need this function. |
| * |
| * Returns: a two-byte CRC checksum. |
| */ |
| static guint16 |
| gst_dp_crc (const guint8 * buffer, guint length) |
| { |
| guint16 crc_register = CRC_INIT; |
| |
| if (length == 0) |
| return 0; |
| |
| g_assert (buffer != NULL); |
| |
| /* calc CRC */ |
| for (; length--;) { |
| crc_register = (guint16) ((crc_register << 8) ^ |
| gst_dp_crc_table[((crc_register >> 8) & 0x00ff) ^ *buffer++]); |
| } |
| return (0xffff ^ crc_register); |
| } |
| |
| static guint16 |
| gst_dp_crc_from_memory_maps (const GstMapInfo * maps, guint n_maps) |
| { |
| guint16 crc_register = CRC_INIT; |
| gsize total_length = 0; |
| |
| if (n_maps == 0) |
| return 0; |
| |
| g_assert (maps != NULL); |
| |
| /* calc CRC */ |
| while (n_maps > 0) { |
| guint8 *buffer = maps->data; |
| gsize length = maps->size; |
| |
| total_length += length; |
| |
| while (length-- > 0) { |
| crc_register = (guint16) ((crc_register << 8) ^ |
| gst_dp_crc_table[((crc_register >> 8) & 0x00ff) ^ *buffer++]); |
| } |
| --n_maps; |
| ++maps; |
| } |
| |
| if (G_UNLIKELY (total_length == 0)) |
| return 0; |
| |
| return (0xffff ^ crc_register); |
| } |
| |
| /** |
| * gst_dp_init: |
| * |
| * Initialize GStreamer Data Protocol library. |
| * |
| * Should be called before using these functions from source linking |
| * to this source file. |
| */ |
| void |
| gst_dp_init (void) |
| { |
| GST_DEBUG_CATEGORY_INIT (data_protocol_debug, "gdp", 0, |
| "GStreamer Data Protocol"); |
| } |
| |
| /** |
| * gst_dp_header_payload_length: |
| * @header: the byte header of the packet array |
| * |
| * Get the length of the payload described by @header. |
| * |
| * Returns: the length of the payload this header describes. |
| */ |
| guint32 |
| gst_dp_header_payload_length (const guint8 * header) |
| { |
| g_return_val_if_fail (header != NULL, 0); |
| |
| return GST_DP_HEADER_PAYLOAD_LENGTH (header); |
| } |
| |
| /** |
| * gst_dp_header_payload_type: |
| * @header: the byte header of the packet array |
| * |
| * Get the type of the payload described by @header. |
| * |
| * Returns: the #GstDPPayloadType the payload this header describes. |
| */ |
| GstDPPayloadType |
| gst_dp_header_payload_type (const guint8 * header) |
| { |
| g_return_val_if_fail (header != NULL, GST_DP_PAYLOAD_NONE); |
| |
| return GST_DP_HEADER_PAYLOAD_TYPE (header); |
| } |
| |
| /*** DEPACKETIZING FUNCTIONS ***/ |
| |
| /** |
| * gst_dp_buffer_from_header: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * @allocator: the allocator used to allocate the new #GstBuffer |
| * @allocation_params: the allocations parameters used to allocate the new #GstBuffer |
| * |
| * Creates a newly allocated #GstBuffer from the given header. |
| * The buffer data needs to be copied into it before validating. |
| * |
| * Use this function if you want to pre-allocate a buffer based on the |
| * packet header to read the packet payload in to. |
| * |
| * This function does not check the header passed to it, use |
| * gst_dp_validate_header() first if the header data is unchecked. |
| * |
| * Returns: A #GstBuffer if the buffer was successfully created, or NULL. |
| */ |
| GstBuffer * |
| gst_dp_buffer_from_header (guint header_length, const guint8 * header, |
| GstAllocator * allocator, GstAllocationParams * allocation_params) |
| { |
| GstBuffer *buffer; |
| |
| g_return_val_if_fail (header != NULL, NULL); |
| g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL); |
| g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) == |
| GST_DP_PAYLOAD_BUFFER, NULL); |
| |
| buffer = |
| gst_buffer_new_allocate (allocator, |
| (guint) GST_DP_HEADER_PAYLOAD_LENGTH (header), allocation_params); |
| |
| GST_BUFFER_TIMESTAMP (buffer) = GST_DP_HEADER_TIMESTAMP (header); |
| GST_BUFFER_DTS (buffer) = GST_DP_HEADER_DTS (header); |
| GST_BUFFER_DURATION (buffer) = GST_DP_HEADER_DURATION (header); |
| GST_BUFFER_OFFSET (buffer) = GST_DP_HEADER_OFFSET (header); |
| GST_BUFFER_OFFSET_END (buffer) = GST_DP_HEADER_OFFSET_END (header); |
| GST_BUFFER_FLAGS (buffer) = GST_DP_HEADER_BUFFER_FLAGS (header); |
| |
| return buffer; |
| } |
| |
| /** |
| * gst_dp_caps_from_packet: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * @payload: the byte array of the packet payload |
| * |
| * Creates a newly allocated #GstCaps from the given packet. |
| * |
| * This function does not check the arguments passed to it, use |
| * gst_dp_validate_packet() first if the header and payload data are |
| * unchecked. |
| * |
| * Returns: A #GstCaps containing the caps represented in the packet, |
| * or NULL if the packet could not be converted. |
| */ |
| GstCaps * |
| gst_dp_caps_from_packet (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| GstCaps *caps; |
| gchar *string; |
| |
| g_return_val_if_fail (header, NULL); |
| g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL); |
| g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) == |
| GST_DP_PAYLOAD_CAPS, NULL); |
| g_return_val_if_fail (payload, NULL); |
| |
| /* 0 sized payload length will work create NULL string */ |
| string = g_strndup ((gchar *) payload, GST_DP_HEADER_PAYLOAD_LENGTH (header)); |
| caps = gst_caps_from_string (string); |
| g_free (string); |
| |
| return caps; |
| } |
| |
| static GstEvent * |
| gst_dp_event_from_packet_0_2 (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| GstEvent *event = NULL; |
| GstEventType type; |
| |
| type = GST_DP_HEADER_PAYLOAD_TYPE (header) - GST_DP_PAYLOAD_EVENT_NONE; |
| switch (type) { |
| case GST_EVENT_UNKNOWN: |
| GST_WARNING ("Unknown event, ignoring"); |
| return NULL; |
| case GST_EVENT_EOS: |
| case GST_EVENT_FLUSH_START: |
| case GST_EVENT_FLUSH_STOP: |
| case GST_EVENT_SEGMENT: |
| event = gst_event_new_custom (type, NULL); |
| GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header); |
| break; |
| case GST_EVENT_SEEK: |
| { |
| gdouble rate; |
| GstFormat format; |
| GstSeekFlags flags; |
| GstSeekType start_type, stop_type; |
| gint64 start, stop; |
| |
| g_return_val_if_fail (payload != NULL, NULL); |
| |
| /* FIXME, read rate */ |
| rate = 1.0; |
| format = (GstFormat) GST_READ_UINT32_BE (payload); |
| flags = (GstSeekFlags) GST_READ_UINT32_BE (payload + 4); |
| start_type = (GstSeekType) GST_READ_UINT32_BE (payload + 8); |
| start = (gint64) GST_READ_UINT64_BE (payload + 12); |
| stop_type = (GstSeekType) GST_READ_UINT32_BE (payload + 20); |
| stop = (gint64) GST_READ_UINT64_BE (payload + 24); |
| |
| event = gst_event_new_seek (rate, format, flags, start_type, start, |
| stop_type, stop); |
| GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header); |
| break; |
| } |
| case GST_EVENT_QOS: |
| case GST_EVENT_NAVIGATION: |
| case GST_EVENT_TAG: |
| GST_WARNING ("Unhandled event type %d, ignoring", type); |
| return NULL; |
| default: |
| GST_WARNING ("Unknown event type %d, ignoring", type); |
| return NULL; |
| } |
| |
| return event; |
| } |
| |
| static GstEvent * |
| gst_dp_event_from_packet_1_0 (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| GstEvent *event = NULL; |
| GstEventType type; |
| gchar *string = NULL; |
| GstStructure *s = NULL; |
| |
| type = GST_DP_HEADER_PAYLOAD_TYPE (header) - GST_DP_PAYLOAD_EVENT_NONE; |
| if (payload) { |
| string = |
| g_strndup ((gchar *) payload, GST_DP_HEADER_PAYLOAD_LENGTH (header)); |
| s = gst_structure_from_string (string, NULL); |
| if (s == NULL) { |
| GST_WARNING ("Could not parse payload string: %s", string); |
| g_free (string); |
| return NULL; |
| } |
| |
| g_free (string); |
| } |
| GST_LOG ("Creating event of type 0x%x with structure '%" GST_PTR_FORMAT "'", |
| type, s); |
| event = gst_event_new_custom (type, s); |
| return event; |
| } |
| |
| |
| /** |
| * gst_dp_event_from_packet: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * @payload: the byte array of the packet payload |
| * |
| * Creates a newly allocated #GstEvent from the given packet. |
| * |
| * This function does not check the arguments passed to it, use |
| * gst_dp_validate_packet() first if the header and payload data are |
| * unchecked. |
| * |
| * Returns: A #GstEvent if the event was successfully created, |
| * or NULL if an event could not be read from the payload. |
| */ |
| GstEvent * |
| gst_dp_event_from_packet (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| guint8 major, minor; |
| |
| g_return_val_if_fail (header, NULL); |
| g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL); |
| |
| major = GST_DP_HEADER_MAJOR_VERSION (header); |
| minor = GST_DP_HEADER_MINOR_VERSION (header); |
| |
| if (major == 0 && minor == 2) |
| return gst_dp_event_from_packet_0_2 (header_length, header, payload); |
| else if (major == 1 && minor == 0) |
| return gst_dp_event_from_packet_1_0 (header_length, header, payload); |
| else { |
| GST_ERROR ("Unknown GDP version %d.%d", major, minor); |
| return NULL; |
| } |
| } |
| |
| /** |
| * gst_dp_validate_header: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * |
| * Validates the given packet header by checking the CRC checksum. |
| * |
| * Returns: %TRUE if the CRC matches, or no CRC checksum is present. |
| */ |
| gboolean |
| gst_dp_validate_header (guint header_length, const guint8 * header) |
| { |
| guint16 crc_read, crc_calculated; |
| |
| g_return_val_if_fail (header != NULL, FALSE); |
| g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, FALSE); |
| |
| if (!(GST_DP_HEADER_FLAGS (header) & GST_DP_HEADER_FLAG_CRC_HEADER)) |
| return TRUE; |
| |
| crc_read = GST_DP_HEADER_CRC_HEADER (header); |
| |
| /* don't include the last two crc fields for the crc check */ |
| crc_calculated = gst_dp_crc (header, header_length - 4); |
| if (crc_read != crc_calculated) |
| goto crc_error; |
| |
| GST_LOG ("header crc validation: %02x", crc_read); |
| return TRUE; |
| |
| /* ERRORS */ |
| crc_error: |
| { |
| GST_WARNING ("header crc mismatch: read %02x, calculated %02x", crc_read, |
| crc_calculated); |
| return FALSE; |
| } |
| } |
| |
| /** |
| * gst_dp_validate_payload: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * @payload: the byte array of the packet payload |
| * |
| * Validates the given packet payload using the given packet header |
| * by checking the CRC checksum. |
| * |
| * Returns: %TRUE if the CRC matches, or no CRC checksum is present. |
| */ |
| gboolean |
| gst_dp_validate_payload (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| guint16 crc_read, crc_calculated; |
| |
| g_return_val_if_fail (header != NULL, FALSE); |
| g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, FALSE); |
| |
| if (!(GST_DP_HEADER_FLAGS (header) & GST_DP_HEADER_FLAG_CRC_PAYLOAD)) |
| return TRUE; |
| |
| crc_read = GST_DP_HEADER_CRC_PAYLOAD (header); |
| crc_calculated = gst_dp_crc (payload, GST_DP_HEADER_PAYLOAD_LENGTH (header)); |
| if (crc_read != crc_calculated) |
| goto crc_error; |
| |
| GST_LOG ("payload crc validation: %02x", crc_read); |
| return TRUE; |
| |
| /* ERRORS */ |
| crc_error: |
| { |
| GST_WARNING ("payload crc mismatch: read %02x, calculated %02x", crc_read, |
| crc_calculated); |
| return FALSE; |
| } |
| } |
| |
| /** |
| * gst_dp_validate_packet: |
| * @header_length: the length of the packet header |
| * @header: the byte array of the packet header |
| * @payload: the byte array of the packet payload |
| * |
| * Validates the given packet by checking version information and checksums. |
| * |
| * Returns: %TRUE if the packet validates. |
| */ |
| gboolean |
| gst_dp_validate_packet (guint header_length, const guint8 * header, |
| const guint8 * payload) |
| { |
| if (!gst_dp_validate_header (header_length, header)) |
| return FALSE; |
| if (!gst_dp_validate_payload (header_length, header, payload)) |
| return FALSE; |
| |
| return TRUE; |
| } |