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https://gitlab.freedesktop.org/gstreamer/gstreamer.git
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749 lines
23 KiB
C
749 lines
23 KiB
C
/* GStreamer
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* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
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* Copyright (C) 2004,2006 Thomas Vander Stichele <thomas at apestaart dot org>
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*
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* dataprotocol.c: Functions implementing the GStreamer Data Protocol
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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/**
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* SECTION:gstdataprotocol
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* @short_description: Serialization of caps, buffers and events.
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* @see_also: #GstCaps, #GstEvent, #GstBuffer
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*
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* This helper library provides serialization of GstBuffer, GstCaps and
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* GstEvent structures.
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*
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* This serialization is useful when GStreamer needs to interface with
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* the outside world to transport data between distinct GStreamer pipelines.
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* The connections with the outside world generally don't have mechanisms
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* to transport properties of these structures.
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*
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* For example, transporting buffers across named pipes or network connections
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* doesn't maintain the buffer size and separation.
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*
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* This data protocol assumes a reliable connection-oriented transport, such as
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* TCP, a pipe, or a file. The protocol does not serialize the caps for
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* each buffer; instead, it transport the caps only when they change in the
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* stream. This implies that there will always be a caps packet before any
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* buffer packets.
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*
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* The versioning of the protocol is independent of GStreamer's version.
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* The major number gets incremented, and the minor reset, for incompatible
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* changes. The minor number gets incremented for compatible changes that
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* allow clients who do not completely understand the newer protocol version
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* to still decode what they do understand.
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*
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* Version 0.2 serializes only a small subset of all events, with a custom
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* payload for each type. Also, all GDP streams start with the initial caps
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* packet.
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*
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* Version 1.0 serializes all events by taking the string representation of
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* the event as the payload. In addition, GDP streams can now start with
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* events as well, as required by the new data stream model in GStreamer 0.10.
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*
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* Converting buffers, caps and events to GDP buffers is done using a
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* #GstDPPacketizer object and invoking its packetizer functions.
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* For backwards-compatibility reasons, the old 0.2 methods are still
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* available but deprecated.
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*
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* For reference, this image shows the byte layout of the GDP header:
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*
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* <inlinegraphic format="PNG" fileref="gdp-header.png"></inlinegraphic>
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <gst/gst.h>
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#include "dataprotocol.h"
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#include <glib/gprintf.h> /* g_sprintf */
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#include <string.h> /* strlen */
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#include "dp-private.h"
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/* debug category */
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GST_DEBUG_CATEGORY_STATIC (data_protocol_debug);
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#ifndef GST_CAT_DEFAULT
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#define GST_CAT_DEFAULT data_protocol_debug
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#endif
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/* helper macros */
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/* write first 6 bytes of header */
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#define GST_DP_INIT_HEADER(h, version, flags, type) \
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G_STMT_START { \
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gint maj = 0, min = 0; \
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switch (version) { \
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case GST_DP_VERSION_0_2: maj = 0; min = 2; break; \
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case GST_DP_VERSION_1_0: maj = 1; min = 0; break; \
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} \
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h[0] = (guint8) maj; \
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h[1] = (guint8) min; \
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h[2] = (guint8) flags; \
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h[3] = 0; /* padding byte */ \
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GST_WRITE_UINT16_BE (h + 4, type); \
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} G_STMT_END
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#define GST_DP_SET_CRC(h, flags, payload, length); \
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G_STMT_START { \
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guint16 crc = 0; \
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if (flags & GST_DP_HEADER_FLAG_CRC_HEADER) \
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/* we don't crc the last four bytes since they are crc's */ \
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crc = gst_dp_crc (h, 58); \
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GST_WRITE_UINT16_BE (h + 58, crc); \
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\
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crc = 0; \
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if (length && (flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD)) \
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crc = gst_dp_crc (payload, length); \
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GST_WRITE_UINT16_BE (h + 60, crc); \
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} G_STMT_END
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/* calculate a CCITT 16 bit CRC check value for a given byte array */
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/*
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* this code snippet is adapted from a web page I found
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* it is identical except for cleanups, and a final XOR with 0xffff
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* as outlined in the uecp spec
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*
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* XMODEM x^16 + x^12 + x^5 + 1
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*/
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#define POLY 0x1021
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#define CRC_INIT 0xFFFF
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/*** HELPER FUNCTIONS ***/
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static gboolean
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gst_dp_header_from_buffer_any (const GstBuffer * buffer, GstDPHeaderFlag flags,
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guint * length, guint8 ** header, GstDPVersion version)
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{
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guint8 *h;
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guint16 flags_mask;
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GstMapInfo map;
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g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
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g_return_val_if_fail (length, FALSE);
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g_return_val_if_fail (header, FALSE);
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*length = GST_DP_HEADER_LENGTH;
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h = g_malloc0 (GST_DP_HEADER_LENGTH);
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/* version, flags, type */
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GST_DP_INIT_HEADER (h, version, flags, GST_DP_PAYLOAD_BUFFER);
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gst_buffer_map ((GstBuffer *) buffer, &map, GST_MAP_READ);
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/* buffer properties */
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GST_WRITE_UINT32_BE (h + 6, map.size);
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GST_WRITE_UINT64_BE (h + 10, GST_BUFFER_TIMESTAMP (buffer));
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GST_WRITE_UINT64_BE (h + 18, GST_BUFFER_DURATION (buffer));
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GST_WRITE_UINT64_BE (h + 26, GST_BUFFER_OFFSET (buffer));
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GST_WRITE_UINT64_BE (h + 34, GST_BUFFER_OFFSET_END (buffer));
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/* data flags; eats two bytes from the ABI area */
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/* we copy everything but the read-only flags */
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flags_mask = GST_BUFFER_FLAG_LIVE | GST_BUFFER_FLAG_DISCONT |
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GST_BUFFER_FLAG_HEADER | GST_BUFFER_FLAG_GAP | GST_BUFFER_FLAG_DELTA_UNIT;
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GST_WRITE_UINT16_BE (h + 42, GST_BUFFER_FLAGS (buffer) & flags_mask);
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/* from gstreamer 1.x, buffers also have the DTS */
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GST_WRITE_UINT64_BE (h + 44, GST_BUFFER_DTS (buffer));
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GST_DP_SET_CRC (h, flags, map.data, map.size);
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gst_buffer_unmap ((GstBuffer *) buffer, &map);
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GST_MEMDUMP ("created header from buffer", h, GST_DP_HEADER_LENGTH);
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*header = h;
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return TRUE;
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}
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static gboolean
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gst_dp_packet_from_caps_any (const GstCaps * caps, GstDPHeaderFlag flags,
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guint * length, guint8 ** header, guint8 ** payload, GstDPVersion version)
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{
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guint8 *h;
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guchar *string;
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guint payload_length;
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g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
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g_return_val_if_fail (length, FALSE);
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g_return_val_if_fail (header, FALSE);
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g_return_val_if_fail (payload, FALSE);
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*length = GST_DP_HEADER_LENGTH;
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h = g_malloc0 (GST_DP_HEADER_LENGTH);
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string = (guchar *) gst_caps_to_string (caps);
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payload_length = strlen ((gchar *) string) + 1; /* include trailing 0 */
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/* version, flags, type */
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GST_DP_INIT_HEADER (h, version, flags, GST_DP_PAYLOAD_CAPS);
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/* buffer properties */
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GST_WRITE_UINT32_BE (h + 6, payload_length);
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GST_WRITE_UINT64_BE (h + 10, (guint64) 0);
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GST_WRITE_UINT64_BE (h + 18, (guint64) 0);
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GST_WRITE_UINT64_BE (h + 26, (guint64) 0);
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GST_WRITE_UINT64_BE (h + 34, (guint64) 0);
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GST_DP_SET_CRC (h, flags, string, payload_length);
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GST_MEMDUMP ("created header from caps", h, GST_DP_HEADER_LENGTH);
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*header = h;
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*payload = string;
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return TRUE;
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}
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/*** PUBLIC FUNCTIONS ***/
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static const guint16 gst_dp_crc_table[256] = {
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
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0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
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0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
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0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
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0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
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0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
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0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
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0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
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0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
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0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
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0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
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0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
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0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
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0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
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0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
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0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
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0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
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0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
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0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
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0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
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0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
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0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
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0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
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0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
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0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
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0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
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0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
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0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
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0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
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0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
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0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
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0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
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};
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/**
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* gst_dp_crc:
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* @buffer: array of bytes
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* @length: the length of @buffer
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*
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* Calculate a CRC for the given buffer over the given number of bytes.
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* This is only provided for verification purposes; typical GDP users
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* will not need this function.
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*
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* Returns: a two-byte CRC checksum.
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*/
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guint16
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gst_dp_crc (const guint8 * buffer, guint length)
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{
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guint16 crc_register = CRC_INIT;
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g_return_val_if_fail (buffer != NULL || length == 0, 0);
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/* calc CRC */
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for (; length--;) {
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crc_register = (guint16) ((crc_register << 8) ^
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gst_dp_crc_table[((crc_register >> 8) & 0x00ff) ^ *buffer++]);
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}
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return (0xffff ^ crc_register);
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}
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GType
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gst_dp_version_get_type (void)
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{
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static gsize gst_dp_version_type = 0;
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static const GEnumValue gst_dp_version[] = {
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{GST_DP_VERSION_0_2, "GST_DP_VERSION_0_2", "0.2"},
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{GST_DP_VERSION_1_0, "GST_DP_VERSION_1_0", "1.0"},
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{0, NULL, NULL},
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};
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if (g_once_init_enter (&gst_dp_version_type)) {
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GType tmp = g_enum_register_static ("GstDPVersion", gst_dp_version);
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g_once_init_leave (&gst_dp_version_type, tmp);
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}
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return (GType) gst_dp_version_type;
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};
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/**
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* gst_dp_init:
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*
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* Initialize GStreamer Data Protocol library.
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*
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* Should be called before using these functions from source linking
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* to this source file.
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*/
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void
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gst_dp_init (void)
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{
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static gboolean _gst_dp_initialized = FALSE;
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if (_gst_dp_initialized)
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return;
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_gst_dp_initialized = TRUE;
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g_type_class_ref (gst_dp_version_get_type ());
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GST_DEBUG_CATEGORY_INIT (data_protocol_debug, "gdp", 0,
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"GStreamer Data Protocol");
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}
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/**
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* gst_dp_header_payload_length:
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* @header: the byte header of the packet array
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*
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* Get the length of the payload described by @header.
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*
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* Returns: the length of the payload this header describes.
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*/
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guint32
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gst_dp_header_payload_length (const guint8 * header)
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{
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g_return_val_if_fail (header != NULL, 0);
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return GST_DP_HEADER_PAYLOAD_LENGTH (header);
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}
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/**
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* gst_dp_header_payload_type:
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* @header: the byte header of the packet array
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*
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* Get the type of the payload described by @header.
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*
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* Returns: the #GstDPPayloadType the payload this header describes.
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*/
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GstDPPayloadType
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gst_dp_header_payload_type (const guint8 * header)
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{
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g_return_val_if_fail (header != NULL, GST_DP_PAYLOAD_NONE);
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return GST_DP_HEADER_PAYLOAD_TYPE (header);
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}
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/*** PACKETIZER FUNCTIONS ***/
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static gboolean
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gst_dp_header_from_buffer_1_0 (const GstBuffer * buffer, GstDPHeaderFlag flags,
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guint * length, guint8 ** header)
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{
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return gst_dp_header_from_buffer_any (buffer, flags, length, header,
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GST_DP_VERSION_1_0);
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}
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static gboolean
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gst_dp_packet_from_caps_1_0 (const GstCaps * caps, GstDPHeaderFlag flags,
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guint * length, guint8 ** header, guint8 ** payload)
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{
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return gst_dp_packet_from_caps_any (caps, flags, length, header, payload,
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GST_DP_VERSION_1_0);
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}
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static gboolean
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gst_dp_packet_from_event_1_0 (const GstEvent * event, GstDPHeaderFlag flags,
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guint * length, guint8 ** header, guint8 ** payload)
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{
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guint8 *h;
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guint32 pl_length; /* length of payload */
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guchar *string = NULL;
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const GstStructure *structure;
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g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
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g_return_val_if_fail (length, FALSE);
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g_return_val_if_fail (header, FALSE);
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g_return_val_if_fail (payload, FALSE);
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*length = GST_DP_HEADER_LENGTH;
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h = g_malloc0 (GST_DP_HEADER_LENGTH);
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structure = gst_event_get_structure ((GstEvent *) event);
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if (structure) {
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string = (guchar *) gst_structure_to_string (structure);
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GST_LOG ("event %p has structure, string %s", event, string);
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pl_length = strlen ((gchar *) string) + 1; /* include trailing 0 */
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} else {
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GST_LOG ("event %p has no structure", event);
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pl_length = 0;
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}
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/* version, flags, type */
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GST_DP_INIT_HEADER (h, GST_DP_VERSION_1_0, flags,
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GST_DP_PAYLOAD_EVENT_NONE + GST_EVENT_TYPE (event));
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/* length */
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GST_WRITE_UINT32_BE (h + 6, pl_length);
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/* timestamp */
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GST_WRITE_UINT64_BE (h + 10, GST_EVENT_TIMESTAMP (event));
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GST_DP_SET_CRC (h, flags, string, pl_length);
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GST_MEMDUMP ("created header from event", h, GST_DP_HEADER_LENGTH);
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*header = h;
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*payload = string;
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return TRUE;
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}
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/*** DEPACKETIZING FUNCTIONS ***/
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/**
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* gst_dp_buffer_from_header:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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*
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* Creates a newly allocated #GstBuffer from the given header.
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* The buffer data needs to be copied into it before validating.
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*
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* Use this function if you want to pre-allocate a buffer based on the
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* packet header to read the packet payload in to.
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*
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* This function does not check the header passed to it, use
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* gst_dp_validate_header() first if the header data is unchecked.
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*
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* Returns: A #GstBuffer if the buffer was successfully created, or NULL.
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*/
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GstBuffer *
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gst_dp_buffer_from_header (guint header_length, const guint8 * header)
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{
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GstBuffer *buffer;
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g_return_val_if_fail (header != NULL, NULL);
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g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL);
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g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) ==
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GST_DP_PAYLOAD_BUFFER, NULL);
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buffer =
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gst_buffer_new_allocate (NULL,
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(guint) GST_DP_HEADER_PAYLOAD_LENGTH (header), NULL);
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GST_BUFFER_TIMESTAMP (buffer) = GST_DP_HEADER_TIMESTAMP (header);
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GST_BUFFER_DTS (buffer) = GST_DP_HEADER_DTS (header);
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GST_BUFFER_DURATION (buffer) = GST_DP_HEADER_DURATION (header);
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GST_BUFFER_OFFSET (buffer) = GST_DP_HEADER_OFFSET (header);
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GST_BUFFER_OFFSET_END (buffer) = GST_DP_HEADER_OFFSET_END (header);
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GST_BUFFER_FLAGS (buffer) = GST_DP_HEADER_BUFFER_FLAGS (header);
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return buffer;
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}
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/**
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* gst_dp_caps_from_packet:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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* @payload: the byte array of the packet payload
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*
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* Creates a newly allocated #GstCaps from the given packet.
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*
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* This function does not check the arguments passed to it, use
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* gst_dp_validate_packet() first if the header and payload data are
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* unchecked.
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*
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* Returns: A #GstCaps containing the caps represented in the packet,
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* or NULL if the packet could not be converted.
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*/
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GstCaps *
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gst_dp_caps_from_packet (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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GstCaps *caps;
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gchar *string;
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g_return_val_if_fail (header, NULL);
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g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL);
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g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) ==
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GST_DP_PAYLOAD_CAPS, NULL);
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g_return_val_if_fail (payload, NULL);
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/* 0 sized payload length will work create NULL string */
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string = g_strndup ((gchar *) payload, GST_DP_HEADER_PAYLOAD_LENGTH (header));
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caps = gst_caps_from_string (string);
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g_free (string);
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return caps;
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}
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static GstEvent *
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gst_dp_event_from_packet_0_2 (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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GstEvent *event = NULL;
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GstEventType type;
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type = GST_DP_HEADER_PAYLOAD_TYPE (header) - GST_DP_PAYLOAD_EVENT_NONE;
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switch (type) {
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case GST_EVENT_UNKNOWN:
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GST_WARNING ("Unknown event, ignoring");
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return NULL;
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case GST_EVENT_EOS:
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case GST_EVENT_FLUSH_START:
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case GST_EVENT_FLUSH_STOP:
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case GST_EVENT_SEGMENT:
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event = gst_event_new_custom (type, NULL);
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GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header);
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break;
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case GST_EVENT_SEEK:
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{
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gdouble rate;
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GstFormat format;
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GstSeekFlags flags;
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GstSeekType start_type, stop_type;
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gint64 start, stop;
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g_return_val_if_fail (payload != NULL, NULL);
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/* FIXME, read rate */
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rate = 1.0;
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format = (GstFormat) GST_READ_UINT32_BE (payload);
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flags = (GstSeekFlags) GST_READ_UINT32_BE (payload + 4);
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start_type = (GstSeekType) GST_READ_UINT32_BE (payload + 8);
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start = (gint64) GST_READ_UINT64_BE (payload + 12);
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stop_type = (GstSeekType) GST_READ_UINT32_BE (payload + 20);
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stop = (gint64) GST_READ_UINT64_BE (payload + 24);
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event = gst_event_new_seek (rate, format, flags, start_type, start,
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stop_type, stop);
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GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header);
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break;
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}
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case GST_EVENT_QOS:
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case GST_EVENT_NAVIGATION:
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case GST_EVENT_TAG:
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GST_WARNING ("Unhandled event type %d, ignoring", type);
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return NULL;
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default:
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GST_WARNING ("Unknown event type %d, ignoring", type);
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return NULL;
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}
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return event;
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}
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static GstEvent *
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gst_dp_event_from_packet_1_0 (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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GstEvent *event = NULL;
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GstEventType type;
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gchar *string = NULL;
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GstStructure *s = NULL;
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type = GST_DP_HEADER_PAYLOAD_TYPE (header) - GST_DP_PAYLOAD_EVENT_NONE;
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if (payload) {
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string =
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g_strndup ((gchar *) payload, GST_DP_HEADER_PAYLOAD_LENGTH (header));
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s = gst_structure_from_string (string, NULL);
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g_free (string);
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}
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GST_LOG ("Creating event of type 0x%x with structure '%" GST_PTR_FORMAT "'",
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type, s);
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event = gst_event_new_custom (type, s);
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return event;
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}
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/**
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* gst_dp_event_from_packet:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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* @payload: the byte array of the packet payload
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*
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* Creates a newly allocated #GstEvent from the given packet.
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*
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* This function does not check the arguments passed to it, use
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* gst_dp_validate_packet() first if the header and payload data are
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* unchecked.
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*
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* Returns: A #GstEvent if the event was successfully created,
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* or NULL if an event could not be read from the payload.
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*/
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GstEvent *
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gst_dp_event_from_packet (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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guint8 major, minor;
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g_return_val_if_fail (header, NULL);
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g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, NULL);
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major = GST_DP_HEADER_MAJOR_VERSION (header);
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minor = GST_DP_HEADER_MINOR_VERSION (header);
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if (major == 0 && minor == 2)
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return gst_dp_event_from_packet_0_2 (header_length, header, payload);
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else if (major == 1 && minor == 0)
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return gst_dp_event_from_packet_1_0 (header_length, header, payload);
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else {
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GST_ERROR ("Unknown GDP version %d.%d", major, minor);
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return NULL;
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}
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}
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/**
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* gst_dp_validate_header:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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*
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* Validates the given packet header by checking the CRC checksum.
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*
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* Returns: %TRUE if the CRC matches, or no CRC checksum is present.
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*/
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gboolean
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gst_dp_validate_header (guint header_length, const guint8 * header)
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{
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guint16 crc_read, crc_calculated;
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g_return_val_if_fail (header != NULL, FALSE);
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g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, FALSE);
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if (!(GST_DP_HEADER_FLAGS (header) & GST_DP_HEADER_FLAG_CRC_HEADER))
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return TRUE;
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crc_read = GST_DP_HEADER_CRC_HEADER (header);
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/* don't include the last two crc fields for the crc check */
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crc_calculated = gst_dp_crc (header, header_length - 4);
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if (crc_read != crc_calculated)
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goto crc_error;
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GST_LOG ("header crc validation: %02x", crc_read);
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return TRUE;
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/* ERRORS */
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crc_error:
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{
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GST_WARNING ("header crc mismatch: read %02x, calculated %02x", crc_read,
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crc_calculated);
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return FALSE;
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}
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}
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/**
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* gst_dp_validate_payload:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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* @payload: the byte array of the packet payload
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*
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* Validates the given packet payload using the given packet header
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* by checking the CRC checksum.
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*
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* Returns: %TRUE if the CRC matches, or no CRC checksum is present.
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*/
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gboolean
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gst_dp_validate_payload (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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guint16 crc_read, crc_calculated;
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g_return_val_if_fail (header != NULL, FALSE);
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g_return_val_if_fail (header_length >= GST_DP_HEADER_LENGTH, FALSE);
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if (!(GST_DP_HEADER_FLAGS (header) & GST_DP_HEADER_FLAG_CRC_PAYLOAD))
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return TRUE;
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crc_read = GST_DP_HEADER_CRC_PAYLOAD (header);
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crc_calculated = gst_dp_crc (payload, GST_DP_HEADER_PAYLOAD_LENGTH (header));
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if (crc_read != crc_calculated)
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goto crc_error;
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GST_LOG ("payload crc validation: %02x", crc_read);
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return TRUE;
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/* ERRORS */
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crc_error:
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{
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GST_WARNING ("payload crc mismatch: read %02x, calculated %02x", crc_read,
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crc_calculated);
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return FALSE;
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}
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}
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/**
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* gst_dp_validate_packet:
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* @header_length: the length of the packet header
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* @header: the byte array of the packet header
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* @payload: the byte array of the packet payload
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*
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* Validates the given packet by checking version information and checksums.
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*
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* Returns: %TRUE if the packet validates.
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*/
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gboolean
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gst_dp_validate_packet (guint header_length, const guint8 * header,
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const guint8 * payload)
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{
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if (!gst_dp_validate_header (header_length, header))
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return FALSE;
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if (!gst_dp_validate_payload (header_length, header, payload))
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return FALSE;
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return TRUE;
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}
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/**
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* gst_dp_packetizer_new:
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* @version: the #GstDPVersion of the protocol to packetize for.
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*
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* Creates a new packetizer.
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*
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* Returns: a newly allocated #GstDPPacketizer
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*/
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GstDPPacketizer *
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gst_dp_packetizer_new (GstDPVersion version)
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{
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GstDPPacketizer *ret;
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ret = g_malloc0 (sizeof (GstDPPacketizer));
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ret->version = version;
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switch (version) {
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case GST_DP_VERSION_1_0:
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ret->header_from_buffer = gst_dp_header_from_buffer_1_0;
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ret->packet_from_caps = gst_dp_packet_from_caps_1_0;
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ret->packet_from_event = gst_dp_packet_from_event_1_0;
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break;
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default:
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g_free (ret);
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ret = NULL;
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break;
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}
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return ret;
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}
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/**
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* gst_dp_packetizer_free:
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* @packetizer: the #GstDPPacketizer to free.
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*
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* Free the given packetizer.
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*/
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void
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gst_dp_packetizer_free (GstDPPacketizer * packetizer)
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{
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g_free (packetizer);
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}
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