blob: 41fdeb43e80bb0e1726be2366f58942fecfdc8d8 [file] [log] [blame]
/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) 2004,2006 Thomas Vander Stichele <thomas at apestaart dot org>
*
* 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 a
* #GstDPPacketizer object and invoking its packetizer functions.
* For backwards-compatibility reasons, the old 0.2 methods are still
* available but deprecated.
*
* 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
/* 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
/*** HELPER FUNCTIONS ***/
static gboolean
gst_dp_header_from_buffer_any (const GstBuffer * buffer, GstDPHeaderFlag flags,
guint * length, guint8 ** header, GstDPVersion version)
{
guint8 *h;
guint16 flags_mask;
GstMapInfo map;
g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
g_return_val_if_fail (length, FALSE);
g_return_val_if_fail (header, FALSE);
*length = GST_DP_HEADER_LENGTH;
h = g_malloc0 (GST_DP_HEADER_LENGTH);
/* version, flags, type */
GST_DP_INIT_HEADER (h, version, flags, GST_DP_PAYLOAD_BUFFER);
gst_buffer_map ((GstBuffer *) buffer, &map, GST_MAP_READ);
/* buffer properties */
GST_WRITE_UINT32_BE (h + 6, map.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));
GST_DP_SET_CRC (h, flags, map.data, map.size);
gst_buffer_unmap ((GstBuffer *) buffer, &map);
GST_MEMDUMP ("created header from buffer", h, GST_DP_HEADER_LENGTH);
*header = h;
return TRUE;
}
static gboolean
gst_dp_packet_from_caps_any (const GstCaps * caps, GstDPHeaderFlag flags,
guint * length, guint8 ** header, guint8 ** payload, GstDPVersion version)
{
guint8 *h;
guchar *string;
guint payload_length;
g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
g_return_val_if_fail (length, FALSE);
g_return_val_if_fail (header, FALSE);
g_return_val_if_fail (payload, FALSE);
*length = GST_DP_HEADER_LENGTH;
h = g_malloc0 (GST_DP_HEADER_LENGTH);
string = (guchar *) gst_caps_to_string (caps);
payload_length = strlen ((gchar *) string) + 1; /* include trailing 0 */
/* version, flags, type */
GST_DP_INIT_HEADER (h, version, 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 ("created header from caps", h, GST_DP_HEADER_LENGTH);
*header = h;
*payload = string;
return TRUE;
}
/*** 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.
*/
guint16
gst_dp_crc (const guint8 * buffer, guint length)
{
guint16 crc_register = CRC_INIT;
g_return_val_if_fail (buffer != NULL || length == 0, 0);
/* calc CRC */
for (; length--;) {
crc_register = (guint16) ((crc_register << 8) ^
gst_dp_crc_table[((crc_register >> 8) & 0x00ff) ^ *buffer++]);
}
return (0xffff ^ crc_register);
}
GType
gst_dp_version_get_type (void)
{
static gsize gst_dp_version_type = 0;
static const GEnumValue gst_dp_version[] = {
{GST_DP_VERSION_0_2, "GST_DP_VERSION_0_2", "0.2"},
{GST_DP_VERSION_1_0, "GST_DP_VERSION_1_0", "1.0"},
{0, NULL, NULL},
};
if (g_once_init_enter (&gst_dp_version_type)) {
GType tmp = g_enum_register_static ("GstDPVersion", gst_dp_version);
g_once_init_leave (&gst_dp_version_type, tmp);
}
return (GType) gst_dp_version_type;
};
/**
* 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)
{
static gboolean _gst_dp_initialized = FALSE;
if (_gst_dp_initialized)
return;
_gst_dp_initialized = TRUE;
g_type_class_ref (gst_dp_version_get_type ());
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);
}
/*** PACKETIZER FUNCTIONS ***/
static gboolean
gst_dp_header_from_buffer_1_0 (const GstBuffer * buffer, GstDPHeaderFlag flags,
guint * length, guint8 ** header)
{
return gst_dp_header_from_buffer_any (buffer, flags, length, header,
GST_DP_VERSION_1_0);
}
static gboolean
gst_dp_packet_from_caps_1_0 (const GstCaps * caps, GstDPHeaderFlag flags,
guint * length, guint8 ** header, guint8 ** payload)
{
return gst_dp_packet_from_caps_any (caps, flags, length, header, payload,
GST_DP_VERSION_1_0);
}
static gboolean
gst_dp_packet_from_event_1_0 (const GstEvent * event, GstDPHeaderFlag flags,
guint * length, guint8 ** header, guint8 ** payload)
{
guint8 *h;
guint32 pl_length; /* length of payload */
guchar *string = NULL;
const GstStructure *structure;
g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
g_return_val_if_fail (length, FALSE);
g_return_val_if_fail (header, FALSE);
g_return_val_if_fail (payload, FALSE);
*length = GST_DP_HEADER_LENGTH;
h = g_malloc0 (GST_DP_HEADER_LENGTH);
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 ("created header from event", h, GST_DP_HEADER_LENGTH);
*header = h;
*payload = string;
return TRUE;
}
/*** DEPACKETIZING FUNCTIONS ***/
/**
* gst_dp_buffer_from_header:
* @header_length: the length of the packet header
* @header: the byte array of the packet header
*
* 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)
{
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 (NULL,
(guint) GST_DP_HEADER_PAYLOAD_LENGTH (header), NULL);
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);
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;
}
/**
* gst_dp_packetizer_new:
* @version: the #GstDPVersion of the protocol to packetize for.
*
* Creates a new packetizer.
*
* Returns: a newly allocated #GstDPPacketizer
*/
GstDPPacketizer *
gst_dp_packetizer_new (GstDPVersion version)
{
GstDPPacketizer *ret;
ret = g_malloc0 (sizeof (GstDPPacketizer));
ret->version = version;
switch (version) {
case GST_DP_VERSION_1_0:
ret->header_from_buffer = gst_dp_header_from_buffer_1_0;
ret->packet_from_caps = gst_dp_packet_from_caps_1_0;
ret->packet_from_event = gst_dp_packet_from_event_1_0;
break;
default:
g_free (ret);
ret = NULL;
break;
}
return ret;
}
/**
* gst_dp_packetizer_free:
* @packetizer: the #GstDPPacketizer to free.
*
* Free the given packetizer.
*/
void
gst_dp_packetizer_free (GstDPPacketizer * packetizer)
{
g_free (packetizer);
}