--- /dev/null
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ * Copyright (C) <2004> 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., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gst/gst.h>
+#include <gst/dataprotocol/dataprotocol.h>
+#include <glib/gprintf.h> /* g_sprintf */
+#include <string.h> /* strlen */
+#include "dp-private.h"
+
+/* debug category */
+GST_DEBUG_CATEGORY (data_protocol_debug);
+#define GST_CAT_DEFAULT data_protocol_debug
+
+/*** private functions ***/
+
+#define GST_DP_WRITE_GUINT64(buf, value) (*((guint64 *) (buf)) = GUINT64_TO_BE (value))
+#define GST_DP_WRITE_GUINT32(buf, value) (*((guint32 *) (buf)) = GUINT32_TO_BE (value))
+#define GST_DP_WRITE_GUINT16(buf, value) (*((guint16 *) (buf)) = GUINT16_TO_BE (value))
+
+/* 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, register guint length)
+{
+ static gboolean initialized = FALSE;
+ static guint16 crc_register, crc_table[256];
+ unsigned long i, j, k;
+
+ if (!initialized) {
+ for (i = 0; i < 256; i++) {
+ j = i << 8;
+ for (k = 8; k--;) {
+ j = j & 0x8000 ? (j << 1) ^ POLY : j << 1;
+ }
+
+ crc_table[i] = (guint16) j;
+ }
+ initialized = TRUE;
+ }
+
+ crc_register = CRC_INIT; /* always init register */
+
+ /* calc CRC */
+ for (; length--;) {
+ crc_register = (guint16) ((crc_register << 8) ^
+ crc_table[((crc_register >> 8) & 0x00ff) ^ *buffer++]);
+ }
+ return (0xffff ^ crc_register);
+}
+
+/* debugging function; dumps byte array values per 8 bytes */
+/* FIXME: would be nice to merge this with gst_util_dump_mem () */
+void
+gst_dp_dump_byte_array (guint8 * array, guint length)
+{
+ int i;
+ int n = 8; /* number of bytes per line */
+ gchar *line = g_malloc (3 * n);
+
+ GST_LOG ("dumping byte array of length %d", length);
+ for (i = 0; i < length; ++i) {
+ g_sprintf (line + 3 * (i % n), "%02x ", array[i]);
+ if (i % n == (n - 1)) {
+ GST_LOG ("%03d: %s", i - (n - 1), line);
+ }
+ }
+ if (i % n != 0) {
+ GST_LOG ("%03d: %s", (i / n) * n, line);
+ }
+ g_free (line);
+}
+
+/**
+ * gst_dp_init:
+ *
+ * Initialize GStreamer Data Protocol library.
+ *
+ * Should be called before using these functions; either from source linking
+ * to this source file or from plugin_init.
+ */
+void
+gst_dp_init (void)
+{
+ static gboolean _gst_dp_initialized = FALSE;
+
+ if (_gst_dp_initialized)
+ return;
+
+ _gst_dp_initialized = TRUE;
+
+ GST_DEBUG_CATEGORY_INIT (data_protocol_debug, "gdp", 0,
+ "GStreamer Data Protocol");
+}
+
+/*** PUBLIC FUNCTIONS ***/
+
+/**
+ * gst_dp_header_payload_length:
+ * @header: the byte header of the packet array
+ *
+ * Returns: the length of the payload this header describes.
+ */
+guint32
+gst_dp_header_payload_length (const guint8 * header)
+{
+ return GST_DP_HEADER_PAYLOAD_LENGTH (header);
+}
+
+/**
+ * gst_dp_header_payload_type:
+ * @header: the byte header of the packet array
+ *
+ * Returns: the #GstDPPayloadType the payload this header describes.
+ */
+GstDPPayloadType
+gst_dp_header_payload_type (const guint8 * header)
+{
+ return GST_DP_HEADER_PAYLOAD_TYPE (header);
+}
+
+/**
+ * gst_dp_header_from_buffer:
+ * @buffer: a #GstBuffer to create a header for
+ * @flags: the #GDPHeaderFlags to create the header with
+ * @length: a guint pointer to store the header length in
+ * @header: a guint8 * pointer to store a newly allocated header byte array in
+ *
+ * Creates a GDP header from the given buffer.
+ *
+ * Returns: %TRUE if the header was successfully created
+ */
+
+gboolean
+gst_dp_header_from_buffer (const GstBuffer * buffer, GstDPHeaderFlag flags,
+ guint * length, guint8 ** header)
+{
+ guint8 *h;
+ guint16 crc;
+
+ g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
+ g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buffer) > 0, FALSE);
+
+ *length = GST_DP_HEADER_LENGTH;
+ h = g_malloc (GST_DP_HEADER_LENGTH);
+
+ /* version, flags, type */
+ h[0] = (guint8) GST_DP_VERSION_MAJOR;
+ h[1] = (guint8) GST_DP_VERSION_MINOR;
+ h[2] = (guint8) flags;
+ h[3] = GST_DP_PAYLOAD_BUFFER;
+
+ /* buffer properties */
+ GST_DP_WRITE_GUINT32 (h + 4, GST_BUFFER_SIZE (buffer));
+ GST_DP_WRITE_GUINT64 (h + 8, GST_BUFFER_TIMESTAMP (buffer));
+ GST_DP_WRITE_GUINT64 (h + 16, GST_BUFFER_DURATION (buffer));
+ GST_DP_WRITE_GUINT64 (h + 24, GST_BUFFER_OFFSET (buffer));
+ GST_DP_WRITE_GUINT64 (h + 32, GST_BUFFER_OFFSET_END (buffer));
+
+ /* ABI padding */
+ GST_DP_WRITE_GUINT64 (h + 40, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 48, (guint64) 0);
+
+ /* CRC */
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_HEADER) {
+ /* we don't crc the last four bytes of the header since they are crc's */
+ crc = gst_dp_crc (h, 56);
+ }
+ GST_DP_WRITE_GUINT16 (h + 56, crc);
+
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD) {
+ crc = gst_dp_crc (GST_BUFFER_DATA (buffer), GST_BUFFER_SIZE (buffer));
+ }
+ GST_DP_WRITE_GUINT16 (h + 58, crc);
+
+ GST_LOG ("created header from buffer:");
+ gst_dp_dump_byte_array (h, GST_DP_HEADER_LENGTH);
+ *header = h;
+ return TRUE;
+}
+
+ /**
+ * gst_dp_packet_from_caps:
+ * @caps: a #GstCaps to create a packet for
+ * @flags: the #GDPHeaderFlags to create the header with
+ * @length: a guint pointer to store the header length in
+ * @header: a guint8 pointer to store a newly allocated header byte array in
+ * @payload: a guint8 pointer to store a newly allocated payload byte array in
+ *
+ * Creates a GDP packet from the given caps.
+ *
+ * Returns: %TRUE if the packet was successfully created
+ */
+gboolean
+gst_dp_packet_from_caps (const GstCaps * caps, GstDPHeaderFlag flags,
+ guint * length, guint8 ** header, guint8 ** payload)
+{
+ guint8 *h;
+ guint16 crc;
+ gchar *string;
+
+ /* FIXME: GST_IS_CAPS doesn't work
+ g_return_val_if_fail (GST_IS_CAPS (caps), FALSE); */
+
+ *length = GST_DP_HEADER_LENGTH;
+ h = g_malloc (GST_DP_HEADER_LENGTH);
+
+ string = gst_caps_to_string (caps);
+
+ /* version, flags, type */
+ h[0] = (guint8) GST_DP_VERSION_MAJOR;
+ h[1] = (guint8) GST_DP_VERSION_MINOR;
+ h[2] = (guint8) flags;
+ h[3] = GST_DP_PAYLOAD_CAPS;
+
+ /* buffer properties */
+ GST_DP_WRITE_GUINT32 (h + 4, strlen (string) + 1); /* include trailing 0 */
+ GST_DP_WRITE_GUINT64 (h + 8, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 16, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 24, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 32, (guint64) 0);
+
+ /* ABI padding */
+ GST_DP_WRITE_GUINT64 (h + 40, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 48, (guint64) 0);
+
+ /* CRC */
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_HEADER) {
+ crc = gst_dp_crc (h, 56);
+ }
+ GST_DP_WRITE_GUINT16 (h + 56, crc);
+
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD) {
+ crc = gst_dp_crc (string, strlen (string) + 1);
+ }
+ GST_DP_WRITE_GUINT16 (h + 58, crc);
+
+ GST_LOG ("created header from caps:");
+ gst_dp_dump_byte_array (h, GST_DP_HEADER_LENGTH);
+ *header = h;
+ *payload = string;
+ return TRUE;
+}
+
+/**
+ * gst_dp_packet_from_event:
+ * @event: a #GstEvent to create a packet for
+ * @flags: the #GDPHeaderFlags to create the header with
+ * @length: a guint pointer to store the header length in
+ * @header: a guint8 pointer to store a newly allocated header byte array in
+ * @payload: a guint8 pointer to store a newly allocated payload byte array in
+ *
+ * Creates a GDP packet from the given event.
+ *
+ * Returns: %TRUE if the packet was successfully created
+ */
+gboolean
+gst_dp_packet_from_event (const GstEvent * event, GstDPHeaderFlag flags,
+ guint * length, guint8 ** header, guint8 ** payload)
+{
+ guint8 *h;
+ guint16 crc;
+ gchar *string = NULL;
+ guint pl_length; /* length of payload */
+
+ g_return_val_if_fail (GST_IS_EVENT (event), FALSE);
+
+ *length = GST_DP_HEADER_LENGTH;
+ h = g_malloc0 (GST_DP_HEADER_LENGTH);
+
+ /* first construct payload, since we need the length */
+ switch (GST_EVENT_TYPE (event)) {
+ case GST_EVENT_UNKNOWN:
+ g_warning ("Unknown event, ignoring");
+ *length = 0;
+ g_free (h);
+ return FALSE;
+ case GST_EVENT_EOS:
+ case GST_EVENT_FLUSH:
+ case GST_EVENT_EMPTY:
+ case GST_EVENT_DISCONTINUOUS:
+ GST_DP_WRITE_GUINT64 (h + 8, GST_EVENT_TIMESTAMP (event));
+ pl_length = 0;
+ *payload = NULL;
+ break;
+ case GST_EVENT_SEEK:
+ pl_length = 4 + 8 + 4;
+ *payload = g_malloc0 (pl_length);
+ GST_DP_WRITE_GUINT32 (*payload, (guint32) GST_EVENT_SEEK_TYPE (event));
+ GST_DP_WRITE_GUINT64 (*payload + 4,
+ (guint64) GST_EVENT_SEEK_OFFSET (event));
+ GST_DP_WRITE_GUINT32 (*payload + 12,
+ (guint32) GST_EVENT_SEEK_ACCURACY (event));
+ break;
+ case GST_EVENT_SEEK_SEGMENT:
+ pl_length = 4 + 8 + 8 + 4;
+ *payload = g_malloc0 (pl_length);
+ GST_DP_WRITE_GUINT32 (*payload, (guint32) GST_EVENT_SEEK_TYPE (event));
+ GST_DP_WRITE_GUINT64 (*payload + 4,
+ (guint64) GST_EVENT_SEEK_OFFSET (event));
+ GST_DP_WRITE_GUINT64 (*payload + 12,
+ (guint64) GST_EVENT_SEEK_ENDOFFSET (event));
+ GST_DP_WRITE_GUINT32 (*payload + 20,
+ (guint32) GST_EVENT_SEEK_ACCURACY (event));
+ break;
+ case GST_EVENT_QOS:
+ case GST_EVENT_SEGMENT_DONE:
+ case GST_EVENT_SIZE:
+ case GST_EVENT_RATE:
+ case GST_EVENT_FILLER:
+ case GST_EVENT_TS_OFFSET:
+ case GST_EVENT_INTERRUPT:
+ case GST_EVENT_NAVIGATION:
+ case GST_EVENT_TAG:
+ g_warning ("Unhandled event type %d, ignoring", GST_EVENT_TYPE (event));
+ return FALSE;
+ default:
+ g_warning ("Unknown event type %d, ignoring", GST_EVENT_TYPE (event));
+ *length = 0;
+ g_free (h);
+ return FALSE;
+ }
+
+ /* version, flags, type */
+ h[0] = (guint8) GST_DP_VERSION_MAJOR;
+ h[1] = (guint8) GST_DP_VERSION_MINOR;
+ h[2] = (guint8) flags;
+ h[3] = GST_DP_PAYLOAD_EVENT_NONE + GST_EVENT_TYPE (event);
+
+ /* length */
+ GST_DP_WRITE_GUINT32 (h + 4, (guint32) pl_length);
+ /* timestamp */
+ GST_DP_WRITE_GUINT64 (h + 8, GST_EVENT_TIMESTAMP (event));
+
+ /* ABI padding */
+ GST_DP_WRITE_GUINT64 (h + 40, (guint64) 0);
+ GST_DP_WRITE_GUINT64 (h + 48, (guint64) 0);
+
+ /* CRC */
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_HEADER) {
+ crc = gst_dp_crc (h, 56);
+ }
+ GST_DP_WRITE_GUINT16 (h + 56, crc);
+
+ crc = 0;
+ if (flags & GST_DP_HEADER_FLAG_CRC_PAYLOAD) {
+ crc = gst_dp_crc (string, strlen (string) + 1);
+ }
+ GST_DP_WRITE_GUINT16 (h + 58, crc);
+
+ GST_LOG ("created header from event:");
+ gst_dp_dump_byte_array (h, GST_DP_HEADER_LENGTH);
+ *header = h;
+ return TRUE;
+}
+
+
+/**
+ * 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.
+ *
+ * Returns: %TRUE if the buffer was successfully created
+ */
+GstBuffer *
+gst_dp_buffer_from_header (guint header_length, const guint8 * header)
+{
+ GstBuffer *buffer;
+
+ g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) ==
+ GST_DP_PAYLOAD_BUFFER, FALSE);
+ buffer =
+ gst_buffer_new_and_alloc ((guint) GST_DP_HEADER_PAYLOAD_LENGTH (header));
+ GST_BUFFER_TIMESTAMP (buffer) = GST_DP_HEADER_TIMESTAMP (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);
+
+ 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.
+ *
+ * Returns: %TRUE if the caps was successfully created
+ */
+GstCaps *
+gst_dp_caps_from_packet (guint header_length, const guint8 * header,
+ const guint8 * payload)
+{
+ GstCaps *caps;
+ const gchar *string;
+
+ g_return_val_if_fail (header, FALSE);
+ g_return_val_if_fail (payload, FALSE);
+ g_return_val_if_fail (GST_DP_HEADER_PAYLOAD_TYPE (header) ==
+ GST_DP_PAYLOAD_CAPS, FALSE);
+
+ string = payload;
+ caps = gst_caps_from_string (string);
+ return caps;
+}
+
+/**
+ * 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.
+ *
+ * Returns: %TRUE if the event was successfully created
+ */
+GstEvent *
+gst_dp_event_from_packet (guint header_length, const guint8 * header,
+ const guint8 * payload)
+{
+ GstEvent *event = NULL;
+ GstEventType type;
+
+ g_return_val_if_fail (header, FALSE);
+ /* payload can be NULL, e.g. for an EOS event */
+
+ type = GST_DP_HEADER_PAYLOAD_TYPE (header) - GST_DP_PAYLOAD_EVENT_NONE;
+ switch (type) {
+ case GST_EVENT_UNKNOWN:
+ g_warning ("Unknown event, ignoring");
+ return FALSE;
+ case GST_EVENT_EOS:
+ case GST_EVENT_FLUSH:
+ case GST_EVENT_EMPTY:
+ case GST_EVENT_DISCONTINUOUS:
+ event = gst_event_new (type);
+ GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header);
+ break;
+ case GST_EVENT_SEEK:
+ {
+ GstSeekType type;
+ gint64 offset;
+ GstSeekAccuracy accuracy;
+
+ type = (GstSeekType) GST_DP_GUINT32 (payload);
+ offset = (gint64) GST_DP_GUINT64 (payload + 4);
+ accuracy = (GstSeekAccuracy) GST_DP_GUINT32 (payload + 12);
+ event = gst_event_new_seek (type, offset);
+ GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header);
+ GST_EVENT_SEEK_ACCURACY (event) = accuracy;
+ break;
+ }
+ case GST_EVENT_SEEK_SEGMENT:
+ {
+ GstSeekType type;
+ gint64 offset, endoffset;
+ GstSeekAccuracy accuracy;
+
+ type = (GstSeekType) GST_DP_GUINT32 (payload);
+ offset = (gint64) GST_DP_GUINT64 (payload + 4);
+ endoffset = (gint64) GST_DP_GUINT64 (payload + 12);
+ accuracy = (GstSeekAccuracy) GST_DP_GUINT32 (payload + 20);
+ event = gst_event_new_segment_seek (type, offset, endoffset);
+ GST_EVENT_TIMESTAMP (event) = GST_DP_HEADER_TIMESTAMP (header);
+ GST_EVENT_SEEK_ACCURACY (event) = accuracy;
+ break;
+ }
+ case GST_EVENT_QOS:
+ case GST_EVENT_SEGMENT_DONE:
+ case GST_EVENT_SIZE:
+ case GST_EVENT_RATE:
+ case GST_EVENT_FILLER:
+ case GST_EVENT_TS_OFFSET:
+ case GST_EVENT_INTERRUPT:
+ case GST_EVENT_NAVIGATION:
+ case GST_EVENT_TAG:
+ g_warning ("Unhandled event type %d, ignoring", GST_EVENT_TYPE (event));
+ return FALSE;
+ default:
+ g_warning ("Unknown event type %d, ignoring", GST_EVENT_TYPE (event));
+ return FALSE;
+ }
+
+ return event;
+}
+
+/**
+ * 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;
+
+ if (!(GST_DP_HEADER_FLAGS (header) & GST_DP_HEADER_FLAG_CRC_HEADER))
+ return TRUE;
+ crc_read = GST_DP_HEADER_CRC_HEADER (header);
+ /* don't included the last two crc fields for the crc check */
+ crc_calculated = gst_dp_crc (header, header_length - 4);
+ if (crc_read != crc_calculated) {
+ GST_WARNING ("header crc mismatch: read %02x, calculated %02x", crc_read,
+ crc_calculated);
+ return FALSE;
+ }
+ GST_LOG ("header crc validation: %02x", crc_read);
+ return TRUE;
+}
+
+/**
+ * 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;
+
+ 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) {
+ GST_WARNING ("payload crc mismatch: read %02x, calculated %02x", crc_read,
+ crc_calculated);
+ return FALSE;
+ }
+ GST_LOG ("payload crc validation: %02x", crc_read);
+ return TRUE;
+}
+
+/**
+ * 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;
+}
+
+/*** PLUGIN STUFF ***/
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+ gst_dp_init ();
+
+ return TRUE;
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+ GST_VERSION_MINOR,
+ "gstdataprotocol",
+ "a data protocol to serialize buffers, caps and events",
+ plugin_init, VERSION, GST_LICENSE, GST_PACKAGE, GST_ORIGIN)
projects / platform / upstream / gstreamer.git / commitdiff