gstreamer/libs/riff/gstriff.c

/* Gnome-Streamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 *
 * 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.
 */


#include <gstriff.h>


GstRiff *gst_riff_new(GstRiffCallback function, gpointer data) {
  GstRiff *riff;

  riff = (GstRiff *)g_malloc(sizeof(GstRiff));
  g_return_val_if_fail(riff != NULL, NULL);

  riff->form = 0;
  riff->chunks = NULL;
  riff->state = 0;
  riff->curoffset = 0;
  riff->nextlikely = 0;
	riff->new_tag_found = function;
	riff->callback_data = data;

  return riff;
}

gint gst_riff_next_buffer(GstRiff *riff,GstBuffer *buf,gulong off) {
  gulong last;
  GstRiffChunk *chunk;

  g_return_val_if_fail(riff != NULL, GST_RIFF_EINVAL);
  g_return_val_if_fail(buf != NULL, GST_RIFF_EINVAL);
  g_return_val_if_fail(GST_BUFFER_DATA(buf) != NULL, GST_RIFF_EINVAL);

  last = off + GST_BUFFER_SIZE(buf);

	//g_print("offset new buffer 0x%08lx\n", off);

  if (off == 0) {
    gulong *words = (gulong *)GST_BUFFER_DATA(buf);

		// don't even try to parse the head if it's not there
		if (last < 12) {
      riff->state = GST_RIFF_ENOTRIFF;
      return riff->state;
		}

    //g_print("testing is 0x%08lx '%s'\n",words[0],gst_riff_id_to_fourcc(words[0]));
    /* verify this is a valid RIFF file, first of all */
    if (words[0] != GST_RIFF_TAG_RIFF) {
      riff->state = GST_RIFF_ENOTRIFF;
      return riff->state;
    }
    riff->form = words[2];
    //g_print("form is 0x%08lx '%s'\n",words[2],gst_riff_id_to_fourcc(words[2]));
    riff->nextlikely = 12;	/* skip 'RIFF', length, and form */
  }

  /* loop while the next likely chunk header is in this buffer */
  while ((riff->nextlikely+12) < last) {
    gulong *words = (gulong *)((guchar *)GST_BUFFER_DATA(buf) + riff->nextlikely - off );

		// loop over all of the chunks to check which one is finished
		while (riff->chunks) {
			chunk = g_list_nth_data(riff->chunks, 0);

      //g_print("next 0x%08x  offset 0x%08lx size 0x%08x\n",riff->nextlikely, chunk->offset, chunk->size);
			if (riff->nextlikely >= chunk->offset+chunk->size) {
        //g_print("found END LIST\n");
				// we have the end of the chunk on the stack, remove it
				riff->chunks = g_list_remove(riff->chunks, chunk);
			}
			else break;
		}

    //g_print("next likely chunk is at offset 0x%08x\n",riff->nextlikely);

    chunk = (GstRiffChunk *)g_malloc(sizeof(GstRiffChunk));
    g_return_val_if_fail(chunk != NULL, GST_RIFF_ENOMEM);

    chunk->offset = riff->nextlikely+8;	/* point to the actual data */
    chunk->id = words[0];
    chunk->size = words[1];
		chunk->data = (gchar *)(words+2);
		// we need word alignment
		if (chunk->size & 0x01) chunk->size++;
		chunk->form = words[2]; /* fill in the form,  might not be valid */

		// send the buffer to the listener if we have received a function
		if (riff->new_tag_found) {
		  riff->new_tag_found(chunk, riff->callback_data);
		}

		if (chunk->id == GST_RIFF_TAG_LIST) {
      //g_print("found LIST %s\n", gst_riff_id_to_fourcc(chunk->form));
      riff->nextlikely += 12;	
			// we push the list chunk on our 'stack'
      riff->chunks = g_list_prepend(riff->chunks,chunk);
		}
		else {

      //g_print("chunk id is 0x%08lx '%s' and is 0x%08lx long\n",words[0],
       //     gst_riff_id_to_fourcc(words[0]),words[1]);

      riff->nextlikely += 8 + chunk->size;	/* doesn't include hdr */
			g_free(chunk);
      //riff->chunks = g_list_prepend(riff->chunks,chunk);
		}
  }

  return 0;
}


gulong gst_riff_fourcc_to_id(gchar *fourcc) {
  g_return_val_if_fail(fourcc != NULL, 0);

  return (fourcc[0] << 0) | (fourcc[1] << 8) |
         (fourcc[2] << 16) | (fourcc[3] << 24);
}

gchar *gst_riff_id_to_fourcc(gulong id) {
  gchar *fourcc = (gchar *)g_malloc(5);

  g_return_val_if_fail(fourcc != NULL, NULL);

  fourcc[0] = (id >> 0) & 0xff;
  fourcc[1] = (id >> 8) & 0xff;
  fourcc[2] = (id >> 16) & 0xff;
  fourcc[3] = (id >> 24) & 0xff;
  fourcc[4] = 0;

  return fourcc;
}