lib/decinfo.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE.   *
   4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   7  *                                                                  *
   8  * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009                *
   9  * by the Xiph.Org Foundation and contributors http://www.xiph.org/ *
  10  *                                                                  *
  11  ********************************************************************
  12
  13   function:
  14     last mod: $Id: decinfo.c 16503 2009-08-22 18:14:02Z giles $
  15
  16  ********************************************************************/
  17
  18 #include <stdlib.h>
  19 #include <string.h>
  20 #include <limits.h>
  21 #include "decint.h"
  22
  23
  24
  25 /*Unpacks a series of octets from a given byte array into the pack buffer.
  26   No checking is done to ensure the buffer contains enough data.
  27   _opb: The pack buffer to read the octets from.
  28   _buf: The byte array to store the unpacked bytes in.
  29   _len: The number of octets to unpack.*/
  30 static void oc_unpack_octets(oc_pack_buf *_opb,char *_buf,size_t _len){
  31   while(_len-->0){
  32     long val;
  33     val=oc_pack_read(_opb,8);
  34     *_buf++=(char)val;
  35   }
  36 }
  37
  38 /*Unpacks a 32-bit integer encoded by octets in little-endian form.*/
  39 static long oc_unpack_length(oc_pack_buf *_opb){
  40   long ret[4];
  41   int  i;
  42   for(i=0;i<4;i++)ret[i]=oc_pack_read(_opb,8);
  43   return ret[0]|ret[1]<<8|ret[2]<<16|ret[3]<<24;
  44 }
  45
  46 static int oc_info_unpack(oc_pack_buf *_opb,th_info *_info){
  47   long val;
  48   /*Check the codec bitstream version.*/
  49   val=oc_pack_read(_opb,8);
  50   _info->version_major=(unsigned char)val;
  51   val=oc_pack_read(_opb,8);
  52   _info->version_minor=(unsigned char)val;
  53   val=oc_pack_read(_opb,8);
  54   _info->version_subminor=(unsigned char)val;
  55   /*verify we can parse this bitstream version.
  56      We accept earlier minors and all subminors, by spec*/
  57   if(_info->version_major>TH_VERSION_MAJOR||
  58    _info->version_major==TH_VERSION_MAJOR&&
  59    _info->version_minor>TH_VERSION_MINOR){
  60     return TH_EVERSION;
  61   }
  62   /*Read the encoded frame description.*/
  63   val=oc_pack_read(_opb,16);
  64   _info->frame_width=(ogg_uint32_t)val<<4;
  65   val=oc_pack_read(_opb,16);
  66   _info->frame_height=(ogg_uint32_t)val<<4;
  67   val=oc_pack_read(_opb,24);
  68   _info->pic_width=(ogg_uint32_t)val;
  69   val=oc_pack_read(_opb,24);
  70   _info->pic_height=(ogg_uint32_t)val;
  71   val=oc_pack_read(_opb,8);
  72   _info->pic_x=(ogg_uint32_t)val;
  73   val=oc_pack_read(_opb,8);
  74   _info->pic_y=(ogg_uint32_t)val;
  75   val=oc_pack_read(_opb,32);
  76   _info->fps_numerator=(ogg_uint32_t)val;
  77   val=oc_pack_read(_opb,32);
  78   _info->fps_denominator=(ogg_uint32_t)val;
  79   if(_info->frame_width==0||_info->frame_height==0||
  80    _info->pic_width+_info->pic_x>_info->frame_width||
  81    _info->pic_height+_info->pic_y>_info->frame_height||
  82    _info->fps_numerator==0||_info->fps_denominator==0){
  83     return TH_EBADHEADER;
  84   }
  85   /*Note: The sense of pic_y is inverted in what we pass back to the
  86      application compared to how it is stored in the bitstream.
  87     This is because the bitstream uses a right-handed coordinate system, while
  88      applications expect a left-handed one.*/
  89   _info->pic_y=_info->frame_height-_info->pic_height-_info->pic_y;
  90   val=oc_pack_read(_opb,24);
  91   _info->aspect_numerator=(ogg_uint32_t)val;
  92   val=oc_pack_read(_opb,24);
  93   _info->aspect_denominator=(ogg_uint32_t)val;
  94   val=oc_pack_read(_opb,8);
  95   _info->colorspace=(th_colorspace)val;
  96   val=oc_pack_read(_opb,24);
  97   _info->target_bitrate=(int)val;
  98   val=oc_pack_read(_opb,6);
  99   _info->quality=(int)val;
 100   val=oc_pack_read(_opb,5);
 101   _info->keyframe_granule_shift=(int)val;
 102   val=oc_pack_read(_opb,2);
 103   _info->pixel_fmt=(th_pixel_fmt)val;
 104   if(_info->pixel_fmt==TH_PF_RSVD)return TH_EBADHEADER;
 105   val=oc_pack_read(_opb,3);
 106   if(val!=0||oc_pack_bytes_left(_opb)<0)return TH_EBADHEADER;
 107   return 0;
 108 }
 109
 110 static int oc_comment_unpack(oc_pack_buf *_opb,th_comment *_tc){
 111   long len;
 112   int  i;
 113   /*Read the vendor string.*/
 114   len=oc_unpack_length(_opb);
 115   if(len<0||len>oc_pack_bytes_left(_opb))return TH_EBADHEADER;
 116   _tc->vendor=_ogg_malloc((size_t)len+1);
 117   if(_tc->vendor==NULL)return TH_EFAULT;
 118   oc_unpack_octets(_opb,_tc->vendor,len);
 119   _tc->vendor[len]='\0';
 120   /*Read the user comments.*/
 121   _tc->comments=(int)oc_unpack_length(_opb);
 122   len=_tc->comments;
 123   if(len<0||len>(LONG_MAX>>2)||len<<2>oc_pack_bytes_left(_opb)){
 124     _tc->comments=0;
 125     return TH_EBADHEADER;
 126   }
 127   _tc->comment_lengths=(int *)_ogg_malloc(
 128    _tc->comments*sizeof(_tc->comment_lengths[0]));
 129   _tc->user_comments=(char **)_ogg_malloc(
 130    _tc->comments*sizeof(_tc->user_comments[0]));
 131   for(i=0;i<_tc->comments;i++){
 132     len=oc_unpack_length(_opb);
 133     if(len<0||len>oc_pack_bytes_left(_opb)){
 134       _tc->comments=i;
 135       return TH_EBADHEADER;
 136     }
 137     _tc->comment_lengths[i]=len;
 138     _tc->user_comments[i]=_ogg_malloc((size_t)len+1);
 139     if(_tc->user_comments[i]==NULL){
 140       _tc->comments=i;
 141       return TH_EFAULT;
 142     }
 143     oc_unpack_octets(_opb,_tc->user_comments[i],len);
 144     _tc->user_comments[i][len]='\0';
 145   }
 146   return oc_pack_bytes_left(_opb)<0?TH_EBADHEADER:0;
 147 }
 148
 149 static int oc_setup_unpack(oc_pack_buf *_opb,th_setup_info *_setup){
 150   int ret;
 151   /*Read the quantizer tables.*/
 152   ret=oc_quant_params_unpack(_opb,&_setup->qinfo);
 153   if(ret<0)return ret;
 154   /*Read the Huffman trees.*/
 155   return oc_huff_trees_unpack(_opb,_setup->huff_tables);
 156 }
 157
 158 static void oc_setup_clear(th_setup_info *_setup){
 159   oc_quant_params_clear(&_setup->qinfo);
 160   oc_huff_trees_clear(_setup->huff_tables);
 161 }
 162
 163 static int oc_dec_headerin(oc_pack_buf *_opb,th_info *_info,
 164  th_comment *_tc,th_setup_info **_setup,ogg_packet *_op){
 165   char buffer[6];
 166   long val;
 167   int  packtype;
 168   int  ret;
 169   val=oc_pack_read(_opb,8);
 170   packtype=(int)val;
 171   /*If we're at a data packet and we have received all three headers, we're
 172      done.*/
 173   if(!(packtype&0x80)&&_info->frame_width>0&&_tc->vendor!=NULL&&*_setup!=NULL){
 174     return 0;
 175   }
 176   /*Check the codec string.*/
 177   oc_unpack_octets(_opb,buffer,6);
 178   if(memcmp(buffer,"theora",6)!=0)return TH_ENOTFORMAT;
 179   switch(packtype){
 180     /*Codec info header.*/
 181     case 0x80:{
 182       /*This should be the first packet, and we should not already be
 183          initialized.*/
 184       if(!_op->b_o_s||_info->frame_width>0)return TH_EBADHEADER;
 185       ret=oc_info_unpack(_opb,_info);
 186       if(ret<0)th_info_clear(_info);
 187       else ret=3;
 188     }break;
 189     /*Comment header.*/
 190     case 0x81:{
 191       if(_tc==NULL)return TH_EFAULT;
 192       /*We shoud have already decoded the info header, and should not yet have
 193          decoded the comment header.*/
 194       if(_info->frame_width==0||_tc->vendor!=NULL)return TH_EBADHEADER;
 195       ret=oc_comment_unpack(_opb,_tc);
 196       if(ret<0)th_comment_clear(_tc);
 197       else ret=2;
 198     }break;
 199     /*Codec setup header.*/
 200     case 0x82:{
 201       oc_setup_info *setup;
 202       if(_tc==NULL||_setup==NULL)return TH_EFAULT;
 203       /*We should have already decoded the info header and the comment header,
 204          and should not yet have decoded the setup header.*/
 205       if(_info->frame_width==0||_tc->vendor==NULL||*_setup!=NULL){
 206         return TH_EBADHEADER;
 207       }
 208       setup=(oc_setup_info *)_ogg_calloc(1,sizeof(*setup));
 209       if(setup==NULL)return TH_EFAULT;
 210       ret=oc_setup_unpack(_opb,setup);
 211       if(ret<0){
 212         oc_setup_clear(setup);
 213         _ogg_free(setup);
 214       }
 215       else{
 216         *_setup=setup;
 217         ret=1;
 218       }
 219     }break;
 220     default:{
 221       /*We don't know what this header is.*/
 222       return TH_EBADHEADER;
 223     }break;
 224   }
 225   return ret;
 226 }
 227
 228
 229 /*Decodes one header packet.
 230   This should be called repeatedly with the packets at the beginning of the
 231    stream until it returns 0.*/
 232 int th_decode_headerin(th_info *_info,th_comment *_tc,
 233  th_setup_info **_setup,ogg_packet *_op){
 234   oc_pack_buf opb;
 235   if(_op==NULL)return TH_EBADHEADER;
 236   if(_info==NULL)return TH_EFAULT;
 237   oc_pack_readinit(&opb,_op->packet,_op->bytes);
 238   return oc_dec_headerin(&opb,_info,_tc,_setup,_op);
 239 }
 240
 241 void th_setup_free(th_setup_info *_setup){
 242   if(_setup!=NULL){
 243     oc_setup_clear(_setup);
 244     _ogg_free(_setup);
 245   }
 246 }