media/libtheora/lib/dec/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) 2002-2007                *
   9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
  10  *                                                                  *
  11  ********************************************************************
  12
  13   function:
  14     last mod: $Id: decinfo.c 14719 2008-04-12 11:36:40Z tterribe $
  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(oggpack_buffer *_opb,char *_buf,size_t _len){
  31   while(_len-->0){
  32     long val;
  33     theorapackB_read(_opb,8,&val);
  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(oggpack_buffer *_opb){
  40   long ret[4];
  41   int  i;
  42   for(i=0;i<4;i++)theorapackB_read(_opb,8,ret+i);
  43   return ret[0]|ret[1]<<8|ret[2]<<16|ret[3]<<24;
  44 }
  45
  46 static int oc_info_unpack(oggpack_buffer *_opb,th_info *_info){
  47   long val;
  48   /*Check the codec bitstream version.*/
  49   theorapackB_read(_opb,8,&val);
  50   _info->version_major=(unsigned char)val;
  51   theorapackB_read(_opb,8,&val);
  52   _info->version_minor=(unsigned char)val;
  53   theorapackB_read(_opb,8,&val);
  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   theorapackB_read(_opb,16,&val);
  64   _info->frame_width=(ogg_uint32_t)val<<4;
  65   theorapackB_read(_opb,16,&val);
  66   _info->frame_height=(ogg_uint32_t)val<<4;
  67   theorapackB_read(_opb,24,&val);
  68   _info->pic_width=(ogg_uint32_t)val;
  69   theorapackB_read(_opb,24,&val);
  70   _info->pic_height=(ogg_uint32_t)val;
  71   theorapackB_read(_opb,8,&val);
  72   _info->pic_x=(ogg_uint32_t)val;
  73   /*Note: The sense of pic_y is inverted in what we pass back to the
  74      application compared to how it is stored in the bitstream.
  75     This is because the bitstream uses a right-handed coordinate system, while
  76      applications expect a left-handed one.*/
  77   theorapackB_read(_opb,8,&val);
  78   _info->pic_y=_info->frame_height-_info->pic_height-(ogg_uint32_t)val;
  79   theorapackB_read(_opb,32,&val);
  80   _info->fps_numerator=(ogg_uint32_t)val;
  81   theorapackB_read(_opb,32,&val);
  82   _info->fps_denominator=(ogg_uint32_t)val;
  83   if(_info->frame_width==0||_info->frame_height==0||
  84    _info->pic_width+_info->pic_x>_info->frame_width||
  85    _info->pic_height+_info->pic_y>_info->frame_height||
  86    _info->fps_numerator==0||_info->fps_denominator==0){
  87     return TH_EBADHEADER;
  88   }
  89   theorapackB_read(_opb,24,&val);
  90   _info->aspect_numerator=(ogg_uint32_t)val;
  91   theorapackB_read(_opb,24,&val);
  92   _info->aspect_denominator=(ogg_uint32_t)val;
  93   theorapackB_read(_opb,8,&val);
  94   _info->colorspace=(th_colorspace)val;
  95   theorapackB_read(_opb,24,&val);
  96   _info->target_bitrate=(int)val;
  97   theorapackB_read(_opb,6,&val);
  98   _info->quality=(int)val;
  99   theorapackB_read(_opb,5,&val);
 100   _info->keyframe_granule_shift=(int)val;
 101   theorapackB_read(_opb,2,&val);
 102   _info->pixel_fmt=(th_pixel_fmt)val;
 103   if(_info->pixel_fmt==TH_PF_RSVD)return TH_EBADHEADER;
 104   if(theorapackB_read(_opb,3,&val)<0||val!=0)return TH_EBADHEADER;
 105   return 0;
 106 }
 107
 108 static int oc_comment_unpack(oggpack_buffer *_opb,th_comment *_tc){
 109   long len;
 110   int  i;
 111   /*Read the vendor string.*/
 112   len=oc_unpack_length(_opb);
 113   if(len<0||theorapackB_bytes(_opb)+len>_opb->storage)return TH_EBADHEADER;
 114   _tc->vendor=_ogg_malloc((size_t)len+1);
 115   oc_unpack_octets(_opb,_tc->vendor,len);
 116   _tc->vendor[len]='\0';
 117   /*Read the user comments.*/
 118   _tc->comments=(int)oc_unpack_length(_opb);
 119   if(_tc->comments<0||_tc->comments>(LONG_MAX>>2)||
 120    theorapackB_bytes(_opb)+((long)_tc->comments<<2)>_opb->storage){
 121     return TH_EBADHEADER;
 122   }
 123   _tc->comment_lengths=(int *)_ogg_malloc(
 124    _tc->comments*sizeof(_tc->comment_lengths[0]));
 125   _tc->user_comments=(char **)_ogg_malloc(
 126    _tc->comments*sizeof(_tc->user_comments[0]));
 127   for(i=0;i<_tc->comments;i++){
 128     len=oc_unpack_length(_opb);
 129     if(len<0||theorapackB_bytes(_opb)+len>_opb->storage){
 130       _tc->comments=i;
 131       return TH_EBADHEADER;
 132     }
 133     _tc->comment_lengths[i]=len;
 134     _tc->user_comments[i]=_ogg_malloc((size_t)len+1);
 135     oc_unpack_octets(_opb,_tc->user_comments[i],len);
 136     _tc->user_comments[i][len]='\0';
 137   }
 138   return theorapackB_read(_opb,0,&len)<0?TH_EBADHEADER:0;
 139 }
 140
 141 static int oc_setup_unpack(oggpack_buffer *_opb,th_setup_info *_setup){
 142   int ret;
 143   /*Read the quantizer tables.*/
 144   ret=oc_quant_params_unpack(_opb,&_setup->qinfo);
 145   if(ret<0)return ret;
 146   /*Read the Huffman trees.*/
 147   return oc_huff_trees_unpack(_opb,_setup->huff_tables);
 148 }
 149
 150 static void oc_setup_clear(th_setup_info *_setup){
 151   oc_quant_params_clear(&_setup->qinfo);
 152   oc_huff_trees_clear(_setup->huff_tables);
 153 }
 154
 155 static int oc_dec_headerin(oggpack_buffer *_opb,th_info *_info,
 156  th_comment *_tc,th_setup_info **_setup,ogg_packet *_op){
 157   char buffer[6];
 158   long val;
 159   int  packtype;
 160   int  ret;
 161   theorapackB_read(_opb,8,&val);
 162   packtype=(int)val;
 163   /*If we're at a data packet and we have received all three headers, we're
 164      done.*/
 165   if(!(packtype&0x80)&&_info->frame_width>0&&_tc->vendor!=NULL&&*_setup!=NULL){
 166     return 0;
 167   }
 168   /*Check the codec string.*/
 169   oc_unpack_octets(_opb,buffer,6);
 170   if(memcmp(buffer,"theora",6)!=0)return TH_ENOTFORMAT;
 171   switch(packtype){
 172     /*Codec info header.*/
 173     case 0x80:{
 174       /*This should be the first packet, and we should not already be
 175          initialized.*/
 176       if(!_op->b_o_s||_info->frame_width>0)return TH_EBADHEADER;
 177       ret=oc_info_unpack(_opb,_info);
 178       if(ret<0)th_info_clear(_info);
 179       else ret=3;
 180     }break;
 181     /*Comment header.*/
 182     case 0x81:{
 183       if(_tc==NULL)return TH_EFAULT;
 184       /*We shoud have already decoded the info header, and should not yet have
 185          decoded the comment header.*/
 186       if(_info->frame_width==0||_tc->vendor!=NULL)return TH_EBADHEADER;
 187       ret=oc_comment_unpack(_opb,_tc);
 188       if(ret<0)th_comment_clear(_tc);
 189       else ret=2;
 190     }break;
 191     /*Codec setup header.*/
 192     case 0x82:{
 193       oc_setup_info *setup;
 194       if(_tc==NULL||_setup==NULL)return TH_EFAULT;
 195       /*We should have already decoded the info header and the comment header,
 196          and should not yet have decoded the setup header.*/
 197       if(_info->frame_width==0||_tc->vendor==NULL||*_setup!=NULL){
 198         return TH_EBADHEADER;
 199       }
 200       setup=(oc_setup_info *)_ogg_calloc(1,sizeof(*setup));
 201       ret=oc_setup_unpack(_opb,setup);
 202       if(ret<0){
 203         oc_setup_clear(setup);
 204         _ogg_free(setup);
 205       }
 206       else{
 207         *_setup=setup;
 208         ret=1;
 209       }
 210     }break;
 211     default:{
 212       /*We don't know what this header is.*/
 213       return TH_EBADHEADER;
 214     }break;
 215   }
 216   return ret;
 217 }
 218
 219
 220 /*Decodes one header packet.
 221   This should be called repeatedly with the packets at the beginning of the
 222    stream until it returns 0.*/
 223 int th_decode_headerin(th_info *_info,th_comment *_tc,
 224  th_setup_info **_setup,ogg_packet *_op){
 225   oggpack_buffer opb;
 226   int            ret;
 227   if(_op==NULL)return TH_EBADHEADER;
 228   if(_info==NULL)return TH_EFAULT;
 229   theorapackB_readinit(&opb,_op->packet,_op->bytes);
 230   ret=oc_dec_headerin(&opb,_info,_tc,_setup,_op);
 231   return ret;
 232 }
 233
 234 void th_setup_free(th_setup_info *_setup){
 235   if(_setup!=NULL){
 236     oc_setup_clear(_setup);
 237     _ogg_free(_setup);
 238   }
 239 }