michael@0: /********************************************************************
michael@0:  *                                                                  *
michael@0:  * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE.   *
michael@0:  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
michael@0:  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
michael@0:  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
michael@0:  *                                                                  *
michael@0:  * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2009                *
michael@0:  * by the Xiph.Org Foundation and contributors http://www.xiph.org/ *
michael@0:  *                                                                  *
michael@0:  ********************************************************************
michael@0: 
michael@0:   function:
michael@0:     last mod: $Id: decinfo.c 17276 2010-06-05 05:57:05Z tterribe $
michael@0: 
michael@0:  ********************************************************************/
michael@0: 
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: #include <limits.h>
michael@0: #include "decint.h"
michael@0: 
michael@0: 
michael@0: 
michael@0: /*Unpacks a series of octets from a given byte array into the pack buffer.
michael@0:   No checking is done to ensure the buffer contains enough data.
michael@0:   _opb: The pack buffer to read the octets from.
michael@0:   _buf: The byte array to store the unpacked bytes in.
michael@0:   _len: The number of octets to unpack.*/
michael@0: static void oc_unpack_octets(oc_pack_buf *_opb,char *_buf,size_t _len){
michael@0:   while(_len-->0){
michael@0:     long val;
michael@0:     val=oc_pack_read(_opb,8);
michael@0:     *_buf++=(char)val;
michael@0:   }
michael@0: }
michael@0: 
michael@0: /*Unpacks a 32-bit integer encoded by octets in little-endian form.*/
michael@0: static long oc_unpack_length(oc_pack_buf *_opb){
michael@0:   long ret[4];
michael@0:   int  i;
michael@0:   for(i=0;i<4;i++)ret[i]=oc_pack_read(_opb,8);
michael@0:   return ret[0]|ret[1]<<8|ret[2]<<16|ret[3]<<24;
michael@0: }
michael@0: 
michael@0: static int oc_info_unpack(oc_pack_buf *_opb,th_info *_info){
michael@0:   long val;
michael@0:   /*Check the codec bitstream version.*/
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->version_major=(unsigned char)val;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->version_minor=(unsigned char)val;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->version_subminor=(unsigned char)val;
michael@0:   /*verify we can parse this bitstream version.
michael@0:      We accept earlier minors and all subminors, by spec*/
michael@0:   if(_info->version_major>TH_VERSION_MAJOR||
michael@0:    _info->version_major==TH_VERSION_MAJOR&&
michael@0:    _info->version_minor>TH_VERSION_MINOR){
michael@0:     return TH_EVERSION;
michael@0:   }
michael@0:   /*Read the encoded frame description.*/
michael@0:   val=oc_pack_read(_opb,16);
michael@0:   _info->frame_width=(ogg_uint32_t)val<<4;
michael@0:   val=oc_pack_read(_opb,16);
michael@0:   _info->frame_height=(ogg_uint32_t)val<<4;
michael@0:   val=oc_pack_read(_opb,24);
michael@0:   _info->pic_width=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,24);
michael@0:   _info->pic_height=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->pic_x=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->pic_y=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,32);
michael@0:   _info->fps_numerator=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,32);
michael@0:   _info->fps_denominator=(ogg_uint32_t)val;
michael@0:   if(_info->frame_width==0||_info->frame_height==0||
michael@0:    _info->pic_width+_info->pic_x>_info->frame_width||
michael@0:    _info->pic_height+_info->pic_y>_info->frame_height||
michael@0:    _info->fps_numerator==0||_info->fps_denominator==0){
michael@0:     return TH_EBADHEADER;
michael@0:   }
michael@0:   /*Note: The sense of pic_y is inverted in what we pass back to the
michael@0:      application compared to how it is stored in the bitstream.
michael@0:     This is because the bitstream uses a right-handed coordinate system, while
michael@0:      applications expect a left-handed one.*/
michael@0:   _info->pic_y=_info->frame_height-_info->pic_height-_info->pic_y;
michael@0:   val=oc_pack_read(_opb,24);
michael@0:   _info->aspect_numerator=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,24);
michael@0:   _info->aspect_denominator=(ogg_uint32_t)val;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   _info->colorspace=(th_colorspace)val;
michael@0:   val=oc_pack_read(_opb,24);
michael@0:   _info->target_bitrate=(int)val;
michael@0:   val=oc_pack_read(_opb,6);
michael@0:   _info->quality=(int)val;
michael@0:   val=oc_pack_read(_opb,5);
michael@0:   _info->keyframe_granule_shift=(int)val;
michael@0:   val=oc_pack_read(_opb,2);
michael@0:   _info->pixel_fmt=(th_pixel_fmt)val;
michael@0:   if(_info->pixel_fmt==TH_PF_RSVD)return TH_EBADHEADER;
michael@0:   val=oc_pack_read(_opb,3);
michael@0:   if(val!=0||oc_pack_bytes_left(_opb)<0)return TH_EBADHEADER;
michael@0:   return 0;
michael@0: }
michael@0: 
michael@0: static int oc_comment_unpack(oc_pack_buf *_opb,th_comment *_tc){
michael@0:   long len;
michael@0:   int  i;
michael@0:   /*Read the vendor string.*/
michael@0:   len=oc_unpack_length(_opb);
michael@0:   if(len<0||len>oc_pack_bytes_left(_opb))return TH_EBADHEADER;
michael@0:   _tc->vendor=_ogg_malloc((size_t)len+1);
michael@0:   if(_tc->vendor==NULL)return TH_EFAULT;
michael@0:   oc_unpack_octets(_opb,_tc->vendor,len);
michael@0:   _tc->vendor[len]='\0';
michael@0:   /*Read the user comments.*/
michael@0:   _tc->comments=(int)oc_unpack_length(_opb);
michael@0:   len=_tc->comments;
michael@0:   if(len<0||len>(LONG_MAX>>2)||len<<2>oc_pack_bytes_left(_opb)){
michael@0:     _tc->comments=0;
michael@0:     return TH_EBADHEADER;
michael@0:   }
michael@0:   _tc->comment_lengths=(int *)_ogg_malloc(
michael@0:    _tc->comments*sizeof(_tc->comment_lengths[0]));
michael@0:   _tc->user_comments=(char **)_ogg_malloc(
michael@0:    _tc->comments*sizeof(_tc->user_comments[0]));
michael@0:   if(_tc->comment_lengths==NULL||_tc->user_comments==NULL){
michael@0:     _tc->comments=0;
michael@0:     return TH_EFAULT;
michael@0:   }
michael@0:   for(i=0;i<_tc->comments;i++){
michael@0:     len=oc_unpack_length(_opb);
michael@0:     if(len<0||len>oc_pack_bytes_left(_opb)){
michael@0:       _tc->comments=i;
michael@0:       return TH_EBADHEADER;
michael@0:     }
michael@0:     _tc->comment_lengths[i]=len;
michael@0:     _tc->user_comments[i]=_ogg_malloc((size_t)len+1);
michael@0:     if(_tc->user_comments[i]==NULL){
michael@0:       _tc->comments=i;
michael@0:       return TH_EFAULT;
michael@0:     }
michael@0:     oc_unpack_octets(_opb,_tc->user_comments[i],len);
michael@0:     _tc->user_comments[i][len]='\0';
michael@0:   }
michael@0:   return oc_pack_bytes_left(_opb)<0?TH_EBADHEADER:0;
michael@0: }
michael@0: 
michael@0: static int oc_setup_unpack(oc_pack_buf *_opb,th_setup_info *_setup){
michael@0:   int ret;
michael@0:   /*Read the quantizer tables.*/
michael@0:   ret=oc_quant_params_unpack(_opb,&_setup->qinfo);
michael@0:   if(ret<0)return ret;
michael@0:   /*Read the Huffman trees.*/
michael@0:   return oc_huff_trees_unpack(_opb,_setup->huff_tables);
michael@0: }
michael@0: 
michael@0: static void oc_setup_clear(th_setup_info *_setup){
michael@0:   oc_quant_params_clear(&_setup->qinfo);
michael@0:   oc_huff_trees_clear(_setup->huff_tables);
michael@0: }
michael@0: 
michael@0: static int oc_dec_headerin(oc_pack_buf *_opb,th_info *_info,
michael@0:  th_comment *_tc,th_setup_info **_setup,ogg_packet *_op){
michael@0:   char buffer[6];
michael@0:   long val;
michael@0:   int  packtype;
michael@0:   int  ret;
michael@0:   val=oc_pack_read(_opb,8);
michael@0:   packtype=(int)val;
michael@0:   /*If we're at a data packet and we have received all three headers, we're
michael@0:      done.*/
michael@0:   if(!(packtype&0x80)&&_info->frame_width>0&&_tc->vendor!=NULL&&*_setup!=NULL){
michael@0:     return 0;
michael@0:   }
michael@0:   /*Check the codec string.*/
michael@0:   oc_unpack_octets(_opb,buffer,6);
michael@0:   if(memcmp(buffer,"theora",6)!=0)return TH_ENOTFORMAT;
michael@0:   switch(packtype){
michael@0:     /*Codec info header.*/
michael@0:     case 0x80:{
michael@0:       /*This should be the first packet, and we should not already be
michael@0:          initialized.*/
michael@0:       if(!_op->b_o_s||_info->frame_width>0)return TH_EBADHEADER;
michael@0:       ret=oc_info_unpack(_opb,_info);
michael@0:       if(ret<0)th_info_clear(_info);
michael@0:       else ret=3;
michael@0:     }break;
michael@0:     /*Comment header.*/
michael@0:     case 0x81:{
michael@0:       if(_tc==NULL)return TH_EFAULT;
michael@0:       /*We shoud have already decoded the info header, and should not yet have
michael@0:          decoded the comment header.*/
michael@0:       if(_info->frame_width==0||_tc->vendor!=NULL)return TH_EBADHEADER;
michael@0:       ret=oc_comment_unpack(_opb,_tc);
michael@0:       if(ret<0)th_comment_clear(_tc);
michael@0:       else ret=2;
michael@0:     }break;
michael@0:     /*Codec setup header.*/
michael@0:     case 0x82:{
michael@0:       oc_setup_info *setup;
michael@0:       if(_tc==NULL||_setup==NULL)return TH_EFAULT;
michael@0:       /*We should have already decoded the info header and the comment header,
michael@0:          and should not yet have decoded the setup header.*/
michael@0:       if(_info->frame_width==0||_tc->vendor==NULL||*_setup!=NULL){
michael@0:         return TH_EBADHEADER;
michael@0:       }
michael@0:       setup=(oc_setup_info *)_ogg_calloc(1,sizeof(*setup));
michael@0:       if(setup==NULL)return TH_EFAULT;
michael@0:       ret=oc_setup_unpack(_opb,setup);
michael@0:       if(ret<0){
michael@0:         oc_setup_clear(setup);
michael@0:         _ogg_free(setup);
michael@0:       }
michael@0:       else{
michael@0:         *_setup=setup;
michael@0:         ret=1;
michael@0:       }
michael@0:     }break;
michael@0:     default:{
michael@0:       /*We don't know what this header is.*/
michael@0:       return TH_EBADHEADER;
michael@0:     }break;
michael@0:   }
michael@0:   return ret;
michael@0: }
michael@0: 
michael@0: 
michael@0: /*Decodes one header packet.
michael@0:   This should be called repeatedly with the packets at the beginning of the
michael@0:    stream until it returns 0.*/
michael@0: int th_decode_headerin(th_info *_info,th_comment *_tc,
michael@0:  th_setup_info **_setup,ogg_packet *_op){
michael@0:   oc_pack_buf opb;
michael@0:   if(_op==NULL)return TH_EBADHEADER;
michael@0:   if(_info==NULL)return TH_EFAULT;
michael@0:   oc_pack_readinit(&opb,_op->packet,_op->bytes);
michael@0:   return oc_dec_headerin(&opb,_info,_tc,_setup,_op);
michael@0: }
michael@0: 
michael@0: void th_setup_free(th_setup_info *_setup){
michael@0:   if(_setup!=NULL){
michael@0:     oc_setup_clear(_setup);
michael@0:     _ogg_free(_setup);
michael@0:   }
michael@0: }