info.c

OGG文件格式音频数解压缩SDK.现在OGG文件格式在一些游戏开发中使用的比较多.

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: maintain the info structure, info <-> header packets
 last mod: $Id: info.c,v 1.61 2002/10/11 11:14:41 xiphmont Exp $

 ********************************************************************/

/* general handling of the header and the vorbis_info structure (and
   substructures) */

#include <stdlib.h>
#include <memory.h>
#include <ogg/ogg.h>
#include "vorbis/codec.h"
#include "codec_internal.h"
#include "codebook.h"
#include "registry.h"
#include "window.h"
#include "psy.h"
#include "misc.h"
#include "os.h"

/* helpers */
static int ilog2(unsigned int v){
  int ret=0;
  if(v)--v;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

char ogg_toupper(char in)
{
    if (in >= 'a' && in <= 'z')
    {
        in += 'A' - 'a';
    }

    return in;
}

#if 0
static void _v_writestring(oggpack_buffer *o,char *s, int bytes){

  while(bytes--){
    oggpack_write(o,*s++,8);
  }
}
#endif

static void _v_readstring(oggpack_buffer *o,char *buf,int bytes){
  while(bytes--){
    *buf++=(char)oggpack_read(o,8);
  }
}

void vorbis_comment_init(vorbis_comment *vc){
  memset(vc,0,sizeof(*vc));
}

void vorbis_comment_add(vorbis_comment *vc,char *comment)
{
  vc->user_comments     = _ogg_realloc(vc->user_comments,   (vc->comments+2)*sizeof(*vc->user_comments));
  vc->comment_lengths   = _ogg_realloc(vc->comment_lengths, (vc->comments+2)*sizeof(*vc->comment_lengths));

  vc->comment_lengths[vc->comments] = (int)ogg_strlen(comment);

  vc->user_comments[vc->comments] = _ogg_malloc(vc->comment_lengths[vc->comments]+1);

  ogg_strcpy(vc->user_comments[vc->comments], comment);

  vc->comments++;
  vc->user_comments[vc->comments]=NULL;
}

void vorbis_comment_add_tag(vorbis_comment *vc, char *tag, char *contents){
  char *comment=alloca(ogg_strlen(tag)+ogg_strlen(contents)+2); /* +2 for = and \0 */
  ogg_strcpy(comment, tag);
  ogg_strcat(comment, "=");
  ogg_strcat(comment, contents);
  vorbis_comment_add(vc, comment);
}

/* This is more or less the same as strncasecmp - but that doesn't exist
 * everywhere, and this is a fairly trivial function, so we include it */
static int tagcompare(const char *s1, const char *s2, int n){
  int c=0;
  while(c < n){
    if(ogg_toupper(s1[c]) != ogg_toupper(s2[c]))
      return !0;
    c++;
  }
  return 0;
}

char *vorbis_comment_query(vorbis_comment *vc, char *tag, int count){
  ogg_int32_t i;
  int found = 0;
  int taglen = (int)ogg_strlen(tag)+1; /* +1 for the = we append */
  char *fulltag = alloca(taglen+ 1);

  ogg_strcpy(fulltag, tag);
  ogg_strcat(fulltag, "=");
  
  for(i=0;i<vc->comments;i++){
    if(!tagcompare(vc->user_comments[i], fulltag, taglen)){
      if(count == found)
	/* We return a pointer to the data, not a copy */
      	return vc->user_comments[i] + taglen;
      else
	found++;
    }
  }
  return NULL; /* didn't find anything */
}

int vorbis_comment_query_count(vorbis_comment *vc, char *tag){
  int i,count=0;
  int taglen = (int)ogg_strlen(tag)+1; /* +1 for the = we append */
  char *fulltag = alloca(taglen+1);
  ogg_strcpy(fulltag,tag);
  ogg_strcat(fulltag, "=");

  for(i=0;i<vc->comments;i++){
    if(!tagcompare(vc->user_comments[i], fulltag, taglen))
      count++;
  }

  return count;
}

void vorbis_comment_clear(vorbis_comment *vc){
  if(vc){
    ogg_int32_t i;
    for(i=0;i<vc->comments;i++)
      if(vc->user_comments[i])_ogg_free(vc->user_comments[i]);
    if(vc->user_comments)_ogg_free(vc->user_comments);
	if(vc->comment_lengths)_ogg_free(vc->comment_lengths);
    if(vc->vendor)_ogg_free(vc->vendor);
  }
  memset(vc,0,sizeof(*vc));
}

/* blocksize 0 is guaranteed to be short, 1 is guarantted to be ogg_int32_t.
   They may be equal, but short will never ge greater than ogg_int32_t */
int vorbis_info_blocksize(vorbis_info *vi,int zo){
  codec_setup_info *ci = vi->codec_setup;
  return ci ? ci->blocksizes[zo] : -1;
}

/* used by synthesis, which has a full, alloced vi */
void vorbis_info_init(vorbis_info *vi){
  memset(vi,0,sizeof(*vi));
  vi->codec_setup=_ogg_calloc(1,sizeof(codec_setup_info));
}

void vorbis_info_clear(vorbis_info *vi){
  codec_setup_info     *ci=vi->codec_setup;
  int i;

  if(ci){

    for(i=0;i<ci->modes;i++)
      if(ci->mode_param[i])_ogg_free(ci->mode_param[i]);

    for(i=0;i<ci->maps;i++) /* unpack does the range checking */
        if (_mapping_P[ci->map_type[i]]->free_info)
            _mapping_P[ci->map_type[i]]->free_info(ci->map_param[i]);
    for(i=0;i<ci->floors;i++) /* unpack does the range checking */
      _floor_P[ci->floor_type[i]]->free_info(ci->floor_param[i]);
    
    for(i=0;i<ci->residues;i++) /* unpack does the range checking */
      _residue_P[ci->residue_type[i]]->free_info(ci->residue_param[i]);

    for(i=0;i<ci->books;i++){
      if(ci->book_param[i]){
	/* knows if the book was not alloced */
	vorbis_staticbook_destroy(ci->book_param[i]);
      }
      if(ci->fullbooks)
	vorbis_book_clear(ci->fullbooks+i);
    }
    if(ci->fullbooks)
	_ogg_free(ci->fullbooks);
    
    for(i=0;i<ci->psys;i++)
      _vi_psy_free(ci->psy_param[i]);

    _ogg_free(ci);
  }

  memset(vi,0,sizeof(*vi));
}

/* Header packing/unpacking ********************************************/

static int _vorbis_unpack_info(vorbis_info *vi,oggpack_buffer *opb){
  codec_setup_info     *ci=vi->codec_setup;
  if(!ci)return(OV_EFAULT);

  vi->version=oggpack_read(opb,32);
  if(vi->version!=0)return(OV_EVERSION);

  vi->channels=oggpack_read(opb,8);
  vi->rate=oggpack_read(opb,32);

  vi->bitrate_upper=oggpack_read(opb,32);
  vi->bitrate_nominal=oggpack_read(opb,32);
  vi->bitrate_lower=oggpack_read(opb,32);

  ci->blocksizes[0]=1<<oggpack_read(opb,4);
  ci->blocksizes[1]=1<<oggpack_read(opb,4);
  
  if(vi->rate<1)goto err_out;
  if(vi->channels<1)goto err_out;
  if(ci->blocksizes[0]<8)goto err_out; 
  if(ci->blocksizes[1]<ci->blocksizes[0])goto err_out;
  
  if(oggpack_read(opb,1)!=1)goto err_out; /* EOP check */

  return(0);
 err_out:
  vorbis_info_clear(vi);
  return(OV_EBADHEADER);
}

static int _vorbis_unpack_comment(vorbis_comment *vc,oggpack_buffer *opb){
  int i;
  int vendorlen=oggpack_read(opb,32);
  if(vendorlen<0)goto err_out;
  vc->vendor=_ogg_calloc(vendorlen+1,1);
  _v_readstring(opb,vc->vendor,vendorlen);
  vc->comments=oggpack_read(opb,32);
  if(vc->comments<0)goto err_out;
  vc->user_comments=_ogg_calloc(vc->comments+1,sizeof(*vc->user_comments));
  vc->comment_lengths=_ogg_calloc(vc->comments+1, sizeof(*vc->comment_lengths));
	    
  for(i=0;i<vc->comments;i++){
    int len=oggpack_read(opb,32);
    if(len<0)goto err_out;
	vc->comment_lengths[i]=len;
    vc->user_comments[i]=_ogg_calloc(len+1,1);
    _v_readstring(opb,vc->user_comments[i],len);
  }	  
  if(oggpack_read(opb,1)!=1)goto err_out; /* EOP check */

  return(0);
 err_out:
  vorbis_comment_clear(vc);
  return(OV_EBADHEADER);
}

/* all of the real encoding details are here.  The modes, books,
   everything */
static int _vorbis_unpack_books(vorbis_info *vi,oggpack_buffer *opb){
  codec_setup_info     *ci=vi->codec_setup;
  int i;
  if(!ci)return(OV_EFAULT);

  /* codebooks */
  ci->books=oggpack_read(opb,8)+1;
  /*ci->book_param=_ogg_calloc(ci->books,sizeof(*ci->book_param));*/
  for(i=0;i<ci->books;i++){
    ci->book_param[i]=_ogg_calloc(1,sizeof(*ci->book_param[i]));
    if(vorbis_staticbook_unpack(opb,ci->book_param[i]))goto err_out;
  }

  /* time backend settings; hooks are unused */
  {
    int times=oggpack_read(opb,6)+1;
    for(i=0;i<times;i++){
      int test=oggpack_read(opb,16);
      if(test<0 || test>=VI_TIMEB)goto err_out;
    }
  }

  /* floor backend settings */
  ci->floors=oggpack_read(opb,6)+1;
  /*ci->floor_type=_ogg_malloc(ci->floors*sizeof(*ci->floor_type));*/
  /*ci->floor_param=_ogg_calloc(ci->floors,sizeof(void *));*/
  for(i=0;i<ci->floors;i++){
    ci->floor_type[i]=oggpack_read(opb,16);
    if(ci->floor_type[i]<0 || ci->floor_type[i]>=VI_FLOORB)goto err_out;
    ci->floor_param[i]=_floor_P[ci->floor_type[i]]->unpack(vi,opb);
    if(!ci->floor_param[i])goto err_out;
  }

  /* residue backend settings */
  ci->residues=oggpack_read(opb,6)+1;
  /*ci->residue_type=_ogg_malloc(ci->residues*sizeof(*ci->residue_type));*/
  /*ci->residue_param=_ogg_calloc(ci->residues,sizeof(void *));*/
  for(i=0;i<ci->residues;i++){
    ci->residue_type[i]=oggpack_read(opb,16);
    if(ci->residue_type[i]<0 || ci->residue_type[i]>=VI_RESB)goto err_out;
    ci->residue_param[i]=_residue_P[ci->residue_type[i]]->unpack(vi,opb);
    if(!ci->residue_param[i])goto err_out;
  }

  /* map backend settings */
  ci->maps=oggpack_read(opb,6)+1;
  /*ci->map_type=_ogg_malloc(ci->maps*sizeof(*ci->map_type));*/
  /*ci->map_param=_ogg_calloc(ci->maps,sizeof(void *));*/
  for(i=0;i<ci->maps;i++){
    ci->map_type[i]=oggpack_read(opb,16);
    if(ci->map_type[i]<0 || ci->map_type[i]>=VI_MAPB)goto err_out;
    ci->map_param[i]=_mapping_P[ci->map_type[i]]->unpack(vi,opb);
    if(!ci->map_param[i])goto err_out;
  }
  
  /* mode settings */
  ci->modes=oggpack_read(opb,6)+1;
  /*vi->mode_param=_ogg_calloc(vi->modes,sizeof(void *));*/
  for(i=0;i<ci->modes;i++){
    ci->mode_param[i]=_ogg_calloc(1,sizeof(*ci->mode_param[i]));
    ci->mode_param[i]->blockflag=oggpack_read(opb,1);
    ci->mode_param[i]->windowtype=oggpack_read(opb,16);
    ci->mode_param[i]->transformtype=oggpack_read(opb,16);
    ci->mode_param[i]->mapping=oggpack_read(opb,8);

    if(ci->mode_param[i]->windowtype>=VI_WINDOWB)goto err_out;
    if(ci->mode_param[i]->transformtype>=VI_WINDOWB)goto err_out;
    if(ci->mode_param[i]->mapping>=ci->maps)goto err_out;
  }
  
  if(oggpack_read(opb,1)!=1)goto err_out; /* top level EOP check */

  return(0);
 err_out:
  vorbis_info_clear(vi);
  return(OV_EBADHEADER);
}

/* The Vorbis header is in three packets; the initial small packet in
   the first page that identifies basic parameters, a second packet
   with bitstream comments and a third packet that holds the
   codebook. */

int vorbis_synthesis_headerin(vorbis_info *vi,vorbis_comment *vc,ogg_packet *op){
  oggpack_buffer opb;
  
  if(op){
    oggpack_readinit(&opb,op->packet,op->bytes);

    /* Which of the three types of header is this? */
    /* Also verify header-ness, vorbis */
    {
      char buffer[6];
      int packtype=oggpack_read(&opb,8);
      memset(buffer,0,6);
      _v_readstring(&opb,buffer,6);
      if(memcmp(buffer,"vorbis",6)){
	/* not a vorbis header */
	return(OV_ENOTVORBIS);
      }
      switch(packtype){
      case 0x01: /* least significant *bit* is read first */
	if(!op->b_o_s){
	  /* Not the initial packet */
	  return(OV_EBADHEADER);
	}
	if(vi->rate!=0){
	  /* previously initialized info header */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_info(vi,&opb));

      case 0x03: /* least significant *bit* is read first */
	if(vi->rate==0){
	  /* um... we didn't get the initial header */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_comment(vc,&opb));

      case 0x05: /* least significant *bit* is read first */
	if(vi->rate==0 || vc->vendor==NULL){
	  /* um... we didn;t get the initial header or comments yet */
	  return(OV_EBADHEADER);
	}

	return(_vorbis_unpack_books(vi,&opb));

      default:
	/* Not a valid vorbis header type */
	return(OV_EBADHEADER);
	break;
      }
    }
  }
  return(OV_EBADHEADER);
}