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interface.c

/* $Id: interface.c,v 1.46 2004/03/10 00:50:54 robert Exp $ */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "common.h"
#include "interface.h"
#include "tabinit.h"
#include "layer3.h"
#include "VbrTag.h"
#include "decode_i386.h"

#ifdef USE_LAYER_1
      #include "layer1.h"
#endif

#ifdef USE_LAYER_2
      #include "layer2.h"
#endif

#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif

BOOL InitMP3( PMPSTR mp) 
{
      memset(mp,0,sizeof(MPSTR));

      mp->framesize = 0;
        mp->num_frames = 0;
        mp->enc_delay = -1;
        mp->enc_padding = -1;
        mp->vbr_header=0;
      mp->header_parsed=0;
      mp->side_parsed=0;
      mp->data_parsed=0;
      mp->free_format=0;
      mp->old_free_format=0;
      mp->ssize = 0;
      mp->dsize=0;
      mp->fsizeold = -1;
      mp->bsize = 0;
      mp->head = mp->tail = NULL;
      mp->fr.single = -1;
      mp->bsnum = 0;
      wordpointer = mp->bsspace[mp->bsnum] + 512;
      mp->synth_bo = 1;
      mp->sync_bitstream = 1;

      make_decode_tables(32767);

      init_layer3(SBLIMIT);

#ifdef USE_LAYER_2
      init_layer2();
#endif

      return !0;
}

void ExitMP3( PMPSTR mp)
{
      struct buf *b,*bn;
      
      b = mp->tail;
      while(b) {
            free(b->pnt);
            bn = b->next;
            free(b);
            b = bn;
      }
}

static struct buf *addbuf( PMPSTR mp, unsigned char *buf,int size)
{
      struct buf *nbuf;

      nbuf = (struct buf*) malloc( sizeof(struct buf) );
      if(!nbuf) {
            fprintf(stderr,"Out of memory!\n");
            return NULL;
      }
      nbuf->pnt = (unsigned char*) malloc((size_t)size);
      if(!nbuf->pnt) {
            free(nbuf);
            return NULL;
      }
      nbuf->size = size;
      memcpy(nbuf->pnt,buf,(size_t)size);
      nbuf->next = NULL;
      nbuf->prev = mp->head;
      nbuf->pos = 0;

      if(!mp->tail) {
            mp->tail = nbuf;
      }
      else {
        mp->head->next = nbuf;
      }

      mp->head = nbuf;
      mp->bsize += size;

      return nbuf;
}

void remove_buf(PMPSTR mp)
{
  struct buf *buf = mp->tail;
  
  mp->tail = buf->next;
  if(mp->tail)
    mp->tail->prev = NULL;
  else {
    mp->tail = mp->head = NULL;
  }
  
  free(buf->pnt);
  free(buf);

}

static int read_buf_byte(PMPSTR mp)
{
      unsigned int b;

      int pos;

      
      pos = mp->tail->pos;
      while(pos >= mp->tail->size) {
              remove_buf(mp);
            if(!mp->tail) {
                  fprintf(stderr,"Fatal error! tried to read past mp buffer\n");
                  exit(1);
            }
            pos = mp->tail->pos;
      }

      b = mp->tail->pnt[pos];
      mp->bsize--;
      mp->tail->pos++;
      

      return b;
}



static void read_head(PMPSTR mp)
{
      unsigned long head;

      head = read_buf_byte(mp);
      head <<= 8;
      head |= read_buf_byte(mp);
      head <<= 8;
      head |= read_buf_byte(mp);
      head <<= 8;
      head |= read_buf_byte(mp);

      mp->header = head;
}






void copy_mp(PMPSTR mp,int size,unsigned char *ptr) 
{
  int len = 0;

  while(len < size && mp->tail) {
    int nlen;
    int blen = mp->tail->size - mp->tail->pos;
    if( (size - len) <= blen) {
      nlen = size-len;
    }
    else {
      nlen = blen;
    }
    memcpy(ptr+len,mp->tail->pnt+mp->tail->pos,(size_t)nlen);
    len += nlen;
    mp->tail->pos += nlen;
    mp->bsize -= nlen;
    if(mp->tail->pos == mp->tail->size) {
      remove_buf(mp);
    }
  }
}

/* number of bytes needed by GetVbrTag to parse header */
#define XING_HEADER_SIZE 194

/* traverse mp data structure without changing it */
/* (just like sync_buffer) */
/* pull out Xing bytes */
/* call vbr header check code from LAME */
/* if we find a header, parse it and also compute the VBR header size */
/* if no header, do nothing. */
/* */
/* bytes = number of bytes before MPEG header.  skip this many bytes */
/* before starting to read */
/* return value: number of bytes in VBR header, including syncword */
int check_vbr_header(PMPSTR mp,int bytes)
{
    return 0;

}







int sync_buffer(PMPSTR mp,int free_match) 
{
  /* traverse mp structure without modifing pointers, looking
   * for a frame valid header.
   * if free_format, valid header must also have the same
   * samplerate.   
   * return number of bytes in mp, before the header
   * return -1 if header is not found
   */
  unsigned int b[4]={0,0,0,0};
  int i,h,pos;
  struct buf *buf=mp->tail;
  if (!buf) return -1;

  pos = buf->pos;
  for (i=0; i<mp->bsize; i++) {
    /* get 4 bytes */
    
    b[0]=b[1]; b[1]=b[2]; b[2]=b[3];
    while(pos >= buf->size) {
      buf  = buf->next;
      pos = buf->pos;
      if(!buf) {
      return -1;
      /* not enough data to read 4 bytes */
      }
    }
    b[3] = buf->pnt[pos];
    ++pos;

    if (i>=3) {
        struct frame *fr = &mp->fr;
      unsigned long head;

      head = b[0];
      head <<= 8;
      head |= b[1];
      head <<= 8;
      head |= b[2];
      head <<= 8;
      head |= b[3];
      h = head_check(head,fr->lay);

      if (h && free_match) {
        /* just to be even more thorough, match the sample rate */
        int mode,stereo,sampling_frequency,mpeg25,lsf;

        if( head & (1<<20) ) {
          lsf = (head & (1<<19)) ? 0x0 : 0x1;
          mpeg25 = 0;
        }
        else {
          lsf = 1;
          mpeg25 = 1;
        }

        mode      = ((head>>6)&0x3);
        stereo    = (mode == MPG_MD_MONO) ? 1 : 2;

        if(mpeg25) 
          sampling_frequency = 6 + ((head>>10)&0x3);
        else
          sampling_frequency = ((head>>10)&0x3) + (lsf*3);
        h = ((stereo==fr->stereo) && (lsf==fr->lsf) && (mpeg25==fr->mpeg25) && 
                 (sampling_frequency == fr->sampling_frequency));
      }

      if (h) {
        return i-3;
      }
    }
  }
  return -1;
}





int decodeMP3_clipchoice( PMPSTR mp,unsigned char *in,int isize,char *out,
                       int osize,int *done,      
                           int (*synth_1to1_mono_ptr)(PMPSTR,real *,unsigned char *,int *),
                           int (*synth_1to1_ptr)(PMPSTR,real *,int,unsigned char *, int *) )
{
      int i,iret,bits,bytes;

      if (in && isize && addbuf(mp,in,isize) == NULL)
          return MP3_ERR;

      /* First decode header */
      if(!mp->header_parsed) {

          if (mp->fsizeold==-1 || mp->sync_bitstream) {
              int vbrbytes;
            mp->sync_bitstream=0;

              /* This is the very first call.   sync with anything */
            /* bytes= number of bytes before header */
              bytes=sync_buffer(mp,0); 

              /* now look for Xing VBR header */
            if (mp->bsize >= bytes+XING_HEADER_SIZE ) {
                /* vbrbytes = number of bytes in entire vbr header */
                vbrbytes=check_vbr_header(mp,bytes);
            } else {
                /* not enough data to look for Xing header */
                return MP3_NEED_MORE;
            }

            if (mp->vbr_header) {
                /* do we have enough data to parse entire Xing header? */
                if (bytes+vbrbytes > mp->bsize) return MP3_NEED_MORE;
                
                /* read in Xing header.  Buffer data in case it
                 * is used by a non zero main_data_begin for the next
                 * frame, but otherwise dont decode Xing header */
/*fprintf(stderr,"found xing header, skipping %i bytes\n",vbrbytes+bytes);*/
                for (i=0; i<vbrbytes+bytes; ++i) read_buf_byte(mp);
                /* now we need to find another syncword */
                /* just return and make user send in more data */
                return MP3_NEED_MORE;
            }
            }else{
              /* match channels, samplerate, etc, when syncing */
                bytes=sync_buffer(mp,1);
          }

          if (bytes<0) return MP3_NEED_MORE;
          if (bytes>0) {
            /* there were some extra bytes in front of header.
             * bitstream problem, but we are now resynced 
             * should try to buffer previous data in case new
             * frame has nonzero main_data_begin, but we need
             * to make sure we do not overflow buffer
             */
            int size;
            fprintf(stderr,"bitstream problem: resyncing...\n");
            mp->old_free_format=0;
                mp->sync_bitstream=1;
            
            /* skip some bytes, buffer the rest */
            size = (int) (wordpointer - (mp->bsspace[mp->bsnum]+512));
            
            if (size > MAXFRAMESIZE) {
                /* wordpointer buffer is trashed.  probably cant recover, but try anyway */
                fprintf(stderr,"mpglib: wordpointer trashed.  size=%i (%i)  bytes=%i \n",
                      size,MAXFRAMESIZE,bytes);         
                size=0;
                wordpointer = mp->bsspace[mp->bsnum]+512;
            }
            
            /* buffer contains 'size' data right now 
               we want to add 'bytes' worth of data, but do not 
               exceed MAXFRAMESIZE, so we through away 'i' bytes */
            i = (size+bytes)-MAXFRAMESIZE;
            for (; i>0; --i) {
                --bytes;
                read_buf_byte(mp);
            }
            
            copy_mp(mp,bytes,wordpointer);
            mp->fsizeold += bytes;
          }
          
          read_head(mp);
          decode_header(&mp->fr,mp->header);
          mp->header_parsed=1;
          mp->framesize = mp->fr.framesize;
          mp->free_format = (mp->framesize==0);
          
          if(mp->fr.lsf)
            mp->ssize = (mp->fr.stereo == 1) ? 9 : 17;
          else
            mp->ssize = (mp->fr.stereo == 1) ? 17 : 32;
          if (mp->fr.error_protection) 
            mp->ssize += 2;
          
          mp->bsnum = 1-mp->bsnum; /* toggle buffer */
          wordpointer = mp->bsspace[mp->bsnum] + 512;
          bitindex = 0;
          
          /* for very first header, never parse rest of data */
          if (mp->fsizeold==-1)
            return MP3_NEED_MORE;
      }
      
      /* now decode side information */
      if (!mp->side_parsed) {

            /* Layer 3 only */
            if (mp->fr.lay==3)
            {
                if (mp->bsize < mp->ssize) 
              return MP3_NEED_MORE;

            copy_mp(mp,mp->ssize,wordpointer);

            if(mp->fr.error_protection)
              getbits(16);
            bits=do_layer3_sideinfo(&mp->fr);
            /* bits = actual number of bits needed to parse this frame */
            /* can be negative, if all bits needed are in the reservoir */
            if (bits<0) bits=0;

            /* read just as many bytes as necessary before decoding */
            mp->dsize = (bits+7)/8;

            /* this will force mpglib to read entire frame before decoding */
            /* mp->dsize= mp->framesize - mp->ssize;*/

            }

            else
            {
                  /* Layers 1 and 2 */

                  /* check if there is enough input data */
                  if(mp->fr.framesize > mp->bsize)
                        return MP3_NEED_MORE;

                  /* takes care that the right amount of data is copied into wordpointer */
                  mp->dsize=mp->fr.framesize;
                  mp->ssize=0;
            }

            mp->side_parsed=1;
      }

      /* now decode main data */
      iret=MP3_NEED_MORE;
      if (!mp->data_parsed ) {
              if(mp->dsize > mp->bsize) {
                        return MP3_NEED_MORE;
            }

            copy_mp(mp,mp->dsize,wordpointer);

            *done = 0;

            /*do_layer3(&mp->fr,(unsigned char *) out,done); */
            switch (mp->fr.lay)
            {
#ifdef USE_LAYER_1
                  case 1:
                        if(mp->fr.error_protection)
                              getbits(16);

                        do_layer1(mp,(unsigned char *) out,done);
                  break;
#endif
#ifdef USE_LAYER_2
                  case 2:
                        if(mp->fr.error_protection)
                              getbits(16);

                        do_layer2(mp,(unsigned char *) out,done);
                  break;
#endif
                  case 3:
                        do_layer3(mp,(unsigned char *) out,done, synth_1to1_mono_ptr, synth_1to1_ptr);
                  break;
                  default:
                        fprintf(stderr,"invalid layer %d\n",mp->fr.lay);
            }

            wordpointer = mp->bsspace[mp->bsnum] + 512 + mp->ssize + mp->dsize;

            mp->data_parsed=1;
            iret=MP3_OK;
      }


      /* remaining bits are ancillary data, or reservoir for next frame 
       * If free format, scan stream looking for next frame to determine
       * mp->framesize */
      if (mp->free_format) {
        if (mp->old_free_format) {
          /* free format.  bitrate must not vary */
          mp->framesize=mp->fsizeold_nopadding + (mp->fr.padding);
        }else{
          bytes=sync_buffer(mp,1);
          if (bytes<0) return iret;
          mp->framesize = bytes + mp->ssize+mp->dsize;
          mp->fsizeold_nopadding= mp->framesize - mp->fr.padding;
          /*
          fprintf(stderr,"freeformat bitstream:  estimated bitrate=%ikbs  \n",
              8*(4+mp->framesize)*freqs[mp->fr.sampling_frequency]/
                (1000*576*(2-mp->fr.lsf)));
          */
        }
      }

      /* buffer the ancillary data and reservoir for next frame */
      bytes = mp->framesize-(mp->ssize+mp->dsize);
      if (bytes > mp->bsize) {
        return iret;
      }

      if (bytes>0) {
        int size;
        copy_mp(mp,bytes,wordpointer);
        wordpointer += bytes;

        size = (int) (wordpointer - (mp->bsspace[mp->bsnum]+512));
        if (size > MAXFRAMESIZE) {
          fprintf(stderr,"fatal error.  MAXFRAMESIZE not large enough.\n");
        }

      }

      /* the above frame is completey parsed.  start looking for next frame */
      mp->fsizeold = mp->framesize;
      mp->old_free_format = mp->free_format;
      mp->framesize =0;
      mp->header_parsed=0;
      mp->side_parsed=0;
      mp->data_parsed=0;

      return iret;
}

int decodeMP3( PMPSTR mp,unsigned char *in,int isize,char *out,
            int osize,int *done)
{
      if(osize < 4608) {
            fprintf(stderr,"To less out space\n");
            return MP3_ERR;
      }

      /* passing pointers to the functions which clip the samples */
      return decodeMP3_clipchoice(mp, in, isize, out, osize, done, synth_1to1_mono, synth_1to1);
}     

int decodeMP3_unclipped( PMPSTR mp,unsigned char *in,int isize,char *out,
                      int osize,int *done)
{
      /* we forbid input with more than 1152 samples per channel for output in unclipped mode */
      if(osize < 1152 * 2 * sizeof(real) ) { 
            fprintf(stderr,"To less out space\n");
            return MP3_ERR;
      }

      /* passing pointers to the functions which don't clip the samples */
      return decodeMP3_clipchoice(mp, in, isize, out, osize, done, synth_1to1_mono_unclipped, synth_1to1_unclipped);
}     


      



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