/* rw_wav.c   read and write .wav files  not working for all .wav files */
#include <stdio.h>
#include <stdlib.h>
#include "rw_wav.h"

#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))

void read_wave(char* file_name, header *w, char sound[])
{
  int i;
  FILE * inp;
  int  sread;
  char sbyte; /* byte of sound */
  int  ibyte;
  short tbyte;
  int  smin;
  int  smax;
  int  savg;
  int  bad; /* flags bad data in read */
  int  nbread; /* number of bytes read */
  int  xtra;   /* nbytes> 16 */
  char cxtra[32];
  int soundi;

  inp = fopen(file_name, "rb");
  if(inp == NULL)
  {
    printf("can not open %s for reading. \n", file_name);
    exit(1);
  }

  printf("reading %s \n", file_name);

  sread = fread(&w->riff[0], 1, 4, inp);
  printf("first 4 bytes should be RIFF, <%c%c%c%c>\n",
         w->riff[0], w->riff[1], w->riff[2], w->riff[3]);

  sread = fread(&w->fsize, 1, 4, inp);
  printf("file has %d +8 bytes \n", w->fsize);

  sread = fread(&w->wave[0], 1, 4, inp);
  printf("should be WAVE, <%c%c%c%c>\n",
         w->wave[0], w->wave[1], w->wave[2], w->wave[3]);

  sread = fread(&w->fmt[0], 1, 4, inp);
  printf("should be fmt, <%c%c%c%c>\n",
         w->fmt[0], w->fmt[1], w->fmt[2], w->fmt[3]);

  sread = fread(&w->nbytes, 1, 4, inp);
  printf("block has %d bytes \n", w->nbytes);
  xtra = w-> nbytes-16;

  sread = fread(&w->ccode, 1, 2, inp);
  printf("compression code = %d \n", w->ccode);

  sread = fread(&w->channels, 1, 2, inp);
  printf("channels = %d \n", w->channels);

  sread = fread(&w->rate, 1, 4, inp);
  printf("rate = %d  \n", w->rate);

  sread = fread(&w->avgrate, 1, 4, inp);
  printf("avg rate = %d \n", w->avgrate);

  sread = fread(&w->blockalign, 1, 2, inp);
  printf("blockalign = %d  \n", w->blockalign);

  sread = fread(&w->bps, 1, 2, inp);
  printf("bits per sample = %d \n", w->bps);

  if(xtra>0)
  {
    sread = fread(&cxtra[0], 1, xtra, inp);
    w->nbytes = 16;
  }

  sread = fread(&w->data[0], 1, 4, inp);
  printf("should be data, <%c%c%c%c>\n",
         w->data[0], w->data[1], w->data[2], w->data[3]);
  if(w->data[0]!='d') { printf("unable to read this format.\n"); exit(1); }  


  sread = fread(&w->csize, 1, 4, inp);
  printf("chunk size, csize %d \n", w->csize);
  if(w->csize<=0) { printf("unable to read this format.\n"); exit(1); }  
  nbread = 44+xtra;
  printf("%d bytes read so far \n", nbread);

  bad = 0;
  savg = 0;
  soundi = 0; /* sound index, in case channels==2 */

  for(i=0; i<w->csize/w->channels; i++)
  {
    if(w->bps==8)
    {
      sread = fread(&sbyte, 1, 1, inp);
      if(sread != 1 && bad==0) { bad=1; printf("no read on byte %d \n", i); } 
      sound[soundi] = sbyte;
      soundi++;
      if(w->channels==2) sread = fread(&sbyte, 1, 1, inp); /* only use one */
    }
    else /* should be 16, 2 bytes */
    {
      sread = fread(&tbyte, 1, 2, inp);
      if(sread != 2 && bad==0) { bad=1; printf("no read on byte %d \n", i); } 
      sound[soundi] = tbyte/128; /* process as 8 bit */
      soundi++;
      if(w->channels==2) sread = fread(&tbyte, 1, 2, inp); /* only use one */
    }
    ibyte = sbyte;
    savg = savg + ibyte;
    if(i==0) {smin=ibyte; smax=ibyte;}
    smin = ibyte<smin?ibyte:smin;
    smax = ibyte>smax?ibyte:smax;
    if(i<10 || i>w->csize-10)
      printf("sound byte %d = %X  %d int= %d \n", i, sbyte, sbyte, ibyte);
  }
  w->bps = 8; /* process as 8 bit, 1 channel */
  if(w->channels==2)
  {
    w->csize = w->csize/w->channels;
    w->channels = 1;
  }
  printf("finished reading csize=%d bytes \n", w->csize);
  fflush(stdout);

  savg = savg / (int)w->csize;
  printf("smin=%d, smax=%d, savg=%d \n", smin, smax, savg);

  nbread = nbread+w->csize;
  printf("%d bytes read \n", nbread);
  fflush(stdout);

  /* not reading remaining chunks */
  
  fclose(inp);
  printf("read_wav done. %s file read \n", file_name);
  fflush(stdout);
} /* end read_wav */


void write_wave(char* file_name, header w, char sound[])
{
  int i;
  FILE * outp; /* .wav */
  int  sread, swrite;
  char sbyte; /* byte of sound */
  int  ibyte;
  char more[4];
  int smin;
  int smax;
  int savg;
  int bad; /* flags bad data in read */
  int nbread; /* number of bytes read */

  printf("write_wav running to write %s \n", file_name);

  if(w.riff[0]!='R' || w.riff[1]!='I')
  {
    printf("invalid header structure, bye \n");
    exit(1);
  }

  outp = fopen(file_name, "wb");
  if(outp == NULL)
  {
    printf("can not open %s for writing. \n", file_name);
    exit(1);
  }

  printf("writing %s \n", file_name);

  swrite = fwrite(&w.riff[0], 1, 4, outp);
  printf("first 4 bytes should be RIFF, <%c%c%c%c>\n",
         w.riff[0],w.riff[1],w.riff[2],w.riff[3]);

  swrite = fwrite(&w.fsize, 1, 4, outp);
  printf("file has %d +8 bytes \n", w.fsize);

  swrite = fwrite(&w.wave[0], 1, 4, outp);
  printf("should be WAVE, <%c%c%c%c>\n",
         w.wave[0],w.wave[1],w.wave[2],w.wave[3]);

  swrite = fwrite(&w.fmt[0], 1, 4, outp);
  printf("should be fmt, <%c%c%c%c>\n",w.fmt[0],w.fmt[1],w.fmt[2],w.fmt[3]);

  swrite = fwrite(&w.nbytes, 1, 4, outp);
  printf("block has %d bytes \n", w.nbytes);

  swrite = fwrite(&w.ccode, 1, 2, outp);
  printf("compression code = %d \n", w.ccode);

  swrite = fwrite(&w.channels, 1, 2, outp);
  printf("channels = %d \n", w.channels);

  swrite = fwrite(&w.rate, 1, 4, outp);
  printf("rate = %d  \n", w.rate);

  swrite = fwrite(&w.avgrate, 1, 4, outp);
  printf("avg rate = %d \n", w.avgrate);

  swrite = fwrite(&w.blockalign, 1, 2, outp);
  printf("blockalign = %d  \n", w.blockalign);

  swrite = fwrite(&w.bps, 1, 2, outp);
  printf("bits per sample = %d \n", w.bps);

  swrite = fwrite(&w.data[0], 1, 4, outp);
  printf("should be data, <%c%c%c%c>\n",
         w.data[0],w.data[1],w.data[2],w.data[3]);

  swrite = fwrite(&w.csize, 1, 4, outp);
  printf("chunk size %d \n", w.csize);
  nbread = 44;
  printf("%d bytes written so far \n", nbread);
  
  bad = 0;
  savg = 0;
  for(i=0; i<w.csize; i++)
  {
    sbyte = sound[i];
    if(i<10 || i>w.csize-10)
      printf("sound byte %d = %X  %d \n", i, sbyte, sbyte);

    swrite = fwrite(&sbyte, 1, 1, outp);
    ibyte = sbyte;
    savg = savg + ibyte;
    if(i==0) {smin=ibyte; smax=ibyte;}
    smin = ibyte<smin?ibyte:smin;
    smax = ibyte>smax?ibyte:smax;
  }
  savg = savg / w.csize;
  printf("smin=%d, smax=%d, savg=%d \n", smin, smax, savg);

  nbread = nbread+w.csize;
  printf("%d bytes written so far \n", nbread);

  /* not copying remaining chunks */
  
  fflush(outp);
  fclose(outp);
  printf("write_wav done. new %s file written \n", file_name);
} /* end write_wav */

/* may need to rescale into -127 .. 127 */
void rescale(int n, float zn[]) /* only rescale real part */
{
  int i;
  float zmin, zmax, zavg;
  float sca, offs;

  zavg = 0.0;
  for(i=0; i<n; i++)
  {
    if(i==0) {zmin = zn[0]; zmax = zn[0];}
    zmin = min(zmin, zn[2*i]);
    zmax = max(zmax, zn[2*i]);
    zavg = zavg + zn[2*i];
  }
  if(zmax<129.0 && zmin>-129.0) return;
  zavg = zavg/(float)n;
  printf("zmin=%f, zmax=%f, zavg=%f \n",
         zmin, zmax, zavg);
  sca = (zmax-zmin)/254.0; /* -127 to +127 */
  offs = (zmax+zmin)/2.0;
  printf("scale=%f, offset=%f \n", sca, offs);
  for(i=0; i<n; i++)
  {
    zn[2*i] = (zn[2*i]-offs)/sca;
  }
} /* end rescale */

/* end rw_wav .c */