/* aoi3.c - Don Yang (uguu.org)

   08/24/02
                                                                           */

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


static FILE *infile, *outfile;
static int t, state, size, headersize, datasize, tag;

static int ParseChunk(void);

static int ParseList(int listsize)
{
   int chunksize;

   fread(&tag, 4, 1, infile);
   state |= (tag == 0x6c726468) ? 1 : (tag == 0x69766f6d) ? 8 : 0;
   for(chunksize = 0;
      listsize > chunksize &&
      (t = ParseChunk());
      chunksize += t);
   return listsize;
}

static int ParseChunk(void)
{
   char *buffer;

   fread(&tag, 4, 1, infile);
   fread(&size, 4, 1, infile);
   if( tag == 0x5453494c )
      return ParseList(size);

   if( (state & 1) && tag == 0x68697661 )
   {
      state |= 2;
      fseek(infile, size, 1);
   }
   else if( (state & 2) && tag == 0x68727473 )
   {
      fread(&tag, 4, 1, infile);
      if( tag == 0x73647561 )
         state |= 4;
      fseek(infile, size - 4, 1);
   }
   else if( ((state & 4) && tag == 0x66727473) ||
            ((state & 24) && (tag & 0xffff00ff) == 0x62770030) )
   {
      if( tag & 1 )
      {
         fwrite("RIFF....WAVEfmt ....", 20, 1, outfile);
         state |= 16;
         headersize = size;
      }
      else
      {
         if( !(state & 32) )
         {
            fwrite("data....", 8, 1, outfile);
            state |= 32;
         }
         datasize += size;
      }
      if( (buffer = (char*)alloca(size)) )
      {
         fread(buffer, size, 1, infile);
         fwrite(buffer, size, 1, outfile);
      }
      else
      {
         size = -8;
      }
   }
   else
   {
      fseek(infile, size, 1);
   }

   if( (size += 8) & 1 )
   {
      fgetc(infile);
      size++;
   }
   return size;
}

int main(int argc, char **argv)
{
   if( argc < 3 )
      return printf("%s <infile> <outfile>\n", *argv);
   if( (infile = fopen(argv[1], "rb")) == NULL )
   {
      printf("Can not open %s\n", argv[1]);
      return 1;
   }
   if( (outfile = fopen(argv[2], "wb+")) == NULL )
   {
      fclose(infile);
      printf("Can not create %s\n", argv[2]);
      return 1;
   }

   headersize = datasize = state = 0;

   fread(&tag, 4, 1, infile);
   fread(&size, 4, 1, infile);
   if( tag == 0x46464952 )
   {
      fread(&tag, 4, 1, infile);
      if( tag == 0x20495641 )
         for(; !(state & 32) && ParseChunk(););
   }
   if( (state & 32) )
   {
      fseek(outfile, 16, 0);
      fwrite(&headersize, 4, 1, outfile);
      fseek(outfile, headersize + 4, 1);
      fwrite(&datasize, 4, 1, outfile);
      datasize += headersize + 20;
      fseek(outfile, 4, 0);
      fwrite(&datasize, 4, 1, outfile);
   }
   else
   {
      puts("failed");
   }

   fclose(infile);
   fclose(outfile);
   return 0;
}