/* aoi2.c - Don Yang (uguu.org)

   08/20/02
                                                                           */

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


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

static int ParseChunk(void);

static int ParseList(int listsize)
{
   int chunksize;

   fread(&tag, 4, 1, infile);
   if( tag == 0x6c726468 )
   {
      state |= 1;
   }
   else if( tag == 0x69766f6d )
   {
      state |= 8;
   }
   chunksize = 0;
   while( listsize > chunksize )
   {
      chunksize += (r = ParseChunk());
      if( r == 0 )
         return 0;
   }
   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 )
   {
      fwrite("RIFF\0\0\0\0WAVEfmt \0\0\0\0", 20, 1, outfile);
      if( (buffer = (char*)alloca(size)) == NULL )
         return 0;
      fread(buffer, size, 1, infile);
      fwrite(buffer, size, 1, outfile);
      headersize = size;
      state |= 16;
   }
   else if( (state & 24) && (tag & 0xffff00ff) == 0x62770030 )
   {
      if( (state & 32) == 0 )
      {
         fwrite("data\0\0\0\0", 8, 1, outfile);
         state |= 32;
      }
      if( (buffer = (char*)alloca(size)) == NULL )
         return 0;
      fread(buffer, size, 1, infile);
      fwrite(buffer, size, 1, outfile);
      datasize += size;
   }
   else
   {
      fseek(infile, size, 1);
   }

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

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 )
      {
         do
         {
            if( !ParseChunk() )
               break;
         } while( (state & 32) == 0 );
      }
   }
   if( (state & 32) == 0 )
   {
      puts("failed");
   }
   else
   {
      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);
   }

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