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

   09/13/01
                                                                           */

#include<stdio.h>
#include"hufftree.h"


static void HuffmanDecode(FILE *infile, FILE *outfile, int size);

/******************************************************************** main */
int main(int argc, char **argv)
{
   FILE *infile, *outfile;
   int size;

   if( argc < 3 )
      return printf("%s <infile> <outfile>\n", *argv);

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

   fread(&size, sizeof(int), 1, infile);
   HuffmanDecode(infile, outfile, size);
   fclose(infile);
   fclose(outfile);

   return 0;

} /* main() */

/*********************************************************** HuffmanDecode */
static void HuffmanDecode(FILE *infile, FILE *outfile, int size)
{
   int bit, byte, i, x;

   bit = 8;
   for(i = x = byte = 0; i < size;)
   {
      if( bit > 7 )
      {
         if( (byte = fgetc(infile)) == EOF )
            break;
         bit = 0;
      }
      if( (byte & (1 << bit)) == 0 )
      {
         if( Left[x] <= 0 )
         {
            fputc(-Left[x], outfile);
            i++;
            x = 0;
         }
         else
         {
            x = Left[x];
         }
      }
      else
      {
         if( Right[x] <= 0 )
         {
            fputc(-Right[x], outfile);
            i++;
            x = 0;
         }
         else
         {
            x = Right[x];
         }
      }
      bit++;
   }

} /* HuffmanDecode() */