Huffman code generator

[Shelwien]

I forgot where my previous huffman implementations are hidden, so
had to make a new one to test something, hope somebody would find
it useful.

#include <stdio.h>

const int CNUM=256;

int freq[2*CNUM], freq1[CNUM], p[2*CNUM][2], cl[CNUM];

char code[CNUM];
void DumpCode( int c, int i=0 ) {
  if( c<CNUM ) {
    code[i]=0; cl[c]=i;
    printf( "%02X <%s>\n", c, code );
  } else {
    code[i]='0'; DumpCode( p[c][0], i+1 );
    code[i]='1'; DumpCode( p[c][1], i+1 );
  }
}

int main( int argc, char** argv ) {

  int c,i,j,n,m,mi;

  FILE* f = fopen( "book1", "rb" ); if( f==0 ) return 1;

  // get symbol freqs
  for( i=0; i<CNUM; i++ ) freq1[i]=0;
  for(; (c=getc(f))!=-1; freq1[c]++ );

  for( i=0; i<CNUM; i++ ) freq[i]=freq1[i];
  for( n=CNUM,mi=0; mi>=0; n++ ) {
    freq[n] = 0;
    for( j=0; j<2; j++ ) {
      for( i=0,mi=-1; i<n; i++ ) if( (freq[i]>0) && ((mi<0)||(freq[i]<m)) ) m=freq[i],mi=i;
      if( mi>=0 ) freq[n]+=freq[mi], freq[mi]=0, p[n][j]=mi;
    }
  }

  DumpCode( p[n-1][0] );

  int sum = 0;
  for( i=0; i<n; i++ ) sum += freq1[i]*cl[i];

  printf( "codelength = %i bits = %i bytes\n", sum, (sum+7)>>3 );

  return 0;
}

[encode]

Cool! Thanks a lot!

[encode]

Slightly changed & compiled: