/*
   This program converts between .bdf font files
   (bitmap distribution format) and a more human-readable
   format.  The second format is easily edited with
   an ordinary text editor.

   Compile with
      gcc -o bdf2readable bdf2readable.c
*/
#include <stdio.h>    /* printf(), fopen(), fgets() */
#include <stdlib.h>   /* exit() */
#include <string.h>   /* strcmp(), strcasecmp() */
#include <ctype.h>    /* toupper() */

#define Boolean char
#define True 1
#define False 0

/* These strings are part of the bdf standard. */
#define BITMAP_START "BITMAP\n"
#define BITMAP_END "ENDCHAR\n"

/* These strings appear in the more human-readable format. */
#define ONE "X"
#define ZERO "."
#define ONE_C 'X'
#define ZERO_C '.'

#define MAX_LINE_LENGTH 1024

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

   FILE * stream;
   char * filename = NULL;
   char buffer[MAX_LINE_LENGTH];
   Boolean convertingBitmap = False;
   Boolean convertingFrom = False;
   char *pc;
   int value, count;

   if (argc != 2 && (argc != 3 || strcmp(argv[1],"r") != 0)) {
      printf("\nUsage: %s [r] file\n"
             "Echos a converted version of the file to stdout.\n"
             "Default behaviour is to convert a bdf (bitmap distribution format) font\n"
             "into a more human-readable format.  The 'r' flag causes the reverse\n"
             "conversion to take place.\n\n",
             argv[0]);
      exit(0);
   }

   if (argc == 3) {
      convertingFrom = True;
      filename = argv[2];
   }
   else filename = argv[1];

   stream = fopen(filename,"r");

   if (NULL == stream) {
      fprintf(stderr,"\nCannot open file %s.\n\n",filename);
      exit(-1);
   }

   while (NULL != fgets(buffer,MAX_LINE_LENGTH,stream)) {
      if (convertingBitmap) {
         if (strcasecmp(buffer,BITMAP_END) == 0) {
            convertingBitmap = False;
            printf(buffer);
         }
         else {
            if (convertingFrom) {   /* convert readable->bdf */
               pc = buffer;
               count = value = 0;
               while ('\0' != *pc) {
                  switch (*pc) {
                  case ZERO_C : value = 2*value;   ++count; break;
                  case  ONE_C : value = 2*value+1; ++count; break;
                  default : printf("%c",*pc); break;
                  }
                  if (count == 4) {
                     printf("%c",value > 9 ? (char)('a'+value-10) : (char)('0'+value));
                     count = value = 0;
                  }
                  ++ pc;
               } /* while */
            }
            else {  /* perform the forward conversion bdf->readable */
               pc = buffer;
               while ('\0' != *pc) {
                  switch (toupper(*pc)) {
                  case '0': printf(ZERO ZERO ZERO ZERO); break;
                  case '1': printf(ZERO ZERO ZERO  ONE); break;
                  case '2': printf(ZERO ZERO  ONE ZERO); break;
                  case '3': printf(ZERO ZERO  ONE  ONE); break;
                  case '4': printf(ZERO  ONE ZERO ZERO); break;
                  case '5': printf(ZERO  ONE ZERO  ONE); break;
                  case '6': printf(ZERO  ONE  ONE ZERO); break;
                  case '7': printf(ZERO  ONE  ONE  ONE); break;
                  case '8': printf( ONE ZERO ZERO ZERO); break;
                  case '9': printf( ONE ZERO ZERO  ONE); break;
                  case 'A': printf( ONE ZERO  ONE ZERO); break;
                  case 'B': printf( ONE ZERO  ONE  ONE); break;
                  case 'C': printf( ONE  ONE ZERO ZERO); break;
                  case 'D': printf( ONE  ONE ZERO  ONE); break;
                  case 'E': printf( ONE  ONE  ONE ZERO); break;
                  case 'F': printf( ONE  ONE  ONE  ONE); break;
                  default : printf("%c",*pc); break;
                  }
                  ++ pc;
               } /* while */
            }
         }
      }
      else {
         printf(buffer);
         if (strcasecmp(buffer,BITMAP_START) == 0) {
            convertingBitmap = True;
         }
      }
   }

   fclose(stream);
}