-rw-r--r-- bdf2flf.c

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #define PROGNAME "bdf2flf"
 
 
 // These are the characters required at the start of FIGfonts.
 const unsigned int REQUIRED[] = {
     32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
     51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69,
     70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88,
     89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105,
     106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120,
     121, 122, 123, 124, 125, 126, 196, 214, 220, 228, 246, 252, 223
 };
 
 
 struct character {
     unsigned int width;
     unsigned int encoding;
     char *bitmap;
     _Bool printed;
 };
 
 
 void die(char *msg)
 {
     fprintf(stderr, msg);
     exit(EXIT_FAILURE);
 }
 
 
 void put_pixel(unsigned int c, unsigned int bit, FILE *out)
 {
 
     if (c & bit) {
 	fputc('#', out);
     } else {
 	fputc(' ', out);
     }
 }
 
 
 void print_character(FILE *out, char *bitmap, unsigned int width, unsigned int height)
 {
     unsigned int y;
     unsigned int x;
     int c;
     unsigned int bit;
     size_t hex_chars = (width + 7) / 8 * 2;
     char *s;
     s = malloc(hex_chars);
 
     for (y = 0; y < height; y++) {
 	memset(s, 0, strlen(s));
 	if (y)
 	    fprintf(out, "\n");
 	for (x = 0; x < hex_chars; x++) {
 	    strncat(s, bitmap, 1);
 	    bitmap++;
 	}
 
 	c = (int)strtol(s, NULL, 16);
 	bit = 0x80 * hex_chars / 2;
 	for (x = 0; x < width; x++) {
 	    put_pixel(c, bit, out);
 	    if (bit == 1)
 		break;
 	    bit = bit / 2;
 	}
 	fprintf(out, "$@");
     }
 
     fprintf(out, "@\n");
     free(s);
 }
 
 
 void bdf2flf(FILE * in, FILE * out)
 {
     char *s;
     char linebuf[1024];
     char font[1024];
     char copyright[1024];
     int baseline, codetags, i;
     int comments = 3;
     int num_chars = 0;
     int width = 0;
     int height = 0;
     char bitmap[4 * 32];
     int n = 0;
     struct character *chars;
     const unsigned int *j;
 
     // Some of the bdf-reading logic is derived from bdf2c (c) Lutz Sammer.
     // extract bdf headers
     for (;;) {
 	if (!fgets(linebuf, sizeof(linebuf), in)) {	// EOF
 	    break;
 	}
 	if (!(s = strtok(linebuf, " \t\n\r"))) {	// empty line
 	    break;
 	}
 	if (!strcasecmp(s, "FONTBOUNDINGBOX")) {
 	    width = atoi(strtok(NULL, " \t\n\r"));
 	    height = atoi(strtok(NULL, " \t\n\r"));
 	    strtok(NULL, " \t\n\r");
 	    baseline = height + atoi(strtok(NULL, " \t\n\r"));
 
 	} else if (!strcasecmp(s, "FONT")) {
 	    strcpy(font, strtok(NULL, "\n"));
 
 	} else if (!strcasecmp(s, "COPYRIGHT")) {
 	    strcpy(copyright, strtok(NULL, "\n"));
 	    comments = 4;
 
 	} else if (!strcasecmp(s, "CHARS")) {
 	    num_chars = atoi(strtok(NULL, " \t\n\r"));
 	    break;
 	}
     }
 
     if (num_chars <= 0 || width <= 0 || height <= 0)
 	die("Could not extract BDF data. Is the input a BDF file?\n");
 
     if (width > 32 || height > 32)
 	die("bdf fonts this large are not supported, sorry.\n");
 
     chars = malloc(num_chars * sizeof(struct character));
     if (!chars)
 	die("Could not allocate memory.\n");
 
     // extract individual char data
     for (;;) {
 	if (!fgets(linebuf, sizeof(linebuf), in))
 	    break;
 	if (!(s = strtok(linebuf, " \t\n\r")))
 	    continue;
 	if (!strcasecmp(s, "ENCODING")) {
 	    chars[n].encoding = atoi(strtok(NULL, " \t\n\r"));
 	} else if (!strcasecmp(s, "BBX")) {
 	    chars[n].width = atoi(strtok(NULL, " \t\n\r"));
 	} else if (!strcasecmp(s, "BITMAP")) {
 	    if (n == num_chars)
 		die("bdf font has incorrect CHARS value.\n");
 	    i = 0;
 	    chars[n].printed = 0;
 	    chars[n].bitmap = malloc((width + 7) / 8 * height * 2);
 	    chars[n].bitmap[0] = '\0';
 	    for (;;) {
 		fgets(linebuf, sizeof(linebuf), in);
 		s = strtok(linebuf, "\n\r");
 		if (!strcasecmp(s, "ENDCHAR")) {
 		    break;
 		}
 		strncat(chars[n].bitmap, s, 4);
 		i++;
 	    }
 	    n++;
 	}
     }
 
     // output flf header
     codetags = 0;
     fprintf(out, "flf2a$ %i %i %i -1 %i 0 16384 %i\n", height, baseline, width+2,
 	    comments, codetags);
     fprintf(out, "FIGlet font derived from %s\n", font);
     if (comments > 3)
 	fprintf(out, "which has copyright: %s\n", copyright);
     fprintf(out, "Converted to flf with bdf2flf (c) 2020 Matt Colligan.\n\n");
 
     // print required characters first
     n = 0;
     j = &REQUIRED[0];
     i = 0;
     for (;;) {
 	if (chars[n].encoding == *j) {
 	    strncpy(bitmap, chars[n].bitmap, ((width + 7) / 8) * height * 2);
 	    print_character(out, bitmap, chars[n].width, height);
 	    chars[n].printed = 1;
 	    if (*j == 223)
 		break;
 	    j++;
 	    i = 0;
 	}
 	n++;
 	i++;
 	if (n == num_chars)
 	    n = 0;
 	if (i == num_chars)
 	    break;
     }
 
     // print additional characters second
     for (n = 0; n < num_chars; n++) {
 	if (!chars[n].printed) {
 	    strncpy(bitmap, chars[n].bitmap, ((width + 7) / 8) * height * 2);
 	    print_character(out, bitmap, chars[n].width, height);
 	}
 	free(chars[n].bitmap);
     }
 }
 
 
 int main(int argc, char *argv[])
 {
     if (argc > 1) {
 	printf(PROGNAME " < input.bdf > output.flf\nbdf data is read from stdin"
 		" and figlet font data is output to stdout.\n");
 	exit(EXIT_SUCCESS);
     }
 
     bdf2flf(stdin, stdout);
 
     (void)(argv);  // shush the compiler
     return 0;
 }