/* This converts a PBM to a C header file containing a DGen font made from the
 * PBM. The PBM width should be divisible by 96, with cells which from left to
 * right are the glyphs from 0x20 (space) to 0x7f (character after ~).
 * The color 1 in the PBM is opaque, and 0 is transparent. */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

int main(int argc, char *argv[])
{
  FILE *pbm, *df;
  char magic[0x20], tmp[0x200];
  int x,y, i,j;
  int width;
  signed char w, h;

  /* Open the pbm and read it */
  if(argc < 3)
    { printf("Usage: %s pbmfile outfile\n", argv[0]); exit(2); }
  if(!(pbm = fopen(argv[1], "r"))) exit(1);

	if (fgets(magic, 0x20, pbm) == NULL) {
	error:
		fclose(pbm);
		return 1;
	}

  /* Throw away possible comments */
  do {
		if (fgets(tmp, 0x200, pbm) == NULL) {
			printf("Invalid file contents\n");
			goto error;
		}
  } while(*tmp == '#');

	sscanf(tmp, "%d%hhd", &width, &h);
	/* Verify magic and dimensions */
	if (strcmp(magic, "P1\n")) {
		printf("Bad magic\n");
		goto error;
	}
	if ((width < 0) || (width % 96) || ((w = (width / 96)) < 0)) {
		printf("Bad X dimension\n");
		goto error;
	}
	if (h < 0) {
		printf("Bad Y dimension\n");
		goto error;
	}

	unsigned char (*pbm_contents)[width][h];

	if ((pbm_contents = calloc(1, sizeof(*pbm_contents))) == NULL)
		goto invalid;
	for (y = 0; (y < h); ++y)
		for (x = 0; (x < width); ++x) {
			char c;

			do {
				if (fread(&c, 1, 1, pbm) != 1)
					goto invalid;
			}
			while (isspace(c));
			if (!isdigit(c))
				goto invalid;
			(*pbm_contents)[x][y] = (c - 0x30);
		}

  fclose(pbm);

  /* Start the header to our output file */
  if(!(df = fopen(argv[2], "w"))) exit(1);
  fprintf(df, "/* DGen font, generated by pbm2df from \"%s\" */\n\n"
	      "#include <stdio.h> /* for NULL definition */\n\n",
	      argv[1]);
  /* Now do each cell */
  for(i = 0; i < 96; ++i)
    {
      fprintf(df, "static const short _glyph_%02X[] = {", i + 32);
      j = 0;
      for(y = 0; (y < h); ++y)
	for(x = (i * w); x < ((i * w) + w); ++x)
	  {
	    if((*pbm_contents)[x][y]) { fprintf(df, "%d, ", j); j = 0; }
	    ++j;
	  }
      fprintf(df, "-1};\n");
    }
  /* Compile it all into one big mess ;) */
  fprintf(df, "const short *dgen_font_%hhdx%hhd[0x80] = {\n"
	      "  /* Fill in for the control characters */\n"
	      "  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,\n"
	      "  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,\n"
	      "  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,\n"
	      "  NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL", w, h);
  for(i = 32; i < 128; ++i)
    fprintf(df, ",\n  _glyph_%02X", i);

  /* Close off the end of the file */
  fprintf(df, "\n};\n");
  fclose(df);

  printf("Successfully generated dgen font source \"%s\" from \"%s\"\n",
	 argv[2], argv[1]);

	free(pbm_contents);

  return 0;
invalid:
	free(pbm_contents);
	fclose(pbm);
	printf("Invalid file contents\n");
	return 1;
}