/*
  bmp2hex - Converts a 1-bit/pixel image in a BMP image file into hexadecimal
  data for use in initializing a C or assembler program data array.

  Only works on 1-bit/pixel images, and probably not on all of those.

  Allan Weber, USC Dept. of Electrical Engineering, 11/7/06
*/

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

// #define DEBUG

unsigned char fileheader[14];
unsigned char infoheader[40];

main(int argc, char *argv[])
{
    int offset, width, height, bitcount;
    int n, widthbytes, padbytes;
    unsigned char *img, *p;
    int row, col, ch, invert;
    extern int optind;
    extern char *optarg;

    invert = 0;

    while ((ch = getopt(argc, argv, "i")) != -1) {
	switch (ch) {
	case 'i':
	    invert = 1;
	    break;
	case '?':
	    usage();
	    exit(1);
	}
    }

    if (fread(fileheader, 1, 14, stdin) != 14) {
	fprintf(stderr, "Error reading fileheader\n");
	exit(1);
    }
    if (strncmp(fileheader, "BM", 2) != 0) {
	fprintf(stderr, "File is not BMP format\n");
	exit(1);
    }
    if (fread(infoheader, 1, 40, stdin) != 40) {
	fprintf(stderr, "Error reading fileheader\n");
	exit(1);
    }

    /* Get some numbers from the headers */
    offset = get4(fileheader + 10);
    width  = get4(infoheader + 4);
    height = get4(infoheader + 8);
    bitcount = get2(infoheader + 14);
	
#ifdef DEBUG
    printf("offset=%d, width=%d, height=%d, bitcount=%d\n",
	   offset, width, height, bitcount);
#endif

    /* Skip over any color table */
    n = offset - (14 + 40);
    if (n > 0)
	fseek(stdin, n, SEEK_CUR);

    /* Check to make sure it's 1-bit per pixel */
    if (bitcount != 1) {
	fprintf(stderr, "Unsupported bit depth - %d\n", bitcount);
	exit(1);
    }

    widthbytes = (width + 7) / 8; /* number of data bytes per line */
    padbytes = ((width + 31) / 32) * 4; /* data+pad bytes per line */

#ifdef DEBUG
    printf("widthbytes=%d, padbytes=%d\n", widthbytes, padbytes);
#endif

    /* Allocate memory for image data */
    n = padbytes * height;
    if ((img = malloc(n)) == NULL) {
	fprintf(stderr, "Can\'t allocate memory\n");
	exit(1);
    }

    /* Read in image data */
    if (fread(img, 1, n, stdin) != n) {
	fprintf(stderr, "Error reading image data\n");
	exit(1);
    }

    /* Loop through image data and print it out */
    for (row = height-1; row >= 0; row--) {
	p = img + (padbytes * row);
	for (col = 0; col < widthbytes; col++) {
	    ch = *p++;
	    if (invert) 
		ch ^= 0xff;
	    printf("0x%02x, ", ch);
	}
	printf("\n");
    }
}

/* Turn an Intel 4-byte quantity into an 32-bit value */
int get4(unsigned char *p)
{
    int x;
    x = (*(p+3) << 24) + (*(p+2) << 16) + (*(p+1) << 8) + (*p);
    return(x);
}

/* Turn an Intel 2-byte quantity into an 32-bit value */
int get2(unsigned char *p)
{
    int x;
    x = (*(p+1) << 8) + (*p);
    return(x);
}

usage()
{
    fprintf(stderr, "bmp2hex [-i] < file.bmp\n");
}