/*
Program: BMP2ASC.C
Author : Kim Moser
Date   : 10/06/1993
System : IBM PC / Borland C 3.0
Descrip: Reads BMP file and outputs an ASCII representation of it.

Usage  :
*/

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

static void usage(void);
static void usage(void)
{
	fputs("\
BMP2ASC  v1.0  10/06/1993  Copyright (C) Kim Moser  All Rights Reserved\n\
Usage: BMP2ASC filename\n\
Sends output to stdout (which can be redirected to a file).\n",
		stderr
	);

	exit(1);
}

typedef struct {
	char id[2];	/* Expected to be "BM" */
	long size;
	int res1;
	int res2;
	long offBits;

	long size2;	/* Always 40? */
	long width;
	long height;
	int planes;
	int bitCount;

	long compression;
	long sizeImage;
	long xPelsPerMeter;
	long yPelsPerMeter;
	long colorUsed;
	long colorImportant;
} BMP_HEADER;

static void process(BMP_HEADER* hdr, unsigned char* data, int plane,
	int scanline_size, int bytesPerPixel);
static void process(BMP_HEADER* hdr, unsigned char* data, int plane,
	int scanline_size, int bytesPerPixel)
{
	int x, y, z;

	for (y=hdr->height-1; y >=0; y--) {
		for (x=0; x < hdr->width; x++) {
			unsigned char* p = data + y*scanline_size + x*bytesPerPixel;

			printf("%02x", (int) p[plane]);
		}
		putchar('\n');
	}
}

static char* PLANE_NAMES[] = {
	"RED",
	"GREEN",
	"BLUE"
};

main(int argc, char** argv)
{
	char* fname;
	FILE* fp;
	BMP_HEADER hdr;
	unsigned char* data=NULL;
	size_t data_size;
	size_t scanline_size; /* Bytes per scanline */
	int bytesPerPixel;  /* hdr.bitCount / 8 */
	size_t tmp_size_t;
	int plane;

	if (argc < 2) usage();

	fname = argv[1];

	do {  /* So 'while' exits loop */
		if ((fp = fopen(fname, "rb")) == NULL) {
			fprintf(stderr, "Error opening file '%s'.\n",
				fname
			);
			break;
		}

		if (fread(&hdr, 1, sizeof(hdr), fp) != sizeof(hdr)) {
			fprintf(stderr, "Error reading header.\n");
			break;
		}

		bytesPerPixel = hdr.bitCount / 8;

		scanline_size = (size_t) (hdr.width+1) * bytesPerPixel;

		data_size = scanline_size * hdr.height;

		fprintf(stderr,
			"type='%c%c'\n"
			"size=%ld\n"
			"res1=%d\n"
			"res2=%d\n"
			"offbits=%ld\n"
			"size2=%ld\n"
			"width=%ld\n"
			"height=%ld\n"
			"planes=%d\n"
			"bitcount=%d (%d bytes per pixel)\n"
			"compression=%ld\n"
			"sizeimage=%ld\n"
			"xPelsPerMeter=%ld\n"
			"yPelsPerMeter=%ld\n"
			"colorUsed=%ld\n"
			"colorImportant=%ld\n"
			"scanline_size=%d\n"
			"data_size=%d\n\n",

			hdr.id[0], hdr.id[1],
			hdr.size,
			hdr.res1,
			hdr.res2,
			hdr.offBits,
			hdr.size2,
			hdr.width,
			hdr.height,
			hdr.planes,
			hdr.bitCount, bytesPerPixel,
			hdr.compression,
			hdr.sizeImage,
			hdr.xPelsPerMeter,
			hdr.yPelsPerMeter,
			hdr.colorUsed,
			hdr.colorImportant,
			scanline_size,
			data_size
		);

		if (hdr.compression) {
			fprintf(stderr, "Sorry, I can't handle compressed files.\n");
			break;
		}

		if (hdr.bitCount % 8) {
			fprintf(stderr, "Sorry, I can handle files only in which the bit count is an even multiple of 8.\n");
			break;
		}

		if ((data = malloc(data_size)) == NULL) {
			fprintf(stderr, "malloc() failed for %u bytes.\n",
				data_size
			);
			break;
		}

		if ((tmp_size_t = fread(data, 1, data_size, fp)) != data_size) {
			fprintf(stderr, "fread() returned %u for %u.\n",
				tmp_size_t,
				data_size
			);
		}

		for (plane=0; plane < 3; plane++) {
			printf("%s plane:\n",
				PLANE_NAMES[plane]
			);
			process(&hdr, data, plane, scanline_size, bytesPerPixel);
			printf("\n");
		}
	} while (0);

	if (data != NULL) free(data);

	if (fclose(fp)) {
		fprintf(stderr, "Error closing file '%s'.\n",
			fname
		);
	}

	return (0);
}