/*
** xvtoppm:  A simple-minded filter to convert xv's .xvpics to ppm format.
**
** @(#)$Id: xvtoppm.c,v 5.3 1999/09/11 08:47:34 mark Exp $
**
**    xvtoppm - .xvpics -> .ppm filter
**    Copyright (C) 1992-1999  Mark B. Hanson (mbh@panix.com)
**
**    This program is free software; you can redistribute it and/or modify
**    it under the terms of the GNU General Public License as published by
**    the Free Software Foundation; either version 2 of the License, or
**    (at your option) any later version.
**
**    This program is distributed in the hope that it will be useful,
**    but WITHOUT ANY WARRANTY; without even the implied warranty of
**    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
**    GNU General Public License for more details.
**
**    You should have received a copy of the GNU General Public License
**    along with this program; if not, write to the Free Software
**    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
**
** to compile:
**    cc -O xvtoppm.c -o xvtoppm
**
** to use:
**    xvtoppm .xvpics/file.xv > file.ppm
*/

#include <stdio.h>

int
main(argc, argv)
    int argc;
    char *argv[];
{
    FILE *file;
    char magic[3];
    char cmap[4];
    char buffer[256];
    int width;
    int height;
    int maxval;
    unsigned char *data;
    int i;

    if (argc != 2) {
	fprintf(stderr, "%s: usage: %s xv-icon-file\n", argv[0], argv[0]);
	exit(1);
    }

    if ((file = fopen(argv[1], "r")) == NULL) {
	fprintf(stderr, "%s: fopen(%s) failed!\n", argv[0], argv[1]);
	exit(1);
    }

    if (fscanf(file, "%2s %3s\n", magic, cmap) != 2) {
	fprintf(stderr, "%s: failed to read magic number!\n", argv[0]);
	exit(1);
    }

    if (strncmp(magic, "P7", 2)) {
	fprintf(stderr, "%s: yikes!  `%s' != `P7'!\n", argv[0], magic);
	exit(1);
    }

    do {
	if (fgets(buffer, 255, file) == NULL) {
	    perror("fgets");
	    exit(1);
	}
    } while (buffer[0] == '#');

    if (sscanf(buffer, "%d %d %d\n", &width, &height, &maxval) != 3) {
	fprintf(stderr, "%s: failed to read file dimensions!\n", argv[0]);
	exit(1);
    }

    if ((data = (unsigned char *)malloc(width * height)) == NULL) {
	fprintf(stderr, "%s: failed to malloc %d bytes!\n", argv[0],
		width * height);
	exit(1);
    }

    if (fread((char *)data, sizeof(char), width * height, file) !=
	    width * height) {
	fprintf(stderr, "%s: failed to read %d bytes!\n", argv[0],
		width * height);
	exit(1);
    }

    fprintf(stdout, "P6\n%d %d\n255\n", width, height);

    for (i = 0; i < width * height; i++) {
	fprintf(stdout, "%c%c%c",
		(data[i] & 0340),
		(data[i] & 0034) << 3,
		(data[i] & 0003) << 6);
    }

    free(data);

    if (fclose(file) == EOF) {
	fprintf(stderr, "%s: fclose(%s) failed!", argv[0], argv[1]);
	exit(1);
    }

    exit(0);
} /* main */