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/*
* cistopbm: Convert images in the CompuServe RLE format to PBM
* Copyright (C) 2009 John Elliott
*
* 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
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "pbm.h"
static void syntax(const char *prog)
{
pm_usage(" { options } { input }\n\n"
"Input file should be in CompuServe RLE format.\n"
"Output file will be in PBM format.\n"
"Options:\n"
"-i, --inverse: Reverse black and white.\n"
"--: End of options\n\n"
"cistopbm v1.01, Copyright 2009 John Elliott <jce@seasip.demon.co.uk>\n"
"This program is redistributable under the terms of the GNU General Public\n"
"License, version 2 or later.\n"
);
}
int main(int argc, const char **argv)
{
FILE *ifP;
int c[3];
int inoptions = 1;
int n, x, y;
int bw = PBM_BLACK; /* Default colouring is white on black */
const char *inpname = NULL;
int height, width;
bit **bits;
pm_proginit(&argc, argv);
for (n = 1; n < argc; n++)
{
if (!strcmp(argv[n], "--"))
{
inoptions = 0;
continue;
}
if (inoptions)
{
if (pm_keymatch(argv[n], "-h", 2) ||
pm_keymatch(argv[n], "-H", 2) ||
pm_keymatch(argv[n], "--help", 6))
{
syntax(argv[0]);
return EXIT_SUCCESS;
}
if (pm_keymatch(argv[n], "-i", 2) ||
pm_keymatch(argv[n], "-I", 2) ||
pm_keymatch(argv[n], "--inverse", 9))
{
bw ^= (PBM_WHITE ^ PBM_BLACK);
continue;
}
if (argv[n][0] == '-' && argv[n][1] != 0)
{
pm_message("Unknown option: %s", argv[n]);
syntax(argv[0]);
return EXIT_FAILURE;
}
}
if (inpname == NULL) inpname = argv[n];
else { syntax(argv[0]); return EXIT_FAILURE; }
}
if (inpname == NULL) inpname = "-";
ifP = pm_openr(inpname);
/* There may be junk before the magic number. If so, skip it. */
x = 0;
c[0] = c[1] = c[2] = EOF;
/* Read until the array c[] holds the magic number. */
do
{
c[0] = c[1];
c[1] = c[2];
c[2] = fgetc(ifP);
/* If character read was EOF, end of file was reached and magic number
* not found.
*/
if (c[2] == EOF)
{
pm_error("Input file is not in CompuServe RLE format");
}
++x;
} while (c[0] != 0x1B || c[1] != 0x47);
/* x = number of bytes read. Should be 3 if signature is at the start */
if (x > 3)
{
pm_message("Warning: %d bytes of junk skipped before image",
x - 3);
}
/* Parse the resolution */
switch(c[2])
{
case 0x48: height = 192; width = 256; break;
case 0x4D: height = 96; width = 128; break;
default: pm_error("Unknown resolution 0x%02x", c[2]);
break;
}
/* Convert the data */
bits = pbm_allocarray(width, height);
x = y = 0;
do
{
c[0] = fgetc(ifP);
/* Stop if we hit EOF or Escape */
if (c[0] == EOF) break; /* EOF */
if (c[0] == 0x1B) break; /* End of graphics */
/* Other non-printing characters are ignored; some files contain a
* BEL
*/
if (c[0] < 0x20) continue;
/* Each character gives the number of pixels to draw in the appropriate
* colour.
*/
for (n = 0x20; n < c[0]; n++)
{
if (x < width && y < height) bits[y][x] = bw;
x++;
/* Wrap at end of line */
if (x >= width)
{
x = 0;
y++;
}
}
/* And toggle colours */
bw ^= (PBM_WHITE ^ PBM_BLACK);
}
while (1);
/* See if the end-graphics signature (ESC G N) is present. */
c[1] = EOF;
if (c[0] == 0x1B)
{
c[1] = fgetc(ifP);
c[2] = fgetc(ifP);
}
if (c[0] != 0x1B || c[1] != 0x47 || c[2] != 0x4E)
{
pm_message("Warning: End-graphics signature not found");
}
/* See if we decoded the right number of pixels */
if (x != 0 || y != height)
{
pm_message("Warning: %d pixels found, should be %d",
y * width + x, width * height);
}
pbm_writepbm(stdout, bits, width, height, 0);
pm_close(ifP);
return 0;
}
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