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/* imgtoppm.c - read an Img-whatnot file and produce a portable pixmap
**
** Based on a simple conversion program posted to comp.graphics by Ed Falk.
**
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation. This software is provided "as is" without express or
** implied warranty.
*/
#include <stdbool.h>
#include <limits.h>
#include <string.h>
#include "nstring.h"
#include "ppm.h"
int
main(int argc, const char ** argv) {
FILE * ifP;
pixel * pixelrow;
pixel colormap[256];
unsigned int cols;
unsigned int rows;
pixval maxval;
unsigned int cmaplen;
bool gotAt, gotCm, gotPd;
unsigned char buf[4096];
pm_proginit(&argc, argv);
if (argc-1 >= 1)
ifP = pm_openr(argv[1]);
else
ifP = stdin;
if (argc-1 > 1)
pm_error("Too many arguments (%u). "
"The only possible argument is the input file name", argc-1);
/* Get signature. */
fread(buf, 8, 1, ifP);
buf[8] = '\0';
/* Get entries. */
gotAt = false; /* initial value */
gotCm = false; /* initial value */
gotPd = false; /* initial value */
while (fread( buf, 2, 1, ifP) == 1) {
if (strneq((char*) buf, "AT", 2)) {
unsigned int len;
if (fread(buf, 8, 1, ifP) != 1)
pm_error("bad attributes header");
buf[8] = '\0';
len = atoi((char*) buf);
if (fread(buf, len, 1, ifP) != 1)
pm_error("bad attributes buf");
buf[len] = '\0';
sscanf((char*) buf, "%4u%4u%4u", &cols, &rows, &cmaplen);
if (cols > UINT_MAX/rows)
pm_message("height (%u) and width (%u) in header are "
"uncomputably large", rows, cols);
if (cmaplen > UINT_MAX/3)
pm_message("colormap length (%u) in header is "
"uncomputably large", cmaplen);
maxval = 255;
gotAt = true;
} else if (strneq((char*) buf, "CM", 2)) {
unsigned int i;
unsigned int len;
if (!gotAt)
pm_error("missing attributes header");
if (fread(buf, 8, 1, ifP) != 1)
pm_error("bad colormap header");
buf[8] = '\0';
len = atoi((char*) buf);
if (fread(buf, len, 1, ifP) != 1)
pm_error("bad colormap buf");
if (len != cmaplen * 3) {
pm_message(
"cmaplen (%u) and colormap buf length (%u) do not match",
cmaplen, len);
if (len > cmaplen * 3)
len = cmaplen * 3;
else
cmaplen = len / 3;
}
for (i = 0; i < len; i += 3)
PPM_ASSIGN(colormap[i / 3], buf[i], buf[i + 1], buf[i + 2]);
gotCm = true;
} else if (strneq((char*) buf, "PD", 2)) {
unsigned int len;
unsigned int row;
if (fread(buf, 8, 1, ifP) != 1)
pm_error("bad pixel data header");
buf[8] = '\0';
len = atoi((char*) buf);
if (len != cols * rows)
pm_message(
"pixel data length (%u) does not match image size (%u)",
len, cols * rows);
ppm_writeppminit(stdout, cols, rows, maxval, 0);
pixelrow = ppm_allocrow(cols);
for (row = 0; row < rows; ++row) {
unsigned int col;
if (fread(buf, 1, cols, ifP) != cols)
pm_error("EOF / read error");
for (col = 0; col < cols; ++col) {
if (gotCm)
pixelrow[col] = colormap[buf[col]];
else
PPM_ASSIGN(pixelrow[col],
buf[col], buf[col], buf[col]);
}
ppm_writeppmrow(stdout, pixelrow, cols, maxval, 0);
}
gotPd = true;
}
}
if (!gotPd)
pm_error("missing pixel data header");
pm_close(ifP);
/* If the program failed, it previously aborted with nonzero completion
code, via various function calls.
*/
return 0;
}
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