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/* pnm.c -- utility functions for testing purposes
* Copyright (C) 2019 SEIKO EPSON Corporation
*
* License: EPSON END USER SOFTWARE LICENSE
* Author : SEIKO EPSON Corporation
*
* This file is part of Image Scan! for Linux.
* It is distributed under the terms of the EPSON END USER SOFTWARE LICENSE.
*
* You should have received a verbatim copy of the EPSON END USER SOFTWARE
* LICENSE along with the software.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "pnm.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
pnm *
read_pnm (const char *file)
{
pnm image, *rv;
char *line = NULL;
size_t sz = 0;
FILE *fp;
if (file)
fp = fopen (file, "r");
else
fp = stdin;
if (!fp) return NULL;
getline (&line, &sz, fp); /* file magic number */
if ('P' != line[0]) return NULL;
image.depth = 8;
/**/ if ('6' == line[1]) image.format = 1;
else if ('5' == line[1]) image.format = 0;
else if ('4' == line[1]) { image.format = 0; image.depth = 1; }
else return NULL;
getline (&line, &sz, fp);
while ('#' == line[0]) /* skip header comments */
getline (&line, &sz, fp);
sscanf (line, "%d%d", &image.pixels_per_line, &image.lines);
if (1 < image.depth)
{
getline (&line, &sz, fp); /* max color value */
sscanf (line, "%d", &image.depth);
/**/ if (image.depth < (1 << 1)) image.depth = 1;
else if (image.depth < (1 << 8)) image.depth = 8;
else if (image.depth < (1 << 16)) image.depth = 16;
else return NULL;
}
free (line);
sz = 0;
image.bytes_per_line = (image.pixels_per_line
* (image.format ? 3 :1)
* (image.depth == 16 ? 2 : 1));
if (1 == image.depth)
{
image.bytes_per_line = (image.bytes_per_line + 7) / 8;
}
image.size = image.bytes_per_line * image.lines;
image.buffer = malloc (image.size);
if (!image.buffer) return NULL;
while (sz < image.size)
{
size_t s = fread (image.buffer, 1, image.size, fp);
if (0 == s)
{
if (ferror (fp))
{
fprintf (stderr, "error reading image file\n");
free (image.buffer);
return NULL;
}
if (feof (fp))
{
fprintf (stderr, "premature end of image file\n");
free (image.buffer);
return NULL;
}
}
sz += s;
}
fclose (fp);
rv = (pnm *) malloc (sizeof (pnm));
if (!rv)
{
free (image.buffer);
return NULL;
}
memcpy (rv, &image, sizeof (pnm));
return rv;
}
void
write_pnm (const char *file, const pnm *image, const char *comment)
{
FILE *fp;
if (file)
fp = fopen (file, "w");
else
fp = stdout;
if (!fp) return;
if (1 == image->depth)
{
fprintf (fp, "P4\n");
}
else
{
fprintf (fp, "P%d\n", (image->format ? 6 : 5));
}
fprintf (fp, "# %s\n", comment);
fprintf (fp, "%d %d\n", image->pixels_per_line, image->lines);
if (1 != image->depth)
{
fprintf (fp, "%d\n", (1 << image->depth) - 1);
}
fwrite (image->buffer, 1, image->bytes_per_line * image->lines, fp);
fflush (fp);
fclose (fp);
}
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