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/* See LICENSE file for copyright and license details. */
#include <arpa/inet.h>
#include <errno.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "arg.h"
char *argv0;
static void
usage(void)
{
fprintf(stderr, "usage: %s [-b #rrggbb]\n", argv0);
exit(1);
}
int
main(int argc, char *argv[])
{
size_t rowlen;
uint64_t a;
uint32_t hdr[4], width, height, i, j, k, l;
uint16_t *row, mask[3] = { 0xffff, 0xffff, 0xffff };
uint8_t *rowout;
char *color, colfmt[] = "%#x%#x%#x";
unsigned int collen, col[3], colfac;
argv0 = argv[0];
ARGBEGIN {
case 'b':
color = EARGF(usage());
if (color[0] == '#') {
color++;
}
collen = strlen(color);
if (collen != 3 && collen != 6 && collen != 12) {
usage();
}
colfmt[1] = colfmt[4] = colfmt[7] = ((collen / 3) - '0');
if (sscanf(color, colfmt, col, col + 1, col + 2) != 3) {
usage();
}
/* UINT16_MAX / 255 = 257; UINT16_MAX / 15 = 4369 */
colfac = (collen == 3) ? 4369 : (collen == 6) ? 257 : 1;
for (i = 0; i < 3; i++) {
mask[i] = col[i] * colfac;
}
default:
usage();
} ARGEND
if (argc)
usage();
/* header */
if (fread(hdr, sizeof(*hdr), 4, stdin) != 4) {
fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
return 1;
}
if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
fprintf(stderr, "%s: invalid magic value\n", argv0);
return 1;
}
if (!(width = ntohl(hdr[2]))) {
fprintf(stderr, "%s: invalid width: zero\n", argv0);
return 1;
}
if (!(height = ntohl(hdr[3]))) {
fprintf(stderr, "%s: invalid height: zero\n", argv0);
return 1;
}
if (width > SIZE_MAX / ((sizeof("RGBA") - 1) * sizeof(uint16_t))) {
fprintf(stderr, "%s: row length integer overflow\n", argv0);
return 1;
}
rowlen = width * (sizeof("RGBA") - 1);
if (!(row = malloc(rowlen * sizeof(uint16_t)))) {
fprintf(stderr, "%s: malloc: %s\n", argv0, strerror(errno));
return 1;
}
if (!(rowout = malloc(width * sizeof("RGB") - 1))) {
fprintf(stderr, "%s: malloc: %s\n", argv0, strerror(errno));
return 1;
}
/* PPM binary */
printf("P6\n%" PRIu32 " %" PRIu32 "\n255\n", width, height);
/* write rows */
for (i = 0; i < height; ++i) {
if (fread(row, sizeof(uint16_t), rowlen, stdin) != rowlen) {
fprintf(stderr, "%s: fread: %s\n", argv0, strerror(errno));
return 1;
}
for (j = 0, k = 0; j < rowlen; j += 4, k += 3) {
a = ntohs(row[j + 3]);
for (l = 0; l < 3; l++) {
rowout[k + l] = (a * ntohs(row[j + l]) +
(65535 - a) * mask[l]) /
(257 * 65535);
}
}
if (fwrite(rowout, 3, width, stdout) != width) {
fprintf(stderr, "%s: fwrite: %s\n", argv0, strerror(errno));
return 1;
}
}
return 0;
}
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