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/* See LICENSE file for copyright and license details. */
#include "arg.h"
#include "util.h"
#include <fcntl.h>
#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static unsigned int
clip(unsigned int value)
{
return value > 255 ? 255 : value;
}
static void
usage(void)
{
eprintf("usage: %s [-r] -f frames -w width -h height\n", argv0);
}
int
main(int argc, char *argv[])
{
int reverse = 0;
size_t frames = 0, width = 0, height = 0;
unsigned char buf[8096];
size_t frame, h, w, max;
size_t ptr = 0, n, i, fm;
ssize_t r;
double a;
ARGBEGIN {
case 'f':
if (tozu(EARGF(usage()), 2, SIZE_MAX, &frames))
eprintf("argument of -f must be an integer in [2, %zu]\n", SIZE_MAX);
break;
case 'w':
if (tozu(EARGF(usage()), 1, SIZE_MAX, &width))
eprintf("argument of -w must be an integer in [1, %zu]\n", SIZE_MAX);
break;
case 'h':
if (tozu(EARGF(usage()), 1, SIZE_MAX, &height))
eprintf("argument of -h must be an integer in [1, %zu]\n", SIZE_MAX);
break;
case 'r':
reverse = 1;
break;
default:
usage();
} ARGEND;
if (argc || !frames || !width || !height)
usage();
fm = frames - 1;
for (frame = 0; frame < frames; frame++) {
for (h = height; h--;) {
for (w = width << 2; w; w -= n) {
max = sizeof(buf) - ptr < w ? sizeof(buf) - ptr : w;
r = read(STDIN_FILENO, buf + ptr, max);
if (r < 0)
eprintf("read <stdin>:");
if (r == 0)
eprintf("content is shorter than specified\n");
n = ptr += (size_t)r;
n -= n & 3;
if (reverse) {
for (i = 0; i < n; i += 4) {
a = buf[i + 3];
a = a * (double)frame / fm;
a += 0.5;
buf[i + 3] = clip((unsigned int)a);
}
} else {
for (i = 0; i < n; i += 4) {
a = buf[i + 3];
a = a * (double)(fm - frame) / fm;
a += 0.5;
buf[i + 3] = clip((unsigned int)a);
}
}
for (i = 0; i < n; i += (size_t)r) {
r = write(STDOUT_FILENO, buf + i, n - i);
if (r < 0)
eprintf("write <stdout>:");
}
memmove(buf, buf + n, ptr -= n);
}
}
}
return 0;
}
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