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/* See LICENSE file for copyright and license details. */
#include <arpa/inet.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "arg.h"
#include <png.h>
char *argv0;
#define HEADER_FORMAT "imagefile########"
static void
usage(void)
{
fprintf(stderr, "usage: %s\n", argv0);
exit(EXIT_FAILURE);
}
int
main(int argc, char *argv[])
{
png_structp png_struct_p;
png_infop png_info_p;
uint8_t hdr[17], *png_row;
png_uint_32 width, height, i;
png_size_t png_row_len;
ARGBEGIN {
default:
usage();
} ARGEND;
if (argc != 0)
usage();
/* header */
if (fread(hdr, 1, strlen(HEADER_FORMAT), stdin) != strlen(HEADER_FORMAT)) {
fprintf(stderr, "failed to read from stdin or input too short\n");
goto err;
}
if (memcmp("imagefile", hdr, 9)) {
fprintf(stderr, "invalid magic in header\n");
goto err;
}
width = ntohl((hdr[9] << 0) | (hdr[10] << 8) | (hdr[11] << 16) | (hdr[12] << 24));
height = ntohl((hdr[13] << 0) | (hdr[14] << 8) | (hdr[15] << 16) | (hdr[16] << 24));
/* load png */
png_struct_p = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
png_info_p = png_create_info_struct(png_struct_p);
if (!png_struct_p || !png_info_p || setjmp(png_jmpbuf(png_struct_p))) {
fprintf(stderr, "failed to initialize libpng\n");
goto err;
}
png_init_io(png_struct_p, stdout);
png_set_IHDR(png_struct_p, png_info_p, width, height, 8, PNG_COLOR_TYPE_RGB_ALPHA,
PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_write_info(png_struct_p, png_info_p);
/* write rows */
png_row_len = strlen("RGBA") * width * sizeof(uint8_t);
png_row = malloc(png_row_len);
if (!png_row) {
fprintf(stderr, "failed to allocate row-buffer\n");
goto err;
}
for (i=0; i < height; ++i) {
if (fread(png_row, 1, png_row_len, stdin) != png_row_len) {
fprintf(stderr, "unexpected EOF or row-skew at %d\n", i);
goto err;
}
png_write_row(png_struct_p, png_row);
}
png_write_end(png_struct_p, NULL);
/* clean up */
png_free_data(png_struct_p, png_info_p, PNG_FREE_ALL, -1);
png_destroy_write_struct(&png_struct_p, NULL);
free(png_row);
return EXIT_SUCCESS;
err:
png_free_data(png_struct_p, png_info_p, PNG_FREE_ALL, -1);
png_destroy_write_struct(&png_struct_p, NULL);
free(png_row);
return EXIT_FAILURE;
}
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