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| /* Fake a PNG - just write it out directly.
| *
| * COPYRIGHT: Written by John Cunningham Bowler, 2014.
| * To the extent possible under law, the author has waived all copyright and
| * related or neighboring rights to this work. This work is published from:
| * United States.
| *
| */
|
| #include <stdio.h>
| #include <zlib.h> /* for crc32 */
|
| void
| put_uLong(uLong val)
| {
| putchar(val >> 24);
| putchar(val >> 16);
| putchar(val >> 8);
| putchar(val >> 0);
| }
|
| void
| put_chunk(const unsigned char *chunk, uInt length)
| {
| uLong crc;
|
| put_uLong(length-4); /* Exclude the tag */
|
| fwrite(chunk, length, 1, stdout);
|
| crc = crc32(0, Z_NULL, 0);
| put_uLong(crc32(crc, chunk, length));
| }
|
| const unsigned char signature[] =
| {
| 137, 80, 78, 71, 13, 10, 26, 10
| };
|
| const unsigned char IHDR[] =
| {
| 73, 72, 68, 82, /* IHDR */
| 0, 0, 0, 1, /* width */
| 0, 0, 0, 1, /* height */
| 1, /* bit depth */
| 0, /* color type: greyscale */
| 0, /* compression method */
| 0, /* filter method */
| 0 /* interlace method: none */
| };
|
| const unsigned char unknown[] =
| {
| 'u', 'n', 'K', 'n' /* "unKn" - private safe to copy */
| };
|
| int
| main(void)
| {
| fwrite(signature, sizeof signature, 1, stdout);
| put_chunk(IHDR, sizeof IHDR);
|
| for (;;)
| put_chunk(unknown, sizeof unknown);
| }
|
|
