66 lines
1.3 KiB
C
66 lines
1.3 KiB
C
|
/* 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);
|
||
|
|
}
|