mewin/libpng
1
0
Fork 0
mirror of https://git.code.sf.net/p/libpng/code.git synced 2025-07-10 18:04:09 +02:00
Code Issues Projects Releases Wiki Activity

[libpng17] Deleted contrib/tools/fixitxt.c, which has been renamed.

Browse Source
This commit is contained in:
Glenn Randers-Pehrson 2013-06-05 17:03:38 -05:00
parent 5c32606ec0
commit 46ad4c5bd4
1 changed files with 0 additions and 144 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

144
contrib/tools/fixitxt.c
View File

@ -1,144 +0,0 @@
#include <stdio.h>
/* fixitxt version 1.0.0
*
* Copyright 2013 Glenn Randers-Pehrson
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*
* Usage:
*
* fixitxt.exe < bad.png > good.png
*
* Fixes a PNG file written with libpng-1.6.0 or 1.6.1 that has one or more
* uncompressed iTXt chunks. Assumes that the actual length is greater
* than or equal to the value in the length byte, and that the CRC is
* correct for the actual length. This program hunts for the CRC and
* adjusts the length byte accordingly. It is not an error to process a
* PNG file that has no iTXt chunks or one that has valid iTXt chunks;
* such files will simply be copied.
*
* Requires zlib (for crc32 and Z_NULL); build with
*
* gcc -O -o fixitxt fixitxt.c -lz
*/
#define MAX_LENGTH 500000
#define GETBREAK c=getchar(); if (c == EOF) break;
#include <zlib.h>
main()
{
unsigned int i;
unsigned char buf[MAX_LENGTH];
unsigned long crc;
unsigned int c;
/* Skip 8-byte signature */
for (i=8; i; i--)
{
c=GETBREAK;
putchar(c);
}
if (c != EOF)
for (;;)
{
/* Read the length */
unsigned long length;
c=GETBREAK; buf[0] = c;
c=GETBREAK; buf[1] = c;
c=GETBREAK; buf[2] = c;
c=GETBREAK; buf[3] = c;
length=((((unsigned long) buf[0]<<8 + buf[1]<<16) + buf[2] << 8) + buf[3]);
/* Read the chunkname */
c=GETBREAK; buf[4] = c;
c=GETBREAK; buf[5] = c;
c=GETBREAK; buf[6] = c;
c=GETBREAK; buf[7] = c;
/* The iTXt chunk type expressed as integers is (105, 84, 88, 116) */
if (buf[4] == 105 && buf[5] == 84 && buf[6] == 88 && buf[7] == 116)
{
if (length >= MAX_LENGTH-12)
break; /* To do: handle this more gracefully */
/* Initialize the CRC */
crc = crc32(0, Z_NULL, 0);
/* Copy the data bytes */
for (i=8; i < length + 12; i++)
{
c=GETBREAK; buf[i] = c;
}
/* Calculate the CRC */
crc = crc32(crc, buf+4, (uInt)length+4);
for (;;)
{
/* Check the CRC */
if (((crc >> 24) & 0xff) == buf[length+8] &&
((crc >> 16) & 0xff) == buf[length+9] &&
((crc >> 8) & 0xff) == buf[length+10] &&
((crc ) & 0xff) == buf[length+11])
break;
length++;
if (length >= MAX_LENGTH-12)
break;
c=GETBREAK;
buf[length+11]=c;
/* Update the CRC */
crc = crc32(crc, buf+7+length, 1);
}
/* Update length bytes */
buf[0] = (length << 24) & 0xff;
buf[1] = (length << 16) & 0xff;
buf[2] = (length << 8) & 0xff;
buf[3] = (length ) & 0xff;
/* Write the fixed iTXt chunk (length, name, data, crc) */
for (i=0; i<length+12; i++)
putchar(buf[i]);
}
else
{
/* Copy bytes that were already read (length and chunk name) */
for (i=0; i<8; i++)
putchar(buf[i]);
/* Copy data bytes and CRC */
for (i=8; i< length+12; i++)
{
c=GETBREAK;
putchar(c);
}
if (c == EOF)
{
break;
}
/* The IEND chunk type expressed as integers is (73, 69, 78, 68) */
if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
break;
}
if (c == EOF)
break;
if (buf[4] == 73 && buf[5] == 69 && buf[6] == 78 && buf[7] == 68)
break;
}
}