mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-11-18 17:00:49 +01:00
43 lines
1.4 KiB
C
43 lines
1.4 KiB
C
/* lzw.h -- define the lzw functions.
|
|
* Copyright (C) 1992-1993 Jean-loup Gailly.
|
|
* This is free software; you can redistribute it and/or modify it under the
|
|
* terms of the GNU General Public License, see the file COPYING.
|
|
*/
|
|
|
|
#if !defined(OF) && defined(lint)
|
|
# include "gzip.h"
|
|
#endif
|
|
|
|
#ifndef BITS
|
|
# define BITS 16
|
|
#endif
|
|
#define INIT_BITS 9 /* Initial number of bits per code */
|
|
|
|
#define LZW_MAGIC "\037\235" /* Magic header for lzw files, 1F 9D */
|
|
|
|
#define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
|
|
/* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
|
|
* It's a pity that old uncompress does not check bit 0x20. That makes
|
|
* extension of the format actually undesirable because old compress
|
|
* would just crash on the new format instead of giving a meaningful
|
|
* error message. It does check the number of bits, but it's more
|
|
* helpful to say "unsupported format, get a new version" than
|
|
* "can only handle 16 bits".
|
|
*/
|
|
|
|
#define BLOCK_MODE 0x80
|
|
/* Block compression: if table is full and compression rate is dropping,
|
|
* clear the dictionary.
|
|
*/
|
|
|
|
#define LZW_RESERVED 0x60 /* reserved bits */
|
|
|
|
#define CLEAR 256 /* flush the dictionary */
|
|
#define FIRST (CLEAR+1) /* first free entry */
|
|
|
|
extern int maxbits; /* max bits per code for LZW */
|
|
extern int block_mode; /* block compress mode -C compatible with 2.0 */
|
|
|
|
extern int lzw OF((int in, int out));
|
|
extern int unlzw OF((int in, int out));
|