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/* 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));
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