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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 void lzw    OF((int in, int out));

extern void unlzw  OF((int in, int out));