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/* Copyright (C) 1993, 1995, 1998, 1999 Aladdin Enterprises. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* $Id: slzwx.h,v 1.5 2002/06/16 05:00:54 lpd Exp $ */
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/* Definitions for LZW filters */
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/* Requires strimpl.h */
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#ifndef slzwx_INCLUDED
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# define slzwx_INCLUDED
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typedef struct lzw_decode_s lzw_decode;
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typedef struct lzw_encode_table_s lzw_encode_table;
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typedef struct stream_LZW_state_s {
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stream_state_common;
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/* The following are set before initialization. */
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int InitialCodeLength; /* decoding only */
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/*
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* Adobe calls FirstBitLowOrder LowBitFirst. Either one will work
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* in PostScript code.
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*/
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bool FirstBitLowOrder; /* decoding only */
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bool BlockData; /* decoding only */
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int EarlyChange; /* decoding only */
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/* The following are updated dynamically. */
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uint bits; /* buffer for input bits */
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int bits_left; /* Decode: # of valid bits left, [0..7] */
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/* (low-order bits if !FirstBitLowOrder, */
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/* high-order bits if FirstBitLowOrder) */
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int bytes_left; /* # of bytes left in current block */
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/* (arbitrary large # if not GIF) */
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union _lzt {
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lzw_decode *decode;
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lzw_encode_table *encode;
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} table;
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uint next_code; /* next code to be assigned */
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int code_size; /* current # of bits per code */
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int prev_code; /* previous code recognized or assigned */
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uint prev_len; /* length of prev_code */
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int copy_code; /* code whose string is being */
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/* copied, -1 if none */
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uint copy_len; /* length of copy_code */
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int copy_left; /* amount of string left to copy */
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bool first; /* true if no output yet */
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} stream_LZW_state;
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extern_st(st_LZW_state);
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#define public_st_LZW_state() /* in slzwc.c */\
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gs_public_st_ptrs1(st_LZW_state, stream_LZW_state,\
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"LZWDecode state", lzwd_enum_ptrs, lzwd_reloc_ptrs, table.decode)
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#define s_LZW_set_defaults_inline(ss)\
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((ss)->InitialCodeLength = 8,\
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(ss)->FirstBitLowOrder = false,\
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(ss)->BlockData = false,\
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(ss)->EarlyChange = 1,\
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/* Clear pointers */\
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(ss)->table.decode /*=encode*/ = 0)
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extern const stream_template s_LZWD_template;
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extern const stream_template s_LZWE_template;
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/* Shared procedures */
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void s_LZW_set_defaults(stream_state *);
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void s_LZW_release(stream_state *);
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#endif /* slzwx_INCLUDED */
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