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