diff options
Diffstat (limited to 'gs/base/slzwx.h')
| -rw-r--r-- | gs/base/slzwx.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/gs/base/slzwx.h b/gs/base/slzwx.h new file mode 100644 index 000000000..a48d49276 --- /dev/null +++ b/gs/base/slzwx.h @@ -0,0 +1,74 @@ +/* Copyright (C) 2001-2006 Artifex Software, Inc. + 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 that + license. Refer to licensing information at http://www.artifex.com/ + or contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134, + San Rafael, CA 94903, U.S.A., +1(415)492-9861, for further information. +*/ + +/* $Id$ */ +/* 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 */ |