1 /* lzw.h -- define the lzw functions.
3 Copyright (C) 1992-1993 Jean-loup Gailly.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
22 #define INIT_BITS 9 /* Initial number of bits per code */
24 #define LZW_MAGIC "\037\235" /* Magic header for lzw files, 1F 9D */
26 #define BIT_MASK 0x1f /* Mask for 'number of compression bits' */
27 /* Mask 0x20 is reserved to mean a fourth header byte, and 0x40 is free.
28 * It's a pity that old uncompress does not check bit 0x20. That makes
29 * extension of the format actually undesirable because old compress
30 * would just crash on the new format instead of giving a meaningful
31 * error message. It does check the number of bits, but it's more
32 * helpful to say "unsupported format, get a new version" than
33 * "can only handle 16 bits".
36 #define BLOCK_MODE 0x80
37 /* Block compression: if table is full and compression rate is dropping,
38 * clear the dictionary.
41 #define LZW_RESERVED 0x60 /* reserved bits */
43 #define CLEAR 256 /* flush the dictionary */
44 #define FIRST (CLEAR+1) /* first free entry */
50 #if defined _REENTRANT || defined _THREAD_SAFE
52 weak_symbol(pthread_sigmask);
56 static __inline__ int sigucmask(int how, const sigset_t * __restrict set, sigset_t * __restrict oset)
58 #if defined _REENTRANT || defined _THREAD_SAFE
60 return pthread_sigmask(how, set, oset);
63 return sigprocmask(how, set, oset);
66 #if defined(__ia64__) && defined(uc_sigmask) /* Broken header sys/ucontext.h -> bits/sigcontext.h */
68 static __inline__ unsigned long int sig_ia64_mask(const sigset_t set)
70 unsigned long int mask = 0;
71 int cnt = (8 * sizeof(unsigned long int));
72 if (cnt > NSIG) cnt = NSIG;
74 if (!sigismember(&set, cnt))
76 mask |= (1 << (cnt - 1)); /* sigmask() macro is is not usable for BSD way */
82 typedef struct _LZW_s {
120 extern LZW_t *openlzw(const char * __restrict, const char * __restrict);
121 extern LZW_t *dopenlzw(int fildes, const char * __restrict);
122 extern ssize_t readlzw(LZW_t * __restrict, char * __restrict, const size_t);
123 extern void closelzw(LZW_t * __restrict);