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/* lzw.h -- define the lzw functions.
Copyright (C) 1992-1993 Jean-loup Gailly.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#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 */
#include <stdint.h>
#include <ucontext.h>
#include "zioP.h"
#if defined _REENTRANT || defined _THREAD_SAFE
# include <pthread.h>
weak_symbol(pthread_sigmask);
#endif
__extension__
static __inline__ int sigucmask(int how, const sigset_t * __restrict set, sigset_t * __restrict oset)
{
#if defined _REENTRANT || defined _THREAD_SAFE
if (&pthread_sigmask)
return pthread_sigmask(how, set, oset);
else
#endif
return sigprocmask(how, set, oset);
}
#if defined(__ia64__) && defined(uc_sigmask) /* Broken header sys/ucontext.h -> bits/sigcontext.h */
__extension__
static __inline__ unsigned long int sig_ia64_mask(const sigset_t set)
{
unsigned long int mask = 0;
int cnt = (8 * sizeof(unsigned long int));
if (cnt > NSIG) cnt = NSIG;
while (--cnt >= 0) {
if (!sigismember(&set, cnt))
continue;
mask |= (1 << (cnt - 1)); /* sigmask() macro is is not usable for BSD way */
}
return mask;
}
#endif
typedef struct _LZW_s {
uint8_t *inbuf;
uint8_t *outbuf;
uint16_t *d_buf;
uint8_t *tab_suffix;
uint16_t *tab_prefix;
uint8_t *transfer;
off_t bytes_in;
off_t bytes_out;
size_t insize;
size_t inptr;
size_t outpos;
size_t tcount;
ssize_t tsize;
ssize_t rsize;
struct unlzw_s {
uint8_t *stackp;
int32_t code;
int finchar;
int32_t oldcode;
int32_t incode;
uint32_t inbits;
uint32_t posbits;
uint32_t bitmask;
int32_t free_ent;
int32_t maxcode;
int32_t maxmaxcode;
off_t newdif;
int n_bits;
int block_mode;
int maxbits;
} n;
int ifd;
char *ifname;
ucontext_t *uc;
uint8_t *stack;
} LZW_t;
extern LZW_t *openlzw(const char * __restrict, const char * __restrict);
extern LZW_t *dopenlzw(int fildes, const char * __restrict);
extern ssize_t readlzw(LZW_t * __restrict, char * __restrict, const size_t);
extern void closelzw(LZW_t * __restrict);
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