diff options
Diffstat (limited to 'lzw.h')
| -rw-r--r-- | lzw.h | 123 |
1 files changed, 123 insertions, 0 deletions
@@ -0,0 +1,123 @@ +/* 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); |