📄 zlib.c
字号:
/* * This file is derived from various .h and .c files from the zlib-0.95 * distribution by Jean-loup Gailly and Mark Adler, with some additions * by Paul Mackerras to aid in implementing Deflate compression and * decompression for PPP packets. See zlib.h for conditions of * distribution and use. * * Changes that have been made include: * - changed functions not used outside this file to "local" * - added minCompression parameter to deflateInit2 * - added Z_PACKET_FLUSH (see zlib.h for details) * - added inflateIncomp *//*+++++*//* zutil.h -- internal interface and configuration of the compression library * Copyright (C) 1995 Jean-loup Gailly. * For conditions of distribution and use, see copyright notice in zlib.h *//* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. *//* From: zutil.h,v 1.9 1995/05/03 17:27:12 jloup Exp */#define _Z_UTIL_H#include "zlib.h"#ifndef local# define local static#endif/* compile with -Dlocal if your debugger can't find static symbols */#define FARtypedef unsigned char uch;typedef uch FAR uchf;typedef unsigned short ush;typedef ush FAR ushf;typedef unsigned long ulg;extern char *z_errmsg[]; /* indexed by 1-zlib_error */#define ERR_RETURN(strm,err) return (strm->msg=z_errmsg[1-err], err)/* To be used only when the state is known to be valid */#ifndef NULL#define NULL ((void *) 0)#endif /* common constants */#define DEFLATED 8#ifndef DEF_WBITS# define DEF_WBITS MAX_WBITS#endif/* default windowBits for decompression. MAX_WBITS is for compression only */#if MAX_MEM_LEVEL >= 8# define DEF_MEM_LEVEL 8#else# define DEF_MEM_LEVEL MAX_MEM_LEVEL#endif/* default memLevel */#define STORED_BLOCK 0#define STATIC_TREES 1#define DYN_TREES 2/* The three kinds of block type */#define MIN_MATCH 3#define MAX_MATCH 258/* The minimum and maximum match lengths */ /* functions */#include <linux/string.h>#define zmemcpy memcpy#define zmemzero(dest, len) memset(dest, 0, len)/* Diagnostic functions */#ifdef DEBUG_ZLIB# include <stdio.h># ifndef verbose# define verbose 0# endif# define Assert(cond,msg) {if(!(cond)) z_error(msg);}# define Trace(x) fprintf x# define Tracev(x) {if (verbose) fprintf x ;}# define Tracevv(x) {if (verbose>1) fprintf x ;}# define Tracec(c,x) {if (verbose && (c)) fprintf x ;}# define Tracecv(c,x) {if (verbose>1 && (c)) fprintf x ;}#else# define Assert(cond,msg)# define Trace(x)# define Tracev(x)# define Tracevv(x)# define Tracec(c,x)# define Tracecv(c,x)#endiftypedef uLong (*check_func) OF((uLong check, Bytef *buf, uInt len));/* voidpf zcalloc OF((voidpf opaque, unsigned items, unsigned size)); *//* void zcfree OF((voidpf opaque, voidpf ptr)); */#define ZALLOC(strm, items, size) \ (*((strm)->zalloc))((strm)->opaque, (items), (size))#define ZFREE(strm, addr, size) \ (*((strm)->zfree))((strm)->opaque, (voidpf)(addr), (size))#define TRY_FREE(s, p, n) {if (p) ZFREE(s, p, n);}/* deflate.h -- internal compression state * Copyright (C) 1995 Jean-loup Gailly * For conditions of distribution and use, see copyright notice in zlib.h *//* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. *//*+++++*//* infblock.h -- header to use infblock.c * Copyright (C) 1995 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h *//* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. */struct inflate_blocks_state;typedef struct inflate_blocks_state FAR inflate_blocks_statef;local inflate_blocks_statef * inflate_blocks_new OF(( z_stream *z, check_func c, /* check function */ uInt w)); /* window size */local int inflate_blocks OF(( inflate_blocks_statef *, z_stream *, int)); /* initial return code */local void inflate_blocks_reset OF(( inflate_blocks_statef *, z_stream *, uLongf *)); /* check value on output */local int inflate_blocks_free OF(( inflate_blocks_statef *, z_stream *, uLongf *)); /* check value on output */local int inflate_addhistory OF(( inflate_blocks_statef *, z_stream *));local int inflate_packet_flush OF(( inflate_blocks_statef *));/*+++++*//* inftrees.h -- header to use inftrees.c * Copyright (C) 1995 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h *//* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. *//* Huffman code lookup table entry--this entry is four bytes for machines that have 16-bit pointers (e.g. PC's in the small or medium model). */typedef struct inflate_huft_s FAR inflate_huft;struct inflate_huft_s { union { struct { Byte Exop; /* number of extra bits or operation */ Byte Bits; /* number of bits in this code or subcode */ } what; uInt Nalloc; /* number of these allocated here */ Bytef *pad; /* pad structure to a power of 2 (4 bytes for */ } word; /* 16-bit, 8 bytes for 32-bit machines) */ union { uInt Base; /* literal, length base, or distance base */ inflate_huft *Next; /* pointer to next level of table */ } more;};#ifdef DEBUG_ZLIB local uInt inflate_hufts;#endiflocal int inflate_trees_bits OF(( uIntf *, /* 19 code lengths */ uIntf *, /* bits tree desired/actual depth */ inflate_huft * FAR *, /* bits tree result */ z_stream *)); /* for zalloc, zfree functions */local int inflate_trees_dynamic OF(( uInt, /* number of literal/length codes */ uInt, /* number of distance codes */ uIntf *, /* that many (total) code lengths */ uIntf *, /* literal desired/actual bit depth */ uIntf *, /* distance desired/actual bit depth */ inflate_huft * FAR *, /* literal/length tree result */ inflate_huft * FAR *, /* distance tree result */ z_stream *)); /* for zalloc, zfree functions */local int inflate_trees_fixed OF(( uIntf *, /* literal desired/actual bit depth */ uIntf *, /* distance desired/actual bit depth */ inflate_huft * FAR *, /* literal/length tree result */ inflate_huft * FAR *)); /* distance tree result */local int inflate_trees_free OF(( inflate_huft *, /* tables to free */ z_stream *)); /* for zfree function *//*+++++*//* infcodes.h -- header to use infcodes.c * Copyright (C) 1995 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h *//* WARNING: this file should *not* be used by applications. It is part of the implementation of the compression library and is subject to change. Applications should only use zlib.h. */struct inflate_codes_state;typedef struct inflate_codes_state FAR inflate_codes_statef;local inflate_codes_statef *inflate_codes_new OF(( uInt, uInt, inflate_huft *, inflate_huft *, z_stream *));local int inflate_codes OF(( inflate_blocks_statef *, z_stream *, int));local void inflate_codes_free OF(( inflate_codes_statef *, z_stream *));/*+++++*//* inflate.c -- zlib interface to inflate modules * Copyright (C) 1995 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h *//* inflate private state */struct internal_state { /* mode */ enum { METHOD, /* waiting for method byte */ FLAG, /* waiting for flag byte */ BLOCKS, /* decompressing blocks */ CHECK4, /* four check bytes to go */ CHECK3, /* three check bytes to go */ CHECK2, /* two check bytes to go */ CHECK1, /* one check byte to go */ DONE, /* finished check, done */ BAD} /* got an error--stay here */ mode; /* current inflate mode */ /* mode dependent information */ union { uInt method; /* if FLAGS, method byte */ struct { uLong was; /* computed check value */ uLong need; /* stream check value */ } check; /* if CHECK, check values to compare */ uInt marker; /* if BAD, inflateSync's marker bytes count */ } sub; /* submode */ /* mode independent information */ int nowrap; /* flag for no wrapper */ uInt wbits; /* log2(window size) (8..15, defaults to 15) */ inflate_blocks_statef *blocks; /* current inflate_blocks state */};int inflateReset(z)z_stream *z;{ uLong c; if (z == Z_NULL || z->state == Z_NULL) return Z_STREAM_ERROR; z->total_in = z->total_out = 0; z->msg = Z_NULL; z->state->mode = z->state->nowrap ? BLOCKS : METHOD; inflate_blocks_reset(z->state->blocks, z, &c); Trace((stderr, "inflate: reset\n")); return Z_OK;}int inflateEnd(z)z_stream *z;{ uLong c; if (z == Z_NULL || z->state == Z_NULL || z->zfree == Z_NULL) return Z_STREAM_ERROR; if (z->state->blocks != Z_NULL) inflate_blocks_free(z->state->blocks, z, &c); ZFREE(z, z->state, sizeof(struct internal_state)); z->state = Z_NULL; Trace((stderr, "inflate: end\n")); return Z_OK;}int inflateInit2(z, w)z_stream *z;int w;{ /* initialize state */ if (z == Z_NULL) return Z_STREAM_ERROR;/* if (z->zalloc == Z_NULL) z->zalloc = zcalloc; *//* if (z->zfree == Z_NULL) z->zfree = zcfree; */ if ((z->state = (struct internal_state FAR *) ZALLOC(z,1,sizeof(struct internal_state))) == Z_NULL) return Z_MEM_ERROR; z->state->blocks = Z_NULL; /* handle undocumented nowrap option (no zlib header or check) */ z->state->nowrap = 0; if (w < 0) { w = - w; z->state->nowrap = 1; } /* set window size */ if (w < 8 || w > 15) { inflateEnd(z); return Z_STREAM_ERROR; } z->state->wbits = (uInt)w; /* create inflate_blocks state */ if ((z->state->blocks = inflate_blocks_new(z, z->state->nowrap ? Z_NULL : adler32, 1 << w)) == Z_NULL) { inflateEnd(z); return Z_MEM_ERROR; } Trace((stderr, "inflate: allocated\n")); /* reset state */ inflateReset(z); return Z_OK;}int inflateInit(z)z_stream *z;{ return inflateInit2(z, DEF_WBITS);}#define NEEDBYTE {if(z->avail_in==0)goto empty;r=Z_OK;}#define NEXTBYTE (z->avail_in--,z->total_in++,*z->next_in++)int inflate(z, f)z_stream *z;int f;{ int r; uInt b; if (z == Z_NULL || z->next_in == Z_NULL) return Z_STREAM_ERROR; r = Z_BUF_ERROR; while (1) switch (z->state->mode) { case METHOD: NEEDBYTE if (((z->state->sub.method = NEXTBYTE) & 0xf) != DEFLATED) { z->state->mode = BAD; z->msg = "unknown compression method"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } if ((z->state->sub.method >> 4) + 8 > z->state->wbits) { z->state->mode = BAD; z->msg = "invalid window size"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } z->state->mode = FLAG; case FLAG: NEEDBYTE if ((b = NEXTBYTE) & 0x20) { z->state->mode = BAD; z->msg = "invalid reserved bit"; z->state->sub.marker = 5; /* can't try inflateSync */ break; } if (((z->state->sub.method << 8) + b) % 31) { z->state->mode = BAD; z->msg = "incorrect header check"; z->state->sub.marker = 5; /* can't try inflateSync */ break; }
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -