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zlib.c
5379 lines (4700 loc) · 174 KB
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zlib.c
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/*
* This file is derived from various .h and .c files from the zlib-1.0.4
* 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:
* - added Z_PACKET_FLUSH (see zlib.h for details)
* - added inflateIncomp and deflateOutputPending
* - allow strm->next_out to be NULL, meaning discard the output
*
* $Id: zlib.c,v 1.7 1998/06/20 16:28:04 peter Exp $
*/
/*
* ==FILEVERSION 971210==
*
* This marker is used by the Linux installation script to determine
* whether an up-to-date version of this file is already installed.
*/
#define NO_DUMMY_DECL
#define NO_ZCFUNCS
#define MY_ZCALLOC
#if defined(__FreeBSD__) && (defined(KERNEL) || defined(_KERNEL))
#define inflate inflate_ppp /* FreeBSD already has an inflate :-( */
#endif
/* +++ zutil.h */
/* zutil.h -- internal interface and configuration of the compression library
* Copyright (C) 1995-1996 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 1.16 1996/07/24 13:41:13 me Exp $ */
#ifndef _Z_UTIL_H
#define _Z_UTIL_H
#ifdef KERNEL
#include <net/zlib.h>
#else
#include "zlib.h"
#endif
#if defined(KERNEL) || defined(_KERNEL)
/* Assume this is a *BSD or SVR4 kernel */
#include <sys/types.h>
#include <sys/time.h>
#include <sys/systm.h>
# define HAVE_MEMCPY
# define memcpy(d, s, n) bcopy((s), (d), (n))
# define memset(d, v, n) bzero((d), (n))
# define memcmp bcmp
#else
#if defined(__KERNEL__)
/* Assume this is a Linux kernel */
#include <linux/string.h>
#define HAVE_MEMCPY
#else /* not kernel */
#if defined(MSDOS)||defined(VMS)||defined(CRAY)||defined(WIN32)||defined(RISCOS)
# include <stddef.h>
# include <errno.h>
#else
extern int errno;
#endif
#ifdef STDC
# include <string.h>
# include <stdlib.h>
#endif
#endif /* __KERNEL__ */
#endif /* _KERNEL || KERNEL */
#ifndef local
# define local static
#endif
/* compile with -Dlocal if your debugger can't find static symbols */
typedef unsigned char uch;
typedef uch FAR uchf;
typedef unsigned short ush;
typedef ush FAR ushf;
typedef unsigned long ulg;
extern const char *z_errmsg[10]; /* indexed by 2-zlib_error */
/* (size given to avoid silly warnings with Visual C++) */
#define ERR_MSG(err) z_errmsg[Z_NEED_DICT-(err)]
#define ERR_RETURN(strm,err) \
return (strm->msg = (char*)ERR_MSG(err), (err))
/* To be used only when the state is known to be valid */
/* common constants */
#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 */
#define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */
/* target dependencies */
#ifdef MSDOS
# define OS_CODE 0x00
# ifdef __TURBOC__
# include <alloc.h>
# else /* MSC or DJGPP */
# include <malloc.h>
# endif
#endif
#ifdef OS2
# define OS_CODE 0x06
#endif
#ifdef WIN32 /* Window 95 & Windows NT */
# define OS_CODE 0x0b
#endif
#if defined(VAXC) || defined(VMS)
# define OS_CODE 0x02
# define FOPEN(name, mode) \
fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
#endif
#ifdef AMIGA
# define OS_CODE 0x01
#endif
#if defined(ATARI) || defined(atarist)
# define OS_CODE 0x05
#endif
#ifdef MACOS
# define OS_CODE 0x07
#endif
#ifdef __50SERIES /* Prime/PRIMOS */
# define OS_CODE 0x0F
#endif
#ifdef TOPS20
# define OS_CODE 0x0a
#endif
#if defined(_BEOS_) || defined(RISCOS)
# define fdopen(fd,mode) NULL /* No fdopen() */
#endif
/* Common defaults */
#ifndef OS_CODE
# define OS_CODE 0x03 /* assume Unix */
#endif
#ifndef FOPEN
# define FOPEN(name, mode) fopen((name), (mode))
#endif
/* functions */
#ifdef HAVE_STRERROR
extern char *strerror OF((int));
# define zstrerror(errnum) strerror(errnum)
#else
# define zstrerror(errnum) ""
#endif
#if defined(pyr)
# define NO_MEMCPY
#endif
#if (defined(M_I86SM) || defined(M_I86MM)) && !defined(_MSC_VER)
/* Use our own functions for small and medium model with MSC <= 5.0.
* You may have to use the same strategy for Borland C (untested).
*/
# define NO_MEMCPY
#endif
#if defined(STDC) && !defined(HAVE_MEMCPY) && !defined(NO_MEMCPY)
# define HAVE_MEMCPY
#endif
#ifdef HAVE_MEMCPY
# ifdef SMALL_MEDIUM /* MSDOS small or medium model */
# define zmemcpy _fmemcpy
# define zmemcmp _fmemcmp
# define zmemzero(dest, len) _fmemset(dest, 0, len)
# else
# define zmemcpy memcpy
# define zmemcmp memcmp
# define zmemzero(dest, len) memset(dest, 0, len)
# endif
#else
extern void zmemcpy OF((Bytef* dest, Bytef* source, uInt len));
extern int zmemcmp OF((Bytef* s1, Bytef* s2, uInt len));
extern void zmemzero OF((Bytef* dest, uInt len));
#endif
/* Diagnostic functions */
#ifdef DEBUG_ZLIB
# include <stdio.h>
# ifndef verbose
# define verbose 0
# endif
extern void z_error OF((char *m));
# 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)
#endif
typedef uLong (*check_func) OF((uLong check, const 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) (*((strm)->zfree))((strm)->opaque, (voidpf)(addr))
#define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
#endif /* _Z_UTIL_H */
/* --- zutil.h */
/* +++ deflate.h */
/* deflate.h -- internal compression state
* Copyright (C) 1995-1996 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: deflate.h,v 1.10 1996/07/02 12:41:00 me Exp $ */
#ifndef _DEFLATE_H
#define _DEFLATE_H
/* #include "zutil.h" */
/* ===========================================================================
* Internal compression state.
*/
#define LENGTH_CODES 29
/* number of length codes, not counting the special END_BLOCK code */
#define LITERALS 256
/* number of literal bytes 0..255 */
#define L_CODES (LITERALS+1+LENGTH_CODES)
/* number of Literal or Length codes, including the END_BLOCK code */
#define D_CODES 30
/* number of distance codes */
#define BL_CODES 19
/* number of codes used to transfer the bit lengths */
#define HEAP_SIZE (2*L_CODES+1)
/* maximum heap size */
#define MAX_BITS 15
/* All codes must not exceed MAX_BITS bits */
#define INIT_STATE 42
#define BUSY_STATE 113
#define FINISH_STATE 666
/* Stream status */
/* Data structure describing a single value and its code string. */
typedef struct ct_data_s {
union {
ush freq; /* frequency count */
ush code; /* bit string */
} fc;
union {
ush dad; /* father node in Huffman tree */
ush len; /* length of bit string */
} dl;
} FAR ct_data;
#define Freq fc.freq
#define Code fc.code
#define Dad dl.dad
#define Len dl.len
typedef struct static_tree_desc_s static_tree_desc;
typedef struct tree_desc_s {
ct_data *dyn_tree; /* the dynamic tree */
int max_code; /* largest code with non zero frequency */
static_tree_desc *stat_desc; /* the corresponding static tree */
} FAR tree_desc;
typedef ush Pos;
typedef Pos FAR Posf;
typedef unsigned IPos;
/* A Pos is an index in the character window. We use short instead of int to
* save space in the various tables. IPos is used only for parameter passing.
*/
typedef struct deflate_state {
z_streamp strm; /* pointer back to this zlib stream */
int status; /* as the name implies */
Bytef *pending_buf; /* output still pending */
ulg pending_buf_size; /* size of pending_buf */
Bytef *pending_out; /* next pending byte to output to the stream */
int pending; /* nb of bytes in the pending buffer */
int noheader; /* suppress zlib header and adler32 */
Byte data_type; /* UNKNOWN, BINARY or ASCII */
Byte method; /* STORED (for zip only) or DEFLATED */
int last_flush; /* value of flush param for previous deflate call */
/* used by deflate.c: */
uInt w_size; /* LZ77 window size (32K by default) */
uInt w_bits; /* log2(w_size) (8..16) */
uInt w_mask; /* w_size - 1 */
Bytef *window;
/* Sliding window. Input bytes are read into the second half of the window,
* and move to the first half later to keep a dictionary of at least wSize
* bytes. With this organization, matches are limited to a distance of
* wSize-MAX_MATCH bytes, but this ensures that IO is always
* performed with a length multiple of the block size. Also, it limits
* the window size to 64K, which is quite useful on MSDOS.
* To do: use the user input buffer as sliding window.
*/
ulg window_size;
/* Actual size of window: 2*wSize, except when the user input buffer
* is directly used as sliding window.
*/
Posf *prev;
/* Link to older string with same hash index. To limit the size of this
* array to 64K, this link is maintained only for the last 32K strings.
* An index in this array is thus a window index modulo 32K.
*/
Posf *head; /* Heads of the hash chains or NIL. */
uInt ins_h; /* hash index of string to be inserted */
uInt hash_size; /* number of elements in hash table */
uInt hash_bits; /* log2(hash_size) */
uInt hash_mask; /* hash_size-1 */
uInt hash_shift;
/* Number of bits by which ins_h must be shifted at each input
* step. It must be such that after MIN_MATCH steps, the oldest
* byte no longer takes part in the hash key, that is:
* hash_shift * MIN_MATCH >= hash_bits
*/
long block_start;
/* Window position at the beginning of the current output block. Gets
* negative when the window is moved backwards.
*/
uInt match_length; /* length of best match */
IPos prev_match; /* previous match */
int match_available; /* set if previous match exists */
uInt strstart; /* start of string to insert */
uInt match_start; /* start of matching string */
uInt lookahead; /* number of valid bytes ahead in window */
uInt prev_length;
/* Length of the best match at previous step. Matches not greater than this
* are discarded. This is used in the lazy match evaluation.
*/
uInt max_chain_length;
/* To speed up deflation, hash chains are never searched beyond this
* length. A higher limit improves compression ratio but degrades the
* speed.
*/
uInt max_lazy_match;
/* Attempt to find a better match only when the current match is strictly
* smaller than this value. This mechanism is used only for compression
* levels >= 4.
*/
# define max_insert_length max_lazy_match
/* Insert new strings in the hash table only if the match length is not
* greater than this length. This saves time but degrades compression.
* max_insert_length is used only for compression levels <= 3.
*/
int level; /* compression level (1..9) */
int strategy; /* favor or force Huffman coding*/
uInt good_match;
/* Use a faster search when the previous match is longer than this */
int nice_match; /* Stop searching when current match exceeds this */
/* used by trees.c: */
/* Didn't use ct_data typedef below to supress compiler warning */
struct ct_data_s dyn_ltree[HEAP_SIZE]; /* literal and length tree */
struct ct_data_s dyn_dtree[2*D_CODES+1]; /* distance tree */
struct ct_data_s bl_tree[2*BL_CODES+1]; /* Huffman tree for bit lengths */
struct tree_desc_s l_desc; /* desc. for literal tree */
struct tree_desc_s d_desc; /* desc. for distance tree */
struct tree_desc_s bl_desc; /* desc. for bit length tree */
ush bl_count[MAX_BITS+1];
/* number of codes at each bit length for an optimal tree */
int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */
int heap_len; /* number of elements in the heap */
int heap_max; /* element of largest frequency */
/* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used.
* The same heap array is used to build all trees.
*/
uch depth[2*L_CODES+1];
/* Depth of each subtree used as tie breaker for trees of equal frequency
*/
uchf *l_buf; /* buffer for literals or lengths */
uInt lit_bufsize;
/* Size of match buffer for literals/lengths. There are 4 reasons for
* limiting lit_bufsize to 64K:
* - frequencies can be kept in 16 bit counters
* - if compression is not successful for the first block, all input
* data is still in the window so we can still emit a stored block even
* when input comes from standard input. (This can also be done for
* all blocks if lit_bufsize is not greater than 32K.)
* - if compression is not successful for a file smaller than 64K, we can
* even emit a stored file instead of a stored block (saving 5 bytes).
* This is applicable only for zip (not gzip or zlib).
* - creating new Huffman trees less frequently may not provide fast
* adaptation to changes in the input data statistics. (Take for
* example a binary file with poorly compressible code followed by
* a highly compressible string table.) Smaller buffer sizes give
* fast adaptation but have of course the overhead of transmitting
* trees more frequently.
* - I can't count above 4
*/
uInt last_lit; /* running index in l_buf */
ushf *d_buf;
/* Buffer for distances. To simplify the code, d_buf and l_buf have
* the same number of elements. To use different lengths, an extra flag
* array would be necessary.
*/
ulg opt_len; /* bit length of current block with optimal trees */
ulg static_len; /* bit length of current block with static trees */
ulg compressed_len; /* total bit length of compressed file */
uInt matches; /* number of string matches in current block */
int last_eob_len; /* bit length of EOB code for last block */
#ifdef DEBUG_ZLIB
ulg bits_sent; /* bit length of the compressed data */
#endif
ush bi_buf;
/* Output buffer. bits are inserted starting at the bottom (least
* significant bits).
*/
int bi_valid;
/* Number of valid bits in bi_buf. All bits above the last valid bit
* are always zero.
*/
} FAR deflate_state;
/* Output a byte on the stream.
* IN assertion: there is enough room in pending_buf.
*/
#define put_byte(s, c) {s->pending_buf[s->pending++] = (c);}
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
#define MAX_DIST(s) ((s)->w_size-MIN_LOOKAHEAD)
/* In order to simplify the code, particularly on 16 bit machines, match
* distances are limited to MAX_DIST instead of WSIZE.
*/
/* in trees.c */
void _tr_init OF((deflate_state *s));
int _tr_tally OF((deflate_state *s, unsigned dist, unsigned lc));
ulg _tr_flush_block OF((deflate_state *s, charf *buf, ulg stored_len,
int eof));
void _tr_align OF((deflate_state *s));
void _tr_stored_block OF((deflate_state *s, charf *buf, ulg stored_len,
int eof));
void _tr_stored_type_only OF((deflate_state *));
#endif
/* --- deflate.h */
/* +++ deflate.c */
/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-1996 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/*
* ALGORITHM
*
* The "deflation" process depends on being able to identify portions
* of the input text which are identical to earlier input (within a
* sliding window trailing behind the input currently being processed).
*
* The most straightforward technique turns out to be the fastest for
* most input files: try all possible matches and select the longest.
* The key feature of this algorithm is that insertions into the string
* dictionary are very simple and thus fast, and deletions are avoided
* completely. Insertions are performed at each input character, whereas
* string matches are performed only when the previous match ends. So it
* is preferable to spend more time in matches to allow very fast string
* insertions and avoid deletions. The matching algorithm for small
* strings is inspired from that of Rabin & Karp. A brute force approach
* is used to find longer strings when a small match has been found.
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
* (by Leonid Broukhis).
* A previous version of this file used a more sophisticated algorithm
* (by Fiala and Greene) which is guaranteed to run in linear amortized
* time, but has a larger average cost, uses more memory and is patented.
* However the F&G algorithm may be faster for some highly redundant
* files if the parameter max_chain_length (described below) is too large.
*
* ACKNOWLEDGEMENTS
*
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
* I found it in 'freeze' written by Leonid Broukhis.
* Thanks to many people for bug reports and testing.
*
* REFERENCES
*
* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
* Available in ftp://ds.internic.net/rfc/rfc1951.txt
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
*/
/* From: deflate.c,v 1.15 1996/07/24 13:40:58 me Exp $ */
/* #include "deflate.h" */
char deflate_copyright[] = " deflate 1.0.4 Copyright 1995-1996 Jean-loup Gailly ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
/* ===========================================================================
* Function prototypes.
*/
typedef enum {
need_more, /* block not completed, need more input or more output */
block_done, /* block flush performed */
finish_started, /* finish started, need only more output at next deflate */
finish_done /* finish done, accept no more input or output */
} block_state;
typedef block_state (*compress_func) OF((deflate_state *s, int flush));
/* Compression function. Returns the block state after the call. */
local void fill_window OF((deflate_state *s));
local block_state deflate_stored OF((deflate_state *s, int flush));
local block_state deflate_fast OF((deflate_state *s, int flush));
local block_state deflate_slow OF((deflate_state *s, int flush));
local void lm_init OF((deflate_state *s));
local void putShortMSB OF((deflate_state *s, uInt b));
local void flush_pending OF((z_streamp strm));
local int read_buf OF((z_streamp strm, charf *buf, unsigned size));
#ifdef ASMV
void match_init OF((void)); /* asm code initialization */
uInt longest_match OF((deflate_state *s, IPos cur_match));
#else
local uInt longest_match OF((deflate_state *s, IPos cur_match));
#endif
#ifdef DEBUG_ZLIB
local void check_match OF((deflate_state *s, IPos start, IPos match,
int length));
#endif
/* ===========================================================================
* Local data
*/
#define NIL 0
/* Tail of hash chains */
#ifndef TOO_FAR
# define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
* found for specific files.
*/
typedef struct config_s {
ush good_length; /* reduce lazy search above this match length */
ush max_lazy; /* do not perform lazy search above this match length */
ush nice_length; /* quit search above this match length */
ush max_chain;
compress_func func;
} config;
local config configuration_table[10] = {
/* good lazy nice chain */
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
/* 1 */ {4, 4, 8, 4, deflate_fast}, /* maximum speed, no lazy matches */
/* 2 */ {4, 5, 16, 8, deflate_fast},
/* 3 */ {4, 6, 32, 32, deflate_fast},
/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
/* 5 */ {8, 16, 32, 32, deflate_slow},
/* 6 */ {8, 16, 128, 128, deflate_slow},
/* 7 */ {8, 32, 128, 256, deflate_slow},
/* 8 */ {32, 128, 258, 1024, deflate_slow},
/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
* meaning.
*/
#define EQUAL 0
/* result of memcmp for equal strings */
#ifndef NO_DUMMY_DECL
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
#endif
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to to UPDATE_HASH are made with consecutive
* input characters, so that a running hash key can be computed from the
* previous key instead of complete recalculation each time.
*/
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
/* ===========================================================================
* Insert string str in the dictionary and set match_head to the previous head
* of the hash chain (the most recent string with same hash key). Return
* the previous length of the hash chain.
* IN assertion: all calls to to INSERT_STRING are made with consecutive
* input characters and the first MIN_MATCH bytes of str are valid
* (except for the last MIN_MATCH-1 bytes of the input file).
*/
#define INSERT_STRING(s, str, match_head) \
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
/* ===========================================================================
* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
* prev[] will be initialized on the fly.
*/
#define CLEAR_HASH(s) \
s->head[s->hash_size-1] = NIL; \
zmemzero((charf *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
/* ========================================================================= */
int deflateInit_(strm, level, version, stream_size)
z_streamp strm;
int level;
const char *version;
int stream_size;
{
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
Z_DEFAULT_STRATEGY, version, stream_size);
/* To do: ignore strm->next_in if we use it as window */
}
/* ========================================================================= */
int deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
version, stream_size)
z_streamp strm;
int level;
int method;
int windowBits;
int memLevel;
int strategy;
const char *version;
int stream_size;
{
deflate_state *s;
int noheader = 0;
static char* my_version = ZLIB_VERSION;
ushf *overlay;
/* We overlay pending_buf and d_buf+l_buf. This works since the average
* output size for (length,distance) codes is <= 24 bits.
*/
if (version == Z_NULL || version[0] != my_version[0] ||
stream_size != sizeof(z_stream)) {
return Z_VERSION_ERROR;
}
if (strm == Z_NULL) return Z_STREAM_ERROR;
strm->msg = Z_NULL;
#ifndef NO_ZCFUNCS
if (strm->zalloc == Z_NULL) {
strm->zalloc = zcalloc;
strm->opaque = (voidpf)0;
}
if (strm->zfree == Z_NULL) strm->zfree = zcfree;
#endif
if (level == Z_DEFAULT_COMPRESSION) level = 6;
if (windowBits < 0) { /* undocumented feature: suppress zlib header */
noheader = 1;
windowBits = -windowBits;
}
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
return Z_STREAM_ERROR;
}
s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
if (s == Z_NULL) return Z_MEM_ERROR;
strm->state = (struct internal_state FAR *)s;
s->strm = strm;
s->noheader = noheader;
s->w_bits = windowBits;
s->w_size = 1 << s->w_bits;
s->w_mask = s->w_size - 1;
s->hash_bits = memLevel + 7;
s->hash_size = 1 << s->hash_bits;
s->hash_mask = s->hash_size - 1;
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
s->pending_buf = (uchf *) overlay;
s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
s->pending_buf == Z_NULL) {
strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
deflateEnd (strm);
return Z_MEM_ERROR;
}
s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
s->level = level;
s->strategy = strategy;
s->method = (Byte)method;
return deflateReset(strm);
}
/* ========================================================================= */
int deflateSetDictionary (strm, dictionary, dictLength)
z_streamp strm;
const Bytef *dictionary;
uInt dictLength;
{
deflate_state *s;
uInt length = dictLength;
uInt n;
IPos hash_head = 0;
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)
return Z_STREAM_ERROR;
s = (deflate_state *) strm->state;
if (s->status != INIT_STATE) return Z_STREAM_ERROR;
strm->adler = adler32(strm->adler, dictionary, dictLength);
if (length < MIN_MATCH) return Z_OK;
if (length > MAX_DIST(s)) {
length = MAX_DIST(s);
#ifndef USE_DICT_HEAD
dictionary += dictLength - length; /* use the tail of the dictionary */
#endif
}
zmemcpy((charf *)s->window, dictionary, length);
s->strstart = length;
s->block_start = (long)length;
/* Insert all strings in the hash table (except for the last two bytes).
* s->lookahead stays null, so s->ins_h will be recomputed at the next
* call of fill_window.
*/
s->ins_h = s->window[0];
UPDATE_HASH(s, s->ins_h, s->window[1]);
for (n = 0; n <= length - MIN_MATCH; n++) {
INSERT_STRING(s, n, hash_head);
}
if (hash_head) hash_head = 0; /* to make compiler happy */
return Z_OK;
}
/* ========================================================================= */
int deflateReset (strm)
z_streamp strm;
{
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;
strm->total_in = strm->total_out = 0;
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
strm->data_type = Z_UNKNOWN;
s = (deflate_state *)strm->state;
s->pending = 0;
s->pending_out = s->pending_buf;
if (s->noheader < 0) {
s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */
}
s->status = s->noheader ? BUSY_STATE : INIT_STATE;
strm->adler = 1;
s->last_flush = Z_NO_FLUSH;
_tr_init(s);
lm_init(s);
return Z_OK;
}
/* ========================================================================= */
int deflateParams(strm, level, strategy)
z_streamp strm;
int level;
int strategy;
{
deflate_state *s;
compress_func func;
int err = Z_OK;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
s = (deflate_state *) strm->state;
if (level == Z_DEFAULT_COMPRESSION) {
level = 6;
}
if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
return Z_STREAM_ERROR;
}
func = configuration_table[s->level].func;
if (func != configuration_table[level].func && strm->total_in != 0) {
/* Flush the last buffer: */
err = deflate(strm, Z_PARTIAL_FLUSH);
}
if (s->level != level) {
s->level = level;
s->max_lazy_match = configuration_table[level].max_lazy;
s->good_match = configuration_table[level].good_length;
s->nice_match = configuration_table[level].nice_length;
s->max_chain_length = configuration_table[level].max_chain;
}
s->strategy = strategy;
return err;
}
/* =========================================================================
* Put a short in the pending buffer. The 16-bit value is put in MSB order.
* IN assertion: the stream state is correct and there is enough room in
* pending_buf.
*/
local void putShortMSB (s, b)
deflate_state *s;
uInt b;
{
put_byte(s, (Byte)(b >> 8));
put_byte(s, (Byte)(b & 0xff));
}
/* =========================================================================
* Flush as much pending output as possible. All deflate() output goes
* through this function so some applications may wish to modify it
* to avoid allocating a large strm->next_out buffer and copying into it.
* (See also read_buf()).
*/
local void flush_pending(strm)
z_streamp strm;
{
deflate_state *s = (deflate_state *) strm->state;
unsigned len = s->pending;
if (len > strm->avail_out) len = strm->avail_out;
if (len == 0) return;
if (strm->next_out != Z_NULL) {
zmemcpy(strm->next_out, s->pending_out, len);
strm->next_out += len;
}
s->pending_out += len;
strm->total_out += len;
strm->avail_out -= len;
s->pending -= len;
if (s->pending == 0) {
s->pending_out = s->pending_buf;
}
}
/* ========================================================================= */
int deflate (strm, flush)
z_streamp strm;
int flush;
{
int old_flush; /* value of flush param for previous deflate call */
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
flush > Z_FINISH || flush < 0) {
return Z_STREAM_ERROR;
}
s = (deflate_state *) strm->state;
if ((strm->next_in == Z_NULL && strm->avail_in != 0) ||
(s->status == FINISH_STATE && flush != Z_FINISH)) {
ERR_RETURN(strm, Z_STREAM_ERROR);
}
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
s->strm = strm; /* just in case */
old_flush = s->last_flush;
s->last_flush = flush;
/* Write the zlib header */
if (s->status == INIT_STATE) {