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/* deflate.c -- compress data using the deflation algorithm
 * Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
 * 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 http://tools.ietf.org/html/rfc1951
 *
 *      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
 *
 */
 
/* @(#) $Id$ */
 
#include "deflate.h"
 
const char deflate_copyright[] =
   " deflate 1.2.8 Copyright 1995-2013 Jean-loup Gailly and Mark Adler ";
/*
  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));
#ifndef FASTEST
local block_state deflate_slow   OF((deflate_state *s, int flush));
#endif
local block_state deflate_rle    OF((deflate_state *s, int flush));
local block_state deflate_huff   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, Bytef *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
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 */
 
/* 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;
 
#ifdef FASTEST
local const config configuration_table[2] = {
/*      good lazy nice chain */
/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
/* 1 */ {4,    4,  8,    4, deflate_fast}}; /* max speed, no lazy matches */
#else
local const config configuration_table[10] = {
/*      good lazy nice chain */
/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
/* 1 */ {4,    4,  8,    4, deflate_fast}, /* max 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}}; /* max compression */
#endif
 
/* 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
 
/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
#define RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 0))
 
/* ===========================================================================
 * 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)<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.
 * If this file is compiled with -DFASTEST, the compression level is forced
 * to 1, and no hash chains are maintained.
 * 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).
 */
#ifdef FASTEST
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
    match_head = s->head[s->ins_h], \
    s->head[s->ins_h] = (Pos)(str))
#else
#define INSERT_STRING(s, str, match_head) \
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
    match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
    s->head[s->ins_h] = (Pos)(str))
#endif
 
/* ===========================================================================
 * 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((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
 
/* ========================================================================= */
int ZEXPORT 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 ZEXPORT 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 wrap = 1;
    static const 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;
    if (strm->zalloc == (alloc_func)0) {
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zalloc = zcalloc;
        strm->opaque = (voidpf)0;
#endif
    }
    if (strm->zfree == (free_func)0)
#ifdef Z_SOLO
        return Z_STREAM_ERROR;
#else
        strm->zfree = zcfree;
#endif
 
#ifdef FASTEST
    if (level != 0) level = 1;
#else
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
 
    if (windowBits < 0) { /* suppress zlib wrapper */
        wrap = 0;
        windowBits = -windowBits;
    }
#ifdef GZIP
    else if (windowBits > 15) {
        wrap = 2;       /* write gzip wrapper instead */
        windowBits -= 16;
    }
#endif
    if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
        windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
        strategy < 0 || strategy > Z_FIXED) {
        return Z_STREAM_ERROR;
    }
    if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
    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->wrap = wrap;
    s->gzhead = Z_NULL;
    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->high_water = 0;      /* nothing written to s->window yet */
 
    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) {
        s->status = FINISH_STATE;
        strm->msg = 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 ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
    z_streamp strm;
    const Bytef *dictionary;
    uInt  dictLength;
{
    deflate_state *s;
    uInt str, n;
    int wrap;
    unsigned avail;
 
 
    z_const unsigned char *next;
 
 
 
    if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL)
        return Z_STREAM_ERROR;
    s = strm->state;
    wrap = s->wrap;
    if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
        return Z_STREAM_ERROR;
 
    /* when using zlib wrappers, compute Adler-32 for provided dictionary */
    if (wrap == 1)
        strm->adler = adler32(strm->adler, dictionary, dictLength);
    s->wrap = 0;                    /* avoid computing Adler-32 in read_buf */
 
 
    /* if dictionary would fill window, just replace the history */
 
    if (dictLength >= s->w_size) {
        if (wrap == 0) {            /* already empty otherwise */
            CLEAR_HASH(s);
 
 
 
 
 
            s->strstart = 0;
 
 
 
            s->block_start = 0L;
            s->insert = 0;
        }
        dictionary += dictLength - s->w_size;  /* use the tail */
        dictLength = s->w_size;
    }
 
    /* insert dictionary into window and hash */
    avail = strm->avail_in;
    next = strm->next_in;
    strm->avail_in = dictLength;
    strm->next_in = (z_const Bytef *)dictionary;
    fill_window(s);
    while (s->lookahead >= MIN_MATCH) {
        str = s->strstart;
        n = s->lookahead - (MIN_MATCH-1);
        do {
            UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
#ifndef FASTEST
            s->prev[str & s->w_mask] = s->head[s->ins_h];
#endif
            s->head[s->ins_h] = (Pos)str;
            str++;
        } while (--n);
        s->strstart = str;
        s->lookahead = MIN_MATCH-1;
        fill_window(s);
    }
    s->strstart += s->lookahead;
    s->block_start = (long)s->strstart;
    s->insert = s->lookahead;
    s->lookahead = 0;
    s->match_length = s->prev_length = MIN_MATCH-1;
    s->match_available = 0;
    strm->next_in = next;
    strm->avail_in = avail;
    s->wrap = wrap;
    return Z_OK;
}
 
/* ========================================================================= */
int ZEXPORT deflateResetKeep (strm)
    z_streamp strm;
{
    deflate_state *s;
 
    if (strm == Z_NULL || strm->state == Z_NULL ||
        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
        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->wrap < 0) {
        s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
    }
    s->status = s->wrap ? INIT_STATE : BUSY_STATE;
    strm->adler =
#ifdef GZIP
        s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
#endif
        adler32(0L, Z_NULL, 0);
    s->last_flush = Z_NO_FLUSH;
 
    _tr_init(s);
 
 
    return Z_OK;
}
 
/* ========================================================================= */
int ZEXPORT deflateReset (strm)
    z_streamp strm;
{
    int ret;
 
    ret = deflateResetKeep(strm);
    if (ret == Z_OK)
        lm_init(strm->state);
    return ret;
}
 
/* ========================================================================= */
int ZEXPORT deflateSetHeader (strm, head)
    z_streamp strm;
    gz_headerp head;
{
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    if (strm->state->wrap != 2) return Z_STREAM_ERROR;
    strm->state->gzhead = head;
    return Z_OK;
}
 
/* ========================================================================= */
int ZEXPORT deflatePending (strm, pending, bits)
    unsigned *pending;
    int *bits;
    z_streamp strm;
{
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    if (pending != Z_NULL)
        *pending = strm->state->pending;
    if (bits != Z_NULL)
        *bits = strm->state->bi_valid;
    return Z_OK;
}
 
/* ========================================================================= */
int ZEXPORT deflatePrime (strm, bits, value)
    z_streamp strm;
    int bits;
    int value;
{
    deflate_state *s;
    int put;
 
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    s = strm->state;
    if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
        return Z_BUF_ERROR;
    do {
        put = Buf_size - s->bi_valid;
        if (put > bits)
            put = bits;
        s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
        s->bi_valid += put;
        _tr_flush_bits(s);
        value >>= put;
        bits -= put;
    } while (bits);
    return Z_OK;
}
 
/* ========================================================================= */
int ZEXPORT 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 = strm->state;
 
#ifdef FASTEST
    if (level != 0) level = 1;
#else
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
    if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
        return Z_STREAM_ERROR;
    }
    func = configuration_table[s->level].func;
 
    if ((strategy != s->strategy || func != configuration_table[level].func) &&
        strm->total_in != 0) {
        /* Flush the last buffer: */
        err = deflate(strm, Z_BLOCK);
        if (err == Z_BUF_ERROR && s->pending == 0)
            err = Z_OK;
    }
    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;
}
 
/* ========================================================================= */
int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
    z_streamp strm;
    int good_length;
    int max_lazy;
    int nice_length;
    int max_chain;
{
    deflate_state *s;
 
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
    s = strm->state;
    s->good_match = good_length;
    s->max_lazy_match = max_lazy;
    s->nice_match = nice_length;
    s->max_chain_length = max_chain;
    return Z_OK;
}
 
/* =========================================================================
 * For the default windowBits of 15 and memLevel of 8, this function returns
 * a close to exact, as well as small, upper bound on the compressed size.
 * They are coded as constants here for a reason--if the #define's are
 * changed, then this function needs to be changed as well.  The return
 * value for 15 and 8 only works for those exact settings.
 *
 * For any setting other than those defaults for windowBits and memLevel,
 * the value returned is a conservative worst case for the maximum expansion
 * resulting from using fixed blocks instead of stored blocks, which deflate
 * can emit on compressed data for some combinations of the parameters.
 *
 * This function could be more sophisticated to provide closer upper bounds for
 * every combination of windowBits and memLevel.  But even the conservative
 * upper bound of about 14% expansion does not seem onerous for output buffer
 * allocation.
 */
uLong ZEXPORT deflateBound(strm, sourceLen)
    z_streamp strm;
    uLong sourceLen;
{
    deflate_state *s;
    uLong complen, wraplen;
    Bytef *str;
 
    /* conservative upper bound for compressed data */
    complen = sourceLen +
              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
 
    /* if can't get parameters, return conservative bound plus zlib wrapper */
    if (strm == Z_NULL || strm->state == Z_NULL)
        return complen + 6;
 
    /* compute wrapper length */
    s = strm->state;
    switch (s->wrap) {
    case 0:                                 /* raw deflate */
        wraplen = 0;
        break;
    case 1:                                 /* zlib wrapper */
        wraplen = 6 + (s->strstart ? 4 : 0);
        break;
    case 2:                                 /* gzip wrapper */
        wraplen = 18;
        if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
            if (s->gzhead->extra != Z_NULL)
                wraplen += 2 + s->gzhead->extra_len;
            str = s->gzhead->name;
            if (str != Z_NULL)
                do {
                    wraplen++;
                } while (*str++);
            str = s->gzhead->comment;
            if (str != Z_NULL)
                do {
                    wraplen++;
                } while (*str++);
            if (s->gzhead->hcrc)
                wraplen += 2;
        }
        break;
    default:                                /* for compiler happiness */
        wraplen = 6;
    }
 
    /* if not default parameters, return conservative bound */
    if (s->w_bits != 15 || s->hash_bits != 8 + 7)
        return complen + wraplen;
 
    /* default settings: return tight bound for that case */
    return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
           (sourceLen >> 25) + 13 - 6 + wraplen;
}
 
/* =========================================================================
 * 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;
{
    unsigned len;
    deflate_state *s = strm->state;
 
    _tr_flush_bits(s);
    len = s->pending;
    if (len > strm->avail_out) len = strm->avail_out;
    if (len == 0) return;
 
    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 ZEXPORT 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_BLOCK || flush < 0) {
        return Z_STREAM_ERROR;
    }
    s = strm->state;
 
    if (strm->next_out == Z_NULL ||
        (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 header */
    if (s->status == INIT_STATE) {
#ifdef GZIP
        if (s->wrap == 2) {
            strm->adler = crc32(0L, Z_NULL, 0);
            put_byte(s, 31);
            put_byte(s, 139);
            put_byte(s, 8);
            if (s->gzhead == Z_NULL) {
                put_byte(s, 0);
                put_byte(s, 0);
                put_byte(s, 0);
                put_byte(s, 0);
                put_byte(s, 0);
                put_byte(s, s->level == 9 ? 2 :
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                             4 : 0));
                put_byte(s, OS_CODE);
                s->status = BUSY_STATE;
            }
            else {
                put_byte(s, (s->gzhead->text ? 1 : 0) +
                            (s->gzhead->hcrc ? 2 : 0) +
                            (s->gzhead->extra == Z_NULL ? 0 : 4) +
                            (s->gzhead->name == Z_NULL ? 0 : 8) +
                            (s->gzhead->comment == Z_NULL ? 0 : 16)
                        );
                put_byte(s, (Byte)(s->gzhead->time & 0xff));
                put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
                put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
                put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
                put_byte(s, s->level == 9 ? 2 :
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
                             4 : 0));
                put_byte(s, s->gzhead->os & 0xff);
                if (s->gzhead->extra != Z_NULL) {
                    put_byte(s, s->gzhead->extra_len & 0xff);
                    put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
                }
                if (s->gzhead->hcrc)
                    strm->adler = crc32(strm->adler, s->pending_buf,
                                        s->pending);
                s->gzindex = 0;
                s->status = EXTRA_STATE;
            }
        }
        else
#endif
        {
            uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
            uInt level_flags;
 
            if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
                level_flags = 0;
            else if (s->level < 6)
                level_flags = 1;
            else if (s->level == 6)
                level_flags = 2;
            else
                level_flags = 3;
            header |= (level_flags << 6);
            if (s->strstart != 0) header |= PRESET_DICT;
            header += 31 - (header % 31);
 
            s->status = BUSY_STATE;
            putShortMSB(s, header);
 
            /* Save the adler32 of the preset dictionary: */
            if (s->strstart != 0) {
                putShortMSB(s, (uInt)(strm->adler >> 16));
                putShortMSB(s, (uInt)(strm->adler & 0xffff));
            }
            strm->adler = adler32(0L, Z_NULL, 0);
        }
    }
#ifdef GZIP
    if (s->status == EXTRA_STATE) {
        if (s->gzhead->extra != Z_NULL) {
            uInt beg = s->pending;  /* start of bytes to update crc */
 
            while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
                if (s->pending == s->pending_buf_size) {
                    if (s->gzhead->hcrc && s->pending > beg)
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                            s->pending - beg);
                    flush_pending(strm);
                    beg = s->pending;
                    if (s->pending == s->pending_buf_size)
                        break;
                }
                put_byte(s, s->gzhead->extra[s->gzindex]);
                s->gzindex++;
            }
            if (s->gzhead->hcrc && s->pending > beg)
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                    s->pending - beg);
            if (s->gzindex == s->gzhead->extra_len) {
                s->gzindex = 0;
                s->status = NAME_STATE;
            }
        }
        else
            s->status = NAME_STATE;
    }
    if (s->status == NAME_STATE) {
        if (s->gzhead->name != Z_NULL) {
            uInt beg = s->pending;  /* start of bytes to update crc */
            int val;
 
            do {
                if (s->pending == s->pending_buf_size) {
                    if (s->gzhead->hcrc && s->pending > beg)
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                            s->pending - beg);
                    flush_pending(strm);
                    beg = s->pending;
                    if (s->pending == s->pending_buf_size) {
                        val = 1;
                        break;
                    }
                }
                val = s->gzhead->name[s->gzindex++];
                put_byte(s, val);
            } while (val != 0);
            if (s->gzhead->hcrc && s->pending > beg)
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                    s->pending - beg);
            if (val == 0) {
                s->gzindex = 0;
                s->status = COMMENT_STATE;
            }
        }
        else
            s->status = COMMENT_STATE;
    }
    if (s->status == COMMENT_STATE) {
        if (s->gzhead->comment != Z_NULL) {
            uInt beg = s->pending;  /* start of bytes to update crc */
            int val;
 
            do {
                if (s->pending == s->pending_buf_size) {
                    if (s->gzhead->hcrc && s->pending > beg)
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                            s->pending - beg);
                    flush_pending(strm);
                    beg = s->pending;
                    if (s->pending == s->pending_buf_size) {
                        val = 1;
                        break;
                    }
                }
                val = s->gzhead->comment[s->gzindex++];
                put_byte(s, val);
            } while (val != 0);
            if (s->gzhead->hcrc && s->pending > beg)
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
                                    s->pending - beg);
            if (val == 0)
                s->status = HCRC_STATE;
        }
        else
            s->status = HCRC_STATE;
    }
    if (s->status == HCRC_STATE) {
        if (s->gzhead->hcrc) {
            if (s->pending + 2 > s->pending_buf_size)
                flush_pending(strm);
            if (s->pending + 2 <= s->pending_buf_size) {
                put_byte(s, (Byte)(strm->adler & 0xff));
                put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
                strm->adler = crc32(0L, Z_NULL, 0);
                s->status = BUSY_STATE;
            }
        }
        else
            s->status = BUSY_STATE;
    }
#endif
 
    /* Flush as much pending output as possible */
    if (s->pending != 0) {
        flush_pending(strm);
        if (strm->avail_out == 0) {
            /* Since avail_out is 0, deflate will be called again with
             * more output space, but possibly with both pending and
             * avail_in equal to zero. There won't be anything to do,
             * but this is not an error situation so make sure we
             * return OK instead of BUF_ERROR at next call of deflate:
             */
            s->last_flush = -1;
            return Z_OK;
        }
 
    /* Make sure there is something to do and avoid duplicate consecutive
     * flushes. For repeated and useless calls with Z_FINISH, we keep
     * returning Z_STREAM_END instead of Z_BUF_ERROR.
     */
    } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
               flush != Z_FINISH) {
        ERR_RETURN(strm, Z_BUF_ERROR);
    }
 
    /* User must not provide more input after the first FINISH: */
    if (s->status == FINISH_STATE && strm->avail_in != 0) {
        ERR_RETURN(strm, Z_BUF_ERROR);
    }
 
    /* Start a new block or continue the current one.
     */
    if (strm->avail_in != 0 || s->lookahead != 0 ||
        (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
        block_state bstate;
 
        bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
                    (s->strategy == Z_RLE ? deflate_rle(s, flush) :
                        (*(configuration_table[s->level].func))(s, flush));
 
        if (bstate == finish_started || bstate == finish_done) {
            s->status = FINISH_STATE;
        }
        if (bstate == need_more || bstate == finish_started) {
            if (strm->avail_out == 0) {
                s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
            }
            return Z_OK;
            /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
             * of deflate should use the same flush parameter to make sure
             * that the flush is complete. So we don't have to output an
             * empty block here, this will be done at next call. This also
             * ensures that for a very small output buffer, we emit at most
             * one empty block.
             */
        }
        if (bstate == block_done) {
            if (flush == Z_PARTIAL_FLUSH) {
                _tr_align(s);
            } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
                _tr_stored_block(s, (char*)0, 0L, 0);
                /* For a full flush, this empty block will be recognized
                 * as a special marker by inflate_sync().
                 */
                if (flush == Z_FULL_FLUSH) {
                    CLEAR_HASH(s);             /* forget history */
                    if (s->lookahead == 0) {
                        s->strstart = 0;
                        s->block_start = 0L;
                        s->insert = 0;
                    }
                }
            }
            flush_pending(strm);
            if (strm->avail_out == 0) {
              s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
              return Z_OK;
            }
        }
    }
    Assert(strm->avail_out > 0, "bug2");
 
    if (flush != Z_FINISH) return Z_OK;
    if (s->wrap <= 0) return Z_STREAM_END;
 
    /* Write the trailer */
#ifdef GZIP
    if (s->wrap == 2) {
        put_byte(s, (Byte)(strm->adler & 0xff));
        put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
        put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
        put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
        put_byte(s, (Byte)(strm->total_in & 0xff));
        put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
        put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
        put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
    }
    else
#endif
    {
        putShortMSB(s, (uInt)(strm->adler >> 16));
        putShortMSB(s, (uInt)(strm->adler & 0xffff));
    }
    flush_pending(strm);
    /* If avail_out is zero, the application will call deflate again
     * to flush the rest.
     */
    if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
    return s->pending != 0 ? Z_OK : Z_STREAM_END;
}
 
/* ========================================================================= */
int ZEXPORT deflateEnd (strm)
    z_streamp strm;
{
    int status;
 
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
 
    status = strm->state->status;
    if (status != INIT_STATE &&
        status != EXTRA_STATE &&
        status != NAME_STATE &&
        status != COMMENT_STATE &&
        status != HCRC_STATE &&
        status != BUSY_STATE &&
        status != FINISH_STATE) {
      return Z_STREAM_ERROR;
    }
 
    /* Deallocate in reverse order of allocations: */
    TRY_FREE(strm, strm->state->pending_buf);
    TRY_FREE(strm, strm->state->head);
    TRY_FREE(strm, strm->state->prev);
    TRY_FREE(strm, strm->state->window);
 
    ZFREE(strm, strm->state);
    strm->state = Z_NULL;
 
    return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}
 
/* =========================================================================
 * Copy the source state to the destination state.
 * To simplify the source, this is not supported for 16-bit MSDOS (which
 * doesn't have enough memory anyway to duplicate compression states).
 */
int ZEXPORT deflateCopy (dest, source)
    z_streamp dest;
    z_streamp source;
{
#ifdef MAXSEG_64K
    return Z_STREAM_ERROR;
#else
    deflate_state *ds;
    deflate_state *ss;
    ushf *overlay;
 
 
    if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
        return Z_STREAM_ERROR;
    }
 
    ss = source->state;
 
    zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
 
    ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
    if (ds == Z_NULL) return Z_MEM_ERROR;
    dest->state = (struct internal_state FAR *) ds;
    zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
    ds->strm = dest;
 
    ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
    ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
    ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
    overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
    ds->pending_buf = (uchf *) overlay;
 
    if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
        ds->pending_buf == Z_NULL) {
        deflateEnd (dest);
        return Z_MEM_ERROR;
    }
    /* following zmemcpy do not work for 16-bit MSDOS */
    zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
    zmemcpy((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
    zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
    zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
 
    ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
    ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
    ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
 
    ds->l_desc.dyn_tree = ds->dyn_ltree;
    ds->d_desc.dyn_tree = ds->dyn_dtree;
    ds->bl_desc.dyn_tree = ds->bl_tree;
 
    return Z_OK;
#endif /* MAXSEG_64K */
}
 
/* ===========================================================================
 * Read a new buffer from the current input stream, update the adler32
 * and total number of bytes read.  All deflate() input goes through
 * this function so some applications may wish to modify it to avoid
 * allocating a large strm->next_in buffer and copying from it.
 * (See also flush_pending()).
 */
local int read_buf(strm, buf, size)
    z_streamp strm;
    Bytef *buf;
    unsigned size;
{
    unsigned len = strm->avail_in;
 
    if (len > size) len = size;
    if (len == 0) return 0;
 
    strm->avail_in  -= len;
 
    zmemcpy(buf, strm->next_in, len);
    if (strm->state->wrap == 1) {
        strm->adler = adler32(strm->adler, buf, len);
    }
#ifdef GZIP
    else if (strm->state->wrap == 2) {
        strm->adler = crc32(strm->adler, buf, len);
    }
#endif
 
    strm->next_in  += len;
    strm->total_in += len;
 
    return (int)len;
}
 
/* ===========================================================================
 * Initialize the "longest match" routines for a new zlib stream
 */
local void lm_init (s)
    deflate_state *s;
{
    s->window_size = (ulg)2L*s->w_size;
 
    CLEAR_HASH(s);
 
    /* Set the default configuration parameters:
     */
    s->max_lazy_match   = configuration_table[s->level].max_lazy;
    s->good_match       = configuration_table[s->level].good_length;
    s->nice_match       = configuration_table[s->level].nice_length;
    s->max_chain_length = configuration_table[s->level].max_chain;
 
    s->strstart = 0;
    s->block_start = 0L;
    s->lookahead = 0;
    s->insert = 0;
    s->match_length = s->prev_length = MIN_MATCH-1;
    s->match_available = 0;
    s->ins_h = 0;
#ifndef FASTEST
#ifdef ASMV
    match_init(); /* initialize the asm code */
#endif
#endif
}
 
#ifndef FASTEST
/* ===========================================================================
 * Set match_start to the longest match starting at the given string and
 * return its length. Matches shorter or equal to prev_length are discarded,
 * in which case the result is equal to prev_length and match_start is
 * garbage.
 * IN assertions: cur_match is the head of the hash chain for the current
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 * OUT assertion: the match length is not greater than s->lookahead.
 */
#ifndef ASMV
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
 * match.S. The code will be functionally equivalent.
 */
local uInt longest_match(s, cur_match)
    deflate_state *s;
    IPos cur_match;                             /* current match */
{
    unsigned chain_length = s->max_chain_length;/* max hash chain length */
    register Bytef *scan = s->window + s->strstart; /* current string */
    register Bytef *match;                       /* matched string */
    register int len;                           /* length of current match */
    int best_len = s->prev_length;              /* best match length so far */
    int nice_match = s->nice_match;             /* stop if match long enough */
    IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
        s->strstart - (IPos)MAX_DIST(s) : NIL;
    /* Stop when cur_match becomes <= limit. To simplify the code,
     * we prevent matches with the string of window index 0.
     */
    Posf *prev = s->prev;
    uInt wmask = s->w_mask;
 
#ifdef UNALIGNED_OK
    /* Compare two bytes at a time. Note: this is not always beneficial.
     * Try with and without -DUNALIGNED_OK to check.
     */
    register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
    register ush scan_start = *(ushf*)scan;
    register ush scan_end   = *(ushf*)(scan+best_len-1);
#else
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
    register Byte scan_end1  = scan[best_len-1];
    register Byte scan_end   = scan[best_len];
#endif
 
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
     * It is easy to get rid of this optimization if necessary.
     */
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
 
    /* Do not waste too much time if we already have a good match: */
    if (s->prev_length >= s->good_match) {
        chain_length >>= 2;
    }
    /* Do not look for matches beyond the end of the input. This is necessary
     * to make deflate deterministic.
     */
    if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
 
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
 
    do {
        Assert(cur_match < s->strstart, "no future");
        match = s->window + cur_match;
 
        /* Skip to next match if the match length cannot increase
         * or if the match length is less than 2.  Note that the checks below
         * for insufficient lookahead only occur occasionally for performance
         * reasons.  Therefore uninitialized memory will be accessed, and
         * conditional jumps will be made that depend on those values.
         * However the length of the match is limited to the lookahead, so
         * the output of deflate is not affected by the uninitialized values.
         */
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
        /* This code assumes sizeof(unsigned short) == 2. Do not use
         * UNALIGNED_OK if your compiler uses a different size.
         */
        if (*(ushf*)(match+best_len-1) != scan_end ||
            *(ushf*)match != scan_start) continue;
 
        /* It is not necessary to compare scan[2] and match[2] since they are
         * always equal when the other bytes match, given that the hash keys
         * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
         * strstart+3, +5, ... up to strstart+257. We check for insufficient
         * lookahead only every 4th comparison; the 128th check will be made
         * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
         * necessary to put more guard bytes at the end of the window, or
         * to check more often for insufficient lookahead.
         */
        Assert(scan[2] == match[2], "scan[2]?");
        scan++, match++;
        do {
        } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
                 scan < strend);
        /* The funny "do {}" generates better code on most compilers */
 
        /* Here, scan <= window+strstart+257 */
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
        if (*scan == *match) scan++;
 
        len = (MAX_MATCH - 1) - (int)(strend-scan);
        scan = strend - (MAX_MATCH-1);
 
#else /* UNALIGNED_OK */
 
        if (match[best_len]   != scan_end  ||
            match[best_len-1] != scan_end1 ||
            *match            != *scan     ||
            *++match          != scan[1])      continue;
 
        /* The check at best_len-1 can be removed because it will be made
         * again later. (This heuristic is not always a win.)
         * It is not necessary to compare scan[2] and match[2] since they
         * are always equal when the other bytes match, given that
         * the hash keys are equal and that HASH_BITS >= 8.
         */
        scan += 2, match++;
        Assert(*scan == *match, "match[2]?");
 
        /* We check for insufficient lookahead only every 8th comparison;
         * the 256th check will be made at strstart+258.
         */
        do {
        } while (*++scan == *++match && *++scan == *++match &&
                 *++scan == *++match && *++scan == *++match &&
                 *++scan == *++match && *++scan == *++match &&
                 *++scan == *++match && *++scan == *++match &&
                 scan < strend);
 
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
        len = MAX_MATCH - (int)(strend - scan);
        scan = strend - MAX_MATCH;
 
#endif /* UNALIGNED_OK */
 
        if (len > best_len) {
            s->match_start = cur_match;
            best_len = len;
            if (len >= nice_match) break;
#ifdef UNALIGNED_OK
            scan_end = *(ushf*)(scan+best_len-1);
#else
            scan_end1  = scan[best_len-1];
            scan_end   = scan[best_len];
#endif
        }
    } while ((cur_match = prev[cur_match & wmask]) > limit
             && --chain_length != 0);
 
    if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
    return s->lookahead;
}
#endif /* ASMV */
 
#else /* FASTEST */
 
/* ---------------------------------------------------------------------------
 * Optimized version for FASTEST only
 */
local uInt longest_match(s, cur_match)
    deflate_state *s;
    IPos cur_match;                             /* current match */
{
    register Bytef *scan = s->window + s->strstart; /* current string */
    register Bytef *match;                       /* matched string */
    register int len;                           /* length of current match */
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
 
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
     * It is easy to get rid of this optimization if necessary.
     */
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
 
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
 
    Assert(cur_match < s->strstart, "no future");
 
    match = s->window + cur_match;
 
    /* Return failure if the match length is less than 2:
     */
    if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
 
    /* The check at best_len-1 can be removed because it will be made
     * again later. (This heuristic is not always a win.)
     * It is not necessary to compare scan[2] and match[2] since they
     * are always equal when the other bytes match, given that
     * the hash keys are equal and that HASH_BITS >= 8.
     */
    scan += 2, match += 2;
    Assert(*scan == *match, "match[2]?");
 
    /* We check for insufficient lookahead only every 8th comparison;
     * the 256th check will be made at strstart+258.
     */
    do {
    } while (*++scan == *++match && *++scan == *++match &&
             *++scan == *++match && *++scan == *++match &&
             *++scan == *++match && *++scan == *++match &&
             *++scan == *++match && *++scan == *++match &&
             scan < strend);
 
    Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
    len = MAX_MATCH - (int)(strend - scan);
 
    if (len < MIN_MATCH) return MIN_MATCH - 1;
 
    s->match_start = cur_match;
    return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}
 
#endif /* FASTEST */
 
#ifdef DEBUG
/* ===========================================================================
 * Check that the match at match_start is indeed a match.
 */
local void check_match(s, start, match, length)
    deflate_state *s;
    IPos start, match;
    int length;
{
    /* check that the match is indeed a match */
    if (zmemcmp(s->window + match,
                s->window + start, length) != EQUAL) {
        fprintf(stderr, " start %u, match %u, length %d\n",
                start, match, length);
        do {
            fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
        } while (--length != 0);
        z_error("invalid match");
    }
    if (z_verbose > 1) {
        fprintf(stderr,"\\[%d,%d]", start-match, length);
        do { putc(s->window[start++], stderr); } while (--length != 0);
    }
}
#else
#  define check_match(s, start, match, length)
#endif /* DEBUG */
 
/* ===========================================================================
 * Fill the window when the lookahead becomes insufficient.
 * Updates strstart and lookahead.
 *
 * IN assertion: lookahead < MIN_LOOKAHEAD
 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
 *    At least one byte has been read, or avail_in == 0; reads are
 *    performed for at least two bytes (required for the zip translate_eol
 *    option -- not supported here).
 */
local void fill_window(s)
    deflate_state *s;
{
    register unsigned n, m;
    register Posf *p;
    unsigned more;    /* Amount of free space at the end of the window. */
    uInt wsize = s->w_size;
 
    Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
 
    do {
        more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
 
        /* Deal with !@#$% 64K limit: */
        if (sizeof(int) <= 2) {
            if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
                more = wsize;
 
            } else if (more == (unsigned)(-1)) {
                /* Very unlikely, but possible on 16 bit machine if
                 * strstart == 0 && lookahead == 1 (input done a byte at time)
                 */
                more--;
            }
        }
 
        /* If the window is almost full and there is insufficient lookahead,
         * move the upper half to the lower one to make room in the upper half.
         */
        if (s->strstart >= wsize+MAX_DIST(s)) {
 
            zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
            s->match_start -= wsize;
            s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
            s->block_start -= (long) wsize;
 
            /* Slide the hash table (could be avoided with 32 bit values
               at the expense of memory usage). We slide even when level == 0
               to keep the hash table consistent if we switch back to level > 0
               later. (Using level 0 permanently is not an optimal usage of
               zlib, so we don't care about this pathological case.)
             */
            n = s->hash_size;
            p = &s->head[n];
            do {
                m = *--p;
                *p = (Pos)(m >= wsize ? m-wsize : NIL);
            } while (--n);
 
            n = wsize;
#ifndef FASTEST
            p = &s->prev[n];
            do {
                m = *--p;
                *p = (Pos)(m >= wsize ? m-wsize : NIL);
                /* If n is not on any hash chain, prev[n] is garbage but
                 * its value will never be used.
                 */
            } while (--n);
#endif
            more += wsize;
        }
        if (s->strm->avail_in == 0) break;
 
        /* If there was no sliding:
         *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
         *    more == window_size - lookahead - strstart
         * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
         * => more >= window_size - 2*WSIZE + 2
         * In the BIG_MEM or MMAP case (not yet supported),
         *   window_size == input_size + MIN_LOOKAHEAD  &&
         *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
         * Otherwise, window_size == 2*WSIZE so more >= 2.
         * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
         */
        Assert(more >= 2, "more < 2");
 
        n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
        s->lookahead += n;
 
        /* Initialize the hash value now that we have some input: */
        if (s->lookahead + s->insert >= MIN_MATCH) {
            uInt str = s->strstart - s->insert;
            s->ins_h = s->window[str];
            UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
#if MIN_MATCH != 3
            Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
            while (s->insert) {
                UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
#ifndef FASTEST
                s->prev[str & s->w_mask] = s->head[s->ins_h];
#endif
                s->head[s->ins_h] = (Pos)str;
                str++;
                s->insert--;
                if (s->lookahead + s->insert < MIN_MATCH)
                    break;
            }
        }
        /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
         * but this is not important since only literal bytes will be emitted.
         */
 
    } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
 
    /* If the WIN_INIT bytes after the end of the current data have never been
     * written, then zero those bytes in order to avoid memory check reports of
     * the use of uninitialized (or uninitialised as Julian writes) bytes by
     * the longest match routines.  Update the high water mark for the next
     * time through here.  WIN_INIT is set to MAX_MATCH since the longest match
     * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
     */
    if (s->high_water < s->window_size) {
        ulg curr = s->strstart + (ulg)(s->lookahead);
        ulg init;
 
        if (s->high_water < curr) {
            /* Previous high water mark below current data -- zero WIN_INIT
             * bytes or up to end of window, whichever is less.
             */
            init = s->window_size - curr;
            if (init > WIN_INIT)
                init = WIN_INIT;
            zmemzero(s->window + curr, (unsigned)init);
            s->high_water = curr + init;
        }
        else if (s->high_water < (ulg)curr + WIN_INIT) {
            /* High water mark at or above current data, but below current data
             * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
             * to end of window, whichever is less.
             */
            init = (ulg)curr + WIN_INIT - s->high_water;
            if (init > s->window_size - s->high_water)
                init = s->window_size - s->high_water;
            zmemzero(s->window + s->high_water, (unsigned)init);
            s->high_water += init;
        }
    }
 
    Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
           "not enough room for search");
}
 
/* ===========================================================================
 * Flush the current block, with given end-of-file flag.
 * IN assertion: strstart is set to the end of the current match.
 */
#define FLUSH_BLOCK_ONLY(s, last) { \
   _tr_flush_block(s, (s->block_start >= 0L ? \
                   (charf *)&s->window[(unsigned)s->block_start] : \
                   (charf *)Z_NULL), \
                (ulg)((long)s->strstart - s->block_start), \
                (last)); \
   s->block_start = s->strstart; \
   flush_pending(s->strm); \
   Tracev((stderr,"[FLUSH]")); \
}
 
/* Same but force premature exit if necessary. */
#define FLUSH_BLOCK(s, last) { \
   FLUSH_BLOCK_ONLY(s, last); \
   if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}
 
/* ===========================================================================
 * Copy without compression as much as possible from the input stream, return
 * the current block state.
 * This function does not insert new strings in the dictionary since
 * uncompressible data is probably not useful. This function is used
 * only for the level=0 compression option.
 * NOTE: this function should be optimized to avoid extra copying from
 * window to pending_buf.
 */
local block_state deflate_stored(s, flush)
    deflate_state *s;
    int flush;
{
    /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
     * to pending_buf_size, and each stored block has a 5 byte header:
     */
    ulg max_block_size = 0xffff;
    ulg max_start;
 
    if (max_block_size > s->pending_buf_size - 5) {
        max_block_size = s->pending_buf_size - 5;
    }
 
    /* Copy as much as possible from input to output: */
    for (;;) {
        /* Fill the window as much as possible: */
        if (s->lookahead <= 1) {
 
            Assert(s->strstart < s->w_size+MAX_DIST(s) ||
                   s->block_start >= (long)s->w_size, "slide too late");
 
            fill_window(s);
            if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
 
            if (s->lookahead == 0) break; /* flush the current block */
        }
        Assert(s->block_start >= 0L, "block gone");
 
        s->strstart += s->lookahead;
        s->lookahead = 0;
 
        /* Emit a stored block if pending_buf will be full: */
        max_start = s->block_start + max_block_size;
        if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
            /* strstart == 0 is possible when wraparound on 16-bit machine */
            s->lookahead = (uInt)(s->strstart - max_start);
            s->strstart = (uInt)max_start;
            FLUSH_BLOCK(s, 0);
        }
        /* Flush if we may have to slide, otherwise block_start may become
         * negative and the data will be gone:
         */
        if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
            FLUSH_BLOCK(s, 0);
        }
    }
    s->insert = 0;
    if (flush == Z_FINISH) {
        FLUSH_BLOCK(s, 1);
        return finish_done;
    }
    if ((long)s->strstart > s->block_start)
        FLUSH_BLOCK(s, 0);
    return block_done;
}
 
/* ===========================================================================
 * Compress as much as possible from the input stream, return the current
 * block state.
 * This function does not perform lazy evaluation of matches and inserts
 * new strings in the dictionary only for unmatched strings or for short
 * matches. It is used only for the fast compression options.
 */
local block_state deflate_fast(s, flush)
    deflate_state *s;
    int flush;
{
    IPos hash_head;       /* head of the hash chain */
    int bflush;           /* set if current block must be flushed */
 
    for (;;) {
        /* Make sure that we always have enough lookahead, except
         * at the end of the input file. We need MAX_MATCH bytes
         * for the next match, plus MIN_MATCH bytes to insert the
         * string following the next match.
         */
        if (s->lookahead < MIN_LOOKAHEAD) {
            fill_window(s);
            if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                return need_more;
            }
            if (s->lookahead == 0) break; /* flush the current block */
        }
 
        /* Insert the string window[strstart .. strstart+2] in the
         * dictionary, and set hash_head to the head of the hash chain:
         */
        hash_head = NIL;
        if (s->lookahead >= MIN_MATCH) {
            INSERT_STRING(s, s->strstart, hash_head);
        }
 
        /* Find the longest match, discarding those <= prev_length.
         * At this point we have always match_length < MIN_MATCH
         */
        if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
            /* To simplify the code, we prevent matches with the string
             * of window index 0 (in particular we have to avoid a match
             * of the string with itself at the start of the input file).
             */
            s->match_length = longest_match (s, hash_head);
            /* longest_match() sets match_start */
        }
        if (s->match_length >= MIN_MATCH) {
            check_match(s, s->strstart, s->match_start, s->match_length);
 
            _tr_tally_dist(s, s->strstart - s->match_start,
                           s->match_length - MIN_MATCH, bflush);
 
            s->lookahead -= s->match_length;
 
            /* Insert new strings in the hash table only if the match length
             * is not too large. This saves time but degrades compression.
             */
#ifndef FASTEST
            if (s->match_length <= s->max_insert_length &&
                s->lookahead >= MIN_MATCH) {
                s->match_length--; /* string at strstart already in table */
                do {
                    s->strstart++;
                    INSERT_STRING(s, s->strstart, hash_head);
                    /* strstart never exceeds WSIZE-MAX_MATCH, so there are
                     * always MIN_MATCH bytes ahead.
                     */
                } while (--s->match_length != 0);
                s->strstart++;
            } else
#endif
            {
                s->strstart += s->match_length;
                s->match_length = 0;
                s->ins_h = s->window[s->strstart];
                UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
#if MIN_MATCH != 3
                Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
                /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
                 * matter since it will be recomputed at next deflate call.
                 */
            }
        } else {
            /* No match, output a literal byte */
            Tracevv((stderr,"%c", s->window[s->strstart]));
            _tr_tally_lit (s, s->window[s->strstart], bflush);
            s->lookahead--;
            s->strstart++;
        }
        if (bflush) FLUSH_BLOCK(s, 0);
    }
    s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
    if (flush == Z_FINISH) {
        FLUSH_BLOCK(s, 1);
        return finish_done;
    }
    if (s->last_lit)
        FLUSH_BLOCK(s, 0);
    return block_done;
}
 
#ifndef FASTEST
/* ===========================================================================
 * Same as above, but achieves better compression. We use a lazy
 * evaluation for matches: a match is finally adopted only if there is
 * no better match at the next window position.
 */
local block_state deflate_slow(s, flush)
    deflate_state *s;
    int flush;
{
    IPos hash_head;          /* head of hash chain */
    int bflush;              /* set if current block must be flushed */
 
    /* Process the input block. */
    for (;;) {
        /* Make sure that we always have enough lookahead, except
         * at the end of the input file. We need MAX_MATCH bytes
         * for the next match, plus MIN_MATCH bytes to insert the
         * string following the next match.
         */
        if (s->lookahead < MIN_LOOKAHEAD) {
            fill_window(s);
            if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
                return need_more;
            }
            if (s->lookahead == 0) break; /* flush the current block */
        }
 
        /* Insert the string window[strstart .. strstart+2] in the
         * dictionary, and set hash_head to the head of the hash chain:
         */
        hash_head = NIL;
        if (s->lookahead >= MIN_MATCH) {
            INSERT_STRING(s, s->strstart, hash_head);
        }
 
        /* Find the longest match, discarding those <= prev_length.
         */
        s->prev_length = s->match_length, s->prev_match = s->match_start;
        s->match_length = MIN_MATCH-1;
 
        if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
            s->strstart - hash_head <= MAX_DIST(s)) {
            /* To simplify the code, we prevent matches with the string
             * of window index 0 (in particular we have to avoid a match
             * of the string with itself at the start of the input file).
             */
            s->match_length = longest_match (s, hash_head);
            /* longest_match() sets match_start */
 
            if (s->match_length <= 5 && (s->strategy == Z_FILTERED
#if TOO_FAR <= 32767
                || (s->match_length == MIN_MATCH &&
                    s->strstart - s->match_start > TOO_FAR)
#endif
                )) {
 
                /* If prev_match is also MIN_MATCH, match_start is garbage
                 * but we will ignore the current match anyway.
                 */
                s->match_length = MIN_MATCH-1;
            }
        }
        /* If there was a match at the previous step and the current
         * match is not better, output the previous match:
         */
        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
            uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
            /* Do not insert strings in hash table beyond this. */
 
            check_match(s, s->strstart-1, s->prev_match, s->prev_length);
 
            _tr_tally_dist(s, s->strstart -1 - s->prev_match,
                           s->prev_length - MIN_MATCH, bflush);
 
            /* Insert in hash table all strings up to the end of the match.
             * strstart-1 and strstart are already inserted. If there is not
             * enough lookahead, the last two strings are not inserted in
             * the hash table.
             */
            s->lookahead -= s->prev_length-1;
            s->prev_length -= 2;
            do {
                if (++s->strstart <= max_insert) {
                    INSERT_STRING(s, s->strstart, hash_head);
                }
            } while (--s->prev_length != 0);
            s->match_available = 0;
            s->match_length = MIN_MATCH-1;
            s->strstart++;
 
            if (bflush) FLUSH_BLOCK(s, 0);
 
        } else if (s->match_available) {
            /* If there was no match at the previous position, output a
             * single literal. If there was a match but the current match
             * is longer, truncate the previous match to a single literal.
             */
            Tracevv((stderr,"%c", s->window[s->strstart-1]));
            _tr_tally_lit(s, s->window[s->strstart-1], bflush);
            if (bflush) {
                FLUSH_BLOCK_ONLY(s, 0);
            }
            s->strstart++;
            s->lookahead--;
            if (s->strm->avail_out == 0) return need_more;
        } else {
            /* There is no previous match to compare with, wait for
             * the next step to decide.
             */
            s->match_available = 1;
            s->strstart++;
            s->lookahead--;
        }
    }
    Assert (flush != Z_NO_FLUSH, "no flush?");
    if (s->match_available) {
        Tracevv((stderr,"%c", s->window[s->strstart-1]));
        _tr_tally_lit(s, s->window[s->strstart-1], bflush);
        s->match_available = 0;
    }
    s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
    if (flush == Z_FINISH) {
        FLUSH_BLOCK(s, 1);
        return finish_done;
    }
    if (s->last_lit)
        FLUSH_BLOCK(s, 0);
    return block_done;
}
#endif /* FASTEST */
 
/* ===========================================================================
 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
 * one.  Do not maintain a hash table.  (It will be regenerated if this run of
 * deflate switches away from Z_RLE.)
 */
local block_state deflate_rle(s, flush)
    deflate_state *s;
    int flush;
{
    int bflush;             /* set if current block must be flushed */
    uInt prev;              /* byte at distance one to match */
    Bytef *scan, *strend;   /* scan goes up to strend for length of run */
 
    for (;;) {
        /* Make sure that we always have enough lookahead, except
         * at the end of the input file. We need MAX_MATCH bytes
         * for the longest run, plus one for the unrolled loop.
         */
        if (s->lookahead <= MAX_MATCH) {
            fill_window(s);
            if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
                return need_more;
            }
            if (s->lookahead == 0) break; /* flush the current block */
        }
 
        /* See how many times the previous byte repeats */
        s->match_length = 0;
        if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
            scan = s->window + s->strstart - 1;
            prev = *scan;
            if (prev == *++scan && prev == *++scan && prev == *++scan) {
                strend = s->window + s->strstart + MAX_MATCH;
                do {
                } while (prev == *++scan && prev == *++scan &&
                         prev == *++scan && prev == *++scan &&
                         prev == *++scan && prev == *++scan &&
                         prev == *++scan && prev == *++scan &&
                         scan < strend);
                s->match_length = MAX_MATCH - (int)(strend - scan);
                if (s->match_length > s->lookahead)
                    s->match_length = s->lookahead;
            }
            Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
        }
 
        /* Emit match if have run of MIN_MATCH or longer, else emit literal */
        if (s->match_length >= MIN_MATCH) {
            check_match(s, s->strstart, s->strstart - 1, s->match_length);
 
            _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
 
            s->lookahead -= s->match_length;
            s->strstart += s->match_length;
            s->match_length = 0;
        } else {
            /* No match, output a literal byte */
            Tracevv((stderr,"%c", s->window[s->strstart]));
            _tr_tally_lit (s, s->window[s->strstart], bflush);
            s->lookahead--;
            s->strstart++;
        }
        if (bflush) FLUSH_BLOCK(s, 0);
    }
    s->insert = 0;
    if (flush == Z_FINISH) {
        FLUSH_BLOCK(s, 1);
        return finish_done;
    }
    if (s->last_lit)
        FLUSH_BLOCK(s, 0);
    return block_done;
}
 
/* ===========================================================================
 * For Z_HUFFMAN_ONLY, do not look for matches.  Do not maintain a hash table.
 * (It will be regenerated if this run of deflate switches away from Huffman.)
 */
local block_state deflate_huff(s, flush)
    deflate_state *s;
    int flush;
{
    int bflush;             /* set if current block must be flushed */
 
    for (;;) {
        /* Make sure that we have a literal to write. */
        if (s->lookahead == 0) {
            fill_window(s);
            if (s->lookahead == 0) {
                if (flush == Z_NO_FLUSH)
                    return need_more;
                break;      /* flush the current block */
            }
        }
 
        /* Output a literal byte */
        s->match_length = 0;
        Tracevv((stderr,"%c", s->window[s->strstart]));
        _tr_tally_lit (s, s->window[s->strstart], bflush);
        s->lookahead--;
        s->strstart++;
        if (bflush) FLUSH_BLOCK(s, 0);
    }
    s->insert = 0;
    if (flush == Z_FINISH) {
        FLUSH_BLOCK(s, 1);
        return finish_done;
    }
    if (s->last_lit)
        FLUSH_BLOCK(s, 0);
    return block_done;
}

Rev 1896	Rev 3926
1	/* deflate.c -- compress data using the deflation algorithm	1	/* deflate.c -- compress data using the deflation algorithm
2	* Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler	2	* Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler
3	* For conditions of distribution and use, see copyright notice in zlib.h	3	* For conditions of distribution and use, see copyright notice in zlib.h
4	*/	4	*/
5		5
6	/*	6	/*
7	* ALGORITHM	7	* ALGORITHM
8	*	8	*
9	* The "deflation" process depends on being able to identify portions	9	* The "deflation" process depends on being able to identify portions
10	* of the input text which are identical to earlier input (within a	10	* of the input text which are identical to earlier input (within a
11	* sliding window trailing behind the input currently being processed).	11	* sliding window trailing behind the input currently being processed).
12	*	12	*
13	* The most straightforward technique turns out to be the fastest for	13	* The most straightforward technique turns out to be the fastest for
14	* most input files: try all possible matches and select the longest.	14	* most input files: try all possible matches and select the longest.
15	* The key feature of this algorithm is that insertions into the string	15	* The key feature of this algorithm is that insertions into the string
16	* dictionary are very simple and thus fast, and deletions are avoided	16	* dictionary are very simple and thus fast, and deletions are avoided
17	* completely. Insertions are performed at each input character, whereas	17	* completely. Insertions are performed at each input character, whereas
18	* string matches are performed only when the previous match ends. So it	18	* string matches are performed only when the previous match ends. So it
19	* is preferable to spend more time in matches to allow very fast string	19	* is preferable to spend more time in matches to allow very fast string
20	* insertions and avoid deletions. The matching algorithm for small	20	* insertions and avoid deletions. The matching algorithm for small
21	* strings is inspired from that of Rabin & Karp. A brute force approach	21	* strings is inspired from that of Rabin & Karp. A brute force approach
22	* is used to find longer strings when a small match has been found.	22	* is used to find longer strings when a small match has been found.
23	* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze	23	* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
24	* (by Leonid Broukhis).	24	* (by Leonid Broukhis).
25	* A previous version of this file used a more sophisticated algorithm	25	* A previous version of this file used a more sophisticated algorithm
26	* (by Fiala and Greene) which is guaranteed to run in linear amortized	26	* (by Fiala and Greene) which is guaranteed to run in linear amortized
27	* time, but has a larger average cost, uses more memory and is patented.	27	* time, but has a larger average cost, uses more memory and is patented.
28	* However the F&G algorithm may be faster for some highly redundant	28	* However the F&G algorithm may be faster for some highly redundant
29	* files if the parameter max_chain_length (described below) is too large.	29	* files if the parameter max_chain_length (described below) is too large.
30	*	30	*
31	* ACKNOWLEDGEMENTS	31	* ACKNOWLEDGEMENTS
32	*	32	*
33	* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and	33	* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
34	* I found it in 'freeze' written by Leonid Broukhis.	34	* I found it in 'freeze' written by Leonid Broukhis.
35	* Thanks to many people for bug reports and testing.	35	* Thanks to many people for bug reports and testing.
36	*	36	*
37	* REFERENCES	37	* REFERENCES
38	*	38	*
39	* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".	39	* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
40	* Available in http://www.ietf.org/rfc/rfc1951.txt	40	* Available in http://tools.ietf.org/html/rfc1951
41	*	41	*
42	* A description of the Rabin and Karp algorithm is given in the book	42	* A description of the Rabin and Karp algorithm is given in the book
43	* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.	43	* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
44	*	44	*
45	* Fiala,E.R., and Greene,D.H.	45	* Fiala,E.R., and Greene,D.H.
46	* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595	46	* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
47	*	47	*
48	*/	48	*/
49		49
50	/* @(#) $Id$ */	50	/* @(#) $Id$ */
51		51
52	#include "deflate.h"	52	#include "deflate.h"
53		53
54	const char deflate_copyright[] =	54	const char deflate_copyright[] =
55	" deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";	55	" deflate 1.2.8 Copyright 1995-2013 Jean-loup Gailly and Mark Adler ";
56	/*	56	/*
57	If you use the zlib library in a product, an acknowledgment is welcome	57	If you use the zlib library in a product, an acknowledgment is welcome
58	in the documentation of your product. If for some reason you cannot	58	in the documentation of your product. If for some reason you cannot
59	include such an acknowledgment, I would appreciate that you keep this	59	include such an acknowledgment, I would appreciate that you keep this
60	copyright string in the executable of your product.	60	copyright string in the executable of your product.
61	*/	61	*/
62		62
63	/* ===========================================================================	63	/* ===========================================================================
64	* Function prototypes.	64	* Function prototypes.
65	*/	65	*/
66	typedef enum {	66	typedef enum {
67	need_more, /* block not completed, need more input or more output */	67	need_more, /* block not completed, need more input or more output */
68	block_done, /* block flush performed */	68	block_done, /* block flush performed */
69	finish_started, /* finish started, need only more output at next deflate */	69	finish_started, /* finish started, need only more output at next deflate */
70	finish_done /* finish done, accept no more input or output */	70	finish_done /* finish done, accept no more input or output */
71	} block_state;	71	} block_state;
72		72
73	typedef block_state (compress_func) OF((deflate_state s, int flush));	73	typedef block_state (compress_func) OF((deflate_state s, int flush));
74	/* Compression function. Returns the block state after the call. */	74	/* Compression function. Returns the block state after the call. */
75		75
76	local void fill_window OF((deflate_state *s));	76	local void fill_window OF((deflate_state *s));
77	local block_state deflate_stored OF((deflate_state *s, int flush));	77	local block_state deflate_stored OF((deflate_state *s, int flush));
78	local block_state deflate_fast OF((deflate_state *s, int flush));	78	local block_state deflate_fast OF((deflate_state *s, int flush));
79	#ifndef FASTEST	79	#ifndef FASTEST
80	local block_state deflate_slow OF((deflate_state *s, int flush));	80	local block_state deflate_slow OF((deflate_state *s, int flush));
81	#endif	81	#endif
82	local block_state deflate_rle OF((deflate_state *s, int flush));	82	local block_state deflate_rle OF((deflate_state *s, int flush));
83	local block_state deflate_huff OF((deflate_state *s, int flush));	83	local block_state deflate_huff OF((deflate_state *s, int flush));
84	local void lm_init OF((deflate_state *s));	84	local void lm_init OF((deflate_state *s));
85	local void putShortMSB OF((deflate_state *s, uInt b));	85	local void putShortMSB OF((deflate_state *s, uInt b));
86	local void flush_pending OF((z_streamp strm));	86	local void flush_pending OF((z_streamp strm));
87	local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));	87	local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
88	#ifdef ASMV	88	#ifdef ASMV
89	void match_init OF((void)); /* asm code initialization */	89	void match_init OF((void)); /* asm code initialization */
90	uInt longest_match OF((deflate_state *s, IPos cur_match));	90	uInt longest_match OF((deflate_state *s, IPos cur_match));
91	#else	91	#else
92	local uInt longest_match OF((deflate_state *s, IPos cur_match));	92	local uInt longest_match OF((deflate_state *s, IPos cur_match));
93	#endif	93	#endif
94		94
95	#ifdef DEBUG	95	#ifdef DEBUG
96	local void check_match OF((deflate_state *s, IPos start, IPos match,	96	local void check_match OF((deflate_state *s, IPos start, IPos match,
97	int length));	97	int length));
98	#endif	98	#endif
99		99
100	/* ===========================================================================	100	/* ===========================================================================
101	* Local data	101	* Local data
102	*/	102	*/
103		103
104	#define NIL 0	104	#define NIL 0
105	/* Tail of hash chains */	105	/* Tail of hash chains */
106		106
107	#ifndef TOO_FAR	107	#ifndef TOO_FAR
108	# define TOO_FAR 4096	108	# define TOO_FAR 4096
109	#endif	109	#endif
110	/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */	110	/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
111		111
112	/* Values for max_lazy_match, good_match and max_chain_length, depending on	112	/* Values for max_lazy_match, good_match and max_chain_length, depending on
113	* the desired pack level (0..9). The values given below have been tuned to	113	* the desired pack level (0..9). The values given below have been tuned to
114	* exclude worst case performance for pathological files. Better values may be	114	* exclude worst case performance for pathological files. Better values may be
115	* found for specific files.	115	* found for specific files.
116	*/	116	*/
117	typedef struct config_s {	117	typedef struct config_s {
118	ush good_length; /* reduce lazy search above this match length */	118	ush good_length; /* reduce lazy search above this match length */
119	ush max_lazy; /* do not perform lazy search above this match length */	119	ush max_lazy; /* do not perform lazy search above this match length */
120	ush nice_length; /* quit search above this match length */	120	ush nice_length; /* quit search above this match length */
121	ush max_chain;	121	ush max_chain;
122	compress_func func;	122	compress_func func;
123	} config;	123	} config;
124		124
125	#ifdef FASTEST	125	#ifdef FASTEST
126	local const config configuration_table[2] = {	126	local const config configuration_table[2] = {
127	/* good lazy nice chain */	127	/* good lazy nice chain */
128	/* 0 / {0, 0, 0, 0, deflate_stored}, / store only */	128	/* 0 / {0, 0, 0, 0, deflate_stored}, / store only */
129	/* 1 / {4, 4, 8, 4, deflate_fast}}; / max speed, no lazy matches */	129	/* 1 / {4, 4, 8, 4, deflate_fast}}; / max speed, no lazy matches */
130	#else	130	#else
131	local const config configuration_table[10] = {	131	local const config configuration_table[10] = {
132	/* good lazy nice chain */	132	/* good lazy nice chain */
133	/* 0 / {0, 0, 0, 0, deflate_stored}, / store only */	133	/* 0 / {0, 0, 0, 0, deflate_stored}, / store only */
134	/* 1 / {4, 4, 8, 4, deflate_fast}, / max speed, no lazy matches */	134	/* 1 / {4, 4, 8, 4, deflate_fast}, / max speed, no lazy matches */
135	/* 2 */ {4, 5, 16, 8, deflate_fast},	135	/* 2 */ {4, 5, 16, 8, deflate_fast},
136	/* 3 */ {4, 6, 32, 32, deflate_fast},	136	/* 3 */ {4, 6, 32, 32, deflate_fast},
137		137
138	/* 4 / {4, 4, 16, 16, deflate_slow}, / lazy matches */	138	/* 4 / {4, 4, 16, 16, deflate_slow}, / lazy matches */
139	/* 5 */ {8, 16, 32, 32, deflate_slow},	139	/* 5 */ {8, 16, 32, 32, deflate_slow},
140	/* 6 */ {8, 16, 128, 128, deflate_slow},	140	/* 6 */ {8, 16, 128, 128, deflate_slow},
141	/* 7 */ {8, 32, 128, 256, deflate_slow},	141	/* 7 */ {8, 32, 128, 256, deflate_slow},
142	/* 8 */ {32, 128, 258, 1024, deflate_slow},	142	/* 8 */ {32, 128, 258, 1024, deflate_slow},
143	/* 9 / {32, 258, 258, 4096, deflate_slow}}; / max compression */	143	/* 9 / {32, 258, 258, 4096, deflate_slow}}; / max compression */
144	#endif	144	#endif
145		145
146	/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4	146	/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
147	* For deflate_fast() (levels <= 3) good is ignored and lazy has a different	147	* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
148	* meaning.	148	* meaning.
149	*/	149	*/
150		150
151	#define EQUAL 0	151	#define EQUAL 0
152	/* result of memcmp for equal strings */	152	/* result of memcmp for equal strings */
153		153
154	#ifndef NO_DUMMY_DECL	154	#ifndef NO_DUMMY_DECL
155	struct static_tree_desc_s {int dummy;}; /* for buggy compilers */	155	struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
156	#endif	156	#endif
-		157
-		158	/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
-		159	#define RANK(f) (((f) << 1) - ((f) > 4 ? 9 : 0))
157		160
158	/* ===========================================================================	161	/* ===========================================================================
159	* Update a hash value with the given input byte	162	* Update a hash value with the given input byte
160	* IN assertion: all calls to to UPDATE_HASH are made with consecutive	163	* IN assertion: all calls to to UPDATE_HASH are made with consecutive
161	* input characters, so that a running hash key can be computed from the	164	* input characters, so that a running hash key can be computed from the
162	* previous key instead of complete recalculation each time.	165	* previous key instead of complete recalculation each time.
163	*/	166	*/
164	#define UPDATE_HASH(s,h,c) (h = (((h)<hash_shift) ^ (c)) & s->hash_mask)	167	#define UPDATE_HASH(s,h,c) (h = (((h)<hash_shift) ^ (c)) & s->hash_mask)
165		168
166		169
167	/* ===========================================================================	170	/* ===========================================================================
168	* Insert string str in the dictionary and set match_head to the previous head	171	* Insert string str in the dictionary and set match_head to the previous head
169	* of the hash chain (the most recent string with same hash key). Return	172	* of the hash chain (the most recent string with same hash key). Return
170	* the previous length of the hash chain.	173	* the previous length of the hash chain.
171	* If this file is compiled with -DFASTEST, the compression level is forced	174	* If this file is compiled with -DFASTEST, the compression level is forced
172	* to 1, and no hash chains are maintained.	175	* to 1, and no hash chains are maintained.
173	* IN assertion: all calls to to INSERT_STRING are made with consecutive	176	* IN assertion: all calls to to INSERT_STRING are made with consecutive
174	* input characters and the first MIN_MATCH bytes of str are valid	177	* input characters and the first MIN_MATCH bytes of str are valid
175	* (except for the last MIN_MATCH-1 bytes of the input file).	178	* (except for the last MIN_MATCH-1 bytes of the input file).
176	*/	179	*/
177	#ifdef FASTEST	180	#ifdef FASTEST
178	#define INSERT_STRING(s, str, match_head) \	181	#define INSERT_STRING(s, str, match_head) \
179	(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \	182	(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
180	match_head = s->head[s->ins_h], \	183	match_head = s->head[s->ins_h], \
181	s->head[s->ins_h] = (Pos)(str))	184	s->head[s->ins_h] = (Pos)(str))
182	#else	185	#else
183	#define INSERT_STRING(s, str, match_head) \	186	#define INSERT_STRING(s, str, match_head) \
184	(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \	187	(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
185	match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \	188	match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
186	s->head[s->ins_h] = (Pos)(str))	189	s->head[s->ins_h] = (Pos)(str))
187	#endif	190	#endif
188		191
189	/* ===========================================================================	192	/* ===========================================================================
190	* Initialize the hash table (avoiding 64K overflow for 16 bit systems).	193	* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
191	* prev[] will be initialized on the fly.	194	* prev[] will be initialized on the fly.
192	*/	195	*/
193	#define CLEAR_HASH(s) \	196	#define CLEAR_HASH(s) \
194	s->head[s->hash_size-1] = NIL; \	197	s->head[s->hash_size-1] = NIL; \
195	zmemzero((Bytef )s->head, (unsigned)(s->hash_size-1)sizeof(*s->head));	198	zmemzero((Bytef )s->head, (unsigned)(s->hash_size-1)sizeof(*s->head));
196		199
197	/* ========================================================================= */	200	/* ========================================================================= */
198	int ZEXPORT deflateInit_(strm, level, version, stream_size)	201	int ZEXPORT deflateInit_(strm, level, version, stream_size)
199	z_streamp strm;	202	z_streamp strm;
200	int level;	203	int level;
201	const char *version;	204	const char *version;
202	int stream_size;	205	int stream_size;
203	{	206	{
204	return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,	207	return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
205	Z_DEFAULT_STRATEGY, version, stream_size);	208	Z_DEFAULT_STRATEGY, version, stream_size);
206	/* To do: ignore strm->next_in if we use it as window */	209	/* To do: ignore strm->next_in if we use it as window */
207	}	210	}
208		211
209	/* ========================================================================= */	212	/* ========================================================================= */
210	int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,	213	int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
211	version, stream_size)	214	version, stream_size)
212	z_streamp strm;	215	z_streamp strm;
213	int level;	216	int level;
214	int method;	217	int method;
215	int windowBits;	218	int windowBits;
216	int memLevel;	219	int memLevel;
217	int strategy;	220	int strategy;
218	const char *version;	221	const char *version;
219	int stream_size;	222	int stream_size;
220	{	223	{
221	deflate_state *s;	224	deflate_state *s;
222	int wrap = 1;	225	int wrap = 1;
223	static const char my_version[] = ZLIB_VERSION;	226	static const char my_version[] = ZLIB_VERSION;
224		227
225	ushf *overlay;	228	ushf *overlay;
226	/* We overlay pending_buf and d_buf+l_buf. This works since the average	229	/* We overlay pending_buf and d_buf+l_buf. This works since the average
227	* output size for (length,distance) codes is <= 24 bits.	230	* output size for (length,distance) codes is <= 24 bits.
228	*/	231	*/
229		232
230	if (version == Z_NULL \|\| version[0] != my_version[0] \|\|	233	if (version == Z_NULL \|\| version[0] != my_version[0] \|\|
231	stream_size != sizeof(z_stream)) {	234	stream_size != sizeof(z_stream)) {
232	return Z_VERSION_ERROR;	235	return Z_VERSION_ERROR;
233	}	236	}
234	if (strm == Z_NULL) return Z_STREAM_ERROR;	237	if (strm == Z_NULL) return Z_STREAM_ERROR;
235		238
236	strm->msg = Z_NULL;	239	strm->msg = Z_NULL;
237	if (strm->zalloc == (alloc_func)0) {	240	if (strm->zalloc == (alloc_func)0) {
-		241	#ifdef Z_SOLO
-		242	return Z_STREAM_ERROR;
-		243	#else
238	strm->zalloc = zcalloc;	244	strm->zalloc = zcalloc;
239	strm->opaque = (voidpf)0;	245	strm->opaque = (voidpf)0;
-		246	#endif
240	}	247	}
241	if (strm->zfree == (free_func)0) strm->zfree = zcfree;	248	if (strm->zfree == (free_func)0)
-		249	#ifdef Z_SOLO
-		250	return Z_STREAM_ERROR;
-		251	#else
-		252	strm->zfree = zcfree;
-		253	#endif
242		254
243	#ifdef FASTEST	255	#ifdef FASTEST
244	if (level != 0) level = 1;	256	if (level != 0) level = 1;
245	#else	257	#else
246	if (level == Z_DEFAULT_COMPRESSION) level = 6;	258	if (level == Z_DEFAULT_COMPRESSION) level = 6;
247	#endif	259	#endif
248		260
249	if (windowBits < 0) { /* suppress zlib wrapper */	261	if (windowBits < 0) { /* suppress zlib wrapper */
250	wrap = 0;	262	wrap = 0;
251	windowBits = -windowBits;	263	windowBits = -windowBits;
252	}	264	}
253	#ifdef GZIP	265	#ifdef GZIP
254	else if (windowBits > 15) {	266	else if (windowBits > 15) {
255	wrap = 2; /* write gzip wrapper instead */	267	wrap = 2; /* write gzip wrapper instead */
256	windowBits -= 16;	268	windowBits -= 16;
257	}	269	}
258	#endif	270	#endif
259	if (memLevel < 1 \|\| memLevel > MAX_MEM_LEVEL \|\| method != Z_DEFLATED \|\|	271	if (memLevel < 1 \|\| memLevel > MAX_MEM_LEVEL \|\| method != Z_DEFLATED \|\|
260	windowBits < 8 \|\| windowBits > 15 \|\| level < 0 \|\| level > 9 \|\|	272	windowBits < 8 \|\| windowBits > 15 \|\| level < 0 \|\| level > 9 \|\|
261	strategy < 0 \|\| strategy > Z_FIXED) {	273	strategy < 0 \|\| strategy > Z_FIXED) {
262	return Z_STREAM_ERROR;	274	return Z_STREAM_ERROR;
263	}	275	}
264	if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */	276	if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
265	s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));	277	s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
266	if (s == Z_NULL) return Z_MEM_ERROR;	278	if (s == Z_NULL) return Z_MEM_ERROR;
267	strm->state = (struct internal_state FAR *)s;	279	strm->state = (struct internal_state FAR *)s;
268	s->strm = strm;	280	s->strm = strm;
269		281
270	s->wrap = wrap;	282	s->wrap = wrap;
271	s->gzhead = Z_NULL;	283	s->gzhead = Z_NULL;
272	s->w_bits = windowBits;	284	s->w_bits = windowBits;
273	s->w_size = 1 << s->w_bits;	285	s->w_size = 1 << s->w_bits;
274	s->w_mask = s->w_size - 1;	286	s->w_mask = s->w_size - 1;
275		287
276	s->hash_bits = memLevel + 7;	288	s->hash_bits = memLevel + 7;
277	s->hash_size = 1 << s->hash_bits;	289	s->hash_size = 1 << s->hash_bits;
278	s->hash_mask = s->hash_size - 1;	290	s->hash_mask = s->hash_size - 1;
279	s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);	291	s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
280		292
281	s->window = (Bytef ) ZALLOC(strm, s->w_size, 2sizeof(Byte));	293	s->window = (Bytef ) ZALLOC(strm, s->w_size, 2sizeof(Byte));
282	s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));	294	s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
283	s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));	295	s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
284		296
285	s->high_water = 0; /* nothing written to s->window yet */	297	s->high_water = 0; /* nothing written to s->window yet */
286		298
287	s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */	299	s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
288		300
289	overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);	301	overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
290	s->pending_buf = (uchf *) overlay;	302	s->pending_buf = (uchf *) overlay;
291	s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);	303	s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
292		304
293	if (s->window == Z_NULL \|\| s->prev == Z_NULL \|\| s->head == Z_NULL \|\|	305	if (s->window == Z_NULL \|\| s->prev == Z_NULL \|\| s->head == Z_NULL \|\|
294	s->pending_buf == Z_NULL) {	306	s->pending_buf == Z_NULL) {
295	s->status = FINISH_STATE;	307	s->status = FINISH_STATE;
296	strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);	308	strm->msg = ERR_MSG(Z_MEM_ERROR);
297	deflateEnd (strm);	309	deflateEnd (strm);
298	return Z_MEM_ERROR;	310	return Z_MEM_ERROR;
299	}	311	}
300	s->d_buf = overlay + s->lit_bufsize/sizeof(ush);	312	s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
301	s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;	313	s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
302		314
303	s->level = level;	315	s->level = level;
304	s->strategy = strategy;	316	s->strategy = strategy;
305	s->method = (Byte)method;	317	s->method = (Byte)method;
306		318
307	return deflateReset(strm);	319	return deflateReset(strm);
308	}	320	}
309		321
310	/* ========================================================================= */	322	/* ========================================================================= */
311	int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)	323	int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
312	z_streamp strm;	324	z_streamp strm;
313	const Bytef *dictionary;	325	const Bytef *dictionary;
314	uInt dictLength;	326	uInt dictLength;
315	{	327	{
316	deflate_state *s;	328	deflate_state *s;
317	uInt length = dictLength;	329	uInt str, n;
318	uInt n;	330	int wrap;
319	IPos hash_head = 0;	331	unsigned avail;
320		-
321	if (strm == Z_NULL \|\| strm->state == Z_NULL \|\| dictionary == Z_NULL \|\|	-
322	strm->state->wrap == 2 \|\|	332	z_const unsigned char *next;
323	(strm->state->wrap == 1 && strm->state->status != INIT_STATE))	-
324	return Z_STREAM_ERROR;	-
-		333
-		334	if (strm == Z_NULL \|\| strm->state == Z_NULL \|\| dictionary == Z_NULL)
325		335	return Z_STREAM_ERROR;
326	s = strm->state;	336	s = strm->state;
-		337	wrap = s->wrap;
-		338	if (wrap == 2 \|\| (wrap == 1 && s->status != INIT_STATE) \|\| s->lookahead)
-		339	return Z_STREAM_ERROR;
-		340
-		341	/* when using zlib wrappers, compute Adler-32 for provided dictionary */
327	if (s->wrap)	342	if (wrap == 1)
-		343	strm->adler = adler32(strm->adler, dictionary, dictLength);
328	strm->adler = adler32(strm->adler, dictionary, dictLength);	344	s->wrap = 0; /* avoid computing Adler-32 in read_buf */
329		345
330	if (length < MIN_MATCH) return Z_OK;	-
331	if (length > s->w_size) {	346	/* if dictionary would fill window, just replace the history */
332	length = s->w_size;	-
333	dictionary += dictLength - length; /* use the tail of the dictionary */	347	if (dictLength >= s->w_size) {
334	}	348	if (wrap == 0) { /* already empty otherwise */
335	zmemcpy(s->window, dictionary, length);	349	CLEAR_HASH(s);
336	s->strstart = length;	-
337	s->block_start = (long)length;	-
338		-
339	/* Insert all strings in the hash table (except for the last two bytes).	-
340	* s->lookahead stays null, so s->ins_h will be recomputed at the next	-
341	* call of fill_window.	350	s->strstart = 0;
342	*/	-
343	s->ins_h = s->window[0];	-
344	UPDATE_HASH(s, s->ins_h, s->window[1]);	-
345	for (n = 0; n <= length - MIN_MATCH; n++) {	351	s->block_start = 0L;
-		352	s->insert = 0;
-		353	}
-		354	dictionary += dictLength - s->w_size; /* use the tail */
-		355	dictLength = s->w_size;
346	INSERT_STRING(s, n, hash_head);	356	}
-		357
-		358	/* insert dictionary into window and hash */
-		359	avail = strm->avail_in;
-		360	next = strm->next_in;
-		361	strm->avail_in = dictLength;
-		362	strm->next_in = (z_const Bytef *)dictionary;
-		363	fill_window(s);
-		364	while (s->lookahead >= MIN_MATCH) {
-		365	str = s->strstart;
-		366	n = s->lookahead - (MIN_MATCH-1);
-		367	do {
-		368	UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
-		369	#ifndef FASTEST
-		370	s->prev[str & s->w_mask] = s->head[s->ins_h];
-		371	#endif
-		372	s->head[s->ins_h] = (Pos)str;
-		373	str++;
-		374	} while (--n);
-		375	s->strstart = str;
-		376	s->lookahead = MIN_MATCH-1;
-		377	fill_window(s);
-		378	}
-		379	s->strstart += s->lookahead;
-		380	s->block_start = (long)s->strstart;
-		381	s->insert = s->lookahead;
-		382	s->lookahead = 0;
-		383	s->match_length = s->prev_length = MIN_MATCH-1;
-		384	s->match_available = 0;
-		385	strm->next_in = next;
347	}	386	strm->avail_in = avail;
348	if (hash_head) hash_head = 0; /* to make compiler happy */	387	s->wrap = wrap;
349	return Z_OK;	388	return Z_OK;
350	}	389	}
351		390
352	/* ========================================================================= */	391	/* ========================================================================= */
353	int ZEXPORT deflateReset (strm)	392	int ZEXPORT deflateResetKeep (strm)
354	z_streamp strm;	393	z_streamp strm;
355	{	394	{
356	deflate_state *s;	395	deflate_state *s;
357		396
358	if (strm == Z_NULL \|\| strm->state == Z_NULL \|\|	397	if (strm == Z_NULL \|\| strm->state == Z_NULL \|\|
359	strm->zalloc == (alloc_func)0 \|\| strm->zfree == (free_func)0) {	398	strm->zalloc == (alloc_func)0 \|\| strm->zfree == (free_func)0) {
360	return Z_STREAM_ERROR;	399	return Z_STREAM_ERROR;
361	}	400	}
362		401
363	strm->total_in = strm->total_out = 0;	402	strm->total_in = strm->total_out = 0;
364	strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */	403	strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
365	strm->data_type = Z_UNKNOWN;	404	strm->data_type = Z_UNKNOWN;
366		405
367	s = (deflate_state *)strm->state;	406	s = (deflate_state *)strm->state;
368	s->pending = 0;	407	s->pending = 0;
369	s->pending_out = s->pending_buf;	408	s->pending_out = s->pending_buf;
370		409
371	if (s->wrap < 0) {	410	if (s->wrap < 0) {
372	s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */	411	s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
373	}	412	}
374	s->status = s->wrap ? INIT_STATE : BUSY_STATE;	413	s->status = s->wrap ? INIT_STATE : BUSY_STATE;
375	strm->adler =	414	strm->adler =
376	#ifdef GZIP	415	#ifdef GZIP
377	s->wrap == 2 ? crc32(0L, Z_NULL, 0) :	416	s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
378	#endif	417	#endif
379	adler32(0L, Z_NULL, 0);	418	adler32(0L, Z_NULL, 0);
380	s->last_flush = Z_NO_FLUSH;	419	s->last_flush = Z_NO_FLUSH;
381		420
382	_tr_init(s);	421	_tr_init(s);
383	lm_init(s);	-
384		422
385	return Z_OK;	423	return Z_OK;
386	}	424	}
387		425
388	/* ========================================================================= */	426	/* ========================================================================= */
-		427	int ZEXPORT deflateReset (strm)
-		428	z_streamp strm;
-		429	{
-		430	int ret;
-		431
-		432	ret = deflateResetKeep(strm);
-		433	if (ret == Z_OK)
-		434	lm_init(strm->state);
-		435	return ret;
-		436	}
-		437
-		438	/* ========================================================================= */
389	int ZEXPORT deflateSetHeader (strm, head)	439	int ZEXPORT deflateSetHeader (strm, head)
390	z_streamp strm;	440	z_streamp strm;
391	gz_headerp head;	441	gz_headerp head;
392	{	442	{
393	if (strm == Z_NULL \|\| strm->state == Z_NULL) return Z_STREAM_ERROR;	443	if (strm == Z_NULL \|\| strm->state == Z_NULL) return Z_STREAM_ERROR;
394	if (strm->state->wrap != 2) return Z_STREAM_ERROR;	444	if (strm->state->wrap != 2) return Z_STREAM_ERROR;
395	strm->state->gzhead = head;	445	strm->state->gzhead = head;
396	return Z_OK;	446	return Z_OK;
397	}	447	}
398		448
399	/* ========================================================================= */	449	/* ========================================================================= */
-		450	int ZEXPORT deflatePending (strm, pending, bits)
-		451	unsigned *pending;
-		452	int *bits;
-		453	z_streamp strm;
-		454	{
-		455	if (strm == Z_NULL \|\| strm->state == Z_NULL) return Z_STREAM_ERROR;
-		456	if (pending != Z_NULL)
-		457	*pending = strm->state->pending;
-		458	if (bits != Z_NULL)
-		459	*bits = strm->state->bi_valid;
-		460	return Z_OK;
-		461	}
-		462
-		463	/* ========================================================================= */
400	int ZEXPORT deflatePrime (strm, bits, value)	464	int ZEXPORT deflatePrime (strm, bits, value)
401	z_streamp strm;	465	z_streamp strm;
402	int bits;	466	int bits;
403	int value;	467	int value;
404	{	468	{
-		469	deflate_state *s;
-		470	int put;
-		471
405	if (strm == Z_NULL \|\| strm->state == Z_NULL) return Z_STREAM_ERROR;	472	if (strm == Z_NULL \|\| strm->state == Z_NULL) return Z_STREAM_ERROR;
-		473	s = strm->state;
-		474	if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3))
-		475	return Z_BUF_ERROR;
-		476	do {
-		477	put = Buf_size - s->bi_valid;
-		478	if (put > bits)
406	strm->state->bi_valid = bits;	479	put = bits;
407	strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));	480	s->bi_buf \|= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
-		481	s->bi_valid += put;
-		482	_tr_flush_bits(s);
-		483	value >>= put;
-		484	bits -= put;
-		485	} while (bits);

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(root)/programs/develop/libraries/zlib/deflate.c – Rev 1896 → 3926