    /* deflate.c -- compress data using the deflation algorithm
     * Copyright (C) 1995-2017 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 1.2.11 Copyright 1995-2017 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 int deflateStateCheck      OF((z_streamp strm));
    local void slide_hash     OF((deflate_state *s));
    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 unsigned read_buf   OF((z_streamp strm, Bytef *buf, unsigned size));
    #ifdef ASMV
    #  pragma message("Assembler code may have bugs -- use at your own risk")
          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 ZLIB_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.
     */

    /* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
    #define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))

    /* ===========================================================================
     * Update a hash value with the given input byte
     * IN  assertion: all calls to UPDATE_HASH are made with consecutive input
     *    characters, so that a running hash key can be computed from the previous
     *    key instead of complete recalculation each time.
     */
    #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)

    /* ===========================================================================
     * Insert string str in the dictionary and set match_head to the previous head
     * of the hash chain (the most recent string with same hash key). Return
     * the previous length of the hash chain.
     * 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 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));

    /* ===========================================================================
     * Slide the hash table when sliding the window down (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.
     */
    local void slide_hash(s)
        deflate_state *s;
    {
        unsigned n, m;
        Posf *p;
        uInt wsize = s->w_size;

        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
    }

    /* ========================================================================= */
    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 || (windowBits == 8 && wrap != 1)) {
            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->status = INIT_STATE;     /* to pass state test in deflateReset() */

        s->wrap = wrap;
        s->gzhead = Z_NULL;
        s->w_bits = (uInt)windowBits;
        s->w_size = 1 << s->w_bits;
        s->w_mask = s->w_size - 1;

        s->hash_bits = (uInt)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);
    }

    /* =========================================================================
     * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
     */
    local int deflateStateCheck (strm)
        z_streamp strm;
    {
        deflate_state *s;
        if (strm == Z_NULL ||
            strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
            return 1;
        s = strm->state;
        if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
    #ifdef GZIP
                                               s->status != GZIP_STATE &&
    #endif
                                               s->status != EXTRA_STATE &&
                                               s->status != NAME_STATE &&
                                               s->status != COMMENT_STATE &&
                                               s->status != HCRC_STATE &&
                                               s->status != BUSY_STATE &&
                                               s->status != FINISH_STATE))
            return 1;
        return 0;
    }

    /* ========================================================================= */
    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 (deflateStateCheck(strm) || 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 deflateGetDictionary (strm, dictionary, dictLength)
        z_streamp strm;
        Bytef *dictionary;
        uInt  *dictLength;
    {
        deflate_state *s;
        uInt len;

        if (deflateStateCheck(strm))
            return Z_STREAM_ERROR;
        s = strm->state;
        len = s->strstart + s->lookahead;
        if (len > s->w_size)
            len = s->w_size;
        if (dictionary != Z_NULL && len)
            zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
        if (dictLength != Z_NULL)
            *dictLength = len;
        return Z_OK;
    }

    /* ========================================================================= */
    int ZEXPORT deflateResetKeep (strm)
        z_streamp strm;
    {
        deflate_state *s;

        if (deflateStateCheck(strm)) {
            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 =
    #ifdef GZIP
            s->wrap == 2 ? GZIP_STATE :
    #endif
            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 (deflateStateCheck(strm) || 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 (deflateStateCheck(strm)) 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 (deflateStateCheck(strm)) 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;

        if (deflateStateCheck(strm)) 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) &&
            s->high_water) {
            /* Flush the last buffer: */
            int err = deflate(strm, Z_BLOCK);
            if (err == Z_STREAM_ERROR)
                return err;
            if (strm->avail_out == 0)
                return Z_BUF_ERROR;
        }
        if (s->level != level) {
            if (s->level == 0 && s->matches != 0) {
                if (s->matches == 1)
                    slide_hash(s);
                else
                    CLEAR_HASH(s);
                s->matches = 0;
            }
            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 Z_OK;
    }

    /* ========================================================================= */
    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 (deflateStateCheck(strm)) return Z_STREAM_ERROR;
        s = strm->state;
        s->good_match = (uInt)good_length;
        s->max_lazy_match = (uInt)max_lazy;
        s->nice_match = nice_length;
        s->max_chain_length = (uInt)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;

        /* 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 (deflateStateCheck(strm))
            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;
    #ifdef GZIP
        case 2:                                 /* gzip wrapper */
            wraplen = 18;
            if (s->gzhead != Z_NULL) {          /* user-supplied gzip header */
                Bytef *str;
                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;
    #endif
        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, except for
     * some deflate_stored() 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;
        }
    }

    /* ===========================================================================
     * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
     */
    #define HCRC_UPDATE(beg) \
        do { \
            if (s->gzhead->hcrc && s->pending > (beg)) \
                strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
                                    s->pending - (beg)); \
        } while (0)

    /* ========================================================================= */
    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 (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
            return Z_STREAM_ERROR;
        }
        s = strm->state;

        if (strm->next_out == Z_NULL ||
            (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
            (s->status == FINISH_STATE && flush != Z_FINISH)) {
            ERR_RETURN(strm, Z_STREAM_ERROR);
        }
        if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);

        old_flush = s->last_flush;
        s->last_flush = flush;

        /* 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);
        }

        /* Write the header */
        if (s->status == INIT_STATE) {
            /* zlib header */
            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);

            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);
            s->status = BUSY_STATE;

            /* Compression must start with an empty pending buffer */
            flush_pending(strm);
            if (s->pending != 0) {
                s->last_flush = -1;
                return Z_OK;
            }
        }
    #ifdef GZIP
        if (s->status == GZIP_STATE) {
            /* gzip header */
            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;

                /* Compression must start with an empty pending buffer */
                flush_pending(strm);
                if (s->pending != 0) {
                    s->last_flush = -1;
                    return Z_OK;
                }
            }
            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;
            }
        }
        if (s->status == EXTRA_STATE) {
            if (s->gzhead->extra != Z_NULL) {
                ulg beg = s->pending;   /* start of bytes to update crc */
                uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
                while (s->pending + left > s->pending_buf_size) {
                    uInt copy = s->pending_buf_size - s->pending;
                    zmemcpy(s->pending_buf + s->pending,
                            s->gzhead->extra + s->gzindex, copy);
                    s->pending = s->pending_buf_size;
                    HCRC_UPDATE(beg);
                    s->gzindex += copy;
                    flush_pending(strm);
                    if (s->pending != 0) {
                        s->last_flush = -1;
                        return Z_OK;
                    }
                    beg = 0;
                    left -= copy;
                }
                zmemcpy(s->pending_buf + s->pending,
                        s->gzhead->extra + s->gzindex, left);
                s->pending += left;
                HCRC_UPDATE(beg);
                s->gzindex = 0;
            }
            s->status = NAME_STATE;
        }
        if (s->status == NAME_STATE) {
            if (s->gzhead->name != Z_NULL) {
                ulg beg = s->pending;   /* start of bytes to update crc */
                int val;
                do {
                    if (s->pending == s->pending_buf_size) {
                        HCRC_UPDATE(beg);
                        flush_pending(strm);
                        if (s->pending != 0) {
                            s->last_flush = -1;
                            return Z_OK;
                        }
                        beg = 0;
                    }
                    val = s->gzhead->name[s->gzindex++];
                    put_byte(s, val);
                } while (val != 0);
                HCRC_UPDATE(beg);
                s->gzindex = 0;
            }
            s->status = COMMENT_STATE;
        }
        if (s->status == COMMENT_STATE) {
            if (s->gzhead->comment != Z_NULL) {
                ulg beg = s->pending;   /* start of bytes to update crc */
                int val;
                do {
                    if (s->pending == s->pending_buf_size) {
                        HCRC_UPDATE(beg);
                        flush_pending(strm);
                        if (s->pending != 0) {
                            s->last_flush = -1;
                            return Z_OK;
                        }
                        beg = 0;
                    }
                    val = s->gzhead->comment[s->gzindex++];
                    put_byte(s, val);
                } while (val != 0);
                HCRC_UPDATE(beg);
            }
            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 != 0) {
                        s->last_flush = -1;
                        return Z_OK;
                    }
                }
                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;

            /* Compression must start with an empty pending buffer */
            flush_pending(strm);
            if (s->pending != 0) {
                s->last_flush = -1;
                return Z_OK;
            }
        }
    #endif

        /* 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->level == 0 ? deflate_stored(s, flush) :
                     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;
                }
            }
        }

        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 (deflateStateCheck(strm)) return Z_STREAM_ERROR;

        status = strm->state->status;

        /* 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 (deflateStateCheck(source) || dest == 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 unsigned 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 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 = (int)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 = (int)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 ZLIB_DEBUG

    #define EQUAL 0
    /* result of memcmp for equal strings */

    /* ===========================================================================
     * 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 /* ZLIB_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;
    {
        unsigned n;
        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 - more);
                s->match_start -= wsize;
                s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
                s->block_start -= (long) wsize;
                slide_hash(s);
                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; \
    }

    /* Maximum stored block length in deflate format (not including header). */
    #define MAX_STORED 65535

    /* Minimum of a and b. */
    #define MIN(a, b) ((a) > (b) ? (b) : (a))

    /* ===========================================================================
     * Copy without compression as much as possible from the input stream, return
     * the current block state.
     *
     * In case deflateParams() is used to later switch to a non-zero compression
     * level, s->matches (otherwise unused when storing) keeps track of the number
     * of hash table slides to perform. If s->matches is 1, then one hash table
     * slide will be done when switching. If s->matches is 2, the maximum value
     * allowed here, then the hash table will be cleared, since two or more slides
     * is the same as a clear.
     *
     * deflate_stored() is written to minimize the number of times an input byte is
     * copied. It is most efficient with large input and output buffers, which
     * maximizes the opportunites to have a single copy from next_in to next_out.
     */
    local block_state deflate_stored(s, flush)
        deflate_state *s;
        int flush;
    {
        /* Smallest worthy block size when not flushing or finishing. By default
         * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
         * large input and output buffers, the stored block size will be larger.
         */
        unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);

        /* Copy as many min_block or larger stored blocks directly to next_out as
         * possible. If flushing, copy the remaining available input to next_out as
         * stored blocks, if there is enough space.
         */
        unsigned len, left, have, last = 0;
        unsigned used = s->strm->avail_in;
        do {
            /* Set len to the maximum size block that we can copy directly with the
             * available input data and output space. Set left to how much of that
             * would be copied from what's left in the window.
             */
            len = MAX_STORED;       /* maximum deflate stored block length */
            have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
            if (s->strm->avail_out < have)          /* need room for header */
                break;
                /* maximum stored block length that will fit in avail_out: */
            have = s->strm->avail_out - have;
            left = s->strstart - s->block_start;    /* bytes left in window */
            if (len > (ulg)left + s->strm->avail_in)
                len = left + s->strm->avail_in;     /* limit len to the input */
            if (len > have)
                len = have;                         /* limit len to the output */

            /* If the stored block would be less than min_block in length, or if
             * unable to copy all of the available input when flushing, then try
             * copying to the window and the pending buffer instead. Also don't
             * write an empty block when flushing -- deflate() does that.
             */
            if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
                                    flush == Z_NO_FLUSH ||
                                    len != left + s->strm->avail_in))
                break;

            /* Make a dummy stored block in pending to get the header bytes,
             * including any pending bits. This also updates the debugging counts.
             */
            last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
            _tr_stored_block(s, (char *)0, 0L, last);

            /* Replace the lengths in the dummy stored block with len. */
            s->pending_buf[s->pending - 4] = len;
            s->pending_buf[s->pending - 3] = len >> 8;
            s->pending_buf[s->pending - 2] = ~len;
            s->pending_buf[s->pending - 1] = ~len >> 8;

            /* Write the stored block header bytes. */
            flush_pending(s->strm);

    #ifdef ZLIB_DEBUG
            /* Update debugging counts for the data about to be copied. */
            s->compressed_len += len << 3;
            s->bits_sent += len << 3;
    #endif

            /* Copy uncompressed bytes from the window to next_out. */
            if (left) {
                if (left > len)
                    left = len;
                zmemcpy(s->strm->next_out, s->window + s->block_start, left);
                s->strm->next_out += left;
                s->strm->avail_out -= left;
                s->strm->total_out += left;
                s->block_start += left;
                len -= left;
            }

            /* Copy uncompressed bytes directly from next_in to next_out, updating
             * the check value.
             */
            if (len) {
                read_buf(s->strm, s->strm->next_out, len);
                s->strm->next_out += len;
                s->strm->avail_out -= len;
                s->strm->total_out += len;
            }
        } while (last == 0);

        /* Update the sliding window with the last s->w_size bytes of the copied
         * data, or append all of the copied data to the existing window if less
         * than s->w_size bytes were copied. Also update the number of bytes to
         * insert in the hash tables, in the event that deflateParams() switches to
         * a non-zero compression level.
         */
        used -= s->strm->avail_in;      /* number of input bytes directly copied */
        if (used) {
            /* If any input was used, then no unused input remains in the window,
             * therefore s->block_start == s->strstart.
             */
            if (used >= s->w_size) {    /* supplant the previous history */
                s->matches = 2;         /* clear hash */
                zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
                s->strstart = s->w_size;
            }
            else {
                if (s->window_size - s->strstart <= used) {
                    /* Slide the window down. */
                    s->strstart -= s->w_size;
                    zmemcpy(s->window, s->window + s->w_size, s->strstart);
                    if (s->matches < 2)
                        s->matches++;   /* add a pending slide_hash() */
                }
                zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
                s->strstart += used;
            }
            s->block_start = s->strstart;
            s->insert += MIN(used, s->w_size - s->insert);
        }
        if (s->high_water < s->strstart)
            s->high_water = s->strstart;

        /* If the last block was written to next_out, then done. */
        if (last)
            return finish_done;

        /* If flushing and all input has been consumed, then done. */
        if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
            s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
            return block_done;

        /* Fill the window with any remaining input. */
        have = s->window_size - s->strstart - 1;
        if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
            /* Slide the window down. */
            s->block_start -= s->w_size;
            s->strstart -= s->w_size;
            zmemcpy(s->window, s->window + s->w_size, s->strstart);
            if (s->matches < 2)
                s->matches++;           /* add a pending slide_hash() */
            have += s->w_size;          /* more space now */
        }
        if (have > s->strm->avail_in)
            have = s->strm->avail_in;
        if (have) {
            read_buf(s->strm, s->window + s->strstart, have);
            s->strstart += have;
        }
        if (s->high_water < s->strstart)
            s->high_water = s->strstart;

        /* There was not enough avail_out to write a complete worthy or flushed
         * stored block to next_out. Write a stored block to pending instead, if we
         * have enough input for a worthy block, or if flushing and there is enough
         * room for the remaining input as a stored block in the pending buffer.
         */
        have = (s->bi_valid + 42) >> 3;         /* number of header bytes */
            /* maximum stored block length that will fit in pending: */
        have = MIN(s->pending_buf_size - have, MAX_STORED);
        min_block = MIN(have, s->w_size);
        left = s->strstart - s->block_start;
        if (left >= min_block ||
            ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
             s->strm->avail_in == 0 && left <= have)) {
            len = MIN(left, have);
            last = flush == Z_FINISH && s->strm->avail_in == 0 &&
                   len == left ? 1 : 0;
            _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
            s->block_start += len;
            flush_pending(s->strm);
        }

        /* We've done all we can with the available input and output. */
        return last ? finish_started : need_more;
    }

    /* ===========================================================================
     * 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 - (uInt)(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;
    }