} else if (count <= 10) {            bl_tree[REPZ_3_10].Freq++;        } else {            bl_tree[REPZ_11_138].Freq++;        }        count = 0; prevlen = curlen;        if (nextlen == 0) {            max_count = 138, min_count = 3;        } else if (curlen == nextlen) {            max_count = 6, min_count = 3;        } else {            max_count = 7, min_count = 4;        }    }}/* =========================================================================== * Send a literal or distance tree in compressed form, using the codes in * bl_tree. */local void send_tree (tree, max_code)    ct_data near *tree; /* the tree to be scanned */    int max_code;       /* and its largest code of non zero frequency */{    int n;                     /* iterates over all tree elements */    int prevlen = -1;          /* last emitted length */    int curlen;                /* length of current code */    int nextlen = tree[0].Len; /* length of next code */    int count = 0;             /* repeat count of the current code */    int max_count = 7;         /* max repeat count */    int min_count = 4;         /* min repeat count */    /* tree[max_code+1].Len = -1; */  /* guard already set */    if (nextlen == 0) max_count = 138, min_count = 3;    for (n = 0; n <= max_code; n++) {        curlen = nextlen; nextlen = tree[n+1].Len;        if (++count < max_count && curlen == nextlen) {            continue;        } else if (count < min_count) {            do { send_code(curlen, bl_tree); } while (--count != 0);        } else if (curlen != 0) {            if (curlen != prevlen) {                send_code(curlen, bl_tree); count--;            }            Assert(count >= 3 && count <= 6, " 3_6?");            send_code(REP_3_6, bl_tree); send_bits(count-3, 2);        } else if (count <= 10) {            send_code(REPZ_3_10, bl_tree); send_bits(count-3, 3);        } else {            send_code(REPZ_11_138, bl_tree); send_bits(count-11, 7);        }        count = 0; prevlen = curlen;        if (nextlen == 0) {            max_count = 138, min_count = 3;        } else if (curlen == nextlen) {            max_count = 6, min_count = 3;        } else {            max_count = 7, min_count = 4;        }    }}/* =========================================================================== * Construct the Huffman tree for the bit lengths and return the index in * bl_order of the last bit length code to send. */local int build_bl_tree(){    int max_blindex;  /* index of last bit length code of non zero freq */    /* Determine the bit length frequencies for literal and distance trees */    scan_tree((ct_data near *)dyn_ltree, l_desc.max_code);    scan_tree((ct_data near *)dyn_dtree, d_desc.max_code);    /* Build the bit length tree: */    build_tree((tree_desc near *)(&bl_desc));    /* opt_len now includes the length of the tree representations, except     * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.     */    /* Determine the number of bit length codes to send. The pkzip format     * requires that at least 4 bit length codes be sent. (appnote.txt says     * 3 but the actual value used is 4.)     */    for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {        if (bl_tree[bl_order[max_blindex]].Len != 0) break;    }    /* Update opt_len to include the bit length tree and counts */    opt_len += 3*(max_blindex+1) + 5+5+4;    Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len, static_len));    return max_blindex;}/* =========================================================================== * Send the header for a block using dynamic Huffman trees: the counts, the * lengths of the bit length codes, the literal tree and the distance tree. * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. */local void send_all_trees(lcodes, dcodes, blcodes)    int lcodes, dcodes, blcodes; /* number of codes for each tree */{    int rank;                    /* index in bl_order */    Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");    Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,            "too many codes");    Tracev((stderr, "\nbl counts: "));    send_bits(lcodes-257, 5); /* not +255 as stated in appnote.txt */    send_bits(dcodes-1,   5);    send_bits(blcodes-4,  4); /* not -3 as stated in appnote.txt */    for (rank = 0; rank < blcodes; rank++) {        Tracev((stderr, "\nbl code %2d ", bl_order[rank]));        send_bits(bl_tree[bl_order[rank]].Len, 3);    }    Tracev((stderr, "\nbl tree: sent %ld", bits_sent));    send_tree((ct_data near *)dyn_ltree, lcodes-1); /* send the literal tree */    Tracev((stderr, "\nlit tree: sent %ld", bits_sent));    send_tree((ct_data near *)dyn_dtree, dcodes-1); /* send the distance tree */    Tracev((stderr, "\ndist tree: sent %ld", bits_sent));}/* =========================================================================== * Determine the best encoding for the current block: dynamic trees, static * trees or store, and output the encoded block to the zip file. This function * returns the total compressed length for the file so far. */ulg flush_block(buf, stored_len, eof)    char *buf;        /* input block, or NULL if too old */    ulg stored_len;   /* length of input block */    int eof;          /* true if this is the last block for a file */{    ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */    int max_blindex;  /* index of last bit length code of non zero freq */    flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */     /* Check if the file is ascii or binary */    if (*file_type == (ush)UNKNOWN) set_file_type();    /* Construct the literal and distance trees */    build_tree((tree_desc near *)(&l_desc));    Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len));    build_tree((tree_desc near *)(&d_desc));    Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len));    /* At this point, opt_len and static_len are the total bit lengths of     * the compressed block data, excluding the tree representations.     */    /* Build the bit length tree for the above two trees, and get the index     * in bl_order of the last bit length code to send.     */    max_blindex = build_bl_tree();    /* Determine the best encoding. Compute first the block length in bytes */    opt_lenb = (opt_len+3+7)>>3;    static_lenb = (static_len+3+7)>>3;    input_len += stored_len; /* for debugging only */    Trace((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ",            opt_lenb, opt_len, static_lenb, static_len, stored_len,            last_lit, last_dist));    if (static_lenb <= opt_lenb) opt_lenb = static_lenb;    /* If compression failed and this is the first and last block,     * and if the zip file can be seeked (to rewrite the local header),     * the whole file is transformed into a stored file:     */#ifdef FORCE_METHOD    if (level == 1 && eof && compressed_len == 0L) { /* force stored file */#else    if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) {#endif        /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */        if (buf == (char*)0) error ("block vanished");        copy_block(buf, (unsigned)stored_len, 0); /* without header */        compressed_len = stored_len << 3;        *file_method = STORED;#ifdef FORCE_METHOD    } else if (level == 2 && buf != (char*)0) { /* force stored block */#else    } else if (stored_len+4 <= opt_lenb && buf != (char*)0) {                       /* 4: two words for the lengths */#endif        /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.         * Otherwise we can't have processed more than WSIZE input bytes since         * the last block flush, because compression would have been         * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to         * transform a block into a stored block.         */        send_bits((STORED_BLOCK<<1)+eof, 3);  /* send block type */        compressed_len = (compressed_len + 3 + 7) & ~7L;        compressed_len += (stored_len + 4) << 3;        copy_block(buf, (unsigned)stored_len, 1); /* with header */#ifdef FORCE_METHOD    } else if (level == 3) { /* force static trees */#else    } else if (static_lenb == opt_lenb) {#endif        send_bits((STATIC_TREES<<1)+eof, 3);        compress_block((ct_data near *)static_ltree, (ct_data near *)static_dtree);        compressed_len += 3 + static_len;    } else {        send_bits((DYN_TREES<<1)+eof, 3);        send_all_trees(l_desc.max_code+1, d_desc.max_code+1, max_blindex+1);        compress_block((ct_data near *)dyn_ltree, (ct_data near *)dyn_dtree);        compressed_len += 3 + opt_len;    }    Assert (compressed_len == bits_sent, "bad compressed size");    init_block();    if (eof) {        Assert (input_len == isize, "bad input size");        bi_windup();        compressed_len += 7;  /* align on byte boundary */    }    Tracev((stderr,"\ncomprlen %lu(%lu) ", compressed_len>>3,           compressed_len-7*eof));    return compressed_len >> 3;}/* =========================================================================== * Save the match info and tally the frequency counts. Return true if * the current block must be flushed. */int ct_tally (dist, lc)    int dist;  /* distance of matched string */    int lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */{    l_buf[last_lit++] = (uch)lc;    if (dist == 0) {        /* lc is the unmatched char */        dyn_ltree[lc].Freq++;    } else {        /* Here, lc is the match length - MIN_MATCH */        dist--;             /* dist = match distance - 1 */        Assert((ush)dist < (ush)MAX_DIST &&               (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&               (ush)d_code(dist) < (ush)D_CODES,  "ct_tally: bad match");        dyn_ltree[length_code[lc]+LITERALS+1].Freq++;        dyn_dtree[d_code(dist)].Freq++;        d_buf[last_dist++] = (ush)dist;        flags |= flag_bit;    }    flag_bit <<= 1;    /* Output the flags if they fill a byte: */    if ((last_lit & 7) == 0) {        flag_buf[last_flags++] = flags;        flags = 0, flag_bit = 1;    }    /* Try to guess if it is profitable to stop the current block here */    if (level > 2 && (last_lit & 0xfff) == 0) {        /* Compute an upper bound for the compressed length */        ulg out_length = (ulg)last_lit*8L;        ulg in_length = (ulg)strstart-block_start;        int dcode;        for (dcode = 0; dcode < D_CODES; dcode++) {            out_length += (ulg)dyn_dtree[dcode].Freq*(5L+extra_dbits[dcode]);        }        out_length >>= 3;        Trace((stderr,"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ",               last_lit, last_dist, in_length, out_length,               100L - out_length*100L/in_length));        if (last_dist < last_lit/2 && out_length < in_length/2) return 1;    }    return (last_lit == LIT_BUFSIZE-1 || last_dist == DIST_BUFSIZE);    /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K     * on 16 bit machines and because stored blocks are restricted to     * 64K-1 bytes.     */}/* =========================================================================== * Send the block data compressed using the given Huffman trees */local void compress_block(ltree, dtree)    ct_data near *ltree; /* literal tree */    ct_data near *dtree; /* distance tree */{    unsigned dist;      /* distance of matched string */    int lc;             /* match length or unmatched char (if dist == 0) */    unsigned lx = 0;    /* running index in l_buf */    unsigned dx = 0;    /* running index in d_buf */    unsigned fx = 0;    /* running index in flag_buf */    uch flag = 0;       /* current flags */    unsigned code;      /* the code to send */    int extra;          /* number of extra bits to send */    if (last_lit != 0) do {        if ((lx & 7) == 0) flag = flag_buf[fx++];        lc = l_buf[lx++];        if ((flag & 1) == 0) {            send_code(lc, ltree); /* send a literal byte */            Tracecv(isgraph(lc), (stderr," '%c' ", lc));        } else {            /* Here, lc is the match length - MIN_MATCH */            code = length_code[lc];            send_code(code+LITERALS+1, ltree); /* send the length code */            extra = extra_lbits[code];            if (extra != 0) {                lc -= base_length[code];                send_bits(lc, extra);        /* send the extra length bits */            }            dist = d_buf[dx++];            /* Here, dist is the match distance - 1 */            code = d_code(dist);            Assert (code < D_CODES, "bad d_code");            send_code(code, dtree);       /* send the distance code */            extra = extra_dbits[code];            if (extra != 0) {                dist -= base_dist[code];                send_bits(dist, extra);   /* send the extra distance bits */            }        } /* literal or match pair ? */        flag >>= 1;    } while (lx < last_lit);    send_code(END_BLOCK, ltree);}/* =========================================================================== * Set the file type to ASCII or BINARY, using a crude approximation: * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. * IN assertion: the fields freq of dyn_ltree are set and the total of all * frequencies does not exceed 64K (to fit in an int on 16 bit machines). */local void set_file_type(){    int n = 0;    unsigned ascii_freq = 0;    unsigned bin_freq = 0;    while (n < 7)        bin_freq += dyn_ltree[n++].Freq;    while (n < 128)    ascii_freq += dyn_ltree[n++].Freq;    while (n < LITERALS) bin_freq += dyn_ltree[n++].Freq;    *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII;    if (*file_type == BINARY && translate_eol) {        warn("-l used on binary file", "");    }}