[mirror_edk2.git] / AppPkg / Applications / Python / Python-2.7.10 / Modules / zlib / trees.c

/* trees.c -- output deflated data using Huffman coding\r
 * Copyright (C) 1995-2012 Jean-loup Gailly\r
 * detect_data_type() function provided freely by Cosmin Truta, 2006\r
 * For conditions of distribution and use, see copyright notice in zlib.h\r
 */\r
\r
/*\r
 *  ALGORITHM\r
 *\r
 *      The "deflation" process uses several Huffman trees. The more\r
 *      common source values are represented by shorter bit sequences.\r
 *\r
 *      Each code tree is stored in a compressed form which is itself\r
 * a Huffman encoding of the lengths of all the code strings (in\r
 * ascending order by source values).  The actual code strings are\r
 * reconstructed from the lengths in the inflate process, as described\r
 * in the deflate specification.\r
 *\r
 *  REFERENCES\r
 *\r
 *      Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".\r
 *      Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc\r
 *\r
 *      Storer, James A.\r
 *          Data Compression:  Methods and Theory, pp. 49-50.\r
 *          Computer Science Press, 1988.  ISBN 0-7167-8156-5.\r
 *\r
 *      Sedgewick, R.\r
 *          Algorithms, p290.\r
 *          Addison-Wesley, 1983. ISBN 0-201-06672-6.\r
 */\r
\r
/* @(#) $Id$ */\r
\r
/* #define GEN_TREES_H */\r
\r
#include "deflate.h"\r
\r
#ifdef DEBUG\r
#  include <ctype.h>\r
#endif\r
\r
/* ===========================================================================\r
 * Constants\r
 */\r
\r
#define MAX_BL_BITS 7\r
/* Bit length codes must not exceed MAX_BL_BITS bits */\r
\r
#define END_BLOCK 256\r
/* end of block literal code */\r
\r
#define REP_3_6      16\r
/* repeat previous bit length 3-6 times (2 bits of repeat count) */\r
\r
#define REPZ_3_10    17\r
/* repeat a zero length 3-10 times  (3 bits of repeat count) */\r
\r
#define REPZ_11_138  18\r
/* repeat a zero length 11-138 times  (7 bits of repeat count) */\r
\r
local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */\r
   = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0};\r
\r
local const int extra_dbits[D_CODES] /* extra bits for each distance code */\r
   = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13};\r
\r
local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */\r
   = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};\r
\r
local const uch bl_order[BL_CODES]\r
   = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};\r
/* The lengths of the bit length codes are sent in order of decreasing\r
 * probability, to avoid transmitting the lengths for unused bit length codes.\r
 */\r
\r
/* ===========================================================================\r
 * Local data. These are initialized only once.\r
 */\r
\r
#define DIST_CODE_LEN  512 /* see definition of array dist_code below */\r
\r
#if defined(GEN_TREES_H) || !defined(STDC)\r
/* non ANSI compilers may not accept trees.h */\r
\r
local ct_data static_ltree[L_CODES+2];\r
/* The static literal tree. Since the bit lengths are imposed, there is no\r
 * need for the L_CODES extra codes used during heap construction. However\r
 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init\r
 * below).\r
 */\r
\r
local ct_data static_dtree[D_CODES];\r
/* The static distance tree. (Actually a trivial tree since all codes use\r
 * 5 bits.)\r
 */\r
\r
uch _dist_code[DIST_CODE_LEN];\r
/* Distance codes. The first 256 values correspond to the distances\r
 * 3 .. 258, the last 256 values correspond to the top 8 bits of\r
 * the 15 bit distances.\r
 */\r
\r
uch _length_code[MAX_MATCH-MIN_MATCH+1];\r
/* length code for each normalized match length (0 == MIN_MATCH) */\r
\r
local int base_length[LENGTH_CODES];\r
/* First normalized length for each code (0 = MIN_MATCH) */\r
\r
local int base_dist[D_CODES];\r
/* First normalized distance for each code (0 = distance of 1) */\r
\r
#else\r
#  include "trees.h"\r
#endif /* GEN_TREES_H */\r
\r
struct static_tree_desc_s {\r
    const ct_data *static_tree;  /* static tree or NULL */\r
    const intf *extra_bits;      /* extra bits for each code or NULL */\r
    int     extra_base;          /* base index for extra_bits */\r
    int     elems;               /* max number of elements in the tree */\r
    int     max_length;          /* max bit length for the codes */\r
};\r
\r
local static_tree_desc  static_l_desc =\r
{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};\r
\r
local static_tree_desc  static_d_desc =\r
{static_dtree, extra_dbits, 0,          D_CODES, MAX_BITS};\r
\r
local static_tree_desc  static_bl_desc =\r
{(const ct_data *)0, extra_blbits, 0,   BL_CODES, MAX_BL_BITS};\r
\r
/* ===========================================================================\r
 * Local (static) routines in this file.\r
 */\r
\r
local void tr_static_init OF((void));\r
local void init_block     OF((deflate_state *s));\r
local void pqdownheap     OF((deflate_state *s, ct_data *tree, int k));\r
local void gen_bitlen     OF((deflate_state *s, tree_desc *desc));\r
local void gen_codes      OF((ct_data *tree, int max_code, ushf *bl_count));\r
local void build_tree     OF((deflate_state *s, tree_desc *desc));\r
local void scan_tree      OF((deflate_state *s, ct_data *tree, int max_code));\r
local void send_tree      OF((deflate_state *s, ct_data *tree, int max_code));\r
local int  build_bl_tree  OF((deflate_state *s));\r
local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,\r
                              int blcodes));\r
local void compress_block OF((deflate_state *s, const ct_data *ltree,\r
                              const ct_data *dtree));\r
local int  detect_data_type OF((deflate_state *s));\r
local unsigned bi_reverse OF((unsigned value, int length));\r
local void bi_windup      OF((deflate_state *s));\r
local void bi_flush       OF((deflate_state *s));\r
local void copy_block     OF((deflate_state *s, charf *buf, unsigned len,\r
                              int header));\r
\r
#ifdef GEN_TREES_H\r
local void gen_trees_header OF((void));\r
#endif\r
\r
#ifndef DEBUG\r
#  define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)\r
   /* Send a code of the given tree. c and tree must not have side effects */\r
\r
#else /* DEBUG */\r
#  define send_code(s, c, tree) \\r
     { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \\r
       send_bits(s, tree[c].Code, tree[c].Len); }\r
#endif\r
\r
/* ===========================================================================\r
 * Output a short LSB first on the stream.\r
 * IN assertion: there is enough room in pendingBuf.\r
 */\r
#define put_short(s, w) { \\r
    put_byte(s, (uch)((w) & 0xff)); \\r
    put_byte(s, (uch)((ush)(w) >> 8)); \\r
}\r
\r
/* ===========================================================================\r
 * Send a value on a given number of bits.\r
 * IN assertion: length <= 16 and value fits in length bits.\r
 */\r
#ifdef DEBUG\r
local void send_bits      OF((deflate_state *s, int value, int length));\r
\r
local void send_bits(s, value, length)\r
    deflate_state *s;\r
    int value;  /* value to send */\r
    int length; /* number of bits */\r
{\r
    Tracevv((stderr," l %2d v %4x ", length, value));\r
    Assert(length > 0 && length <= 15, "invalid length");\r
    s->bits_sent += (ulg)length;\r
\r
    /* If not enough room in bi_buf, use (valid) bits from bi_buf and\r
     * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))\r
     * unused bits in value.\r
     */\r
    if (s->bi_valid > (int)Buf_size - length) {\r
        s->bi_buf |= (ush)value << s->bi_valid;\r
        put_short(s, s->bi_buf);\r
        s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);\r
        s->bi_valid += length - Buf_size;\r
    } else {\r
        s->bi_buf |= (ush)value << s->bi_valid;\r
        s->bi_valid += length;\r
    }\r
}\r
#else /* !DEBUG */\r
\r
#define send_bits(s, value, length) \\r
{ int len = length;\\r
  if (s->bi_valid > (int)Buf_size - len) {\\r
    int val = value;\\r
    s->bi_buf |= (ush)val << s->bi_valid;\\r
    put_short(s, s->bi_buf);\\r
    s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\\r
    s->bi_valid += len - Buf_size;\\r
  } else {\\r
    s->bi_buf |= (ush)(value) << s->bi_valid;\\r
    s->bi_valid += len;\\r
  }\\r
}\r
#endif /* DEBUG */\r
\r
\r
/* the arguments must not have side effects */\r
\r
/* ===========================================================================\r
 * Initialize the various 'constant' tables.\r
 */\r
local void tr_static_init()\r
{\r
#if defined(GEN_TREES_H) || !defined(STDC)\r
    static int static_init_done = 0;\r
    int n;        /* iterates over tree elements */\r
    int bits;     /* bit counter */\r
    int length;   /* length value */\r
    int code;     /* code value */\r
    int dist;     /* distance index */\r
    ush bl_count[MAX_BITS+1];\r
    /* number of codes at each bit length for an optimal tree */\r
\r
    if (static_init_done) return;\r
\r
    /* For some embedded targets, global variables are not initialized: */\r
#ifdef NO_INIT_GLOBAL_POINTERS\r
    static_l_desc.static_tree = static_ltree;\r
    static_l_desc.extra_bits = extra_lbits;\r
    static_d_desc.static_tree = static_dtree;\r
    static_d_desc.extra_bits = extra_dbits;\r
    static_bl_desc.extra_bits = extra_blbits;\r
#endif\r
\r
    /* Initialize the mapping length (0..255) -> length code (0..28) */\r
    length = 0;\r
    for (code = 0; code < LENGTH_CODES-1; code++) {\r
        base_length[code] = length;\r
        for (n = 0; n < (1<<extra_lbits[code]); n++) {\r
            _length_code[length++] = (uch)code;\r
        }\r
    }\r
    Assert (length == 256, "tr_static_init: length != 256");\r
    /* Note that the length 255 (match length 258) can be represented\r
     * in two different ways: code 284 + 5 bits or code 285, so we\r
     * overwrite length_code[255] to use the best encoding:\r
     */\r
    _length_code[length-1] = (uch)code;\r
\r
    /* Initialize the mapping dist (0..32K) -> dist code (0..29) */\r
    dist = 0;\r
    for (code = 0 ; code < 16; code++) {\r
        base_dist[code] = dist;\r
        for (n = 0; n < (1<<extra_dbits[code]); n++) {\r
            _dist_code[dist++] = (uch)code;\r
        }\r
    }\r
    Assert (dist == 256, "tr_static_init: dist != 256");\r
    dist >>= 7; /* from now on, all distances are divided by 128 */\r
    for ( ; code < D_CODES; code++) {\r
        base_dist[code] = dist << 7;\r
        for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {\r
            _dist_code[256 + dist++] = (uch)code;\r
        }\r
    }\r
    Assert (dist == 256, "tr_static_init: 256+dist != 512");\r
\r
    /* Construct the codes of the static literal tree */\r
    for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;\r
    n = 0;\r
    while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;\r
    while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;\r
    while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;\r
    while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;\r
    /* Codes 286 and 287 do not exist, but we must include them in the\r
     * tree construction to get a canonical Huffman tree (longest code\r
     * all ones)\r
     */\r
    gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);\r
\r
    /* The static distance tree is trivial: */\r
    for (n = 0; n < D_CODES; n++) {\r
        static_dtree[n].Len = 5;\r
        static_dtree[n].Code = bi_reverse((unsigned)n, 5);\r
    }\r
    static_init_done = 1;\r
\r
#  ifdef GEN_TREES_H\r
    gen_trees_header();\r
#  endif\r
#endif /* defined(GEN_TREES_H) || !defined(STDC) */\r
}\r
\r
/* ===========================================================================\r
 * Genererate the file trees.h describing the static trees.\r
 */\r
#ifdef GEN_TREES_H\r
#  ifndef DEBUG\r
#    include <stdio.h>\r
#  endif\r
\r
#  define SEPARATOR(i, last, width) \\r
      ((i) == (last)? "\n};\n\n" :    \\r
       ((i) % (width) == (width)-1 ? ",\n" : ", "))\r
\r
void gen_trees_header()\r
{\r
    FILE *header = fopen("trees.h", "w");\r
    int i;\r
\r
    Assert (header != NULL, "Can't open trees.h");\r
    fprintf(header,\r
            "/* header created automatically with -DGEN_TREES_H */\n\n");\r
\r
    fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");\r
    for (i = 0; i < L_CODES+2; i++) {\r
        fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,\r
                static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));\r
    }\r
\r
    fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");\r
    for (i = 0; i < D_CODES; i++) {\r
        fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,\r
                static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));\r
    }\r
\r
    fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");\r
    for (i = 0; i < DIST_CODE_LEN; i++) {\r
        fprintf(header, "%2u%s", _dist_code[i],\r
                SEPARATOR(i, DIST_CODE_LEN-1, 20));\r
    }\r
\r
    fprintf(header,\r
        "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");\r
    for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {\r
        fprintf(header, "%2u%s", _length_code[i],\r
                SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));\r
    }\r
\r
    fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");\r
    for (i = 0; i < LENGTH_CODES; i++) {\r
        fprintf(header, "%1u%s", base_length[i],\r
                SEPARATOR(i, LENGTH_CODES-1, 20));\r
    }\r
\r
    fprintf(header, "local const int base_dist[D_CODES] = {\n");\r
    for (i = 0; i < D_CODES; i++) {\r
        fprintf(header, "%5u%s", base_dist[i],\r
                SEPARATOR(i, D_CODES-1, 10));\r
    }\r
\r
    fclose(header);\r
}\r
#endif /* GEN_TREES_H */\r
\r
/* ===========================================================================\r
 * Initialize the tree data structures for a new zlib stream.\r
 */\r
void ZLIB_INTERNAL _tr_init(s)\r
    deflate_state *s;\r
{\r
    tr_static_init();\r
\r
    s->l_desc.dyn_tree = s->dyn_ltree;\r
    s->l_desc.stat_desc = &static_l_desc;\r
\r
    s->d_desc.dyn_tree = s->dyn_dtree;\r
    s->d_desc.stat_desc = &static_d_desc;\r
\r
    s->bl_desc.dyn_tree = s->bl_tree;\r
    s->bl_desc.stat_desc = &static_bl_desc;\r
\r
    s->bi_buf = 0;\r
    s->bi_valid = 0;\r
#ifdef DEBUG\r
    s->compressed_len = 0L;\r
    s->bits_sent = 0L;\r
#endif\r
\r
    /* Initialize the first block of the first file: */\r
    init_block(s);\r
}\r
\r
/* ===========================================================================\r
 * Initialize a new block.\r
 */\r
local void init_block(s)\r
    deflate_state *s;\r
{\r
    int n; /* iterates over tree elements */\r
\r
    /* Initialize the trees. */\r
    for (n = 0; n < L_CODES;  n++) s->dyn_ltree[n].Freq = 0;\r
    for (n = 0; n < D_CODES;  n++) s->dyn_dtree[n].Freq = 0;\r
    for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;\r
\r
    s->dyn_ltree[END_BLOCK].Freq = 1;\r
    s->opt_len = s->static_len = 0L;\r
    s->last_lit = s->matches = 0;\r
}\r
\r
#define SMALLEST 1\r
/* Index within the heap array of least frequent node in the Huffman tree */\r
\r
\r
/* ===========================================================================\r
 * Remove the smallest element from the heap and recreate the heap with\r
 * one less element. Updates heap and heap_len.\r
 */\r
#define pqremove(s, tree, top) \\r
{\\r
    top = s->heap[SMALLEST]; \\r
    s->heap[SMALLEST] = s->heap[s->heap_len--]; \\r
    pqdownheap(s, tree, SMALLEST); \\r
}\r
\r
/* ===========================================================================\r
 * Compares to subtrees, using the tree depth as tie breaker when\r
 * the subtrees have equal frequency. This minimizes the worst case length.\r
 */\r
#define smaller(tree, n, m, depth) \\r
   (tree[n].Freq < tree[m].Freq || \\r
   (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))\r
\r
/* ===========================================================================\r
 * Restore the heap property by moving down the tree starting at node k,\r
 * exchanging a node with the smallest of its two sons if necessary, stopping\r
 * when the heap property is re-established (each father smaller than its\r
 * two sons).\r
 */\r
local void pqdownheap(s, tree, k)\r
    deflate_state *s;\r
    ct_data *tree;  /* the tree to restore */\r
    int k;               /* node to move down */\r
{\r
    int v = s->heap[k];\r
    int j = k << 1;  /* left son of k */\r
    while (j <= s->heap_len) {\r
        /* Set j to the smallest of the two sons: */\r
        if (j < s->heap_len &&\r
            smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {\r
            j++;\r
        }\r
        /* Exit if v is smaller than both sons */\r
        if (smaller(tree, v, s->heap[j], s->depth)) break;\r
\r
        /* Exchange v with the smallest son */\r
        s->heap[k] = s->heap[j];  k = j;\r
\r
        /* And continue down the tree, setting j to the left son of k */\r
        j <<= 1;\r
    }\r
    s->heap[k] = v;\r
}\r
\r
/* ===========================================================================\r
 * Compute the optimal bit lengths for a tree and update the total bit length\r
 * for the current block.\r
 * IN assertion: the fields freq and dad are set, heap[heap_max] and\r
 *    above are the tree nodes sorted by increasing frequency.\r
 * OUT assertions: the field len is set to the optimal bit length, the\r
 *     array bl_count contains the frequencies for each bit length.\r
 *     The length opt_len is updated; static_len is also updated if stree is\r
 *     not null.\r
 */\r
local void gen_bitlen(s, desc)\r
    deflate_state *s;\r
    tree_desc *desc;    /* the tree descriptor */\r
{\r
    ct_data *tree        = desc->dyn_tree;\r
    int max_code         = desc->max_code;\r
    const ct_data *stree = desc->stat_desc->static_tree;\r
    const intf *extra    = desc->stat_desc->extra_bits;\r
    int base             = desc->stat_desc->extra_base;\r
    int max_length       = desc->stat_desc->max_length;\r
    int h;              /* heap index */\r
    int n, m;           /* iterate over the tree elements */\r
    int bits;           /* bit length */\r
    int xbits;          /* extra bits */\r
    ush f;              /* frequency */\r
    int overflow = 0;   /* number of elements with bit length too large */\r
\r
    for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;\r
\r
    /* In a first pass, compute the optimal bit lengths (which may\r
     * overflow in the case of the bit length tree).\r
     */\r
    tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */\r
\r
    for (h = s->heap_max+1; h < HEAP_SIZE; h++) {\r
        n = s->heap[h];\r
        bits = tree[tree[n].Dad].Len + 1;\r
        if (bits > max_length) bits = max_length, overflow++;\r
        tree[n].Len = (ush)bits;\r
        /* We overwrite tree[n].Dad which is no longer needed */\r
\r
        if (n > max_code) continue; /* not a leaf node */\r
\r
        s->bl_count[bits]++;\r
        xbits = 0;\r
        if (n >= base) xbits = extra[n-base];\r
        f = tree[n].Freq;\r
        s->opt_len += (ulg)f * (bits + xbits);\r
        if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);\r
    }\r
    if (overflow == 0) return;\r
\r
    Trace((stderr,"\nbit length overflow\n"));\r
    /* This happens for example on obj2 and pic of the Calgary corpus */\r
\r
    /* Find the first bit length which could increase: */\r
    do {\r
        bits = max_length-1;\r
        while (s->bl_count[bits] == 0) bits--;\r
        s->bl_count[bits]--;      /* move one leaf down the tree */\r
        s->bl_count[bits+1] += 2; /* move one overflow item as its brother */\r
        s->bl_count[max_length]--;\r
        /* The brother of the overflow item also moves one step up,\r
         * but this does not affect bl_count[max_length]\r
         */\r
        overflow -= 2;\r
    } while (overflow > 0);\r
\r
    /* Now recompute all bit lengths, scanning in increasing frequency.\r
     * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all\r
     * lengths instead of fixing only the wrong ones. This idea is taken\r
     * from 'ar' written by Haruhiko Okumura.)\r
     */\r
    for (bits = max_length; bits != 0; bits--) {\r
        n = s->bl_count[bits];\r
        while (n != 0) {\r
            m = s->heap[--h];\r
            if (m > max_code) continue;\r
            if ((unsigned) tree[m].Len != (unsigned) bits) {\r
                Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));\r
                s->opt_len += ((long)bits - (long)tree[m].Len)\r
                              *(long)tree[m].Freq;\r
                tree[m].Len = (ush)bits;\r
            }\r
            n--;\r
        }\r
    }\r
}\r
\r
/* ===========================================================================\r
 * Generate the codes for a given tree and bit counts (which need not be\r
 * optimal).\r
 * IN assertion: the array bl_count contains the bit length statistics for\r
 * the given tree and the field len is set for all tree elements.\r
 * OUT assertion: the field code is set for all tree elements of non\r
 *     zero code length.\r
 */\r
local void gen_codes (tree, max_code, bl_count)\r
    ct_data *tree;             /* the tree to decorate */\r
    int max_code;              /* largest code with non zero frequency */\r
    ushf *bl_count;            /* number of codes at each bit length */\r
{\r
    ush next_code[MAX_BITS+1]; /* next code value for each bit length */\r
    ush code = 0;              /* running code value */\r
    int bits;                  /* bit index */\r
    int n;                     /* code index */\r
\r
    /* The distribution counts are first used to generate the code values\r
     * without bit reversal.\r
     */\r
    for (bits = 1; bits <= MAX_BITS; bits++) {\r
        next_code[bits] = code = (code + bl_count[bits-1]) << 1;\r
    }\r
    /* Check that the bit counts in bl_count are consistent. The last code\r
     * must be all ones.\r
     */\r
    Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,\r
            "inconsistent bit counts");\r
    Tracev((stderr,"\ngen_codes: max_code %d ", max_code));\r
\r
    for (n = 0;  n <= max_code; n++) {\r
        int len = tree[n].Len;\r
        if (len == 0) continue;\r
        /* Now reverse the bits */\r
        tree[n].Code = bi_reverse(next_code[len]++, len);\r
\r
        Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",\r
             n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));\r
    }\r
}\r
\r
/* ===========================================================================\r
 * Construct one Huffman tree and assigns the code bit strings and lengths.\r
 * Update the total bit length for the current block.\r
 * IN assertion: the field freq is set for all tree elements.\r
 * OUT assertions: the fields len and code are set to the optimal bit length\r
 *     and corresponding code. The length opt_len is updated; static_len is\r
 *     also updated if stree is not null. The field max_code is set.\r
 */\r
local void build_tree(s, desc)\r
    deflate_state *s;\r
    tree_desc *desc; /* the tree descriptor */\r
{\r
    ct_data *tree         = desc->dyn_tree;\r
    const ct_data *stree  = desc->stat_desc->static_tree;\r
    int elems             = desc->stat_desc->elems;\r
    int n, m;          /* iterate over heap elements */\r
    int max_code = -1; /* largest code with non zero frequency */\r
    int node;          /* new node being created */\r
\r
    /* Construct the initial heap, with least frequent element in\r
     * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].\r
     * heap[0] is not used.\r
     */\r
    s->heap_len = 0, s->heap_max = HEAP_SIZE;\r
\r
    for (n = 0; n < elems; n++) {\r
        if (tree[n].Freq != 0) {\r
            s->heap[++(s->heap_len)] = max_code = n;\r
            s->depth[n] = 0;\r
        } else {\r
            tree[n].Len = 0;\r
        }\r
    }\r
\r
    /* The pkzip format requires that at least one distance code exists,\r
     * and that at least one bit should be sent even if there is only one\r
     * possible code. So to avoid special checks later on we force at least\r
     * two codes of non zero frequency.\r
     */\r
    while (s->heap_len < 2) {\r
        node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);\r
        tree[node].Freq = 1;\r
        s->depth[node] = 0;\r
        s->opt_len--; if (stree) s->static_len -= stree[node].Len;\r
        /* node is 0 or 1 so it does not have extra bits */\r
    }\r
    desc->max_code = max_code;\r
\r
    /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,\r
     * establish sub-heaps of increasing lengths:\r
     */\r
    for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);\r
\r
    /* Construct the Huffman tree by repeatedly combining the least two\r
     * frequent nodes.\r
     */\r
    node = elems;              /* next internal node of the tree */\r
    do {\r
        pqremove(s, tree, n);  /* n = node of least frequency */\r
        m = s->heap[SMALLEST]; /* m = node of next least frequency */\r
\r
        s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */\r
        s->heap[--(s->heap_max)] = m;\r
\r
        /* Create a new node father of n and m */\r
        tree[node].Freq = tree[n].Freq + tree[m].Freq;\r
        s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?\r
                                s->depth[n] : s->depth[m]) + 1);\r
        tree[n].Dad = tree[m].Dad = (ush)node;\r
#ifdef DUMP_BL_TREE\r
        if (tree == s->bl_tree) {\r
            fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",\r
                    node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);\r
        }\r
#endif\r
        /* and insert the new node in the heap */\r
        s->heap[SMALLEST] = node++;\r
        pqdownheap(s, tree, SMALLEST);\r
\r
    } while (s->heap_len >= 2);\r
\r
    s->heap[--(s->heap_max)] = s->heap[SMALLEST];\r
\r
    /* At this point, the fields freq and dad are set. We can now\r
     * generate the bit lengths.\r
     */\r
    gen_bitlen(s, (tree_desc *)desc);\r
\r
    /* The field len is now set, we can generate the bit codes */\r
    gen_codes ((ct_data *)tree, max_code, s->bl_count);\r
}\r
\r
/* ===========================================================================\r
 * Scan a literal or distance tree to determine the frequencies of the codes\r
 * in the bit length tree.\r
 */\r
local void scan_tree (s, tree, max_code)\r
    deflate_state *s;\r
    ct_data *tree;   /* the tree to be scanned */\r
    int max_code;    /* and its largest code of non zero frequency */\r
{\r
    int n;                     /* iterates over all tree elements */\r
    int prevlen = -1;          /* last emitted length */\r
    int curlen;                /* length of current code */\r
    int nextlen = tree[0].Len; /* length of next code */\r
    int count = 0;             /* repeat count of the current code */\r
    int max_count = 7;         /* max repeat count */\r
    int min_count = 4;         /* min repeat count */\r
\r
    if (nextlen == 0) max_count = 138, min_count = 3;\r
    tree[max_code+1].Len = (ush)0xffff; /* guard */\r
\r
    for (n = 0; n <= max_code; n++) {\r
        curlen = nextlen; nextlen = tree[n+1].Len;\r
        if (++count < max_count && curlen == nextlen) {\r
            continue;\r
        } else if (count < min_count) {\r
            s->bl_tree[curlen].Freq += count;\r
        } else if (curlen != 0) {\r
            if (curlen != prevlen) s->bl_tree[curlen].Freq++;\r
            s->bl_tree[REP_3_6].Freq++;\r
        } else if (count <= 10) {\r
            s->bl_tree[REPZ_3_10].Freq++;\r
        } else {\r
            s->bl_tree[REPZ_11_138].Freq++;\r
        }\r
        count = 0; prevlen = curlen;\r
        if (nextlen == 0) {\r
            max_count = 138, min_count = 3;\r
        } else if (curlen == nextlen) {\r
            max_count = 6, min_count = 3;\r
        } else {\r
            max_count = 7, min_count = 4;\r
        }\r
    }\r
}\r
\r
/* ===========================================================================\r
 * Send a literal or distance tree in compressed form, using the codes in\r
 * bl_tree.\r
 */\r
local void send_tree (s, tree, max_code)\r
    deflate_state *s;\r
    ct_data *tree; /* the tree to be scanned */\r
    int max_code;       /* and its largest code of non zero frequency */\r
{\r
    int n;                     /* iterates over all tree elements */\r
    int prevlen = -1;          /* last emitted length */\r
    int curlen;                /* length of current code */\r
    int nextlen = tree[0].Len; /* length of next code */\r
    int count = 0;             /* repeat count of the current code */\r
    int max_count = 7;         /* max repeat count */\r
    int min_count = 4;         /* min repeat count */\r
\r
    /* tree[max_code+1].Len = -1; */  /* guard already set */\r
    if (nextlen == 0) max_count = 138, min_count = 3;\r
\r
    for (n = 0; n <= max_code; n++) {\r
        curlen = nextlen; nextlen = tree[n+1].Len;\r
        if (++count < max_count && curlen == nextlen) {\r
            continue;\r
        } else if (count < min_count) {\r
            do { send_code(s, curlen, s->bl_tree); } while (--count != 0);\r
\r
        } else if (curlen != 0) {\r
            if (curlen != prevlen) {\r
                send_code(s, curlen, s->bl_tree); count--;\r
            }\r
            Assert(count >= 3 && count <= 6, " 3_6?");\r
            send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);\r
\r
        } else if (count <= 10) {\r
            send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);\r
\r
        } else {\r
            send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);\r
        }\r
        count = 0; prevlen = curlen;\r
        if (nextlen == 0) {\r
            max_count = 138, min_count = 3;\r
        } else if (curlen == nextlen) {\r
            max_count = 6, min_count = 3;\r
        } else {\r
            max_count = 7, min_count = 4;\r
        }\r
    }\r
}\r
\r
/* ===========================================================================\r
 * Construct the Huffman tree for the bit lengths and return the index in\r
 * bl_order of the last bit length code to send.\r
 */\r
local int build_bl_tree(s)\r
    deflate_state *s;\r
{\r
    int max_blindex;  /* index of last bit length code of non zero freq */\r
\r
    /* Determine the bit length frequencies for literal and distance trees */\r
    scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);\r
    scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);\r
\r
    /* Build the bit length tree: */\r
    build_tree(s, (tree_desc *)(&(s->bl_desc)));\r
    /* opt_len now includes the length of the tree representations, except\r
     * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.\r
     */\r
\r
    /* Determine the number of bit length codes to send. The pkzip format\r
     * requires that at least 4 bit length codes be sent. (appnote.txt says\r
     * 3 but the actual value used is 4.)\r
     */\r
    for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {\r
        if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;\r
    }\r
    /* Update opt_len to include the bit length tree and counts */\r
    s->opt_len += 3*(max_blindex+1) + 5+5+4;\r
    Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",\r
            s->opt_len, s->static_len));\r
\r
    return max_blindex;\r
}\r
\r
/* ===========================================================================\r
 * Send the header for a block using dynamic Huffman trees: the counts, the\r
 * lengths of the bit length codes, the literal tree and the distance tree.\r
 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.\r
 */\r
local void send_all_trees(s, lcodes, dcodes, blcodes)\r
    deflate_state *s;\r
    int lcodes, dcodes, blcodes; /* number of codes for each tree */\r
{\r
    int rank;                    /* index in bl_order */\r
\r
    Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");\r
    Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,\r
            "too many codes");\r
    Tracev((stderr, "\nbl counts: "));\r
    send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */\r
    send_bits(s, dcodes-1,   5);\r
    send_bits(s, blcodes-4,  4); /* not -3 as stated in appnote.txt */\r
    for (rank = 0; rank < blcodes; rank++) {\r
        Tracev((stderr, "\nbl code %2d ", bl_order[rank]));\r
        send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);\r
    }\r
    Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));\r
\r
    send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */\r
    Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));\r
\r
    send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */\r
    Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));\r
}\r
\r
/* ===========================================================================\r
 * Send a stored block\r
 */\r
void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)\r
    deflate_state *s;\r
    charf *buf;       /* input block */\r
    ulg stored_len;   /* length of input block */\r
    int last;         /* one if this is the last block for a file */\r
{\r
    send_bits(s, (STORED_BLOCK<<1)+last, 3);    /* send block type */\r
#ifdef DEBUG\r
    s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;\r
    s->compressed_len += (stored_len + 4) << 3;\r
#endif\r
    copy_block(s, buf, (unsigned)stored_len, 1); /* with header */\r
}\r
\r
/* ===========================================================================\r
 * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)\r
 */\r
void ZLIB_INTERNAL _tr_flush_bits(s)\r
    deflate_state *s;\r
{\r
    bi_flush(s);\r
}\r
\r
/* ===========================================================================\r
 * Send one empty static block to give enough lookahead for inflate.\r
 * This takes 10 bits, of which 7 may remain in the bit buffer.\r
 */\r
void ZLIB_INTERNAL _tr_align(s)\r
    deflate_state *s;\r
{\r
    send_bits(s, STATIC_TREES<<1, 3);\r
    send_code(s, END_BLOCK, static_ltree);\r
#ifdef DEBUG\r
    s->compressed_len += 10L; /* 3 for block type, 7 for EOB */\r
#endif\r
    bi_flush(s);\r
}\r
\r
/* ===========================================================================\r
 * Determine the best encoding for the current block: dynamic trees, static\r
 * trees or store, and output the encoded block to the zip file.\r
 */\r
void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)\r
    deflate_state *s;\r
    charf *buf;       /* input block, or NULL if too old */\r
    ulg stored_len;   /* length of input block */\r
    int last;         /* one if this is the last block for a file */\r
{\r
    ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */\r
    int max_blindex = 0;  /* index of last bit length code of non zero freq */\r
\r
    /* Build the Huffman trees unless a stored block is forced */\r
    if (s->level > 0) {\r
\r
        /* Check if the file is binary or text */\r
        if (s->strm->data_type == Z_UNKNOWN)\r
            s->strm->data_type = detect_data_type(s);\r
\r
        /* Construct the literal and distance trees */\r
        build_tree(s, (tree_desc *)(&(s->l_desc)));\r
        Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,\r
                s->static_len));\r
\r
        build_tree(s, (tree_desc *)(&(s->d_desc)));\r
        Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,\r
                s->static_len));\r
        /* At this point, opt_len and static_len are the total bit lengths of\r
         * the compressed block data, excluding the tree representations.\r
         */\r
\r
        /* Build the bit length tree for the above two trees, and get the index\r
         * in bl_order of the last bit length code to send.\r
         */\r
        max_blindex = build_bl_tree(s);\r
\r
        /* Determine the best encoding. Compute the block lengths in bytes. */\r
        opt_lenb = (s->opt_len+3+7)>>3;\r
        static_lenb = (s->static_len+3+7)>>3;\r
\r
        Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",\r
                opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,\r
                s->last_lit));\r
\r
        if (static_lenb <= opt_lenb) opt_lenb = static_lenb;\r
\r
    } else {\r
        Assert(buf != (char*)0, "lost buf");\r
        opt_lenb = static_lenb = stored_len + 5; /* force a stored block */\r
    }\r
\r
#ifdef FORCE_STORED\r
    if (buf != (char*)0) { /* force stored block */\r
#else\r
    if (stored_len+4 <= opt_lenb && buf != (char*)0) {\r
                       /* 4: two words for the lengths */\r
#endif\r
        /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.\r
         * Otherwise we can't have processed more than WSIZE input bytes since\r
         * the last block flush, because compression would have been\r
         * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to\r
         * transform a block into a stored block.\r
         */\r
        _tr_stored_block(s, buf, stored_len, last);\r
\r
#ifdef FORCE_STATIC\r
    } else if (static_lenb >= 0) { /* force static trees */\r
#else\r
    } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {\r
#endif\r
        send_bits(s, (STATIC_TREES<<1)+last, 3);\r
        compress_block(s, (const ct_data *)static_ltree,\r
                       (const ct_data *)static_dtree);\r
#ifdef DEBUG\r
        s->compressed_len += 3 + s->static_len;\r
#endif\r
    } else {\r
        send_bits(s, (DYN_TREES<<1)+last, 3);\r
        send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,\r
                       max_blindex+1);\r
        compress_block(s, (const ct_data *)s->dyn_ltree,\r
                       (const ct_data *)s->dyn_dtree);\r
#ifdef DEBUG\r
        s->compressed_len += 3 + s->opt_len;\r
#endif\r
    }\r
    Assert (s->compressed_len == s->bits_sent, "bad compressed size");\r
    /* The above check is made mod 2^32, for files larger than 512 MB\r
     * and uLong implemented on 32 bits.\r
     */\r
    init_block(s);\r
\r
    if (last) {\r
        bi_windup(s);\r
#ifdef DEBUG\r
        s->compressed_len += 7;  /* align on byte boundary */\r
#endif\r
    }\r
    Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,\r
           s->compressed_len-7*last));\r
}\r
\r
/* ===========================================================================\r
 * Save the match info and tally the frequency counts. Return true if\r
 * the current block must be flushed.\r
 */\r
int ZLIB_INTERNAL _tr_tally (s, dist, lc)\r
    deflate_state *s;\r
    unsigned dist;  /* distance of matched string */\r
    unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */\r
{\r
    s->d_buf[s->last_lit] = (ush)dist;\r
    s->l_buf[s->last_lit++] = (uch)lc;\r
    if (dist == 0) {\r
        /* lc is the unmatched char */\r
        s->dyn_ltree[lc].Freq++;\r
    } else {\r
        s->matches++;\r
        /* Here, lc is the match length - MIN_MATCH */\r
        dist--;             /* dist = match distance - 1 */\r
        Assert((ush)dist < (ush)MAX_DIST(s) &&\r
               (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&\r
               (ush)d_code(dist) < (ush)D_CODES,  "_tr_tally: bad match");\r
\r
        s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;\r
        s->dyn_dtree[d_code(dist)].Freq++;\r
    }\r
\r
#ifdef TRUNCATE_BLOCK\r
    /* Try to guess if it is profitable to stop the current block here */\r
    if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {\r
        /* Compute an upper bound for the compressed length */\r
        ulg out_length = (ulg)s->last_lit*8L;\r
        ulg in_length = (ulg)((long)s->strstart - s->block_start);\r
        int dcode;\r
        for (dcode = 0; dcode < D_CODES; dcode++) {\r
            out_length += (ulg)s->dyn_dtree[dcode].Freq *\r
                (5L+extra_dbits[dcode]);\r
        }\r
        out_length >>= 3;\r
        Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",\r
               s->last_lit, in_length, out_length,\r
               100L - out_length*100L/in_length));\r
        if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;\r
    }\r
#endif\r
    return (s->last_lit == s->lit_bufsize-1);\r
    /* We avoid equality with lit_bufsize because of wraparound at 64K\r
     * on 16 bit machines and because stored blocks are restricted to\r
     * 64K-1 bytes.\r
     */\r
}\r
\r
/* ===========================================================================\r
 * Send the block data compressed using the given Huffman trees\r
 */\r
local void compress_block(s, ltree, dtree)\r
    deflate_state *s;\r
    const ct_data *ltree; /* literal tree */\r
    const ct_data *dtree; /* distance tree */\r
{\r
    unsigned dist;      /* distance of matched string */\r
    int lc;             /* match length or unmatched char (if dist == 0) */\r
    unsigned lx = 0;    /* running index in l_buf */\r
    unsigned code;      /* the code to send */\r
    int extra;          /* number of extra bits to send */\r
\r
    if (s->last_lit != 0) do {\r
        dist = s->d_buf[lx];\r
        lc = s->l_buf[lx++];\r
        if (dist == 0) {\r
            send_code(s, lc, ltree); /* send a literal byte */\r
            Tracecv(isgraph(lc), (stderr," '%c' ", lc));\r
        } else {\r
            /* Here, lc is the match length - MIN_MATCH */\r
            code = _length_code[lc];\r
            send_code(s, code+LITERALS+1, ltree); /* send the length code */\r
            extra = extra_lbits[code];\r
            if (extra != 0) {\r
                lc -= base_length[code];\r
                send_bits(s, lc, extra);       /* send the extra length bits */\r
            }\r
            dist--; /* dist is now the match distance - 1 */\r
            code = d_code(dist);\r
            Assert (code < D_CODES, "bad d_code");\r
\r
            send_code(s, code, dtree);       /* send the distance code */\r
            extra = extra_dbits[code];\r
            if (extra != 0) {\r
                dist -= base_dist[code];\r
                send_bits(s, dist, extra);   /* send the extra distance bits */\r
            }\r
        } /* literal or match pair ? */\r
\r
        /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */\r
        Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,\r
               "pendingBuf overflow");\r
\r
    } while (lx < s->last_lit);\r
\r
    send_code(s, END_BLOCK, ltree);\r
}\r
\r
/* ===========================================================================\r
 * Check if the data type is TEXT or BINARY, using the following algorithm:\r
 * - TEXT if the two conditions below are satisfied:\r
 *    a) There are no non-portable control characters belonging to the\r
 *       "black list" (0..6, 14..25, 28..31).\r
 *    b) There is at least one printable character belonging to the\r
 *       "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).\r
 * - BINARY otherwise.\r
 * - The following partially-portable control characters form a\r
 *   "gray list" that is ignored in this detection algorithm:\r
 *   (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).\r
 * IN assertion: the fields Freq of dyn_ltree are set.\r
 */\r
local int detect_data_type(s)\r
    deflate_state *s;\r
{\r
    /* black_mask is the bit mask of black-listed bytes\r
     * set bits 0..6, 14..25, and 28..31\r
     * 0xf3ffc07f = binary 11110011111111111100000001111111\r
     */\r
    unsigned long black_mask = 0xf3ffc07fUL;\r
    int n;\r
\r
    /* Check for non-textual ("black-listed") bytes. */\r
    for (n = 0; n <= 31; n++, black_mask >>= 1)\r
        if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))\r
            return Z_BINARY;\r
\r
    /* Check for textual ("white-listed") bytes. */\r
    if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0\r
            || s->dyn_ltree[13].Freq != 0)\r
        return Z_TEXT;\r
    for (n = 32; n < LITERALS; n++)\r
        if (s->dyn_ltree[n].Freq != 0)\r
            return Z_TEXT;\r
\r
    /* There are no "black-listed" or "white-listed" bytes:\r
     * this stream either is empty or has tolerated ("gray-listed") bytes only.\r
     */\r
    return Z_BINARY;\r
}\r
\r
/* ===========================================================================\r
 * Reverse the first len bits of a code, using straightforward code (a faster\r
 * method would use a table)\r
 * IN assertion: 1 <= len <= 15\r
 */\r
local unsigned bi_reverse(code, len)\r
    unsigned code; /* the value to invert */\r
    int len;       /* its bit length */\r
{\r
    register unsigned res = 0;\r
    do {\r
        res |= code & 1;\r
        code >>= 1, res <<= 1;\r
    } while (--len > 0);\r
    return res >> 1;\r
}\r
\r
/* ===========================================================================\r
 * Flush the bit buffer, keeping at most 7 bits in it.\r
 */\r
local void bi_flush(s)\r
    deflate_state *s;\r
{\r
    if (s->bi_valid == 16) {\r
        put_short(s, s->bi_buf);\r
        s->bi_buf = 0;\r
        s->bi_valid = 0;\r
    } else if (s->bi_valid >= 8) {\r
        put_byte(s, (Byte)s->bi_buf);\r
        s->bi_buf >>= 8;\r
        s->bi_valid -= 8;\r
    }\r
}\r
\r
/* ===========================================================================\r
 * Flush the bit buffer and align the output on a byte boundary\r
 */\r
local void bi_windup(s)\r
    deflate_state *s;\r
{\r
    if (s->bi_valid > 8) {\r
        put_short(s, s->bi_buf);\r
    } else if (s->bi_valid > 0) {\r
        put_byte(s, (Byte)s->bi_buf);\r
    }\r
    s->bi_buf = 0;\r
    s->bi_valid = 0;\r
#ifdef DEBUG\r
    s->bits_sent = (s->bits_sent+7) & ~7;\r
#endif\r
}\r
\r
/* ===========================================================================\r
 * Copy a stored block, storing first the length and its\r
 * one's complement if requested.\r
 */\r
local void copy_block(s, buf, len, header)\r
    deflate_state *s;\r
    charf    *buf;    /* the input data */\r
    unsigned len;     /* its length */\r
    int      header;  /* true if block header must be written */\r
{\r
    bi_windup(s);        /* align on byte boundary */\r
\r
    if (header) {\r
        put_short(s, (ush)len);\r
        put_short(s, (ush)~len);\r
#ifdef DEBUG\r
        s->bits_sent += 2*16;\r
#endif\r
    }\r
#ifdef DEBUG\r
    s->bits_sent += (ulg)len<<3;\r
#endif\r
    while (len--) {\r
        put_byte(s, *buf++);\r
    }\r
}\r