'use strict';

var trees = require('../../../../_virtual/trees.js');
var common = require('../utils/common.js');

var hasRequiredTrees;

function requireTrees () {
	if (hasRequiredTrees) return trees.__exports;
	hasRequiredTrees = 1;

	// (C) 1995-2013 Jean-loup Gailly and Mark Adler
	// (C) 2014-2017 Vitaly Puzrin and Andrey Tupitsin
	//
	// This software is provided 'as-is', without any express or implied
	// warranty. In no event will the authors be held liable for any damages
	// arising from the use of this software.
	//
	// Permission is granted to anyone to use this software for any purpose,
	// including commercial applications, and to alter it and redistribute it
	// freely, subject to the following restrictions:
	//
	// 1. The origin of this software must not be misrepresented; you must not
	//   claim that you wrote the original software. If you use this software
	//   in a product, an acknowledgment in the product documentation would be
	//   appreciated but is not required.
	// 2. Altered source versions must be plainly marked as such, and must not be
	//   misrepresented as being the original software.
	// 3. This notice may not be removed or altered from any source distribution.

	/* eslint-disable space-unary-ops */

	var utils = common.__require();

	/* Public constants ==========================================================*/
	/* ===========================================================================*/


	//var Z_FILTERED          = 1;
	//var Z_HUFFMAN_ONLY      = 2;
	//var Z_RLE               = 3;
	var Z_FIXED               = 4;
	//var Z_DEFAULT_STRATEGY  = 0;

	/* Possible values of the data_type field (though see inflate()) */
	var Z_BINARY              = 0;
	var Z_TEXT                = 1;
	//var Z_ASCII             = 1; // = Z_TEXT
	var Z_UNKNOWN             = 2;

	/*============================================================================*/


	function zero(buf) { var len = buf.length; while (--len >= 0) { buf[len] = 0; } }

	// From zutil.h

	var STORED_BLOCK = 0;
	var STATIC_TREES = 1;
	var DYN_TREES    = 2;
	/* The three kinds of block type */

	var MIN_MATCH    = 3;
	var MAX_MATCH    = 258;
	/* The minimum and maximum match lengths */

	// From deflate.h
	/* ===========================================================================
	 * Internal compression state.
	 */

	var LENGTH_CODES  = 29;
	/* number of length codes, not counting the special END_BLOCK code */

	var LITERALS      = 256;
	/* number of literal bytes 0..255 */

	var L_CODES       = LITERALS + 1 + LENGTH_CODES;
	/* number of Literal or Length codes, including the END_BLOCK code */

	var D_CODES       = 30;
	/* number of distance codes */

	var BL_CODES      = 19;
	/* number of codes used to transfer the bit lengths */

	var HEAP_SIZE     = 2 * L_CODES + 1;
	/* maximum heap size */

	var MAX_BITS      = 15;
	/* All codes must not exceed MAX_BITS bits */

	var Buf_size      = 16;
	/* size of bit buffer in bi_buf */


	/* ===========================================================================
	 * Constants
	 */

	var MAX_BL_BITS = 7;
	/* Bit length codes must not exceed MAX_BL_BITS bits */

	var END_BLOCK   = 256;
	/* end of block literal code */

	var REP_3_6     = 16;
	/* repeat previous bit length 3-6 times (2 bits of repeat count) */

	var REPZ_3_10   = 17;
	/* repeat a zero length 3-10 times  (3 bits of repeat count) */

	var REPZ_11_138 = 18;
	/* repeat a zero length 11-138 times  (7 bits of repeat count) */

	/* eslint-disable comma-spacing,array-bracket-spacing */
	var extra_lbits =   /* extra bits for each length code */
	  [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];

	var extra_dbits =   /* extra bits for each distance code */
	  [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];

	var extra_blbits =  /* extra bits for each bit length code */
	  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7];

	var bl_order =
	  [16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15];
	/* eslint-enable comma-spacing,array-bracket-spacing */

	/* The lengths of the bit length codes are sent in order of decreasing
	 * probability, to avoid transmitting the lengths for unused bit length codes.
	 */

	/* ===========================================================================
	 * Local data. These are initialized only once.
	 */

	// We pre-fill arrays with 0 to avoid uninitialized gaps

	var DIST_CODE_LEN = 512; /* see definition of array dist_code below */

	// !!!! Use flat array instead of structure, Freq = i*2, Len = i*2+1
	var static_ltree  = new Array((L_CODES + 2) * 2);
	zero(static_ltree);
	/* The static literal tree. Since the bit lengths are imposed, there is no
	 * need for the L_CODES extra codes used during heap construction. However
	 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
	 * below).
	 */

	var static_dtree  = new Array(D_CODES * 2);
	zero(static_dtree);
	/* The static distance tree. (Actually a trivial tree since all codes use
	 * 5 bits.)
	 */

	var _dist_code    = new Array(DIST_CODE_LEN);
	zero(_dist_code);
	/* Distance codes. The first 256 values correspond to the distances
	 * 3 .. 258, the last 256 values correspond to the top 8 bits of
	 * the 15 bit distances.
	 */

	var _length_code  = new Array(MAX_MATCH - MIN_MATCH + 1);
	zero(_length_code);
	/* length code for each normalized match length (0 == MIN_MATCH) */

	var base_length   = new Array(LENGTH_CODES);
	zero(base_length);
	/* First normalized length for each code (0 = MIN_MATCH) */

	var base_dist     = new Array(D_CODES);
	zero(base_dist);
	/* First normalized distance for each code (0 = distance of 1) */


	function StaticTreeDesc(static_tree, extra_bits, extra_base, elems, max_length) {

	  this.static_tree  = static_tree;  /* static tree or NULL */
	  this.extra_bits   = extra_bits;   /* extra bits for each code or NULL */
	  this.extra_base   = extra_base;   /* base index for extra_bits */
	  this.elems        = elems;        /* max number of elements in the tree */
	  this.max_length   = max_length;   /* max bit length for the codes */

	  // show if `static_tree` has data or dummy - needed for monomorphic objects
	  this.has_stree    = static_tree && static_tree.length;
	}


	var static_l_desc;
	var static_d_desc;
	var static_bl_desc;


	function TreeDesc(dyn_tree, stat_desc) {
	  this.dyn_tree = dyn_tree;     /* the dynamic tree */
	  this.max_code = 0;            /* largest code with non zero frequency */
	  this.stat_desc = stat_desc;   /* the corresponding static tree */
	}



	function d_code(dist) {
	  return dist < 256 ? _dist_code[dist] : _dist_code[256 + (dist >>> 7)];
	}


	/* ===========================================================================
	 * Output a short LSB first on the stream.
	 * IN assertion: there is enough room in pendingBuf.
	 */
	function put_short(s, w) {
	//    put_byte(s, (uch)((w) & 0xff));
	//    put_byte(s, (uch)((ush)(w) >> 8));
	  s.pending_buf[s.pending++] = (w) & 0xff;
	  s.pending_buf[s.pending++] = (w >>> 8) & 0xff;
	}


	/* ===========================================================================
	 * Send a value on a given number of bits.
	 * IN assertion: length <= 16 and value fits in length bits.
	 */
	function send_bits(s, value, length) {
	  if (s.bi_valid > (Buf_size - length)) {
	    s.bi_buf |= (value << s.bi_valid) & 0xffff;
	    put_short(s, s.bi_buf);
	    s.bi_buf = value >> (Buf_size - s.bi_valid);
	    s.bi_valid += length - Buf_size;
	  } else {
	    s.bi_buf |= (value << s.bi_valid) & 0xffff;
	    s.bi_valid += length;
	  }
	}


	function send_code(s, c, tree) {
	  send_bits(s, tree[c * 2]/*.Code*/, tree[c * 2 + 1]/*.Len*/);
	}


	/* ===========================================================================
	 * Reverse the first len bits of a code, using straightforward code (a faster
	 * method would use a table)
	 * IN assertion: 1 <= len <= 15
	 */
	function bi_reverse(code, len) {
	  var res = 0;
	  do {
	    res |= code & 1;
	    code >>>= 1;
	    res <<= 1;
	  } while (--len > 0);
	  return res >>> 1;
	}


	/* ===========================================================================
	 * Flush the bit buffer, keeping at most 7 bits in it.
	 */
	function bi_flush(s) {
	  if (s.bi_valid === 16) {
	    put_short(s, s.bi_buf);
	    s.bi_buf = 0;
	    s.bi_valid = 0;

	  } else if (s.bi_valid >= 8) {
	    s.pending_buf[s.pending++] = s.bi_buf & 0xff;
	    s.bi_buf >>= 8;
	    s.bi_valid -= 8;
	  }
	}


	/* ===========================================================================
	 * Compute the optimal bit lengths for a tree and update the total bit length
	 * for the current block.
	 * IN assertion: the fields freq and dad are set, heap[heap_max] and
	 *    above are the tree nodes sorted by increasing frequency.
	 * OUT assertions: the field len is set to the optimal bit length, the
	 *     array bl_count contains the frequencies for each bit length.
	 *     The length opt_len is updated; static_len is also updated if stree is
	 *     not null.
	 */
	function gen_bitlen(s, desc)
	//    deflate_state *s;
	//    tree_desc *desc;    /* the tree descriptor */
	{
	  var tree            = desc.dyn_tree;
	  var max_code        = desc.max_code;
	  var stree           = desc.stat_desc.static_tree;
	  var has_stree       = desc.stat_desc.has_stree;
	  var extra           = desc.stat_desc.extra_bits;
	  var base            = desc.stat_desc.extra_base;
	  var max_length      = desc.stat_desc.max_length;
	  var h;              /* heap index */
	  var n, m;           /* iterate over the tree elements */
	  var bits;           /* bit length */
	  var xbits;          /* extra bits */
	  var f;              /* frequency */
	  var overflow = 0;   /* number of elements with bit length too large */

	  for (bits = 0; bits <= MAX_BITS; bits++) {
	    s.bl_count[bits] = 0;
	  }

	  /* In a first pass, compute the optimal bit lengths (which may
	   * overflow in the case of the bit length tree).
	   */
	  tree[s.heap[s.heap_max] * 2 + 1]/*.Len*/ = 0; /* root of the heap */

	  for (h = s.heap_max + 1; h < HEAP_SIZE; h++) {
	    n = s.heap[h];
	    bits = tree[tree[n * 2 + 1]/*.Dad*/ * 2 + 1]/*.Len*/ + 1;
	    if (bits > max_length) {
	      bits = max_length;
	      overflow++;
	    }
	    tree[n * 2 + 1]/*.Len*/ = bits;
	    /* We overwrite tree[n].Dad which is no longer needed */

	    if (n > max_code) { continue; } /* not a leaf node */

	    s.bl_count[bits]++;
	    xbits = 0;
	    if (n >= base) {
	      xbits = extra[n - base];
	    }
	    f = tree[n * 2]/*.Freq*/;
	    s.opt_len += f * (bits + xbits);
	    if (has_stree) {
	      s.static_len += f * (stree[n * 2 + 1]/*.Len*/ + xbits);
	    }
	  }
	  if (overflow === 0) { return; }

	  // Trace((stderr,"\nbit length overflow\n"));
	  /* This happens for example on obj2 and pic of the Calgary corpus */

	  /* Find the first bit length which could increase: */
	  do {
	    bits = max_length - 1;
	    while (s.bl_count[bits] === 0) { bits--; }
	    s.bl_count[bits]--;      /* move one leaf down the tree */
	    s.bl_count[bits + 1] += 2; /* move one overflow item as its brother */
	    s.bl_count[max_length]--;
	    /* The brother of the overflow item also moves one step up,
	     * but this does not affect bl_count[max_length]
	     */
	    overflow -= 2;
	  } while (overflow > 0);

	  /* Now recompute all bit lengths, scanning in increasing frequency.
	   * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
	   * lengths instead of fixing only the wrong ones. This idea is taken
	   * from 'ar' written by Haruhiko Okumura.)
	   */
	  for (bits = max_length; bits !== 0; bits--) {
	    n = s.bl_count[bits];
	    while (n !== 0) {
	      m = s.heap[--h];
	      if (m > max_code) { continue; }
	      if (tree[m * 2 + 1]/*.Len*/ !== bits) {
	        // Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
	        s.opt_len += (bits - tree[m * 2 + 1]/*.Len*/) * tree[m * 2]/*.Freq*/;
	        tree[m * 2 + 1]/*.Len*/ = bits;
	      }
	      n--;
	    }
	  }
	}


	/* ===========================================================================
	 * Generate the codes for a given tree and bit counts (which need not be
	 * optimal).
	 * IN assertion: the array bl_count contains the bit length statistics for
	 * the given tree and the field len is set for all tree elements.
	 * OUT assertion: the field code is set for all tree elements of non
	 *     zero code length.
	 */
	function gen_codes(tree, max_code, bl_count)
	//    ct_data *tree;             /* the tree to decorate */
	//    int max_code;              /* largest code with non zero frequency */
	//    ushf *bl_count;            /* number of codes at each bit length */
	{
	  var next_code = new Array(MAX_BITS + 1); /* next code value for each bit length */
	  var code = 0;              /* running code value */
	  var bits;                  /* bit index */
	  var n;                     /* code index */

	  /* The distribution counts are first used to generate the code values
	   * without bit reversal.
	   */
	  for (bits = 1; bits <= MAX_BITS; bits++) {
	    next_code[bits] = code = (code + bl_count[bits - 1]) << 1;
	  }
	  /* Check that the bit counts in bl_count are consistent. The last code
	   * must be all ones.
	   */
	  //Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
	  //        "inconsistent bit counts");
	  //Tracev((stderr,"\ngen_codes: max_code %d ", max_code));

	  for (n = 0;  n <= max_code; n++) {
	    var len = tree[n * 2 + 1]/*.Len*/;
	    if (len === 0) { continue; }
	    /* Now reverse the bits */
	    tree[n * 2]/*.Code*/ = bi_reverse(next_code[len]++, len);

	    //Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
	    //     n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
	  }
	}


	/* ===========================================================================
	 * Initialize the various 'constant' tables.
	 */
	function tr_static_init() {
	  var n;        /* iterates over tree elements */
	  var bits;     /* bit counter */
	  var length;   /* length value */
	  var code;     /* code value */
	  var dist;     /* distance index */
	  var bl_count = new Array(MAX_BITS + 1);
	  /* number of codes at each bit length for an optimal tree */

	  // do check in _tr_init()
	  //if (static_init_done) return;

	  /* For some embedded targets, global variables are not initialized: */
	/*#ifdef NO_INIT_GLOBAL_POINTERS
	  static_l_desc.static_tree = static_ltree;
	  static_l_desc.extra_bits = extra_lbits;
	  static_d_desc.static_tree = static_dtree;
	  static_d_desc.extra_bits = extra_dbits;
	  static_bl_desc.extra_bits = extra_blbits;
	#endif*/

	  /* Initialize the mapping length (0..255) -> length code (0..28) */
	  length = 0;
	  for (code = 0; code < LENGTH_CODES - 1; code++) {
	    base_length[code] = length;
	    for (n = 0; n < (1 << extra_lbits[code]); n++) {
	      _length_code[length++] = code;
	    }
	  }
	  //Assert (length == 256, "tr_static_init: length != 256");
	  /* Note that the length 255 (match length 258) can be represented
	   * in two different ways: code 284 + 5 bits or code 285, so we
	   * overwrite length_code[255] to use the best encoding:
	   */
	  _length_code[length - 1] = code;

	  /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
	  dist = 0;
	  for (code = 0; code < 16; code++) {
	    base_dist[code] = dist;
	    for (n = 0; n < (1 << extra_dbits[code]); n++) {
	      _dist_code[dist++] = code;
	    }
	  }
	  //Assert (dist == 256, "tr_static_init: dist != 256");
	  dist >>= 7; /* from now on, all distances are divided by 128 */
	  for (; code < D_CODES; code++) {
	    base_dist[code] = dist << 7;
	    for (n = 0; n < (1 << (extra_dbits[code] - 7)); n++) {
	      _dist_code[256 + dist++] = code;
	    }
	  }
	  //Assert (dist == 256, "tr_static_init: 256+dist != 512");

	  /* Construct the codes of the static literal tree */
	  for (bits = 0; bits <= MAX_BITS; bits++) {
	    bl_count[bits] = 0;
	  }

	  n = 0;
	  while (n <= 143) {
	    static_ltree[n * 2 + 1]/*.Len*/ = 8;
	    n++;
	    bl_count[8]++;
	  }
	  while (n <= 255) {
	    static_ltree[n * 2 + 1]/*.Len*/ = 9;
	    n++;
	    bl_count[9]++;
	  }
	  while (n <= 279) {
	    static_ltree[n * 2 + 1]/*.Len*/ = 7;
	    n++;
	    bl_count[7]++;
	  }
	  while (n <= 287) {
	    static_ltree[n * 2 + 1]/*.Len*/ = 8;
	    n++;
	    bl_count[8]++;
	  }
	  /* Codes 286 and 287 do not exist, but we must include them in the
	   * tree construction to get a canonical Huffman tree (longest code
	   * all ones)
	   */
	  gen_codes(static_ltree, L_CODES + 1, bl_count);

	  /* The static distance tree is trivial: */
	  for (n = 0; n < D_CODES; n++) {
	    static_dtree[n * 2 + 1]/*.Len*/ = 5;
	    static_dtree[n * 2]/*.Code*/ = bi_reverse(n, 5);
	  }

	  // Now data ready and we can init static trees
	  static_l_desc = new StaticTreeDesc(static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_BITS);
	  static_d_desc = new StaticTreeDesc(static_dtree, extra_dbits, 0,          D_CODES, MAX_BITS);
	  static_bl_desc = new StaticTreeDesc(new Array(0), extra_blbits, 0,         BL_CODES, MAX_BL_BITS);

	  //static_init_done = true;
	}


	/* ===========================================================================
	 * Initialize a new block.
	 */
	function init_block(s) {
	  var n; /* iterates over tree elements */

	  /* Initialize the trees. */
	  for (n = 0; n < L_CODES;  n++) { s.dyn_ltree[n * 2]/*.Freq*/ = 0; }
	  for (n = 0; n < D_CODES;  n++) { s.dyn_dtree[n * 2]/*.Freq*/ = 0; }
	  for (n = 0; n < BL_CODES; n++) { s.bl_tree[n * 2]/*.Freq*/ = 0; }

	  s.dyn_ltree[END_BLOCK * 2]/*.Freq*/ = 1;
	  s.opt_len = s.static_len = 0;
	  s.last_lit = s.matches = 0;
	}


	/* ===========================================================================
	 * Flush the bit buffer and align the output on a byte boundary
	 */
	function bi_windup(s)
	{
	  if (s.bi_valid > 8) {
	    put_short(s, s.bi_buf);
	  } else if (s.bi_valid > 0) {
	    //put_byte(s, (Byte)s->bi_buf);
	    s.pending_buf[s.pending++] = s.bi_buf;
	  }
	  s.bi_buf = 0;
	  s.bi_valid = 0;
	}

	/* ===========================================================================
	 * Copy a stored block, storing first the length and its
	 * one's complement if requested.
	 */
	function copy_block(s, buf, len, header)
	//DeflateState *s;
	//charf    *buf;    /* the input data */
	//unsigned len;     /* its length */
	//int      header;  /* true if block header must be written */
	{
	  bi_windup(s);        /* align on byte boundary */

	  {
	    put_short(s, len);
	    put_short(s, ~len);
	  }
	//  while (len--) {
	//    put_byte(s, *buf++);
	//  }
	  utils.arraySet(s.pending_buf, s.window, buf, len, s.pending);
	  s.pending += len;
	}

	/* ===========================================================================
	 * Compares to subtrees, using the tree depth as tie breaker when
	 * the subtrees have equal frequency. This minimizes the worst case length.
	 */
	function smaller(tree, n, m, depth) {
	  var _n2 = n * 2;
	  var _m2 = m * 2;
	  return (tree[_n2]/*.Freq*/ < tree[_m2]/*.Freq*/ ||
	         (tree[_n2]/*.Freq*/ === tree[_m2]/*.Freq*/ && depth[n] <= depth[m]));
	}

	/* ===========================================================================
	 * Restore the heap property by moving down the tree starting at node k,
	 * exchanging a node with the smallest of its two sons if necessary, stopping
	 * when the heap property is re-established (each father smaller than its
	 * two sons).
	 */
	function pqdownheap(s, tree, k)
	//    deflate_state *s;
	//    ct_data *tree;  /* the tree to restore */
	//    int k;               /* node to move down */
	{
	  var v = s.heap[k];
	  var j = k << 1;  /* left son of k */
	  while (j <= s.heap_len) {
	    /* Set j to the smallest of the two sons: */
	    if (j < s.heap_len &&
	      smaller(tree, s.heap[j + 1], s.heap[j], s.depth)) {
	      j++;
	    }
	    /* Exit if v is smaller than both sons */
	    if (smaller(tree, v, s.heap[j], s.depth)) { break; }

	    /* Exchange v with the smallest son */
	    s.heap[k] = s.heap[j];
	    k = j;

	    /* And continue down the tree, setting j to the left son of k */
	    j <<= 1;
	  }
	  s.heap[k] = v;
	}


	// inlined manually
	// var SMALLEST = 1;

	/* ===========================================================================
	 * Send the block data compressed using the given Huffman trees
	 */
	function compress_block(s, ltree, dtree)
	//    deflate_state *s;
	//    const ct_data *ltree; /* literal tree */
	//    const ct_data *dtree; /* distance tree */
	{
	  var dist;           /* distance of matched string */
	  var lc;             /* match length or unmatched char (if dist == 0) */
	  var lx = 0;         /* running index in l_buf */
	  var code;           /* the code to send */
	  var extra;          /* number of extra bits to send */

	  if (s.last_lit !== 0) {
	    do {
	      dist = (s.pending_buf[s.d_buf + lx * 2] << 8) | (s.pending_buf[s.d_buf + lx * 2 + 1]);
	      lc = s.pending_buf[s.l_buf + lx];
	      lx++;

	      if (dist === 0) {
	        send_code(s, 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(s, code + LITERALS + 1, ltree); /* send the length code */
	        extra = extra_lbits[code];
	        if (extra !== 0) {
	          lc -= base_length[code];
	          send_bits(s, lc, extra);       /* send the extra length bits */
	        }
	        dist--; /* dist is now the match distance - 1 */
	        code = d_code(dist);
	        //Assert (code < D_CODES, "bad d_code");

	        send_code(s, code, dtree);       /* send the distance code */
	        extra = extra_dbits[code];
	        if (extra !== 0) {
	          dist -= base_dist[code];
	          send_bits(s, dist, extra);   /* send the extra distance bits */
	        }
	      } /* literal or match pair ? */

	      /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
	      //Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
	      //       "pendingBuf overflow");

	    } while (lx < s.last_lit);
	  }

	  send_code(s, END_BLOCK, ltree);
	}


	/* ===========================================================================
	 * Construct one Huffman tree and assigns the code bit strings and lengths.
	 * Update the total bit length for the current block.
	 * IN assertion: the field freq is set for all tree elements.
	 * OUT assertions: the fields len and code are set to the optimal bit length
	 *     and corresponding code. The length opt_len is updated; static_len is
	 *     also updated if stree is not null. The field max_code is set.
	 */
	function build_tree(s, desc)
	//    deflate_state *s;
	//    tree_desc *desc; /* the tree descriptor */
	{
	  var tree     = desc.dyn_tree;
	  var stree    = desc.stat_desc.static_tree;
	  var has_stree = desc.stat_desc.has_stree;
	  var elems    = desc.stat_desc.elems;
	  var n, m;          /* iterate over heap elements */
	  var max_code = -1; /* largest code with non zero frequency */
	  var node;          /* new node being created */

	  /* Construct the initial heap, with least frequent element in
	   * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
	   * heap[0] is not used.
	   */
	  s.heap_len = 0;
	  s.heap_max = HEAP_SIZE;

	  for (n = 0; n < elems; n++) {
	    if (tree[n * 2]/*.Freq*/ !== 0) {
	      s.heap[++s.heap_len] = max_code = n;
	      s.depth[n] = 0;

	    } else {
	      tree[n * 2 + 1]/*.Len*/ = 0;
	    }
	  }

	  /* The pkzip format requires that at least one distance code exists,
	   * and that at least one bit should be sent even if there is only one
	   * possible code. So to avoid special checks later on we force at least
	   * two codes of non zero frequency.
	   */
	  while (s.heap_len < 2) {
	    node = s.heap[++s.heap_len] = (max_code < 2 ? ++max_code : 0);
	    tree[node * 2]/*.Freq*/ = 1;
	    s.depth[node] = 0;
	    s.opt_len--;

	    if (has_stree) {
	      s.static_len -= stree[node * 2 + 1]/*.Len*/;
	    }
	    /* node is 0 or 1 so it does not have extra bits */
	  }
	  desc.max_code = max_code;

	  /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
	   * establish sub-heaps of increasing lengths:
	   */
	  for (n = (s.heap_len >> 1/*int /2*/); n >= 1; n--) { pqdownheap(s, tree, n); }

	  /* Construct the Huffman tree by repeatedly combining the least two
	   * frequent nodes.
	   */
	  node = elems;              /* next internal node of the tree */
	  do {
	    //pqremove(s, tree, n);  /* n = node of least frequency */
	    /*** pqremove ***/
	    n = s.heap[1/*SMALLEST*/];
	    s.heap[1/*SMALLEST*/] = s.heap[s.heap_len--];
	    pqdownheap(s, tree, 1/*SMALLEST*/);
	    /***/

	    m = s.heap[1/*SMALLEST*/]; /* m = node of next least frequency */

	    s.heap[--s.heap_max] = n; /* keep the nodes sorted by frequency */
	    s.heap[--s.heap_max] = m;

	    /* Create a new node father of n and m */
	    tree[node * 2]/*.Freq*/ = tree[n * 2]/*.Freq*/ + tree[m * 2]/*.Freq*/;
	    s.depth[node] = (s.depth[n] >= s.depth[m] ? s.depth[n] : s.depth[m]) + 1;
	    tree[n * 2 + 1]/*.Dad*/ = tree[m * 2 + 1]/*.Dad*/ = node;

	    /* and insert the new node in the heap */
	    s.heap[1/*SMALLEST*/] = node++;
	    pqdownheap(s, tree, 1/*SMALLEST*/);

	  } while (s.heap_len >= 2);

	  s.heap[--s.heap_max] = s.heap[1/*SMALLEST*/];

	  /* At this point, the fields freq and dad are set. We can now
	   * generate the bit lengths.
	   */
	  gen_bitlen(s, desc);

	  /* The field len is now set, we can generate the bit codes */
	  gen_codes(tree, max_code, s.bl_count);
	}


	/* ===========================================================================
	 * Scan a literal or distance tree to determine the frequencies of the codes
	 * in the bit length tree.
	 */
	function scan_tree(s, tree, max_code)
	//    deflate_state *s;
	//    ct_data *tree;   /* the tree to be scanned */
	//    int max_code;    /* and its largest code of non zero frequency */
	{
	  var n;                     /* iterates over all tree elements */
	  var prevlen = -1;          /* last emitted length */
	  var curlen;                /* length of current code */

	  var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */

	  var count = 0;             /* repeat count of the current code */
	  var max_count = 7;         /* max repeat count */
	  var min_count = 4;         /* min repeat count */

	  if (nextlen === 0) {
	    max_count = 138;
	    min_count = 3;
	  }
	  tree[(max_code + 1) * 2 + 1]/*.Len*/ = 0xffff; /* guard */

	  for (n = 0; n <= max_code; n++) {
	    curlen = nextlen;
	    nextlen = tree[(n + 1) * 2 + 1]/*.Len*/;

	    if (++count < max_count && curlen === nextlen) {
	      continue;

	    } else if (count < min_count) {
	      s.bl_tree[curlen * 2]/*.Freq*/ += count;

	    } else if (curlen !== 0) {

	      if (curlen !== prevlen) { s.bl_tree[curlen * 2]/*.Freq*/++; }
	      s.bl_tree[REP_3_6 * 2]/*.Freq*/++;

	    } else if (count <= 10) {
	      s.bl_tree[REPZ_3_10 * 2]/*.Freq*/++;

	    } else {
	      s.bl_tree[REPZ_11_138 * 2]/*.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.
	 */
	function send_tree(s, tree, max_code)
	//    deflate_state *s;
	//    ct_data *tree; /* the tree to be scanned */
	//    int max_code;       /* and its largest code of non zero frequency */
	{
	  var n;                     /* iterates over all tree elements */
	  var prevlen = -1;          /* last emitted length */
	  var curlen;                /* length of current code */

	  var nextlen = tree[0 * 2 + 1]/*.Len*/; /* length of next code */

	  var count = 0;             /* repeat count of the current code */
	  var max_count = 7;         /* max repeat count */
	  var 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) * 2 + 1]/*.Len*/;

	    if (++count < max_count && curlen === nextlen) {
	      continue;

	    } else if (count < min_count) {
	      do { send_code(s, curlen, s.bl_tree); } while (--count !== 0);

	    } else if (curlen !== 0) {
	      if (curlen !== prevlen) {
	        send_code(s, curlen, s.bl_tree);
	        count--;
	      }
	      //Assert(count >= 3 && count <= 6, " 3_6?");
	      send_code(s, REP_3_6, s.bl_tree);
	      send_bits(s, count - 3, 2);

	    } else if (count <= 10) {
	      send_code(s, REPZ_3_10, s.bl_tree);
	      send_bits(s, count - 3, 3);

	    } else {
	      send_code(s, REPZ_11_138, s.bl_tree);
	      send_bits(s, 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.
	 */
	function build_bl_tree(s) {
	  var max_blindex;  /* index of last bit length code of non zero freq */

	  /* Determine the bit length frequencies for literal and distance trees */
	  scan_tree(s, s.dyn_ltree, s.l_desc.max_code);
	  scan_tree(s, s.dyn_dtree, s.d_desc.max_code);

	  /* Build the bit length tree: */
	  build_tree(s, s.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 (s.bl_tree[bl_order[max_blindex] * 2 + 1]/*.Len*/ !== 0) {
	      break;
	    }
	  }
	  /* Update opt_len to include the bit length tree and counts */
	  s.opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
	  //Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
	  //        s->opt_len, s->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.
	 */
	function send_all_trees(s, lcodes, dcodes, blcodes)
	//    deflate_state *s;
	//    int lcodes, dcodes, blcodes; /* number of codes for each tree */
	{
	  var 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(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */
	  send_bits(s, dcodes - 1,   5);
	  send_bits(s, 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(s, s.bl_tree[bl_order[rank] * 2 + 1]/*.Len*/, 3);
	  }
	  //Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));

	  send_tree(s, s.dyn_ltree, lcodes - 1); /* literal tree */
	  //Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));

	  send_tree(s, s.dyn_dtree, dcodes - 1); /* distance tree */
	  //Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
	}


	/* ===========================================================================
	 * Check if the data type is TEXT or BINARY, using the following algorithm:
	 * - TEXT if the two conditions below are satisfied:
	 *    a) There are no non-portable control characters belonging to the
	 *       "black list" (0..6, 14..25, 28..31).
	 *    b) There is at least one printable character belonging to the
	 *       "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
	 * - BINARY otherwise.
	 * - The following partially-portable control characters form a
	 *   "gray list" that is ignored in this detection algorithm:
	 *   (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
	 * IN assertion: the fields Freq of dyn_ltree are set.
	 */
	function detect_data_type(s) {
	  /* black_mask is the bit mask of black-listed bytes
	   * set bits 0..6, 14..25, and 28..31
	   * 0xf3ffc07f = binary 11110011111111111100000001111111
	   */
	  var black_mask = 0xf3ffc07f;
	  var n;

	  /* Check for non-textual ("black-listed") bytes. */
	  for (n = 0; n <= 31; n++, black_mask >>>= 1) {
	    if ((black_mask & 1) && (s.dyn_ltree[n * 2]/*.Freq*/ !== 0)) {
	      return Z_BINARY;
	    }
	  }

	  /* Check for textual ("white-listed") bytes. */
	  if (s.dyn_ltree[9 * 2]/*.Freq*/ !== 0 || s.dyn_ltree[10 * 2]/*.Freq*/ !== 0 ||
	      s.dyn_ltree[13 * 2]/*.Freq*/ !== 0) {
	    return Z_TEXT;
	  }
	  for (n = 32; n < LITERALS; n++) {
	    if (s.dyn_ltree[n * 2]/*.Freq*/ !== 0) {
	      return Z_TEXT;
	    }
	  }

	  /* There are no "black-listed" or "white-listed" bytes:
	   * this stream either is empty or has tolerated ("gray-listed") bytes only.
	   */
	  return Z_BINARY;
	}


	var static_init_done = false;

	/* ===========================================================================
	 * Initialize the tree data structures for a new zlib stream.
	 */
	function _tr_init(s)
	{

	  if (!static_init_done) {
	    tr_static_init();
	    static_init_done = true;
	  }

	  s.l_desc  = new TreeDesc(s.dyn_ltree, static_l_desc);
	  s.d_desc  = new TreeDesc(s.dyn_dtree, static_d_desc);
	  s.bl_desc = new TreeDesc(s.bl_tree, static_bl_desc);

	  s.bi_buf = 0;
	  s.bi_valid = 0;

	  /* Initialize the first block of the first file: */
	  init_block(s);
	}


	/* ===========================================================================
	 * Send a stored block
	 */
	function _tr_stored_block(s, buf, stored_len, last)
	//DeflateState *s;
	//charf *buf;       /* input block */
	//ulg stored_len;   /* length of input block */
	//int last;         /* one if this is the last block for a file */
	{
	  send_bits(s, (STORED_BLOCK << 1) + (last ? 1 : 0), 3);    /* send block type */
	  copy_block(s, buf, stored_len); /* with header */
	}


	/* ===========================================================================
	 * Send one empty static block to give enough lookahead for inflate.
	 * This takes 10 bits, of which 7 may remain in the bit buffer.
	 */
	function _tr_align(s) {
	  send_bits(s, STATIC_TREES << 1, 3);
	  send_code(s, END_BLOCK, static_ltree);
	  bi_flush(s);
	}


	/* ===========================================================================
	 * Determine the best encoding for the current block: dynamic trees, static
	 * trees or store, and output the encoded block to the zip file.
	 */
	function _tr_flush_block(s, buf, stored_len, last)
	//DeflateState *s;
	//charf *buf;       /* input block, or NULL if too old */
	//ulg stored_len;   /* length of input block */
	//int last;         /* one if this is the last block for a file */
	{
	  var opt_lenb, static_lenb;  /* opt_len and static_len in bytes */
	  var max_blindex = 0;        /* index of last bit length code of non zero freq */

	  /* Build the Huffman trees unless a stored block is forced */
	  if (s.level > 0) {

	    /* Check if the file is binary or text */
	    if (s.strm.data_type === Z_UNKNOWN) {
	      s.strm.data_type = detect_data_type(s);
	    }

	    /* Construct the literal and distance trees */
	    build_tree(s, s.l_desc);
	    // Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
	    //        s->static_len));

	    build_tree(s, s.d_desc);
	    // Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
	    //        s->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(s);

	    /* Determine the best encoding. Compute the block lengths in bytes. */
	    opt_lenb = (s.opt_len + 3 + 7) >>> 3;
	    static_lenb = (s.static_len + 3 + 7) >>> 3;

	    // Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
	    //        opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
	    //        s->last_lit));

	    if (static_lenb <= opt_lenb) { opt_lenb = static_lenb; }

	  } else {
	    // Assert(buf != (char*)0, "lost buf");
	    opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
	  }

	  if ((stored_len + 4 <= opt_lenb) && (buf !== -1)) {
	    /* 4: two words for the lengths */

	    /* 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.
	     */
	    _tr_stored_block(s, buf, stored_len, last);

	  } else if (s.strategy === Z_FIXED || static_lenb === opt_lenb) {

	    send_bits(s, (STATIC_TREES << 1) + (last ? 1 : 0), 3);
	    compress_block(s, static_ltree, static_dtree);

	  } else {
	    send_bits(s, (DYN_TREES << 1) + (last ? 1 : 0), 3);
	    send_all_trees(s, s.l_desc.max_code + 1, s.d_desc.max_code + 1, max_blindex + 1);
	    compress_block(s, s.dyn_ltree, s.dyn_dtree);
	  }
	  // Assert (s->compressed_len == s->bits_sent, "bad compressed size");
	  /* The above check is made mod 2^32, for files larger than 512 MB
	   * and uLong implemented on 32 bits.
	   */
	  init_block(s);

	  if (last) {
	    bi_windup(s);
	  }
	  // Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
	  //       s->compressed_len-7*last));
	}

	/* ===========================================================================
	 * Save the match info and tally the frequency counts. Return true if
	 * the current block must be flushed.
	 */
	function _tr_tally(s, dist, lc)
	//    deflate_state *s;
	//    unsigned dist;  /* distance of matched string */
	//    unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */
	{
	  //var out_length, in_length, dcode;

	  s.pending_buf[s.d_buf + s.last_lit * 2]     = (dist >>> 8) & 0xff;
	  s.pending_buf[s.d_buf + s.last_lit * 2 + 1] = dist & 0xff;

	  s.pending_buf[s.l_buf + s.last_lit] = lc & 0xff;
	  s.last_lit++;

	  if (dist === 0) {
	    /* lc is the unmatched char */
	    s.dyn_ltree[lc * 2]/*.Freq*/++;
	  } else {
	    s.matches++;
	    /* Here, lc is the match length - MIN_MATCH */
	    dist--;             /* dist = match distance - 1 */
	    //Assert((ush)dist < (ush)MAX_DIST(s) &&
	    //       (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
	    //       (ush)d_code(dist) < (ush)D_CODES,  "_tr_tally: bad match");

	    s.dyn_ltree[(_length_code[lc] + LITERALS + 1) * 2]/*.Freq*/++;
	    s.dyn_dtree[d_code(dist) * 2]/*.Freq*/++;
	  }

	// (!) This block is disabled in zlib defaults,
	// don't enable it for binary compatibility

	//#ifdef TRUNCATE_BLOCK
	//  /* Try to guess if it is profitable to stop the current block here */
	//  if ((s.last_lit & 0x1fff) === 0 && s.level > 2) {
	//    /* Compute an upper bound for the compressed length */
	//    out_length = s.last_lit*8;
	//    in_length = s.strstart - s.block_start;
	//
	//    for (dcode = 0; dcode < D_CODES; dcode++) {
	//      out_length += s.dyn_dtree[dcode*2]/*.Freq*/ * (5 + extra_dbits[dcode]);
	//    }
	//    out_length >>>= 3;
	//    //Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
	//    //       s->last_lit, in_length, out_length,
	//    //       100L - out_length*100L/in_length));
	//    if (s.matches < (s.last_lit>>1)/*int /2*/ && out_length < (in_length>>1)/*int /2*/) {
	//      return true;
	//    }
	//  }
	//#endif

	  return (s.last_lit === s.lit_bufsize - 1);
	  /* 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.
	   */
	}

	trees.__exports._tr_init  = _tr_init;
	trees.__exports._tr_stored_block = _tr_stored_block;
	trees.__exports._tr_flush_block  = _tr_flush_block;
	trees.__exports._tr_tally = _tr_tally;
	trees.__exports._tr_align = _tr_align;
	return trees.__exports;
}

exports.__require = requireTrees;
