pako.js

/*! pako 2.1.0 https://github.com/nodeca/pako @license (MIT AND Zlib) */
(function (global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
  typeof define === 'function' && define.amd ? define(['exports'], factory) :
  (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.pako = {}));
})(this, (function (exports) { 'use strict';

  // (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 */

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


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

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

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


  function zero$1(buf) { let len = buf.length; while (--len >= 0) { buf[len] = 0; } }

  // From zutil.h

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

  const MIN_MATCH$1    = 3;
  const MAX_MATCH$1    = 258;
  /* The minimum and maximum match lengths */

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

  const LENGTH_CODES$1  = 29;
  /* number of length codes, not counting the special END_BLOCK code */

  const LITERALS$1      = 256;
  /* number of literal bytes 0..255 */

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

  const D_CODES$1       = 30;
  /* number of distance codes */

  const BL_CODES$1      = 19;
  /* number of codes used to transfer the bit lengths */

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

  const MAX_BITS$1      = 15;
  /* All codes must not exceed MAX_BITS bits */

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


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

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

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

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

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

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

  /* eslint-disable comma-spacing,array-bracket-spacing */
  const extra_lbits =   /* extra bits for each length code */
    new Uint8Array([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]);

  const extra_dbits =   /* extra bits for each distance code */
    new Uint8Array([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]);

  const extra_blbits =  /* extra bits for each bit length code */
    new Uint8Array([0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7]);

  const bl_order =
    new Uint8Array([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

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

  // !!!! Use flat array instead of structure, Freq = i*2, Len = i*2+1
  const static_ltree  = new Array((L_CODES$1 + 2) * 2);
  zero$1(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).
   */

  const static_dtree  = new Array(D_CODES$1 * 2);
  zero$1(static_dtree);
  /* The static distance tree. (Actually a trivial tree since all codes use
   * 5 bits.)
   */

  const _dist_code    = new Array(DIST_CODE_LEN);
  zero$1(_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.
   */

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

  const base_length   = new Array(LENGTH_CODES$1);
  zero$1(base_length);
  /* First normalized length for each code (0 = MIN_MATCH) */

  const base_dist     = new Array(D_CODES$1);
  zero$1(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;
  }


  let static_l_desc;
  let static_d_desc;
  let 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 */
  }



  const d_code = (dist) => {

    return dist < 256 ? _dist_code[dist] : _dist_code[256 + (dist >>> 7)];