pdfjs-dist/lib/core/murmurhash3.js

/* Copyright 2017 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var Uint32ArrayView = sharedUtil.Uint32ArrayView;
var MurmurHash3_64 = function MurmurHash3_64Closure(seed) {
 var MASK_HIGH = 0xffff0000;
 var MASK_LOW = 0xffff;
 function MurmurHash3_64(seed) {
  var SEED = 0xc3d2e1f0;
  this.h1 = seed ? seed & 0xffffffff : SEED;
  this.h2 = seed ? seed & 0xffffffff : SEED;
 }
 var alwaysUseUint32ArrayView = false;
 try {
  new Uint32Array(new Uint8Array(5).buffer, 0, 1);
 } catch (e) {
  alwaysUseUint32ArrayView = true;
 }
 MurmurHash3_64.prototype = {
  update: function MurmurHash3_64_update(input) {
   var useUint32ArrayView = alwaysUseUint32ArrayView;
   var i;
   if (typeof input === 'string') {
    var data = new Uint8Array(input.length * 2);
    var length = 0;
    for (i = 0; i < input.length; i++) {
     var code = input.charCodeAt(i);
     if (code <= 0xff) {
      data[length++] = code;
     } else {
      data[length++] = code >>> 8;
      data[length++] = code & 0xff;
     }
    }
   } else if (input instanceof Uint8Array) {
    data = input;
    length = data.length;
   } else if (typeof input === 'object' && 'length' in input) {
    data = input;
    length = data.length;
    useUint32ArrayView = true;
   } else {
    throw new Error('Wrong data format in MurmurHash3_64_update. ' + 'Input must be a string or array.');
   }
   var blockCounts = length >> 2;
   var tailLength = length - blockCounts * 4;
   var dataUint32 = useUint32ArrayView ? new Uint32ArrayView(data, blockCounts) : new Uint32Array(data.buffer, 0, blockCounts);
   var k1 = 0;
   var k2 = 0;
   var h1 = this.h1;
   var h2 = this.h2;
   var C1 = 0xcc9e2d51;
   var C2 = 0x1b873593;
   var C1_LOW = C1 & MASK_LOW;
   var C2_LOW = C2 & MASK_LOW;
   for (i = 0; i < blockCounts; i++) {
    if (i & 1) {
     k1 = dataUint32[i];
     k1 = k1 * C1 & MASK_HIGH | k1 * C1_LOW & MASK_LOW;
     k1 = k1 << 15 | k1 >>> 17;
     k1 = k1 * C2 & MASK_HIGH | k1 * C2_LOW & MASK_LOW;
     h1 ^= k1;
     h1 = h1 << 13 | h1 >>> 19;
     h1 = h1 * 5 + 0xe6546b64;
    } else {
     k2 = dataUint32[i];
     k2 = k2 * C1 & MASK_HIGH | k2 * C1_LOW & MASK_LOW;
     k2 = k2 << 15 | k2 >>> 17;
     k2 = k2 * C2 & MASK_HIGH | k2 * C2_LOW & MASK_LOW;
     h2 ^= k2;
     h2 = h2 << 13 | h2 >>> 19;
     h2 = h2 * 5 + 0xe6546b64;
    }
   }
   k1 = 0;
   switch (tailLength) {
   case 3:
    k1 ^= data[blockCounts * 4 + 2] << 16;
   case 2:
    k1 ^= data[blockCounts * 4 + 1] << 8;
   case 1:
    k1 ^= data[blockCounts * 4];
    k1 = k1 * C1 & MASK_HIGH | k1 * C1_LOW & MASK_LOW;
    k1 = k1 << 15 | k1 >>> 17;
    k1 = k1 * C2 & MASK_HIGH | k1 * C2_LOW & MASK_LOW;
    if (blockCounts & 1) {
     h1 ^= k1;
    } else {
     h2 ^= k1;
    }
   }
   this.h1 = h1;
   this.h2 = h2;
   return this;
  },
  hexdigest: function MurmurHash3_64_hexdigest() {
   var h1 = this.h1;
   var h2 = this.h2;
   h1 ^= h2 >>> 1;
   h1 = h1 * 0xed558ccd & MASK_HIGH | h1 * 0x8ccd & MASK_LOW;
   h2 = h2 * 0xff51afd7 & MASK_HIGH | ((h2 << 16 | h1 >>> 16) * 0xafd7ed55 & MASK_HIGH) >>> 16;
   h1 ^= h2 >>> 1;
   h1 = h1 * 0x1a85ec53 & MASK_HIGH | h1 * 0xec53 & MASK_LOW;
   h2 = h2 * 0xc4ceb9fe & MASK_HIGH | ((h2 << 16 | h1 >>> 16) * 0xb9fe1a85 & MASK_HIGH) >>> 16;
   h1 ^= h2 >>> 1;
   for (var i = 0, arr = [
      h1,
      h2
     ], str = ''; i < arr.length; i++) {
    var hex = (arr[i] >>> 0).toString(16);
    while (hex.length < 8) {
     hex = '0' + hex;
    }
    str += hex;
   }
   return str;
  }
 };
 return MurmurHash3_64;
}();
exports.MurmurHash3_64 = MurmurHash3_64;