# Code coverage report for lib\crc.js

## Statements: 100% (21 / 21) Branches: 100% (2 / 2) Functions: 100% (4 / 4) Lines: 100% (21 / 21) Ignored: none

All files » lib/ » crc.js

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     // Copyright (c) 2012 Kuba Niegowski
    //
    // Permission is hereby granted, free of charge, to any person obtaining a copy
    // of this software and associated documentation files (the "Software"), to deal
    // in the Software without restriction, including without limitation the rights
    // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    // copies of the Software, and to permit persons to whom the Software is
    // furnished to do so, subject to the following conditions:
    //
    // The above copyright notice and this permission notice shall be included in
    // all copies or substantial portions of the Software.
    //
    // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    // THE SOFTWARE.

    'use strict';

    var CrcCalculator = module.exports = function() {
        this._crc = -1;
    };

    CrcCalculator.prototype.write = function(data) {

        for (var i = 0; i < data.length; i++) {
            this._crc = crcTable[(this._crc ^ data[i]) & 0xff] ^ (this._crc >>> 8);
        }
        return true;
    };

    CrcCalculator.prototype.crc32 = function() {
        return this._crc ^ -1;
    };

    CrcCalculator.crc32 = function(buf) {

        var crc = -1;
        for (var i = 0; i < buf.length; i++) {
            crc = crcTable[(crc ^ buf[i]) & 0xff] ^ (crc >>> 8);
        }
        return crc ^ -1;
    };

    var crcTable = [];

    for (var i = 0; i < 256; i++) {
        var c = i;
        for (var j = 0; j < 8; j++) {
            if (c & 1) {
                c = 0xedb88320 ^ (c >>> 1);
            } else {
                c = c >>> 1;
            }
        }
        crcTable[i] = c;
    }