84 lines
2.4 KiB
JavaScript
84 lines
2.4 KiB
JavaScript
var table = require('../').table;
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function strToArr(str) {
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// sweet hack to turn string into a 'byte' array
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return Array.prototype.map.call(str, function (c) {
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return c.charCodeAt(0);
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});
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}
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function crcTable(arr, append) {
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var crc, i, l;
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// if we're in append mode, don't reset crc
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// if arr is null or undefined, reset table and return
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if (typeof crcTable.crc === 'undefined' || !append || !arr) {
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crcTable.crc = 0 ^ -1;
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if (!arr) {
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return;
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}
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}
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// store in temp variable for minor speed gain
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crc = crcTable.crc;
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for (i = 0, l = arr.length; i < l; i += 1) {
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crc = (crc >>> 8) ^ table[(crc ^ arr[i]) & 0xff];
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}
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crcTable.crc = crc;
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return crc ^ -1;
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}
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function node_crc32(bstr) {
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return crcTable(strToArr(bstr));
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}
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function sheetjs1(bstr) {
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for(var crc = -1, i = 0; i != bstr.length; ++i) {
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i)) & 0xFF];
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}
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return crc ^ -1;
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}
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function sheetjs2(bstr) {
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for(var crc = -1, i = 0, L=bstr.length-1; i < L;) {
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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}
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if(i === L) crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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return crc ^ -1;
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}
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function sheetjs3(bstr) {
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for(var crc = -1, i = 0, L=bstr.length-2; i < L;) {
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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}
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if(i === L++) crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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if(i === L++) crc = (crc >>> 8) ^ table[(crc ^ bstr.charCodeAt(i++)) & 0xFF];
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return crc ^ -1;
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}
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var BM = require('./bm');
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var suite = new BM('binary string');
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var foobar = "foobarbazqux";
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foobar += " " + foobar;
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foobar += " " + foobar;
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foobar += " " + foobar;
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foobar += " " + foobar;
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suite.add('npm crc32', function() { for(var j = 0; j != 1000; ++j) node_crc32(foobar); });
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suite.add('sheetjs 1', function() { for(var j = 0; j != 1000; ++j) sheetjs1(foobar); });
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suite.add('sheetjs 2', function() { for(var j = 0; j != 1000; ++j) sheetjs2(foobar); });
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suite.add('sheetjs 3', function() { for(var j = 0; j != 1000; ++j) sheetjs3(foobar); });
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suite.run();
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var assert = require('assert');
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assert.equal(node_crc32(foobar), sheetjs1(foobar));
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assert.equal(node_crc32(foobar), sheetjs2(foobar));
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assert.equal(node_crc32(foobar), sheetjs3(foobar));
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