js-crc32/perf/crc32table.js
2014-06-16 17:27:47 -04:00

87 lines
2.2 KiB
JavaScript

var t=[], poly = 0xEDB88320;
function node_crc32() {
var c, n, k;
for (n = 0; n < 256; n += 1) {
c = n;
for (k = 0; k < 8; k += 1) {
if (c & 1) {
c = poly ^ (c >>> 1);
} else {
c = c >>> 1;
}
}
t[n] = c >>> 0;
}
}
function node_pako() {
var c, table = [];
for(var n =0; n < 256; n++){
c = n;
for(var k =0; k < 8; k++){
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
}
table[n] = c;
}
return table;
}
function sheetjs1() {
var c, table = [];
for(var n =0; n != 256; ++n){
c = n;
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
table[n] = c;
}
return table;
}
function sheetjs2() {
var c, table = new Array(256);
for(var n =0; n != 256; ++n){
c = n;
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
c = ((c&1) ? (-306674912 ^ (c >>> 1)) : (c >>> 1));
table[n] = c;
}
return table;
}
var BM = require('./bm');
var suite = new BM('building crc32 table');
suite.add('npm crc32', function() { for(var j = 0; j != 1000; ++j) node_crc32(); });
suite.add('npm pako', function() { for(var j = 0; j != 1000; ++j) node_pako(); });
suite.add('sheetjs 1', function() { for(var j = 0; j != 1000; ++j) sheetjs1(); });
suite.add('sheetjs 2', function() { for(var j = 0; j != 1000; ++j) sheetjs2(); });
suite.run()
var assert = require('assert');
var m1 = (node_pako());
var m2 = (sheetjs1());
var m3 = (sheetjs2());
assert.equal(m1.length, m2.length);
assert.equal(m1.length, m3.length);
for(var i = 0; i != m1.length; ++i) { assert.equal(m1[i], m2[i]); assert.equal(m1[i], m3[i]); }