| // Note: we can't get significant speed boost here. | |
| // So write code to minimize size - no pregenerated tables | |
| // and array tools dependencies. | |
| // Use ordinary array, since untyped makes no boost here | |
| function makeTable() { | |
| 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; | |
| } | |
| // Create table on load. Just 255 signed longs. Not a problem. | |
| var crcTable = makeTable(); | |
| function crc32(crc, buf, len, pos) { | |
| var t = crcTable, | |
| end = pos + len; | |
| crc ^= -1; | |
| for (var i = pos; i < end; i++) { | |
| crc = (crc >>> 8) ^ t[(crc ^ buf[i]) & 0xFF]; | |
| } | |
| return (crc ^ (-1)); // >>> 0; | |
| } | |
| export default crc32; | |