crc32 · JavaScript Function to Calculate CRC32 of a String
Description
Below is a JavaScript function to calculate CRC32 of a string. The string can be either ASCII or Unicode. Unicode strings will be encoded in UTF-8. The polynomial used in calculation is 0xedb88320. This polynomial is used in Ethernet, Gzip, PNG, SATA and many other technologies.var crc32 = (function () {
var table = []
for (var i = 0; i < 256; i++) {
var c = i
for (var j = 0; j < 8; j++) {
c = (c & 1) ? (0xedb88320 ^ (c >>> 1)) : (c >>> 1)
}
table.push(c)
}
return function (str, crc) {
str = unescape(encodeURIComponent(str))
if (!crc) crc = 0
crc = crc ^ (-1)
for (var i = 0; i < str.length; i++) {
var y = (crc ^ str.charCodeAt(i)) & 0xff
crc = (crc >>> 8) ^ table[y]
}
crc = crc ^ (-1)
return crc >>> 0
}
})()
Last updated 10 years ago.