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Shortest JavaScript String Hash implementation
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// 32 bit FNV-1a hash | |
// Ref.: http://isthe.com/chongo/tech/comp/fnv/ | |
function fnv32a(str) { | |
var FNV1_32A_INIT = 0x811c9dc5, | |
hval = FNV1_32A_INIT, | |
i, len; | |
for (i = 0, len = str.length; i < len; i++) { | |
hval ^= str.charCodeAt(i); | |
hval += (hval << 1) + (hval << 4) + (hval << 7) + (hval << 8) + (hval << 24); | |
} | |
return hval >>> 0; | |
} | |
// Hex http://engineering.chartbeat.com/2014/08/13/you-dont-know-jack-about-hashing/ | |
function fnv32h(str) { | |
var h = [0x6295c58d, 0x62b82175, 0x07bb0142, 0x6c62272e]; | |
for (var i = 0, len = str.lenth; i < len; i++) { | |
h[i % 4] ^= str.charCodeAt(i); | |
h[i % 4] *= 0x01000193; | |
} | |
/* returns 4 concatenated hex representations */ | |
return h[0].toString(16) + h[1].toString(16) + h[2].toString(16) + h[3].toString(16); | |
} | |
console.log(fnv32a('abc')); // 440920331 | |
console.log(fnv32a('abc').toString(2)); // 11010010001111110100100001011 | |
console.log(fnv32a('abc').toString(4)); // 122101332210023 | |
console.log(fnv32a('abc').toString(8)); // 3221764413 | |
console.log(fnv32a('abc').toString(16)); // 1a47e90b | |
console.log(fnv32a('abc').toString(32)); // d4fq8b | |
console.log(fnv32a('abc').toString(36)); // 7aigaz | |
console.log(fnv32h('abc')); // 6295c58d62b821757bb01426c62272e | |
(1234567890).toString(36) // => "kf12oi" | |
parseInt("kf12oi",36) // => 1234567890 | |
// Good read: http://programmers.stackexchange.com/questions/49550/which-hashing-algorithm-is-best-for-uniqueness-and-speed |
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