mirror of
https://github.com/fluencelabs/assemblyscript
synced 2025-04-26 23:42:15 +00:00
62 lines
2.5 KiB
TypeScript
62 lines
2.5 KiB
TypeScript
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import {
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HEADER_SIZE as HEADER_SIZE_STR
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} from "./string";
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// FNV-1a 32-bit as a starting point, see: http://isthe.com/chongo/tech/comp/fnv/
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const FNV_OFFSET: u32 = 2166136261;
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const FNV_PRIME: u32 = 16777619;
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export function hash<T>(key: T): u32 {
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var hash: u32 = FNV_OFFSET;
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if (isString(key)) {
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for (let i: usize = 0, k: usize = key.length << 1; i < k; ++i) {
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hash = (hash ^ <u32>load<u8>(changetype<usize>(key) + i, HEADER_SIZE_STR)) * FNV_PRIME;
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}
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} else if (isFloat(key)) {
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if (sizeof<T>() == 4) { // f32
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let u = reinterpret<u32>(key);
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hash = (hash ^ ( u & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((u >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((u >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( u >>> 24 )) * FNV_PRIME;
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} else if (sizeof<T>() == 8) { // f64
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let u = reinterpret<u64>(key);
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let l = <u32> u;
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let h = <u32>(u >>> 32);
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hash = (hash ^ ( l & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((l >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((l >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( l >>> 24 )) * FNV_PRIME;
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hash = (hash ^ ( h & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((h >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((h >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( h >>> 24 )) * FNV_PRIME;
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} else unreachable();
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} else if (sizeof<T>() == 1) { // bool, i8, u8
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hash = (hash ^ (<u32>key & 0xff)) * FNV_PRIME;
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} else if (sizeof<T>() == 2) { // i16, u16
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let u = <u32>key;
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hash = (hash ^ ( u & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( u >>> 8 )) * FNV_PRIME;
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} else if (sizeof<T>() == 4) { // i32, u32
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let u = <u32>key;
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hash = (hash ^ ( u & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((u >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((u >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( u >>> 24 )) * FNV_PRIME;
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} else if (sizeof<T>() == 8) { // i64, u64
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let l = <u32> <u64>key;
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let h = <u32>(<u64>key >>> 32);
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hash = (hash ^ ( l & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((l >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((l >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( l >>> 24 )) * FNV_PRIME;
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hash = (hash ^ ( h & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((h >>> 8) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ((h >>> 16) & 0xff)) * FNV_PRIME;
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hash = (hash ^ ( h >>> 24 )) * FNV_PRIME;
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} else unreachable();
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return hash;
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}
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