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XXHash32 JS Implementation
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| const getUint32 = (arr: Uint8Array, i: number) => ( | |
| arr[i] | arr[i + 1 | 0] << 8 | arr[i + 2 | 0] << 16 | arr[i + 3 | 0] << 24 | |
| ); | |
| const rotl32 = (x: number, r: number) => (x << r) | (x >>> 32 - r); | |
| const xxh32 = (buf: Uint8Array, seed = 0) => { | |
| seed |= 0; | |
| const len = buf.length | 0; | |
| let i = 0; | |
| let h = (seed + len | 0) + 0x165667B1 | 0; | |
| if (len < 16) { | |
| for (; (i + 3 | 0) < len; i = i + 4 | 0) | |
| h = Math.imul(rotl32(h + Math.imul(getUint32(buf, i), 0xC2B2AE3D) | 0, 17), 0x27D4EB2F); | |
| } else { | |
| let v0 = seed + 0x24234428 | 0; | |
| let v1 = seed + 0x85EBCA77 | 0; | |
| let v2 = seed; | |
| let v3 = seed - 0x9E3779B1 | 0; | |
| if (len < 256) { | |
| for (; (i + 15 | 0) < len; i = i + 16 | 0) { | |
| v0 = Math.imul(rotl32(v0 + Math.imul(getUint32(buf, i + 0 | 0), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v1 = Math.imul(rotl32(v1 + Math.imul(getUint32(buf, i + 4 | 0), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v2 = Math.imul(rotl32(v2 + Math.imul(getUint32(buf, i + 8 | 0), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v3 = Math.imul(rotl32(v3 + Math.imul(getUint32(buf, i + 12 | 0), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| } | |
| h = (((rotl32(v0, 1) + rotl32(v1, 7) | 0) + rotl32(v2, 12) | 0) + rotl32(v3, 18) | 0) + len | 0; | |
| for (; (i + 3 | 0) < len; i = i + 4 | 0) | |
| h = Math.imul(rotl32(h + Math.imul(getUint32(buf, i), 0xC2B2AE3D) | 0, 17), 0x27D4EB2F); | |
| } else { | |
| const view = new DataView(buf.buffer); | |
| for (; (i + 15 | 0) < len; i = i + 16 | 0) { | |
| v0 = Math.imul(rotl32(v0 + Math.imul(view.getUint32(i + 0 | 0, true), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v1 = Math.imul(rotl32(v1 + Math.imul(view.getUint32(i + 4 | 0, true), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v2 = Math.imul(rotl32(v2 + Math.imul(view.getUint32(i + 8 | 0, true), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| v3 = Math.imul(rotl32(v3 + Math.imul(view.getUint32(i + 12 | 0, true), 0x85EBCA77) | 0, 13), 0x9E3779B1); | |
| } | |
| h = (((rotl32(v0, 1) + rotl32(v1, 7) | 0) + rotl32(v2, 12) | 0) + rotl32(v3, 18) | 0) + len | 0; | |
| for (; (i + 3 | 0) < len; i = i + 4 | 0) | |
| h = Math.imul(rotl32(h + Math.imul(view.getUint32(i, true), 0xC2B2AE3D) | 0, 17), 0x27D4EB2F); | |
| } | |
| } | |
| for (; i < len; i = i + 1 | 0) | |
| h = Math.imul(rotl32(h + Math.imul(buf[i], 0x165667B1) | 0, 11), 0x9E3779B1); | |
| h = Math.imul(h ^ h >>> 15, 0x85EBCA77); | |
| h = Math.imul(h ^ h >>> 13, 0xC2B2AE3D); | |
| return (h ^ h >>> 16) >>> 0; | |
| }; | |
| export default xxh32; |
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