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0865492 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | "use strict";
/**
* gearhash-jit — Fast GEAR rolling hash for content-defined chunking.
*
* Uses a tiny hand-written WASM module with native i64 arithmetic.
* The hash state is kept as raw bytes in JS (avoiding BigInt in the hot path)
* and written to WASM memory only for the `nextMatch` call.
*/
Object.defineProperty(exports, "__esModule", { value: true });
exports.Hasher = exports.GEAR_TABLE = void 0;
const wasm_js_1 = require("./wasm.js");
var table_js_1 = require("./table.js");
Object.defineProperty(exports, "GEAR_TABLE", { enumerable: true, get: function () { return table_js_1.GEAR_TABLE; } });
class Hasher {
maskBytes;
/**
* The current 64-bit rolling hash state as 8 little-endian bytes.
* Updated after every `nextMatch` call. Zeroed by `resetHash()`.
*/
hash;
constructor(mask) {
(0, wasm_js_1.initWasm)();
this.maskBytes = new Uint8Array(8);
this.hash = new Uint8Array(8);
new DataView(this.maskBytes.buffer).setBigUint64(0, mask, true);
}
/**
* Scan `buf` for the next gear-hash match. The internal hash state
* carries over between calls (for split-buffer scanning).
*
* @returns 1-based byte position of the match, or -1 if none found.
*/
nextMatch(buf) {
const len = buf.length;
if (len === 0)
return -1;
if (len > wasm_js_1.MAX_INPUT_SIZE) {
throw new RangeError(`Input too large: ${len} > ${wasm_js_1.MAX_INPUT_SIZE}`);
}
const view = (0, wasm_js_1.getView)();
view.set(this.hash, wasm_js_1.HASH_OFFSET);
view.set(this.maskBytes, wasm_js_1.MASK_OFFSET);
view.set(buf, wasm_js_1.INPUT_OFFSET);
const pos = (0, wasm_js_1.wasmNextMatch)(wasm_js_1.INPUT_OFFSET, len);
this.hash.set(view.subarray(wasm_js_1.HASH_OFFSET, wasm_js_1.HASH_OFFSET + 8));
return pos;
}
/** Reset rolling hash to zero (call when starting a new chunk). */
resetHash() {
this.hash.fill(0);
}
}
exports.Hasher = Hasher;
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