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fix: preserve unsigned multiplication by MIN_VALUE without wasm #141

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fix: preserve unsigned multiplication by MIN_VALUE without wasm #141

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5 changes: 4 additions & 1 deletion index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -983,7 +983,10 @@ LongPrototype.multiply = function multiply(multiplier) {

if (multiplier.isZero()) return this.unsigned ? UZERO : ZERO;
if (this.eq(MIN_VALUE)) return multiplier.isOdd() ? MIN_VALUE : ZERO;
if (multiplier.eq(MIN_VALUE)) return this.isOdd() ? MIN_VALUE : ZERO;
if (multiplier.eq(MIN_VALUE)) {
if (this.isOdd()) return this.unsigned ? MIN_VALUE.toUnsigned() : MIN_VALUE;
return this.unsigned ? UZERO : ZERO;
}

if (this.isNegative()) {
if (multiplier.isNegative()) return this.neg().mul(multiplier.neg());
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24 changes: 24 additions & 0 deletions tests/index.js
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Original file line number Diff line number Diff line change
@@ -1,4 +1,6 @@
import assert from "assert";
import fs from "fs";
import vm from "vm";
import Long from "../index.js";

var tests = [
Expand Down Expand Up @@ -198,6 +200,28 @@ var tests = [
assert.strictEqual(x.unsigned, true);
},

function testUnsignedMinValueMultiplication() {
var context = { module: { exports: {} }, WebAssembly: undefined };
context.exports = context.module.exports;
vm.runInNewContext(
fs.readFileSync(new URL("../umd/index.js", import.meta.url), "utf8"),
context,
);
var implementations = [Long, context.module.exports];
var expected = ["0", "9223372036854775808", "0", "9223372036854775808"];
for (var i = 0; i < implementations.length; i++) {
var LongImpl = implementations[i];
for (var n = 0; n < expected.length; n++) {
var product = LongImpl.fromInt(n, true).mul(LongImpl.MIN_VALUE);
assert.strictEqual(product.unsigned, true);
assert.strictEqual(product.toString(), expected[n]);
}
var signedProduct = LongImpl.ONE.mul(LongImpl.MIN_VALUE);
assert.strictEqual(signedProduct.unsigned, false);
assert.strictEqual(signedProduct.toString(), "-9223372036854775808");
}
},

function testRotateLeft() {
var longVal = Long.fromBits(0x01234567, 0x89abcdef);
var longValL = Long.fromBits(0x12345678, 0x9abcdef0);
Expand Down