Tomasz Zawadzki
31 lines
1.8 KiB
Diff
31 lines
1.8 KiB
Diff
diff --git a/index.js b/index.js
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index 12101e1b954e1a8c7bf7887bef4f4e08fb06a8be..51d7af352a8a222c5320426f376d51c5a173300b 100644
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--- a/index.js
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+++ b/index.js
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@@ -170,6 +170,13 @@ var BigDecimal = class BigDecimal {
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times(y) {
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const other = BigDecimal._coerce(y);
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if (this._special || other._special) return this._specialArith(other, "times");
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+ // Fast path: multiplying by exactly 1 is an identity operation. ECMA-402's
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+ // ToRawFixed multiplies by roundingIncrement, which defaults to 1, on every
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+ // format call - without this check that is a full BigInt multiply followed
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+ // by a trailing-zero strip. BigDecimal is immutable, so returning the
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+ // existing instance is safe.
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+ if (other._mantissa === 1n && other._exponent === 0) return this;
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+ if (this._mantissa === 1n && this._exponent === 0) return other;
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if (this._mantissa === 0n || other._mantissa === 0n) {
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const negZero = this._isSignNegative() ? !other._isSignNegative() : other._isSignNegative();
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return BigDecimal._create(0n, 0, SpecialValue.NONE, negZero);
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@@ -189,6 +196,11 @@ var BigDecimal = class BigDecimal {
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const negZero = this._isSignNegative() !== other._isSignNegative();
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return BigDecimal._create(0n, 0, SpecialValue.NONE, negZero);
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}
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+ // Fast path: dividing by exactly 1 is an identity operation. ECMA-402's
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+ // ToRawFixed divides by roundingIncrement, which defaults to 1, on every
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+ // format call - without this check that is a 10^DIV_PRECISION BigInt
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+ // scale-up, a division, and a trailing-zero strip that undoes the scaling.
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+ if (other._mantissa === 1n && other._exponent === 0) return this;
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const [nm, ne] = removeTrailingZeros(this._mantissa * bigintPow10(DIV_PRECISION) / other._mantissa, this._exponent - other._exponent - DIV_PRECISION);
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return BigDecimal._create(nm, ne, SpecialValue.NONE, false);
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}
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