Function floatToParts

javascript/packages/core/lib/compatible/scalar.ts:242–285

(value: number)

}

function floatToParts(value: number): DecimalParts {
  if (!Number.isFinite(value)) {
    throw new Error(`Non-finite scalar value ${value}.`);
  }
  if (Object.is(value, -0)) {
    return { unscaled: 0n, scale: 0, negativeZero: true };
  }
  if (value === 0) {
    return { unscaled: 0n, scale: 0, negativeZero: false };
  }
  float64DataView.setFloat64(0, value, false);
  const bits = float64DataView.getBigUint64(0, false);
  const negative = bits >> 63n !== 0n;
  const exponentBits = Number((bits >> 52n) & 0x7ffn);
  const fraction = bits & ((1n << 52n) - 1n);
  let mantissa: bigint;
  let exponent: number;
  if (exponentBits === 0) {
    mantissa = fraction;
    exponent = 1 - 1023 - 52;
  } else {
    mantissa = (1n << 52n) | fraction;
    exponent = exponentBits - 1023 - 52;
  }
  if (negative) {
    mantissa = -mantissa;
  }
  if (exponent >= 0) {
    return normalizeParts({
      unscaled: mantissa << BigInt(exponent),
      scale: 0,
      negativeZero: false,
    });
  }
  const scale = -exponent;
  if (scale > MAX_COMPATIBLE_DECIMAL_DIGITS) {
    throw new Error("Scalar float decimal expansion exceeds compatible limit.");
  }
  return normalizeParts({
    unscaled: mantissa * pow5(scale),
    scale,
    negativeZero: false,
  });
}

function parseDecimalString(value: string): DecimalParts {
  if (value.length === 0 || value.length > MAX_COMPATIBLE_NUMERIC_TEXT_LENGTH) {