public static BigFraction from()

in commons-numbers-fraction/src/main/java/org/apache/commons/numbers/fraction/BigFraction.java [263:304]

• 34 lines of code
• 8 McCabe index (conditional complexity)

    public static BigFraction from(final double value) {
        if (!Double.isFinite(value)) {
            throw new IllegalArgumentException(NOT_FINITE + value);
        }
        if (value == 0) {
            return ZERO;
        }

        final long bits = Double.doubleToLongBits(value);
        final long sign = bits & 0x8000000000000000L;
        final long exponent = bits & 0x7ff0000000000000L;
        final long mantissa = bits & 0x000fffffffffffffL;

        // Compute m and k such that value = m * 2^k
        long m;
        int k;

        if (exponent == 0) {
            // Subnormal number, the effective exponent bias is 1022, not 1023.
            // Note: mantissa is never zero as that case has been eliminated.
            m = mantissa;
            k = -1074;
        } else {
            // Normalized number: Add the implicit most significant bit.
            m = mantissa | 0x0010000000000000L;
            k = ((int) (exponent >> 52)) - 1075; // Exponent bias is 1023.
        }
        if (sign != 0) {
            m = -m;
        }
        while ((m & 0x001ffffffffffffeL) != 0 &&
               (m & 0x1) == 0) {
            m >>= 1;
            ++k;
        }

        return k < 0 ?
            new BigFraction(BigInteger.valueOf(m),
                            BigInteger.ZERO.flipBit(-k)) :
            new BigFraction(BigInteger.valueOf(m).multiply(BigInteger.ZERO.flipBit(k)),
                            BigInteger.ONE);
    }