Java BigDecimal Log log10AbsCeil(BigDecimal x)

Description

log Abs Ceil

License

Open Source License

Declaration

public static int log10AbsCeil(BigDecimal x) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.math.BigDecimal;
import java.math.BigInteger;

public class Main {
    public static int log10AbsCeil(BigInteger x) {
        if (x.signum() == 0) {
            throw new IllegalArgumentException("x == 0");
        }//from   w  w  w  .  ja  va2 s  .  co m
        if (x.signum() < 0) {
            x = x.negate();
        }
        if (x.equals(BigInteger.ONE)) {
            return 0;
        }
        return x.subtract(BigInteger.ONE).toString().length();
    }

    public static int log10AbsCeil(BigDecimal x) {
        int log10 = log10AbsCeil(x.unscaledValue());
        return subInts(log10, x.scale());
    }

    public static int subInts(int a, int b) {
        if ((b > 0 && a < Integer.MIN_VALUE + b) || (b < 0 && a > Integer.MAX_VALUE + b)) {
            throw new ArithmeticException("int \"-\" overflow");
        }
        return a - b;
    }
}

Related

1. log(int base_int, BigDecimal x)
2. log10(BigDecimal b)
3. log2AbsCeil(BigDecimal x)