Java Byte Array Create toBytes(int i)

Description

to Bytes

License

Open Source License

Declaration

public static byte[] toBytes(int i) 

Method Source Code

//package com.java2s;

public class Main {
    static final byte[] minValue = "-2147483648".getBytes();
    static final int[] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999,
            Integer.MAX_VALUE };//from  w  w w  .  ja v a 2s .  c  o m
    static final byte[] digitTens = { '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1',
            '1', '1', '1', '1', '1', '2', '2', '2', '2', '2', '2', '2', '2', '2', '2', '3', '3', '3', '3', '3', '3',
            '3', '3', '3', '3', '4', '4', '4', '4', '4', '4', '4', '4', '4', '4', '5', '5', '5', '5', '5', '5', '5',
            '5', '5', '5', '6', '6', '6', '6', '6', '6', '6', '6', '6', '6', '7', '7', '7', '7', '7', '7', '7', '7',
            '7', '7', '8', '8', '8', '8', '8', '8', '8', '8', '8', '8', '9', '9', '9', '9', '9', '9', '9', '9', '9',
            '9', };
    static final byte[] digitOnes = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4',
            '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5',
            '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6',
            '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7',
            '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8',
            '9', };
    static final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
            'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z' };

    public static byte[] toBytes(int i) {
        if (i == Integer.MIN_VALUE)
            return minValue;
        int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
        byte[] buf = new byte[size];
        getBytes(i, size, buf);
        return buf;
    }

    static int stringSize(int x) {
        for (int i = 0;; i++) {
            if (x <= sizeTable[i])
                return i + 1;
        }
    }

    static void getBytes(int i, int index, byte[] buf) {
        int q, r;
        int charPos = index;
        byte sign = 0;

        if (i < 0) {
            sign = '-';
            i = -i;
        }

        // Generate two digits per iteration
        while (i >= 65536) {
            q = i / 100;
            // really: r = i - (q * 100);
            r = i - ((q << 6) + (q << 5) + (q << 2));
            i = q;
            buf[--charPos] = digitOnes[r];
            buf[--charPos] = digitTens[r];
        }

        // Fall thru to fast mode for smaller numbers
        // assert(i <= 65536, i);
        for (;;) {
            q = (i * 52429) >>> (16 + 3);
            r = i - ((q << 3) + (q << 1)); // r = i-(q*10) ...
            buf[--charPos] = digits[r];
            i = q;
            if (i == 0)
                break;
        }
        if (sign != 0) {
            buf[--charPos] = sign;
        }
    }
}

Related

1. toBytes(int i)
2. toBytes(int i)
3. toBytes(int i)
4. toBytes(int i)
5. toBytes(int i)
6. toBytes(int i)
7. toBytes(int integer)
8. toBytes(int integer)
9. toBytes(int intValue)