Java Char Create toChars(int number, char chars[])

Description

to Chars

License

Open Source License

Declaration

public static int toChars(int number, char chars[])

Method Source Code

//package com.java2s;
/*//  w ww  .j ava 2  s.  c  o  m
 * Copyright (C) ${year} Omry Yadan <${email}>
 * All rights reserved.
 *
 * See https://github.com/omry/banana/blob/master/BSD-LICENSE for licensing information
 */

public class Main {
    static char min_value[] = "-2147483648".toCharArray();
    /**
     * All possible chars for representing a number as a String
     */
    final static char[] 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' };
    final static char[] 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', };
    final static char[] 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', };
    final static int[] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999,
            Integer.MAX_VALUE };

    public static int toChars(int number, char chars[]) {
        if (number == Integer.MIN_VALUE) {
            System.arraycopy(min_value, 0, chars, 0, min_value.length);
            return min_value.length;
        }
        int size = (number < 0) ? stringSize(-number) + 1 : stringSize(number);
        getChars(number, size, chars);
        return size;
    }

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

    /**
     * Places characters representing the integer i into the character array buf.
     * The characters are placed into the buffer backwards starting with the least
     * significant digit at the specified index (exclusive), and working backwards
     * from there.
     *
     * Will fail if i == Integer.MIN_VALUE
     */
    static void getChars(int i, int index, char[] buf) {
        int q, r;
        int charPos = index;
        char 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;
        }
    }
}

Java Char Create toChars(int number, char chars[])

Description

License

Declaration

Method Source Code

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