/*
 * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 */

package com.jfinal.template.io;

import java.io.IOException;

public class IntegerWriter {
	
    final static int [] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999,
            99999999, 999999999, Integer.MAX_VALUE };
    
    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 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[] 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'
        };
    
    private static final byte[] minValueBytes = "-2147483648".getBytes();
    private static final char[] minValueChars = "-2147483648".toCharArray();
    
	public static void write(ByteWriter byteWriter, int i) throws IOException {
        if (i == Integer.MIN_VALUE) {
        	byteWriter.out.write(minValueBytes, 0, minValueBytes.length);
        	return ;
        }
        
        int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
        char[] chars = byteWriter.chars;
        byte[] bytes = byteWriter.bytes;
        getChars(i, size, chars);
        
        // int len = Utf8Encoder.me.encode(chars, 0, size, bytes);
        // byteWriter.out.write(bytes, 0, len);
        
        for (int j=0; j<size; j++) {
        	bytes[j] = (byte)chars[j];
        }
        byteWriter.out.write(bytes, 0, size);
    }
	
	public static void write(CharWriter charWriter, int i) throws IOException {
        if (i == Integer.MIN_VALUE) {
        	charWriter.out.write(minValueChars, 0, minValueChars.length);
        	return ;
        }
        
        int size = (i < 0) ? stringSize(-i) + 1 : stringSize(i);
        char[] chars = charWriter.chars;
        getChars(i, size, chars);
        charWriter.out.write(chars, 0, size);
    }
	
    static int stringSize(int x) {
        for (int i=0; ; i++)
            if (x <= sizeTable[i])
                return i+1;
    }
    
    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;
        }
    }
}