/*
* Copyright (c) 2013, OpenCloudDB/MyCAT and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software;Designed and Developed mainly by many Chinese
* opensource volunteers. you can redistribute it and/or modify it under the
* terms of the GNU General Public License version 2 only, as published by the
* Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Any questions about this component can be directed to it's project Web address
* https://code.google.com/p/opencloudb/.
*
*/
package org.opencloudb.util;
/**
* @author mycat
*/
public final class LongUtil {
private static final byte[] minValue = "-9223372036854775808".getBytes();
public static byte[] toBytes(long i) {
if (i == Long.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(long x) {
long p = 10;
for (int i = 1; i < 19; i++) {
if (x < p)
return i;
p = 10 * p;
}
return 19;
}
static void getBytes(long i, int index, byte[] buf) {
long q;
int r;
int charPos = index;
byte sign = 0;
if (i < 0) {
sign = '-';
i = -i;
}
// Get 2 digits/iteration using longs until quotient fits into an int
while (i > Integer.MAX_VALUE) {
q = i / 100;
// really: r = i - (q * 100);
r = (int) (i - ((q << 6) + (q << 5) + (q << 2)));
i = q;
buf[--charPos] = IntegerUtil.digitOnes[r];
buf[--charPos] = IntegerUtil.digitTens[r];
}
// Get 2 digits/iteration using ints
int q2;
int i2 = (int) i;
while (i2 >= 65536) {
q2 = i2 / 100;
// really: r = i2 - (q * 100);
r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
i2 = q2;
buf[--charPos] = IntegerUtil.digitOnes[r];
buf[--charPos] = IntegerUtil.digitTens[r];
}
// Fall thru to fast mode for smaller numbers
// assert(i2 <= 65536, i2);
for (;;) {
q2 = (i2 * 52429) >>> (16 + 3);
r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
buf[--charPos] = IntegerUtil.digits[r];
i2 = q2;
if (i2 == 0)
break;
}
if (sign != 0) {
buf[--charPos] = sign;
}
}
}