Java Double to doubleToLex(double v)

Description

Converts a regular java double to a lexicographical sortable double

License

Apache License

Parameter

Parameter	Description
v	a parameter

Declaration

public static byte[] doubleToLex(double v) 

Method Source Code

//package com.java2s;
/*//w  w  w  .  j  ava  2s.c om
 * Copyright 2013 Jive Software, Inc
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

public class Main {
    static private final long c64 = 0x8000000000000000L;

    /**
     * Converts a regular java double to a lexicographical sortable double
     *
     * @param v
     * @return
     */
    public static byte[] doubleToLex(double v) {
        long l = Double.doubleToLongBits(v);
        if (Double.isNaN(v)) { // == on double in this case is ok
        } else if (v >= 0) {
            l ^= c64;
        } else {
            l ^= 0xFFFFFFFFFFFFFFFFL;
        }
        return longBytes(l, new byte[8], 0);
    }

    /**
     *
     * @param v
     * @param _bytes
     * @param _offset
     * @return
     */
    public static byte[] longBytes(long v, byte[] _bytes, int _offset) {
        _bytes[_offset + 0] = (byte) (v >>> 56);
        _bytes[_offset + 1] = (byte) (v >>> 48);
        _bytes[_offset + 2] = (byte) (v >>> 40);
        _bytes[_offset + 3] = (byte) (v >>> 32);
        _bytes[_offset + 4] = (byte) (v >>> 24);
        _bytes[_offset + 5] = (byte) (v >>> 16);
        _bytes[_offset + 6] = (byte) (v >>> 8);
        _bytes[_offset + 7] = (byte) v;
        return _bytes;
    }
}

Related

1. doubleToFractionStr(final Double d)
2. doubleToHashString(double value)
3. doubleToHexString(double val)
4. doubleToI18nString(double d)
5. doubleToIndex(final double x)
6. doubleToPercent(double value, int precision)
7. doubleToRational(double number)
8. doubleToRegisters(double d)
9. doubleToScale(double val)