1 /*
2 * Copyright (c) 2003, Henri Yandell
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or
6 * without modification, are permitted provided that the
7 * following conditions are met:
8 *
9 * + Redistributions of source code must retain the above copyright notice,
10 * this list of conditions and the following disclaimer.
11 *
12 * + Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the documentation
14 * and/or other materials provided with the distribution.
15 *
16 * + Neither the name of Genjava-Core nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
24 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32 package com.generationjava.lang;
33
34 import java.math.BigInteger;
35
36 // NOTE: A BigInteger runs counter-intuitive possible. For an integer made
37 // of the bits: 11010101 the first two bits are '01' and not 11.
38 // That is, the indexing starts from the right and goes left.
39 public class BigIntegerUtils {
40
41 public static float extractFloat(BigInteger bi, int start, int end, int decimal) {
42 int intpart = extractInt(bi, start+decimal, end);
43 int decpart = extractInt(bi, start, start+decimal);
44 float decf = decpart;
45 while(decf >= 1.0) {
46 decf = decf / 10;
47 }
48 float ret = intpart + decf;
49 return ret;
50 }
51 public static int extractInt(BigInteger bi, int start, int end) {
52 bi = bi.shiftRight(start);
53 int foo = (int)Math.pow(2, end - start) - 1;
54 BigInteger mask = BigInteger.valueOf(foo);
55 bi = bi.and(mask);
56 return bi.intValue();
57 }
58 public static boolean extractBoolean(BigInteger bi, int index) {
59 return bi.testBit(index);
60 }
61
62 }