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HSQLDB example source code file (BitMap.java)
The HSQLDB BitMap.java source code/* Copyright (c) 2001-2008, The HSQL Development Group * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the HSQL Development Group nor the names of its * contributors may be used to endorse or promote products derived from this * software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG, * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package org.hsqldb.store; /** * Implementation of a bit map of any size, together with static methods to * manipulate int values as bit maps. * * @author fredt@users * @version 1.8.0 * @since 1.8.0 */ public class BitMap { int defaultCapacity; int capacity; int[] map; public BitMap(int initialCapacity) { int words = initialCapacity / 32; if (initialCapacity % 32 != 0) { words++; } defaultCapacity = capacity = words * 32; map = new int[words]; } /** * Resets to blank with original capacity */ public void reset() { map = new int[defaultCapacity / 32]; capacity = defaultCapacity; } /** * Sets pos and returns old value */ public int set(int pos) { while (pos >= capacity) { doubleCapacity(); } int windex = pos >> 5; int mask = 0x80000000 >>> (pos & 0x1F); int word = map[windex]; int result = (word & mask) == 0 ? 0 : 1; map[windex] = (word | mask); return result; } /** * Unsets pos and returns old value */ public int unset(int pos) { if (pos >= capacity) { return 0; } int windex = pos >> 5; int mask = 0x80000000 >>> (pos & 0x1F); int word = map[windex]; int result = (word & mask) == 0 ? 0 : 1; mask = ~mask; map[windex] = (word & mask); return result; } public int get(int pos) { while (pos >= capacity) { doubleCapacity(); } int windex = pos >> 5; int mask = 0x80000000 >>> (pos & 0x1F); int word = map[windex]; return (word & mask) == 0 ? 0 : 1; } public static int set(int map, int pos) { int mask = 0x80000000 >>> pos; return (map | mask); } public static int unset(int map, int pos) { int mask = 0x80000000 >>> pos; mask = ~mask; return (map & mask); } public static boolean isSet(int map, int pos) { int mask = 0x80000000 >>> pos; return (map & mask) == 0 ? false : true; } private void doubleCapacity() { int[] newmap = new int[map.length * 2]; capacity *= 2; System.arraycopy(map, 0, newmap, 0, map.length); map = newmap; } } Other HSQLDB examples (source code examples)Here is a short list of links related to this HSQLDB BitMap.java source code file: |
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