1 /* 2 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.core.common; 24 25 /** 26 * A compact representation of the different encoding strategies for Objects and metadata. 27 */ 28 public final class CompressEncoding { 29 private final long base; 30 private final int shift; 31 32 public CompressEncoding(long base, int shift) { 33 this.base = base; 34 this.shift = shift; 35 } 36 37 public int compress(long ptr) { 38 if (ptr == 0L) { 39 return 0; 40 } else { 41 return (int) ((ptr - base) >>> shift); 42 } 43 } 44 45 public boolean hasBase() { 46 return base != 0; 47 } 48 49 public boolean hasShift() { 50 return shift != 0; 51 } 52 53 public long getBase() { 54 return base; 55 } 56 57 public int getShift() { 58 return shift; 59 } 60 61 public long uncompress(int ptr) { 62 if (ptr == 0) { 63 return 0L; 64 } else { 65 return ((ptr & 0xFFFFFFFFL) << shift) + base; 66 } 67 } 68 69 @Override 70 public String toString() { 71 return "base: " + base + " shift: " + shift; 72 } 73 74 @Override 75 public int hashCode() { 76 final int prime = 31; 77 int result = 1; 78 result = prime * result + (int) (base ^ (base >>> 32)); 79 result = prime * result + shift; 80 return result; 81 } 82 83 @Override 84 public boolean equals(Object obj) { 85 if (obj instanceof CompressEncoding) { 86 CompressEncoding other = (CompressEncoding) obj; 87 return base == other.base && shift == other.shift; 88 } else { 89 return false; 90 } 91 } 92 }