1 /* 2 * Copyright (c) 2016, 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.hotspot; 24 25 /** 26 * A compact representation of the different encoding strategies for Objects and metadata. 27 */ 28 public class CompressEncoding { 29 public final long base; 30 public final int shift; 31 public final int alignment; 32 33 CompressEncoding(long base, int shift, int alignment) { 34 this.base = base; 35 this.shift = shift; 36 this.alignment = alignment; 37 } 38 39 public int compress(long ptr) { 40 if (ptr == 0L) { 41 return 0; 42 } else { 43 return (int) ((ptr - base) >>> shift); 44 } 45 } 46 47 public long uncompress(int ptr) { 48 if (ptr == 0) { 49 return 0L; 50 } else { 51 return ((ptr & 0xFFFFFFFFL) << shift) + base; 52 } 53 } 54 55 @Override 56 public String toString() { 57 return "base: " + base + " shift: " + shift + " alignment: " + alignment; 58 } 59 60 @Override 61 public int hashCode() { 62 final int prime = 31; 63 int result = 1; 64 result = prime * result + alignment; 65 result = prime * result + (int) (base ^ (base >>> 32)); 66 result = prime * result + shift; 67 return result; 68 } 69 70 @Override 71 public boolean equals(Object obj) { 72 if (obj instanceof CompressEncoding) { 73 CompressEncoding other = (CompressEncoding) obj; 74 return alignment == other.alignment && base == other.base && shift == other.shift; 75 } else { 76 return false; 77 } 78 } 79 }