Mercurial > hg > graal-compiler
view graal/com.oracle.jvmci.common/src/com/oracle/jvmci/common/UnsafeAccess.java @ 21746:372fd062bb85
improved names of arraycopy snippet counters
author | Doug Simon <doug.simon@oracle.com> |
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date | Fri, 05 Jun 2015 17:07:45 +0200 |
parents | 5e868236654f |
children | 5b9adb645217 |
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/* * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.jvmci.common; import java.lang.reflect.*; import sun.misc.*; public class UnsafeAccess { /** * An instance of {@link Unsafe} for use within Graal. */ public static final Unsafe unsafe; static { try { Field theUnsafeInstance = Unsafe.class.getDeclaredField("theUnsafe"); theUnsafeInstance.setAccessible(true); unsafe = (Unsafe) theUnsafeInstance.get(Unsafe.class); } catch (Exception e) { throw new RuntimeException("exception while trying to get Unsafe", e); } } /** * Copies the contents of a {@link String} to a native memory buffer as a {@code '\0'} * terminated C string. The native memory buffer is allocated via * {@link Unsafe#allocateMemory(long)}. The caller is responsible for releasing the buffer when * it is no longer needed via {@link Unsafe#freeMemory(long)}. * * @return the native memory pointer of the C string created from {@code s} */ public static long createCString(String s) { return writeCString(s, unsafe.allocateMemory(s.length() + 1)); } /** * Reads a {@code '\0'} terminated C string from native memory and converts it to a * {@link String}. * * @return a Java string */ public static String readCString(long address) { if (address == 0) { return null; } StringBuilder sb = new StringBuilder(); for (int i = 0;; i++) { char c = (char) unsafe.getByte(address + i); if (c == 0) { break; } sb.append(c); } return sb.toString(); } /** * Writes the contents of a {@link String} to a native memory buffer as a {@code '\0'} * terminated C string. The caller is responsible for ensuring the buffer is at least * {@code s.length() + 1} bytes long. The caller is also responsible for releasing the buffer * when it is no longer. * * @return the value of {@code buf} */ public static long writeCString(String s, long buf) { int size = s.length(); for (int i = 0; i < size; i++) { unsafe.putByte(buf + i, (byte) s.charAt(i)); } unsafe.putByte(buf + size, (byte) '\0'); return buf; } }