893N/A/*
2362N/A * Copyright (c) 2008, 2009, Oracle and/or its affiliates. All rights reserved.
893N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
893N/A *
893N/A * This code is free software; you can redistribute it and/or modify it
893N/A * under the terms of the GNU General Public License version 2 only, as
2362N/A * published by the Free Software Foundation. Oracle designates this
893N/A * particular file as subject to the "Classpath" exception as provided
2362N/A * by Oracle in the LICENSE file that accompanied this code.
893N/A *
893N/A * This code is distributed in the hope that it will be useful, but WITHOUT
893N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
893N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
893N/A * version 2 for more details (a copy is included in the LICENSE file that
893N/A * accompanied this code).
893N/A *
893N/A * You should have received a copy of the GNU General Public License version
893N/A * 2 along with this work; if not, write to the Free Software Foundation,
893N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
893N/A *
2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
2362N/A * or visit www.oracle.com if you need additional information or have any
2362N/A * questions.
893N/A */
893N/A
893N/Apackage sun.nio.fs;
893N/A
893N/Aimport sun.misc.Unsafe;
893N/A
893N/A/**
893N/A * Factory for native buffers.
893N/A */
893N/A
893N/Aclass NativeBuffers {
893N/A private NativeBuffers() { }
893N/A
893N/A private static final Unsafe unsafe = Unsafe.getUnsafe();
893N/A
893N/A private static final int TEMP_BUF_POOL_SIZE = 3;
893N/A private static ThreadLocal<NativeBuffer[]> threadLocal =
893N/A new ThreadLocal<NativeBuffer[]>();
893N/A
893N/A /**
893N/A * Allocates a native buffer, of at least the given size, from the heap.
893N/A */
893N/A static NativeBuffer allocNativeBuffer(int size) {
893N/A // Make a new one of at least 2k
893N/A if (size < 2048) size = 2048;
893N/A return new NativeBuffer(size);
893N/A }
893N/A
893N/A /**
893N/A * Returns a native buffer, of at least the given size, from the thread
893N/A * local cache.
893N/A */
893N/A static NativeBuffer getNativeBufferFromCache(int size) {
893N/A // return from cache if possible
893N/A NativeBuffer[] buffers = threadLocal.get();
893N/A if (buffers != null) {
893N/A for (int i=0; i<TEMP_BUF_POOL_SIZE; i++) {
893N/A NativeBuffer buffer = buffers[i];
893N/A if (buffer != null && buffer.size() >= size) {
893N/A buffers[i] = null;
893N/A return buffer;
893N/A }
893N/A }
893N/A }
893N/A return null;
893N/A }
893N/A
893N/A /**
893N/A * Returns a native buffer, of at least the given size. The native buffer
893N/A * is taken from the thread local cache if possible; otherwise it is
893N/A * allocated from the heap.
893N/A */
893N/A static NativeBuffer getNativeBuffer(int size) {
893N/A NativeBuffer buffer = getNativeBufferFromCache(size);
893N/A if (buffer != null) {
893N/A buffer.setOwner(null);
893N/A return buffer;
893N/A } else {
893N/A return allocNativeBuffer(size);
893N/A }
893N/A }
893N/A
893N/A /**
893N/A * Releases the given buffer. If there is space in the thread local cache
893N/A * then the buffer goes into the cache; otherwise the memory is deallocated.
893N/A */
893N/A static void releaseNativeBuffer(NativeBuffer buffer) {
893N/A // create cache if it doesn't exist
893N/A NativeBuffer[] buffers = threadLocal.get();
893N/A if (buffers == null) {
893N/A buffers = new NativeBuffer[TEMP_BUF_POOL_SIZE];
893N/A buffers[0] = buffer;
893N/A threadLocal.set(buffers);
893N/A return;
893N/A }
893N/A // Put it in an empty slot if such exists
893N/A for (int i=0; i<TEMP_BUF_POOL_SIZE; i++) {
893N/A if (buffers[i] == null) {
893N/A buffers[i] = buffer;
893N/A return;
893N/A }
893N/A }
893N/A // Otherwise replace a smaller one in the cache if such exists
893N/A for (int i=0; i<TEMP_BUF_POOL_SIZE; i++) {
893N/A NativeBuffer existing = buffers[i];
893N/A if (existing.size() < buffer.size()) {
893N/A existing.cleaner().clean();
893N/A buffers[i] = buffer;
893N/A return;
893N/A }
893N/A }
893N/A
893N/A // free it
893N/A buffer.cleaner().clean();
893N/A }
893N/A
893N/A /**
893N/A * Copies a byte array and zero terminator into a given native buffer.
893N/A */
893N/A static void copyCStringToNativeBuffer(byte[] cstr, NativeBuffer buffer) {
893N/A long offset = Unsafe.ARRAY_BYTE_BASE_OFFSET;
893N/A long len = cstr.length;
893N/A assert buffer.size() >= (len + 1);
893N/A unsafe.copyMemory(cstr, offset, null, buffer.address(), len);
893N/A unsafe.putByte(buffer.address() + len, (byte)0);
893N/A }
893N/A
893N/A /**
893N/A * Copies a byte array and zero terminator into a native buffer, returning
893N/A * the buffer.
893N/A */
893N/A static NativeBuffer asNativeBuffer(byte[] cstr) {
893N/A NativeBuffer buffer = getNativeBuffer(cstr.length+1);
893N/A copyCStringToNativeBuffer(cstr, buffer);
893N/A return buffer;
893N/A }
893N/A}