| /* |
| * Copyright (c) 2000, 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * 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 java.nio; |
| |
| import java.security.AccessController; |
| import java.util.concurrent.atomic.AtomicLong; |
| import java.util.concurrent.atomic.LongAdder; |
| |
| import sun.misc.JavaLangRefAccess; |
| import sun.misc.SharedSecrets; |
| import sun.misc.Unsafe; |
| import sun.misc.VM; |
| |
| /** |
| * Access to bits, native and otherwise. |
| */ |
| |
| class Bits { // package-private |
| |
| private Bits() { } |
| |
| |
| // -- Swapping -- |
| |
| static short swap(short x) { |
| return Short.reverseBytes(x); |
| } |
| |
| static char swap(char x) { |
| return Character.reverseBytes(x); |
| } |
| |
| static int swap(int x) { |
| return Integer.reverseBytes(x); |
| } |
| |
| static long swap(long x) { |
| return Long.reverseBytes(x); |
| } |
| |
| |
| // -- get/put char -- |
| |
| static private char makeChar(byte b1, byte b0) { |
| return (char)((b1 << 8) | (b0 & 0xff)); |
| } |
| |
| static char getCharL(ByteBuffer bb, int bi) { |
| return makeChar(bb._get(bi + 1), |
| bb._get(bi )); |
| } |
| |
| static char getCharL(long a) { |
| return makeChar(_get(a + 1), |
| _get(a )); |
| } |
| |
| static char getCharB(ByteBuffer bb, int bi) { |
| return makeChar(bb._get(bi ), |
| bb._get(bi + 1)); |
| } |
| |
| static char getCharB(long a) { |
| return makeChar(_get(a ), |
| _get(a + 1)); |
| } |
| |
| static char getChar(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getCharB(bb, bi) : getCharL(bb, bi); |
| } |
| |
| static char getChar(long a, boolean bigEndian) { |
| return bigEndian ? getCharB(a) : getCharL(a); |
| } |
| |
| private static byte char1(char x) { return (byte)(x >> 8); } |
| private static byte char0(char x) { return (byte)(x ); } |
| |
| static void putCharL(ByteBuffer bb, int bi, char x) { |
| bb._put(bi , char0(x)); |
| bb._put(bi + 1, char1(x)); |
| } |
| |
| static void putCharL(long a, char x) { |
| _put(a , char0(x)); |
| _put(a + 1, char1(x)); |
| } |
| |
| static void putCharB(ByteBuffer bb, int bi, char x) { |
| bb._put(bi , char1(x)); |
| bb._put(bi + 1, char0(x)); |
| } |
| |
| static void putCharB(long a, char x) { |
| _put(a , char1(x)); |
| _put(a + 1, char0(x)); |
| } |
| |
| static void putChar(ByteBuffer bb, int bi, char x, boolean bigEndian) { |
| if (bigEndian) |
| putCharB(bb, bi, x); |
| else |
| putCharL(bb, bi, x); |
| } |
| |
| static void putChar(long a, char x, boolean bigEndian) { |
| if (bigEndian) |
| putCharB(a, x); |
| else |
| putCharL(a, x); |
| } |
| |
| |
| // -- get/put short -- |
| |
| static private short makeShort(byte b1, byte b0) { |
| return (short)((b1 << 8) | (b0 & 0xff)); |
| } |
| |
| static short getShortL(ByteBuffer bb, int bi) { |
| return makeShort(bb._get(bi + 1), |
| bb._get(bi )); |
| } |
| |
| static short getShortL(long a) { |
| return makeShort(_get(a + 1), |
| _get(a )); |
| } |
| |
| static short getShortB(ByteBuffer bb, int bi) { |
| return makeShort(bb._get(bi ), |
| bb._get(bi + 1)); |
| } |
| |
| static short getShortB(long a) { |
| return makeShort(_get(a ), |
| _get(a + 1)); |
| } |
| |
| static short getShort(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getShortB(bb, bi) : getShortL(bb, bi); |
| } |
| |
| static short getShort(long a, boolean bigEndian) { |
| return bigEndian ? getShortB(a) : getShortL(a); |
| } |
| |
| private static byte short1(short x) { return (byte)(x >> 8); } |
| private static byte short0(short x) { return (byte)(x ); } |
| |
| static void putShortL(ByteBuffer bb, int bi, short x) { |
| bb._put(bi , short0(x)); |
| bb._put(bi + 1, short1(x)); |
| } |
| |
| static void putShortL(long a, short x) { |
| _put(a , short0(x)); |
| _put(a + 1, short1(x)); |
| } |
| |
| static void putShortB(ByteBuffer bb, int bi, short x) { |
| bb._put(bi , short1(x)); |
| bb._put(bi + 1, short0(x)); |
| } |
| |
| static void putShortB(long a, short x) { |
| _put(a , short1(x)); |
| _put(a + 1, short0(x)); |
| } |
| |
| static void putShort(ByteBuffer bb, int bi, short x, boolean bigEndian) { |
| if (bigEndian) |
| putShortB(bb, bi, x); |
| else |
| putShortL(bb, bi, x); |
| } |
| |
| static void putShort(long a, short x, boolean bigEndian) { |
| if (bigEndian) |
| putShortB(a, x); |
| else |
| putShortL(a, x); |
| } |
| |
| |
| // -- get/put int -- |
| |
| static private int makeInt(byte b3, byte b2, byte b1, byte b0) { |
| return (((b3 ) << 24) | |
| ((b2 & 0xff) << 16) | |
| ((b1 & 0xff) << 8) | |
| ((b0 & 0xff) )); |
| } |
| |
| static int getIntL(ByteBuffer bb, int bi) { |
| return makeInt(bb._get(bi + 3), |
| bb._get(bi + 2), |
| bb._get(bi + 1), |
| bb._get(bi )); |
| } |
| |
| static int getIntL(long a) { |
| return makeInt(_get(a + 3), |
| _get(a + 2), |
| _get(a + 1), |
| _get(a )); |
| } |
| |
| static int getIntB(ByteBuffer bb, int bi) { |
| return makeInt(bb._get(bi ), |
| bb._get(bi + 1), |
| bb._get(bi + 2), |
| bb._get(bi + 3)); |
| } |
| |
| static int getIntB(long a) { |
| return makeInt(_get(a ), |
| _get(a + 1), |
| _get(a + 2), |
| _get(a + 3)); |
| } |
| |
| static int getInt(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getIntB(bb, bi) : getIntL(bb, bi) ; |
| } |
| |
| static int getInt(long a, boolean bigEndian) { |
| return bigEndian ? getIntB(a) : getIntL(a) ; |
| } |
| |
| private static byte int3(int x) { return (byte)(x >> 24); } |
| private static byte int2(int x) { return (byte)(x >> 16); } |
| private static byte int1(int x) { return (byte)(x >> 8); } |
| private static byte int0(int x) { return (byte)(x ); } |
| |
| static void putIntL(ByteBuffer bb, int bi, int x) { |
| bb._put(bi + 3, int3(x)); |
| bb._put(bi + 2, int2(x)); |
| bb._put(bi + 1, int1(x)); |
| bb._put(bi , int0(x)); |
| } |
| |
| static void putIntL(long a, int x) { |
| _put(a + 3, int3(x)); |
| _put(a + 2, int2(x)); |
| _put(a + 1, int1(x)); |
| _put(a , int0(x)); |
| } |
| |
| static void putIntB(ByteBuffer bb, int bi, int x) { |
| bb._put(bi , int3(x)); |
| bb._put(bi + 1, int2(x)); |
| bb._put(bi + 2, int1(x)); |
| bb._put(bi + 3, int0(x)); |
| } |
| |
| static void putIntB(long a, int x) { |
| _put(a , int3(x)); |
| _put(a + 1, int2(x)); |
| _put(a + 2, int1(x)); |
| _put(a + 3, int0(x)); |
| } |
| |
| static void putInt(ByteBuffer bb, int bi, int x, boolean bigEndian) { |
| if (bigEndian) |
| putIntB(bb, bi, x); |
| else |
| putIntL(bb, bi, x); |
| } |
| |
| static void putInt(long a, int x, boolean bigEndian) { |
| if (bigEndian) |
| putIntB(a, x); |
| else |
| putIntL(a, x); |
| } |
| |
| |
| // -- get/put long -- |
| |
| static private long makeLong(byte b7, byte b6, byte b5, byte b4, |
| byte b3, byte b2, byte b1, byte b0) |
| { |
| return ((((long)b7 ) << 56) | |
| (((long)b6 & 0xff) << 48) | |
| (((long)b5 & 0xff) << 40) | |
| (((long)b4 & 0xff) << 32) | |
| (((long)b3 & 0xff) << 24) | |
| (((long)b2 & 0xff) << 16) | |
| (((long)b1 & 0xff) << 8) | |
| (((long)b0 & 0xff) )); |
| } |
| |
| static long getLongL(ByteBuffer bb, int bi) { |
| return makeLong(bb._get(bi + 7), |
| bb._get(bi + 6), |
| bb._get(bi + 5), |
| bb._get(bi + 4), |
| bb._get(bi + 3), |
| bb._get(bi + 2), |
| bb._get(bi + 1), |
| bb._get(bi )); |
| } |
| |
| static long getLongL(long a) { |
| return makeLong(_get(a + 7), |
| _get(a + 6), |
| _get(a + 5), |
| _get(a + 4), |
| _get(a + 3), |
| _get(a + 2), |
| _get(a + 1), |
| _get(a )); |
| } |
| |
| static long getLongB(ByteBuffer bb, int bi) { |
| return makeLong(bb._get(bi ), |
| bb._get(bi + 1), |
| bb._get(bi + 2), |
| bb._get(bi + 3), |
| bb._get(bi + 4), |
| bb._get(bi + 5), |
| bb._get(bi + 6), |
| bb._get(bi + 7)); |
| } |
| |
| static long getLongB(long a) { |
| return makeLong(_get(a ), |
| _get(a + 1), |
| _get(a + 2), |
| _get(a + 3), |
| _get(a + 4), |
| _get(a + 5), |
| _get(a + 6), |
| _get(a + 7)); |
| } |
| |
| static long getLong(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getLongB(bb, bi) : getLongL(bb, bi); |
| } |
| |
| static long getLong(long a, boolean bigEndian) { |
| return bigEndian ? getLongB(a) : getLongL(a); |
| } |
| |
| private static byte long7(long x) { return (byte)(x >> 56); } |
| private static byte long6(long x) { return (byte)(x >> 48); } |
| private static byte long5(long x) { return (byte)(x >> 40); } |
| private static byte long4(long x) { return (byte)(x >> 32); } |
| private static byte long3(long x) { return (byte)(x >> 24); } |
| private static byte long2(long x) { return (byte)(x >> 16); } |
| private static byte long1(long x) { return (byte)(x >> 8); } |
| private static byte long0(long x) { return (byte)(x ); } |
| |
| static void putLongL(ByteBuffer bb, int bi, long x) { |
| bb._put(bi + 7, long7(x)); |
| bb._put(bi + 6, long6(x)); |
| bb._put(bi + 5, long5(x)); |
| bb._put(bi + 4, long4(x)); |
| bb._put(bi + 3, long3(x)); |
| bb._put(bi + 2, long2(x)); |
| bb._put(bi + 1, long1(x)); |
| bb._put(bi , long0(x)); |
| } |
| |
| static void putLongL(long a, long x) { |
| _put(a + 7, long7(x)); |
| _put(a + 6, long6(x)); |
| _put(a + 5, long5(x)); |
| _put(a + 4, long4(x)); |
| _put(a + 3, long3(x)); |
| _put(a + 2, long2(x)); |
| _put(a + 1, long1(x)); |
| _put(a , long0(x)); |
| } |
| |
| static void putLongB(ByteBuffer bb, int bi, long x) { |
| bb._put(bi , long7(x)); |
| bb._put(bi + 1, long6(x)); |
| bb._put(bi + 2, long5(x)); |
| bb._put(bi + 3, long4(x)); |
| bb._put(bi + 4, long3(x)); |
| bb._put(bi + 5, long2(x)); |
| bb._put(bi + 6, long1(x)); |
| bb._put(bi + 7, long0(x)); |
| } |
| |
| static void putLongB(long a, long x) { |
| _put(a , long7(x)); |
| _put(a + 1, long6(x)); |
| _put(a + 2, long5(x)); |
| _put(a + 3, long4(x)); |
| _put(a + 4, long3(x)); |
| _put(a + 5, long2(x)); |
| _put(a + 6, long1(x)); |
| _put(a + 7, long0(x)); |
| } |
| |
| static void putLong(ByteBuffer bb, int bi, long x, boolean bigEndian) { |
| if (bigEndian) |
| putLongB(bb, bi, x); |
| else |
| putLongL(bb, bi, x); |
| } |
| |
| static void putLong(long a, long x, boolean bigEndian) { |
| if (bigEndian) |
| putLongB(a, x); |
| else |
| putLongL(a, x); |
| } |
| |
| |
| // -- get/put float -- |
| |
| static float getFloatL(ByteBuffer bb, int bi) { |
| return Float.intBitsToFloat(getIntL(bb, bi)); |
| } |
| |
| static float getFloatL(long a) { |
| return Float.intBitsToFloat(getIntL(a)); |
| } |
| |
| static float getFloatB(ByteBuffer bb, int bi) { |
| return Float.intBitsToFloat(getIntB(bb, bi)); |
| } |
| |
| static float getFloatB(long a) { |
| return Float.intBitsToFloat(getIntB(a)); |
| } |
| |
| static float getFloat(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getFloatB(bb, bi) : getFloatL(bb, bi); |
| } |
| |
| static float getFloat(long a, boolean bigEndian) { |
| return bigEndian ? getFloatB(a) : getFloatL(a); |
| } |
| |
| static void putFloatL(ByteBuffer bb, int bi, float x) { |
| putIntL(bb, bi, Float.floatToRawIntBits(x)); |
| } |
| |
| static void putFloatL(long a, float x) { |
| putIntL(a, Float.floatToRawIntBits(x)); |
| } |
| |
| static void putFloatB(ByteBuffer bb, int bi, float x) { |
| putIntB(bb, bi, Float.floatToRawIntBits(x)); |
| } |
| |
| static void putFloatB(long a, float x) { |
| putIntB(a, Float.floatToRawIntBits(x)); |
| } |
| |
| static void putFloat(ByteBuffer bb, int bi, float x, boolean bigEndian) { |
| if (bigEndian) |
| putFloatB(bb, bi, x); |
| else |
| putFloatL(bb, bi, x); |
| } |
| |
| static void putFloat(long a, float x, boolean bigEndian) { |
| if (bigEndian) |
| putFloatB(a, x); |
| else |
| putFloatL(a, x); |
| } |
| |
| |
| // -- get/put double -- |
| |
| static double getDoubleL(ByteBuffer bb, int bi) { |
| return Double.longBitsToDouble(getLongL(bb, bi)); |
| } |
| |
| static double getDoubleL(long a) { |
| return Double.longBitsToDouble(getLongL(a)); |
| } |
| |
| static double getDoubleB(ByteBuffer bb, int bi) { |
| return Double.longBitsToDouble(getLongB(bb, bi)); |
| } |
| |
| static double getDoubleB(long a) { |
| return Double.longBitsToDouble(getLongB(a)); |
| } |
| |
| static double getDouble(ByteBuffer bb, int bi, boolean bigEndian) { |
| return bigEndian ? getDoubleB(bb, bi) : getDoubleL(bb, bi); |
| } |
| |
| static double getDouble(long a, boolean bigEndian) { |
| return bigEndian ? getDoubleB(a) : getDoubleL(a); |
| } |
| |
| static void putDoubleL(ByteBuffer bb, int bi, double x) { |
| putLongL(bb, bi, Double.doubleToRawLongBits(x)); |
| } |
| |
| static void putDoubleL(long a, double x) { |
| putLongL(a, Double.doubleToRawLongBits(x)); |
| } |
| |
| static void putDoubleB(ByteBuffer bb, int bi, double x) { |
| putLongB(bb, bi, Double.doubleToRawLongBits(x)); |
| } |
| |
| static void putDoubleB(long a, double x) { |
| putLongB(a, Double.doubleToRawLongBits(x)); |
| } |
| |
| static void putDouble(ByteBuffer bb, int bi, double x, boolean bigEndian) { |
| if (bigEndian) |
| putDoubleB(bb, bi, x); |
| else |
| putDoubleL(bb, bi, x); |
| } |
| |
| static void putDouble(long a, double x, boolean bigEndian) { |
| if (bigEndian) |
| putDoubleB(a, x); |
| else |
| putDoubleL(a, x); |
| } |
| |
| |
| // -- Unsafe access -- |
| |
| private static final Unsafe unsafe = Unsafe.getUnsafe(); |
| |
| private static byte _get(long a) { |
| return unsafe.getByte(a); |
| } |
| |
| private static void _put(long a, byte b) { |
| unsafe.putByte(a, b); |
| } |
| |
| static Unsafe unsafe() { |
| return unsafe; |
| } |
| |
| |
| // -- Processor and memory-system properties -- |
| |
| private static final ByteOrder byteOrder; |
| |
| static ByteOrder byteOrder() { |
| if (byteOrder == null) |
| throw new Error("Unknown byte order"); |
| return byteOrder; |
| } |
| |
| static { |
| long a = unsafe.allocateMemory(8); |
| try { |
| unsafe.putLong(a, 0x0102030405060708L); |
| byte b = unsafe.getByte(a); |
| switch (b) { |
| case 0x01: byteOrder = ByteOrder.BIG_ENDIAN; break; |
| case 0x08: byteOrder = ByteOrder.LITTLE_ENDIAN; break; |
| default: |
| assert false; |
| byteOrder = null; |
| } |
| } finally { |
| unsafe.freeMemory(a); |
| } |
| } |
| |
| |
| private static int pageSize = -1; |
| |
| static int pageSize() { |
| if (pageSize == -1) |
| pageSize = unsafe().pageSize(); |
| return pageSize; |
| } |
| |
| static int pageCount(long size) { |
| return (int)(size + (long)pageSize() - 1L) / pageSize(); |
| } |
| |
| private static boolean unaligned; |
| private static boolean unalignedKnown = false; |
| |
| static boolean unaligned() { |
| if (unalignedKnown) |
| return unaligned; |
| String arch = AccessController.doPrivileged( |
| new sun.security.action.GetPropertyAction("os.arch")); |
| unaligned = arch.equals("i386") || arch.equals("x86") |
| || arch.equals("amd64") || arch.equals("x86_64"); |
| unalignedKnown = true; |
| return unaligned; |
| } |
| |
| |
| // -- Direct memory management -- |
| |
| // A user-settable upper limit on the maximum amount of allocatable |
| // direct buffer memory. This value may be changed during VM |
| // initialization if it is launched with "-XX:MaxDirectMemorySize=<size>". |
| private static volatile long maxMemory = VM.maxDirectMemory(); |
| private static final AtomicLong reservedMemory = new AtomicLong(); |
| private static final AtomicLong totalCapacity = new AtomicLong(); |
| private static final AtomicLong count = new AtomicLong(); |
| private static volatile boolean memoryLimitSet = false; |
| // max. number of sleeps during try-reserving with exponentially |
| // increasing delay before throwing OutOfMemoryError: |
| // 1, 2, 4, 8, 16, 32, 64, 128, 256 (total 511 ms ~ 0.5 s) |
| // which means that OOME will be thrown after 0.5 s of trying |
| private static final int MAX_SLEEPS = 9; |
| |
| // These methods should be called whenever direct memory is allocated or |
| // freed. They allow the user to control the amount of direct memory |
| // which a process may access. All sizes are specified in bytes. |
| static void reserveMemory(long size, int cap) { |
| |
| if (!memoryLimitSet && VM.isBooted()) { |
| maxMemory = VM.maxDirectMemory(); |
| memoryLimitSet = true; |
| } |
| |
| // optimist! |
| if (tryReserveMemory(size, cap)) { |
| return; |
| } |
| |
| final JavaLangRefAccess jlra = SharedSecrets.getJavaLangRefAccess(); |
| |
| // retry while helping enqueue pending Reference objects |
| // which includes executing pending Cleaner(s) which includes |
| // Cleaner(s) that free direct buffer memory |
| while (jlra.tryHandlePendingReference()) { |
| if (tryReserveMemory(size, cap)) { |
| return; |
| } |
| } |
| |
| // trigger VM's Reference processing |
| System.gc(); |
| |
| // a retry loop with exponential back-off delays |
| // (this gives VM some time to do it's job) |
| boolean interrupted = false; |
| try { |
| long sleepTime = 1; |
| int sleeps = 0; |
| while (true) { |
| if (tryReserveMemory(size, cap)) { |
| return; |
| } |
| if (sleeps >= MAX_SLEEPS) { |
| break; |
| } |
| if (!jlra.tryHandlePendingReference()) { |
| try { |
| Thread.sleep(sleepTime); |
| sleepTime <<= 1; |
| sleeps++; |
| } catch (InterruptedException e) { |
| interrupted = true; |
| } |
| } |
| } |
| |
| // no luck |
| throw new OutOfMemoryError("Direct buffer memory"); |
| |
| } finally { |
| if (interrupted) { |
| // don't swallow interrupts |
| Thread.currentThread().interrupt(); |
| } |
| } |
| } |
| |
| private static boolean tryReserveMemory(long size, int cap) { |
| |
| // -XX:MaxDirectMemorySize limits the total capacity rather than the |
| // actual memory usage, which will differ when buffers are page |
| // aligned. |
| long totalCap; |
| while (cap <= maxMemory - (totalCap = totalCapacity.get())) { |
| if (totalCapacity.compareAndSet(totalCap, totalCap + cap)) { |
| reservedMemory.addAndGet(size); |
| count.incrementAndGet(); |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| |
| static void unreserveMemory(long size, int cap) { |
| long cnt = count.decrementAndGet(); |
| long reservedMem = reservedMemory.addAndGet(-size); |
| long totalCap = totalCapacity.addAndGet(-cap); |
| assert cnt >= 0 && reservedMem >= 0 && totalCap >= 0; |
| } |
| |
| // -- Monitoring of direct buffer usage -- |
| |
| static { |
| // setup access to this package in SharedSecrets |
| sun.misc.SharedSecrets.setJavaNioAccess( |
| new sun.misc.JavaNioAccess() { |
| @Override |
| public sun.misc.JavaNioAccess.BufferPool getDirectBufferPool() { |
| return new sun.misc.JavaNioAccess.BufferPool() { |
| @Override |
| public String getName() { |
| return "direct"; |
| } |
| @Override |
| public long getCount() { |
| return Bits.count.get(); |
| } |
| @Override |
| public long getTotalCapacity() { |
| return Bits.totalCapacity.get(); |
| } |
| @Override |
| public long getMemoryUsed() { |
| return Bits.reservedMemory.get(); |
| } |
| }; |
| } |
| @Override |
| public ByteBuffer newDirectByteBuffer(long addr, int cap, Object ob) { |
| return new DirectByteBuffer(addr, cap, ob); |
| } |
| @Override |
| public void truncate(Buffer buf) { |
| buf.truncate(); |
| } |
| }); |
| } |
| |
| // -- Bulk get/put acceleration -- |
| |
| // These numbers represent the point at which we have empirically |
| // determined that the average cost of a JNI call exceeds the expense |
| // of an element by element copy. These numbers may change over time. |
| static final int JNI_COPY_TO_ARRAY_THRESHOLD = 6; |
| static final int JNI_COPY_FROM_ARRAY_THRESHOLD = 6; |
| |
| // This number limits the number of bytes to copy per call to Unsafe's |
| // copyMemory method. A limit is imposed to allow for safepoint polling |
| // during a large copy |
| static final long UNSAFE_COPY_THRESHOLD = 1024L * 1024L; |
| |
| // These methods do no bounds checking. Verification that the copy will not |
| // result in memory corruption should be done prior to invocation. |
| // All positions and lengths are specified in bytes. |
| |
| /** |
| * Copy from given source array to destination address. |
| * |
| * @param src |
| * source array |
| * @param srcBaseOffset |
| * offset of first element of storage in source array |
| * @param srcPos |
| * offset within source array of the first element to read |
| * @param dstAddr |
| * destination address |
| * @param length |
| * number of bytes to copy |
| */ |
| static void copyFromArray(Object src, long srcBaseOffset, long srcPos, |
| long dstAddr, long length) |
| { |
| long offset = srcBaseOffset + srcPos; |
| while (length > 0) { |
| long size = (length > UNSAFE_COPY_THRESHOLD) ? UNSAFE_COPY_THRESHOLD : length; |
| unsafe.copyMemory(src, offset, null, dstAddr, size); |
| length -= size; |
| offset += size; |
| dstAddr += size; |
| } |
| } |
| |
| /** |
| * Copy from source address into given destination array. |
| * |
| * @param srcAddr |
| * source address |
| * @param dst |
| * destination array |
| * @param dstBaseOffset |
| * offset of first element of storage in destination array |
| * @param dstPos |
| * offset within destination array of the first element to write |
| * @param length |
| * number of bytes to copy |
| */ |
| static void copyToArray(long srcAddr, Object dst, long dstBaseOffset, long dstPos, |
| long length) |
| { |
| long offset = dstBaseOffset + dstPos; |
| while (length > 0) { |
| long size = (length > UNSAFE_COPY_THRESHOLD) ? UNSAFE_COPY_THRESHOLD : length; |
| unsafe.copyMemory(null, srcAddr, dst, offset, size); |
| length -= size; |
| srcAddr += size; |
| offset += size; |
| } |
| } |
| |
| static void copyFromCharArray(Object src, long srcPos, long dstAddr, |
| long length) |
| { |
| copyFromShortArray(src, srcPos, dstAddr, length); |
| } |
| |
| static void copyToCharArray(long srcAddr, Object dst, long dstPos, |
| long length) |
| { |
| copyToShortArray(srcAddr, dst, dstPos, length); |
| } |
| |
| static native void copyFromShortArray(Object src, long srcPos, long dstAddr, |
| long length); |
| static native void copyToShortArray(long srcAddr, Object dst, long dstPos, |
| long length); |
| |
| static native void copyFromIntArray(Object src, long srcPos, long dstAddr, |
| long length); |
| static native void copyToIntArray(long srcAddr, Object dst, long dstPos, |
| long length); |
| |
| static native void copyFromLongArray(Object src, long srcPos, long dstAddr, |
| long length); |
| static native void copyToLongArray(long srcAddr, Object dst, long dstPos, |
| long length); |
| |
| } |
