Java example source code file (ByteArrayAccess.java)
The ByteArrayAccess.java Java example source code
/*
* Copyright (c) 2006, 2013, 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 sun.security.provider;
import static java.lang.Integer.reverseBytes;
import static java.lang.Long.reverseBytes;
import java.nio.ByteOrder;
import sun.misc.Unsafe;
/**
* Optimized methods for converting between byte[] and int[]/long[], both for
* big endian and little endian byte orders.
*
* Currently, it includes a default code path plus two optimized code paths.
* One is for little endian architectures that support full speed int/long
* access at unaligned addresses (i.e. x86/amd64). The second is for big endian
* architectures (that only support correctly aligned access), such as SPARC.
* These are the only platforms we currently support, but other optimized
* variants could be added as needed.
*
* NOTE that ArrayIndexOutOfBoundsException will be thrown if the bounds checks
* failed.
*
* This class may also be helpful in improving the performance of the
* crypto code in the SunJCE provider. However, for now it is only accessible by
* the message digest implementation in the SUN provider.
*
* @since 1.6
* @author Andreas Sterbenz
*/
final class ByteArrayAccess {
private ByteArrayAccess() {
// empty
}
private static final Unsafe unsafe = Unsafe.getUnsafe();
// whether to use the optimized path for little endian platforms that
// support full speed unaligned memory access.
private static final boolean littleEndianUnaligned;
// whether to use the optimzied path for big endian platforms that
// support only correctly aligned full speed memory access.
// (Note that on SPARC unaligned memory access is possible, but it is
// implemented using a software trap and therefore very slow)
private static final boolean bigEndian;
private final static int byteArrayOfs = unsafe.arrayBaseOffset(byte[].class);
static {
boolean scaleOK = ((unsafe.arrayIndexScale(byte[].class) == 1)
&& (unsafe.arrayIndexScale(int[].class) == 4)
&& (unsafe.arrayIndexScale(long[].class) == 8)
&& ((byteArrayOfs & 3) == 0));
ByteOrder byteOrder = ByteOrder.nativeOrder();
littleEndianUnaligned =
scaleOK && unaligned() && (byteOrder == ByteOrder.LITTLE_ENDIAN);
bigEndian =
scaleOK && (byteOrder == ByteOrder.BIG_ENDIAN);
}
// Return whether this platform supports full speed int/long memory access
// at unaligned addresses.
// This code was copied from java.nio.Bits because there is no equivalent
// public API.
private static boolean unaligned() {
String arch = java.security.AccessController.doPrivileged
(new sun.security.action.GetPropertyAction("os.arch", ""));
return arch.equals("i386") || arch.equals("x86") || arch.equals("amd64")
|| arch.equals("x86_64");
}
/**
* byte[] to int[] conversion, little endian byte order.
*/
static void b2iLittle(byte[] in, int inOfs, int[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len) ||
(outOfs < 0) || ((out.length - outOfs) < len/4)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] = unsafe.getInt(in, (long)inOfs);
inOfs += 4;
}
} else if (bigEndian && ((inOfs & 3) == 0)) {
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] = reverseBytes(unsafe.getInt(in, (long)inOfs));
inOfs += 4;
}
} else {
len += inOfs;
while (inOfs < len) {
out[outOfs++] = ((in[inOfs ] & 0xff) )
| ((in[inOfs + 1] & 0xff) << 8)
| ((in[inOfs + 2] & 0xff) << 16)
| ((in[inOfs + 3] ) << 24);
inOfs += 4;
}
}
}
// Special optimization of b2iLittle(in, inOfs, out, 0, 64)
static void b2iLittle64(byte[] in, int inOfs, int[] out) {
if ((inOfs < 0) || ((in.length - inOfs) < 64) ||
(out.length < 16)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
out[ 0] = unsafe.getInt(in, (long)(inOfs ));
out[ 1] = unsafe.getInt(in, (long)(inOfs + 4));
out[ 2] = unsafe.getInt(in, (long)(inOfs + 8));
out[ 3] = unsafe.getInt(in, (long)(inOfs + 12));
out[ 4] = unsafe.getInt(in, (long)(inOfs + 16));
out[ 5] = unsafe.getInt(in, (long)(inOfs + 20));
out[ 6] = unsafe.getInt(in, (long)(inOfs + 24));
out[ 7] = unsafe.getInt(in, (long)(inOfs + 28));
out[ 8] = unsafe.getInt(in, (long)(inOfs + 32));
out[ 9] = unsafe.getInt(in, (long)(inOfs + 36));
out[10] = unsafe.getInt(in, (long)(inOfs + 40));
out[11] = unsafe.getInt(in, (long)(inOfs + 44));
out[12] = unsafe.getInt(in, (long)(inOfs + 48));
out[13] = unsafe.getInt(in, (long)(inOfs + 52));
out[14] = unsafe.getInt(in, (long)(inOfs + 56));
out[15] = unsafe.getInt(in, (long)(inOfs + 60));
} else if (bigEndian && ((inOfs & 3) == 0)) {
inOfs += byteArrayOfs;
out[ 0] = reverseBytes(unsafe.getInt(in, (long)(inOfs )));
out[ 1] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 4)));
out[ 2] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 8)));
out[ 3] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 12)));
out[ 4] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 16)));
out[ 5] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 20)));
out[ 6] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 24)));
out[ 7] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 28)));
out[ 8] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 32)));
out[ 9] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 36)));
out[10] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 40)));
out[11] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 44)));
out[12] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 48)));
out[13] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 52)));
out[14] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 56)));
out[15] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 60)));
} else {
b2iLittle(in, inOfs, out, 0, 64);
}
}
/**
* int[] to byte[] conversion, little endian byte order.
*/
static void i2bLittle(int[] in, int inOfs, byte[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len/4) ||
(outOfs < 0) || ((out.length - outOfs) < len)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
outOfs += byteArrayOfs;
len += outOfs;
while (outOfs < len) {
unsafe.putInt(out, (long)outOfs, in[inOfs++]);
outOfs += 4;
}
} else if (bigEndian && ((outOfs & 3) == 0)) {
outOfs += byteArrayOfs;
len += outOfs;
while (outOfs < len) {
unsafe.putInt(out, (long)outOfs, reverseBytes(in[inOfs++]));
outOfs += 4;
}
} else {
len += outOfs;
while (outOfs < len) {
int i = in[inOfs++];
out[outOfs++] = (byte)(i );
out[outOfs++] = (byte)(i >> 8);
out[outOfs++] = (byte)(i >> 16);
out[outOfs++] = (byte)(i >> 24);
}
}
}
// Store one 32-bit value into out[outOfs..outOfs+3] in little endian order.
static void i2bLittle4(int val, byte[] out, int outOfs) {
if ((outOfs < 0) || ((out.length - outOfs) < 4)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
unsafe.putInt(out, (long)(byteArrayOfs + outOfs), val);
} else if (bigEndian && ((outOfs & 3) == 0)) {
unsafe.putInt(out, (long)(byteArrayOfs + outOfs), reverseBytes(val));
} else {
out[outOfs ] = (byte)(val );
out[outOfs + 1] = (byte)(val >> 8);
out[outOfs + 2] = (byte)(val >> 16);
out[outOfs + 3] = (byte)(val >> 24);
}
}
/**
* byte[] to int[] conversion, big endian byte order.
*/
static void b2iBig(byte[] in, int inOfs, int[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len) ||
(outOfs < 0) || ((out.length - outOfs) < len/4)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] = reverseBytes(unsafe.getInt(in, (long)inOfs));
inOfs += 4;
}
} else if (bigEndian && ((inOfs & 3) == 0)) {
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] = unsafe.getInt(in, (long)inOfs);
inOfs += 4;
}
} else {
len += inOfs;
while (inOfs < len) {
out[outOfs++] = ((in[inOfs + 3] & 0xff) )
| ((in[inOfs + 2] & 0xff) << 8)
| ((in[inOfs + 1] & 0xff) << 16)
| ((in[inOfs ] ) << 24);
inOfs += 4;
}
}
}
// Special optimization of b2iBig(in, inOfs, out, 0, 64)
static void b2iBig64(byte[] in, int inOfs, int[] out) {
if ((inOfs < 0) || ((in.length - inOfs) < 64) ||
(out.length < 16)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
out[ 0] = reverseBytes(unsafe.getInt(in, (long)(inOfs )));
out[ 1] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 4)));
out[ 2] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 8)));
out[ 3] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 12)));
out[ 4] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 16)));
out[ 5] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 20)));
out[ 6] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 24)));
out[ 7] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 28)));
out[ 8] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 32)));
out[ 9] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 36)));
out[10] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 40)));
out[11] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 44)));
out[12] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 48)));
out[13] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 52)));
out[14] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 56)));
out[15] = reverseBytes(unsafe.getInt(in, (long)(inOfs + 60)));
} else if (bigEndian && ((inOfs & 3) == 0)) {
inOfs += byteArrayOfs;
out[ 0] = unsafe.getInt(in, (long)(inOfs ));
out[ 1] = unsafe.getInt(in, (long)(inOfs + 4));
out[ 2] = unsafe.getInt(in, (long)(inOfs + 8));
out[ 3] = unsafe.getInt(in, (long)(inOfs + 12));
out[ 4] = unsafe.getInt(in, (long)(inOfs + 16));
out[ 5] = unsafe.getInt(in, (long)(inOfs + 20));
out[ 6] = unsafe.getInt(in, (long)(inOfs + 24));
out[ 7] = unsafe.getInt(in, (long)(inOfs + 28));
out[ 8] = unsafe.getInt(in, (long)(inOfs + 32));
out[ 9] = unsafe.getInt(in, (long)(inOfs + 36));
out[10] = unsafe.getInt(in, (long)(inOfs + 40));
out[11] = unsafe.getInt(in, (long)(inOfs + 44));
out[12] = unsafe.getInt(in, (long)(inOfs + 48));
out[13] = unsafe.getInt(in, (long)(inOfs + 52));
out[14] = unsafe.getInt(in, (long)(inOfs + 56));
out[15] = unsafe.getInt(in, (long)(inOfs + 60));
} else {
b2iBig(in, inOfs, out, 0, 64);
}
}
/**
* int[] to byte[] conversion, big endian byte order.
*/
static void i2bBig(int[] in, int inOfs, byte[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len/4) ||
(outOfs < 0) || ((out.length - outOfs) < len)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
outOfs += byteArrayOfs;
len += outOfs;
while (outOfs < len) {
unsafe.putInt(out, (long)outOfs, reverseBytes(in[inOfs++]));
outOfs += 4;
}
} else if (bigEndian && ((outOfs & 3) == 0)) {
outOfs += byteArrayOfs;
len += outOfs;
while (outOfs < len) {
unsafe.putInt(out, (long)outOfs, in[inOfs++]);
outOfs += 4;
}
} else {
len += outOfs;
while (outOfs < len) {
int i = in[inOfs++];
out[outOfs++] = (byte)(i >> 24);
out[outOfs++] = (byte)(i >> 16);
out[outOfs++] = (byte)(i >> 8);
out[outOfs++] = (byte)(i );
}
}
}
// Store one 32-bit value into out[outOfs..outOfs+3] in big endian order.
static void i2bBig4(int val, byte[] out, int outOfs) {
if ((outOfs < 0) || ((out.length - outOfs) < 4)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
unsafe.putInt(out, (long)(byteArrayOfs + outOfs), reverseBytes(val));
} else if (bigEndian && ((outOfs & 3) == 0)) {
unsafe.putInt(out, (long)(byteArrayOfs + outOfs), val);
} else {
out[outOfs ] = (byte)(val >> 24);
out[outOfs + 1] = (byte)(val >> 16);
out[outOfs + 2] = (byte)(val >> 8);
out[outOfs + 3] = (byte)(val );
}
}
/**
* byte[] to long[] conversion, big endian byte order.
*/
static void b2lBig(byte[] in, int inOfs, long[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len) ||
(outOfs < 0) || ((out.length - outOfs) < len/8)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] = reverseBytes(unsafe.getLong(in, (long)inOfs));
inOfs += 8;
}
} else if (bigEndian && ((inOfs & 3) == 0)) {
// In the current HotSpot memory layout, the first element of a
// byte[] is only 32-bit aligned, not 64-bit.
// That means we could use getLong() only for offset 4, 12, etc.,
// which would rarely occur in practice. Instead, we use an
// optimization that uses getInt() so that it works for offset 0.
inOfs += byteArrayOfs;
len += inOfs;
while (inOfs < len) {
out[outOfs++] =
((long)unsafe.getInt(in, (long)inOfs) << 32)
| (unsafe.getInt(in, (long)(inOfs + 4)) & 0xffffffffL);
inOfs += 8;
}
} else {
len += inOfs;
while (inOfs < len) {
int i1 = ((in[inOfs + 3] & 0xff) )
| ((in[inOfs + 2] & 0xff) << 8)
| ((in[inOfs + 1] & 0xff) << 16)
| ((in[inOfs ] ) << 24);
inOfs += 4;
int i2 = ((in[inOfs + 3] & 0xff) )
| ((in[inOfs + 2] & 0xff) << 8)
| ((in[inOfs + 1] & 0xff) << 16)
| ((in[inOfs ] ) << 24);
out[outOfs++] = ((long)i1 << 32) | (i2 & 0xffffffffL);
inOfs += 4;
}
}
}
// Special optimization of b2lBig(in, inOfs, out, 0, 128)
static void b2lBig128(byte[] in, int inOfs, long[] out) {
if ((inOfs < 0) || ((in.length - inOfs) < 128) ||
(out.length < 16)) {
throw new ArrayIndexOutOfBoundsException();
}
if (littleEndianUnaligned) {
inOfs += byteArrayOfs;
out[ 0] = reverseBytes(unsafe.getLong(in, (long)(inOfs )));
out[ 1] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 8)));
out[ 2] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 16)));
out[ 3] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 24)));
out[ 4] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 32)));
out[ 5] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 40)));
out[ 6] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 48)));
out[ 7] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 56)));
out[ 8] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 64)));
out[ 9] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 72)));
out[10] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 80)));
out[11] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 88)));
out[12] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 96)));
out[13] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 104)));
out[14] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 112)));
out[15] = reverseBytes(unsafe.getLong(in, (long)(inOfs + 120)));
} else {
// no optimization for big endian, see comments in b2lBig
b2lBig(in, inOfs, out, 0, 128);
}
}
/**
* long[] to byte[] conversion, big endian byte order.
*/
static void l2bBig(long[] in, int inOfs, byte[] out, int outOfs, int len) {
if ((inOfs < 0) || ((in.length - inOfs) < len/8) ||
(outOfs < 0) || ((out.length - outOfs) < len)) {
throw new ArrayIndexOutOfBoundsException();
}
len += outOfs;
while (outOfs < len) {
long i = in[inOfs++];
out[outOfs++] = (byte)(i >> 56);
out[outOfs++] = (byte)(i >> 48);
out[outOfs++] = (byte)(i >> 40);
out[outOfs++] = (byte)(i >> 32);
out[outOfs++] = (byte)(i >> 24);
out[outOfs++] = (byte)(i >> 16);
out[outOfs++] = (byte)(i >> 8);
out[outOfs++] = (byte)(i );
}
}
}
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