/*
* Copyright 2005-2007 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.java2d.pipe;
import sun.misc.Unsafe;
/**
* The RenderBuffer class is a simplified, high-performance, Unsafe wrapper
* used for buffering rendering operations in a single-threaded rendering
* environment. It's functionality is similar to the ByteBuffer and related
* NIO classes. However, the methods in this class perform little to no
* alignment or bounds checks for performance reasons. Therefore, it is
* the caller's responsibility to ensure that all put() calls are properly
* aligned and within bounds:
* - int and float values must be aligned on 4-byte boundaries
* - long and double values must be aligned on 8-byte boundaries
*
* This class only includes the bare minimum of methods to support
* single-threaded rendering. For example, there is no put(double[]) method
* because we currently have no need for such a method in the STR classes.
*/
public class RenderBuffer {
/**
* These constants represent the size of various data types (in bytes).
*/
protected static final long SIZEOF_BYTE = 1L;
protected static final long SIZEOF_SHORT = 2L;
protected static final long SIZEOF_INT = 4L;
protected static final long SIZEOF_FLOAT = 4L;
protected static final long SIZEOF_LONG = 8L;
protected static final long SIZEOF_DOUBLE = 8L;
/**
* Represents the number of elements at which we have empirically
* determined that the average cost of a JNI call exceeds the expense
* of an element by element copy. In other words, if the number of
* elements in an array to be copied exceeds this value, then we should
* use the copyFromArray() method to complete the bulk put operation.
* (This value can be adjusted if the cost of JNI downcalls is reduced
* in a future release.)
*/
private static final int COPY_FROM_ARRAY_THRESHOLD = 28;
protected final Unsafe unsafe;
protected final long baseAddress;
protected final long endAddress;
protected long curAddress;
protected final int capacity;
protected RenderBuffer(int numBytes) {
unsafe = Unsafe.getUnsafe();
curAddress = baseAddress = unsafe.allocateMemory(numBytes);
endAddress = baseAddress + numBytes;
capacity = numBytes;
}
/**
* Allocates a fresh buffer using the machine endianness.
*/
public static RenderBuffer allocate(int numBytes) {
return new RenderBuffer(numBytes);
}
/**
* Returns the base address of the underlying memory buffer.
*/
public final long getAddress() {
return baseAddress;
}
/**
* Copies length bytes from the Java-level srcArray to the native
* memory located at dstAddr. Note that this method performs no bounds
* checking. Verification that the copy will not result in memory
* corruption should be done by the caller prior to invocation.
*
* @param srcArray the source array
* @param srcPos the starting position of the source array (in bytes)
* @param dstAddr pointer to the destination block of native memory
* @param length the number of bytes to copy from source to destination
*/
private static native void copyFromArray(Object srcArray, long srcPos,
long dstAddr, long length);
/**
* The behavior (and names) of the following methods are nearly
* identical to their counterparts in the various NIO Buffer classes.
*/
public final int capacity() {
return capacity;
}
public final int remaining() {
return (int)(endAddress - curAddress);
}
public final int position() {
return (int)(curAddress - baseAddress);
}
public final void position(long numBytes) {
curAddress = baseAddress + numBytes;
}
public final void clear() {
curAddress = baseAddress;
}
/**
* putByte() methods...
*/
public final RenderBuffer putByte(byte x) {
unsafe.putByte(curAddress, x);
curAddress += SIZEOF_BYTE;
return this;
}
public RenderBuffer put(byte[] x) {
return put(x, 0, x.length);
}
public RenderBuffer put(byte[] x, int offset, int length) {
if (length > COPY_FROM_ARRAY_THRESHOLD) {
long offsetInBytes = offset * SIZEOF_BYTE;
long lengthInBytes = length * SIZEOF_BYTE;
copyFromArray(x, offsetInBytes, curAddress, lengthInBytes);
position(position() + lengthInBytes);
} else {
int end = offset + length;
for (int i = offset; i < end; i++) {
putByte(x[i]);
}
}
return this;
}
/**
* putShort() methods...
*/
public final RenderBuffer putShort(short x) {
// assert (position() % SIZEOF_SHORT == 0);
unsafe.putShort(curAddress, x);
curAddress += SIZEOF_SHORT;
return this;
}
public RenderBuffer put(short[] x) {
return put(x, 0, x.length);
}
public RenderBuffer put(short[] x, int offset, int length) {
// assert (position() % SIZEOF_SHORT == 0);
if (length > COPY_FROM_ARRAY_THRESHOLD) {
long offsetInBytes = offset * SIZEOF_SHORT;
long lengthInBytes = length * SIZEOF_SHORT;
copyFromArray(x, offsetInBytes, curAddress, lengthInBytes);
position(position() + lengthInBytes);
} else {
int end = offset + length;
for (int i = offset; i < end; i++) {
putShort(x[i]);
}
}
return this;
}
/**
* putInt() methods...
*/
public final RenderBuffer putInt(int pos, int x) {
// assert (baseAddress + pos % SIZEOF_INT == 0);
unsafe.putInt(baseAddress + pos, x);
return this;
}
public final RenderBuffer putInt(int x) {
// assert (position() % SIZEOF_INT == 0);
unsafe.putInt(curAddress, x);
curAddress += SIZEOF_INT;
return this;
}
public RenderBuffer put(int[] x) {
return put(x, 0, x.length);
}
public RenderBuffer put(int[] x, int offset, int length) {
// assert (position() % SIZEOF_INT == 0);
if (length > COPY_FROM_ARRAY_THRESHOLD) {
long offsetInBytes = offset * SIZEOF_INT;
long lengthInBytes = length * SIZEOF_INT;
copyFromArray(x, offsetInBytes, curAddress, lengthInBytes);
position(position() + lengthInBytes);
} else {
int end = offset + length;
for (int i = offset; i < end; i++) {
putInt(x[i]);
}
}
return this;
}
/**
* putFloat() methods...
*/
public final RenderBuffer putFloat(float x) {
// assert (position() % SIZEOF_FLOAT == 0);
unsafe.putFloat(curAddress, x);
curAddress += SIZEOF_FLOAT;
return this;
}
public RenderBuffer put(float[] x) {
return put(x, 0, x.length);
}
public RenderBuffer put(float[] x, int offset, int length) {
// assert (position() % SIZEOF_FLOAT == 0);
if (length > COPY_FROM_ARRAY_THRESHOLD) {
long offsetInBytes = offset * SIZEOF_FLOAT;
long lengthInBytes = length * SIZEOF_FLOAT;
copyFromArray(x, offsetInBytes, curAddress, lengthInBytes);
position(position() + lengthInBytes);
} else {
int end = offset + length;
for (int i = offset; i < end; i++) {
putFloat(x[i]);
}
}
return this;
}
/**
* putLong() methods...
*/
public final RenderBuffer putLong(long x) {
// assert (position() % SIZEOF_LONG == 0);
unsafe.putLong(curAddress, x);
curAddress += SIZEOF_LONG;
return this;
}
public RenderBuffer put(long[] x) {
return put(x, 0, x.length);
}
public RenderBuffer put(long[] x, int offset, int length) {
// assert (position() % SIZEOF_LONG == 0);
if (length > COPY_FROM_ARRAY_THRESHOLD) {
long offsetInBytes = offset * SIZEOF_LONG;
long lengthInBytes = length * SIZEOF_LONG;
copyFromArray(x, offsetInBytes, curAddress, lengthInBytes);
position(position() + lengthInBytes);
} else {
int end = offset + length;
for (int i = offset; i < end; i++) {
putLong(x[i]);
}
}
return this;
}
/**
* putDouble() method(s)...
*/
public final RenderBuffer putDouble(double x) {
// assert (position() % SIZEOF_DOUBLE == 0);
unsafe.putDouble(curAddress, x);
curAddress += SIZEOF_DOUBLE;
return this;
}
}