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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.nio;
/** A buffer of doubles.
* A double buffer can be created in either one of the following ways:
*
* - {@link #allocate(int) Allocate} a new double array and create a buffer based on it;
* - {@link #wrap(double[]) Wrap} an existing double array to create a new buffer;
* - Use {@link java.nio.ByteBuffer#asDoubleBuffer() ByteBuffer.asDoubleBuffer} to create a
* double buffer based on a byte buffer.
*
*/
public abstract class DoubleBuffer extends Buffer implements Comparable {
// /** Creates a double buffer based on a newly allocated double array.
// *
// * @param capacity the capacity of the new buffer.
// * @return the created double buffer.
// * @throws IllegalArgumentException if {@code capacity} is less than zero.
// */
// public static DoubleBuffer allocate (int capacity) {
// if (capacity < 0) {
// throw new IllegalArgumentException();
// }
// ByteBuffer bb = ByteBuffer.allocateDirect(capacity * 8);
// bb.order(ByteOrder.nativeOrder());
// return bb.asDoubleBuffer();
// }
/** Constructs a {@code DoubleBuffer} with given capacity.
*
* @param capacity the capacity of the buffer. */
DoubleBuffer (int capacity) {
super(capacity);
}
/** Returns the double array which this buffer is based on, if there is one.
*
* @return the double array which this buffer is based on.
* @exception ReadOnlyBufferException if this buffer is based on an array but it is read-only.
* @exception UnsupportedOperationException if this buffer is not based on an array.
*/
public final double[] array () {
return protectedArray();
}
/** Returns the offset of the double array which this buffer is based on, if there is one.
*
* The offset is the index of the array corresponding to the zero position of the buffer.
*
*
* @return the offset of the double array which this buffer is based on.
* @exception ReadOnlyBufferException if this buffer is based on an array, but it is read-only.
* @exception UnsupportedOperationException if this buffer is not based on an array.
*/
public final int arrayOffset () {
return protectedArrayOffset();
}
/** Returns a read-only buffer that shares its content with this buffer.
* The returned buffer is guaranteed to be a new instance, even if this buffer is read-only
* itself. The new buffer's position, limit, capacity and mark are the same as this buffer's.
*
* The new buffer shares its content with this buffer, which means that this buffer's
* change of content will be visible to the new buffer. The two buffer's position, limit and
* mark are independent.
*
* @return a read-only version of this buffer.
*/
public abstract DoubleBuffer asReadOnlyBuffer ();
/** Compacts this double buffer.
* The remaining doubles will be moved to the head of the buffer, staring from position
* zero. Then the position is set to {@code remaining()}; the limit is set to capacity; the
* mark is cleared.
*
* @return this buffer.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract DoubleBuffer compact ();
/** Compare the remaining doubles of this buffer to another double buffer's remaining doubles.
*
* @param otherBuffer another double buffer.
* @return a negative value if this is less than {@code other}; 0 if this equals to {@code
* other}; a positive value if this is greater than {@code other}.
* @exception ClassCastException if {@code other} is not a double buffer.
*/
public int compareTo (DoubleBuffer otherBuffer) {
int compareRemaining = (remaining() < otherBuffer.remaining()) ?
remaining() : otherBuffer.remaining();
int thisPos = position;
int otherPos = otherBuffer.position;
// BEGIN android-changed
double thisDouble, otherDouble;
while (compareRemaining > 0) {
thisDouble = get(thisPos);
otherDouble = otherBuffer.get(otherPos);
// checks for double and NaN inequality
if ((thisDouble != otherDouble) &&
((thisDouble == thisDouble) || (otherDouble == otherDouble))) {
return thisDouble < otherDouble ? -1 : 1;
}
thisPos++;
otherPos++;
compareRemaining--;
}
// END android-changed
return remaining() - otherBuffer.remaining();
}
/** Returns a duplicated buffer that shares its content with this buffer.
* The duplicated buffer's position, limit, capacity and mark are the same as this
* buffer's. The duplicated buffer's read-only property and byte order are the same as this
* buffer's, too.
* The new buffer shares its content with this buffer, which means either buffer's change
* of content will be visible to the other. The two buffer's position, limit and mark are
* independent.
*
* @return a duplicated buffer that shares its content with this buffer.
*/
public abstract DoubleBuffer duplicate ();
/** Checks whether this double buffer is equal to another object.
* If {@code other} is not a double buffer then {@code false} is returned. Two double
* buffers are equal if and only if their remaining doubles are exactly the same. Position,
* limit, capacity and mark are not considered.
*
* @param other the object to compare with this double buffer.
* @return {@code true} if this double buffer is equal to {@code other}, {@code false} otherwise.
*/
public boolean equals (Object other) {
if (!(other instanceof DoubleBuffer)) {
return false;
}
DoubleBuffer otherBuffer = (DoubleBuffer)other;
if (remaining() != otherBuffer.remaining()) {
return false;
}
int myPosition = position;
int otherPosition = otherBuffer.position;
boolean equalSoFar = true;
while (equalSoFar && (myPosition < limit)) {
equalSoFar = get(myPosition++) == otherBuffer.get(otherPosition++);
}
return equalSoFar;
}
/** Returns the double at the current position and increases the position by 1.
*
* @return the double at the current position.
* @exception BufferUnderflowException if the position is equal or greater than limit.
*/
public abstract double get ();
/** Reads doubles from the current position into the specified double array and increases the
* position by the number of doubles read.
* Calling this method has the same effect as {@code get(dest, 0, dest.length)}.
*
* @param dest the destination double array.
* @return this buffer.
* @exception BufferUnderflowException if {@code dest.length} is greater than {@code remaining()}.
*/
public DoubleBuffer get (double[] dest) {
return get(dest, 0, dest.length);
}
/** Reads doubles from the current position into the specified double array, starting from the
* specified offset, and increases the position by the number of doubles read.
*
* @param dest the target double array.
* @param off the offset of the double array, must not be negative and not greater than {@code
* dest.length}.
* @param len the number of doubles to read, must be no less than zero and not greater than
* {@code dest.length - off}.
* @return this buffer.
* @exception IndexOutOfBoundsException if either {@code off} or {@code len} is invalid.
* @exception BufferUnderflowException if {@code len} is greater than {@code remaining()}.
*/
public DoubleBuffer get (double[] dest, int off, int len) {
int length = dest.length;
if (off < 0 || len < 0 || (long)off + (long)len > length) {
throw new IndexOutOfBoundsException();
}
if (len > remaining()) {
throw new BufferUnderflowException();
}
for (int i = off; i < off + len; i++) {
dest[i] = get();
}
return this;
}
/** Returns a double at the specified index; the position is not changed.
*
* @param index the index, must not be negative and less than limit.
* @return a double at the specified index.
* @exception IndexOutOfBoundsException if index is invalid.
*/
public abstract double get (int index);
/** Indicates whether this buffer is based on a double array and is read/write.
*
* @return {@code true} if this buffer is based on a double array and provides read/write
* access, {@code false} otherwise.
*/
public final boolean hasArray () {
return protectedHasArray();
}
// /**
// * Calculates this buffer's hash code from the remaining chars. The
// * position, limit, capacity and mark don't affect the hash code.
// *
// * @return the hash code calculated from the remaining chars.
// */
// public int hashCode() {
// int myPosition = position;
// int hash = 0;
// long l;
// while (myPosition < limit) {
// l = Double.doubleToLongBits(get(myPosition++));
// hash = hash + ((int) l) ^ ((int) (l >> 32));
// }
// return hash;
// }
/** Indicates whether this buffer is direct. A direct buffer will try its best to take advantage
* of native memory APIs and it may not stay in the Java heap, so it is not affected by garbage
* collection.
* A double buffer is direct if it is based on a byte buffer and the byte buffer is direct.
*
*
* @return {@code true} if this buffer is direct, {@code false} otherwise.
*/
public abstract boolean isDirect ();
/** Returns the byte order used by this buffer when converting doubles from/to bytes.
* If this buffer is not based on a byte buffer, then this always returns the platform's
* native byte order.
*
* @return the byte order used by this buffer when converting doubles from/to bytes.
*/
public abstract ByteOrder order ();
/** Child class implements this method to realize {@code array()}.
*
* @see #array() */
abstract double[] protectedArray ();
/** Child class implements this method to realize {@code arrayOffset()}.
*
* @see #arrayOffset() */
abstract int protectedArrayOffset ();
/** Child class implements this method to realize {@code hasArray()}.
*
* @see #hasArray() */
abstract boolean protectedHasArray ();
/** Writes the given double to the current position and increases the position by 1.
*
* @param d the double to write.
* @return this buffer.
* @exception BufferOverflowException if position is equal or greater than limit.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract DoubleBuffer put (double d);
/** Writes doubles from the given double array to the current position and increases the
* position by the number of doubles written. Calling this method has the same effect as
* {@code put(src, 0, src.length)}.
*
* @param src the source double array.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code src.length}.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public final DoubleBuffer put (double[] src) {
return put(src, 0, src.length);
}
/** Writes doubles from the given double array, starting from the specified offset, to the
* current position and increases the position by the number of doubles written.
*
* @param src the source double array.
* @param off the offset of double array, must not be negative and not greater than {@code
* src.length}.
* @param len the number of doubles to write, must be no less than zero and not greater than
* {@code src.length - off}.
* @return this buffer.
* @exception BufferOverflowException if {@code remaining()} is less than {@code len}.
* @exception IndexOutOfBoundsException if either {@code off} or {@code len} is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public DoubleBuffer put (double[] src, int off, int len) {
int length = src.length;
if (off < 0 || len < 0 || (long)off + (long)len > length) {
throw new IndexOutOfBoundsException();
}
if (len > remaining()) {
throw new BufferOverflowException();
}
for (int i = off; i < off + len; i++) {
put(src[i]);
}
return this;
}
/** Writes all the remaining doubles of the {@code src} double buffer to this buffer's current
* position, and increases both buffers' position by the number of doubles copied.
*
* @param src the source double buffer.
* @return this buffer.
* @exception BufferOverflowException if {@code src.remaining()} is greater than this buffer's
* {@code remaining()}.
* @exception IllegalArgumentException if {@code src} is this buffer.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public DoubleBuffer put (DoubleBuffer src) {
if (src == this) {
throw new IllegalArgumentException();
}
if (src.remaining() > remaining()) {
throw new BufferOverflowException();
}
double[] doubles = new double[src.remaining()];
src.get(doubles);
put(doubles);
return this;
}
/** Write a double to the specified index of this buffer and the position is not changed.
*
* @param index the index, must not be negative and less than the limit.
* @param d the double to write.
* @return this buffer.
* @exception IndexOutOfBoundsException if index is invalid.
* @exception ReadOnlyBufferException if no changes may be made to the contents of this buffer.
*/
public abstract DoubleBuffer put (int index, double d);
/** Returns a sliced buffer that shares its content with this buffer.
* The sliced buffer's capacity will be this buffer's {@code remaining()}, and its zero
* position will correspond to this buffer's current position. The new buffer's position will
* be 0, limit will be its capacity, and its mark is cleared. The new buffer's read-only
* property and byte order are the same as this buffer's.
* The new buffer shares its content with this buffer, which means either buffer's change
* of content will be visible to the other. The two buffer's position, limit and mark are
* independent.
*
* @return a sliced buffer that shares its content with this buffer.
*/
public abstract DoubleBuffer slice ();
/** Returns a string representing the state of this double buffer.
*
* @return A string representing the state of this double buffer.
*/
public String toString () {
StringBuffer buf = new StringBuffer();
buf.append(getClass().getName());
buf.append(", status: capacity="); //$NON-NLS-1$
buf.append(capacity());
buf.append(" position="); //$NON-NLS-1$
buf.append(position());
buf.append(" limit="); //$NON-NLS-1$
buf.append(limit());
return buf.toString();
}
}