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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,
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 *  See the License for the specific language governing permissions and
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 */

package java.nio;

import com.jtransc.JTranscArrays;

import java.util.Arrays;

/**
 * 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 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("capacity < 0: " + capacity); } return new DoubleArrayBuffer(new double[capacity]); } /** * Creates a new double buffer by wrapping the given double array. *

* Calling this method has the same effect as * {@code wrap(array, 0, array.length)}. * * @param array * the double array which the new buffer will be based on. * @return the created double buffer. */ public static DoubleBuffer wrap(double[] array) { return wrap(array, 0, array.length); } /** * Creates a new double buffer by wrapping the given double array. *

* The new buffer's position will be {@code start}, limit will be * {@code start + doubleCount}, capacity will be the length of the array. * * @param array * the double array which the new buffer will be based on. * @param start * the start index, must not be negative and not greater than * {@code array.length}. * @param doubleCount * the length, must not be negative and not greater than * {@code array.length - start}. * @return the created double buffer. * @exception IndexOutOfBoundsException * if either {@code start} or {@code doubleCount} is invalid. */ public static DoubleBuffer wrap(double[] array, int start, int doubleCount) { JTranscArrays.checkOffsetAndCount(array.length, start, doubleCount); DoubleBuffer buf = new DoubleArrayBuffer(array); buf.position = start; buf.limit = start + doubleCount; return buf; } DoubleBuffer(int capacity) { super(3, capacity, null); } public final double[] array() { return protectedArray(); } 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; 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--; } 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 buffers' * position, limit and mark are independent. */ public abstract DoubleBuffer duplicate(); /** * Checks whether this double buffer is equal to another object. If {@code * other} is not a {@code DoubleBuffer} then {@code false} is returned. * *

Two double buffers are equal if their remaining doubles are equal. * Position, limit, capacity and mark are not considered. * *

This method considers two doubles {@code a} and {@code b} to be equal * if {@code a == b} or if {@code a} and {@code b} are both {@code NaN}. * Unlike {@link Double#equals}, this method considers {@code -0.0} and * {@code +0.0} to be equal. * * @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. */ @Override 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)) { double a = get(myPosition++); double b = otherBuffer.get(otherPosition++); equalSoFar = a == b || (a != a && b != b); } 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(dst, 0, dst.length)}. * * @param dst * the destination double array. * @return this buffer. * @exception BufferUnderflowException * if {@code dst.length} is greater than {@code remaining()}. */ public DoubleBuffer get(double[] dst) { return get(dst, 0, dst.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 dst * the target double array. * @param dstOffset * the offset of the double array, must not be negative and not * greater than {@code dst.length}. * @param doubleCount * the number of doubles to read, must be no less than zero and * not greater than {@code dst.length - dstOffset}. * @return this buffer. * @exception IndexOutOfBoundsException * if either {@code dstOffset} or {@code doubleCount} is invalid. * @exception BufferUnderflowException * if {@code doubleCount} is greater than {@code remaining()}. */ public DoubleBuffer get(double[] dst, int dstOffset, int doubleCount) { JTranscArrays.checkOffsetAndCount(dst.length, dstOffset, doubleCount); if (doubleCount > remaining()) { throw new BufferUnderflowException(); } for (int i = dstOffset; i < dstOffset + doubleCount; ++i) { dst[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); 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. */ @Override 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 srcOffset * the offset of double array, must not be negative and not * greater than {@code src.length}. * @param doubleCount * the number of doubles to write, must be no less than zero and * not greater than {@code src.length - srcOffset}. * @return this buffer. * @exception BufferOverflowException * if {@code remaining()} is less than {@code doubleCount}. * @exception IndexOutOfBoundsException * if either {@code srcOffset} or {@code doubleCount} is invalid. * @exception ReadOnlyBufferException * if no changes may be made to the contents of this buffer. */ public DoubleBuffer put(double[] src, int srcOffset, int doubleCount) { JTranscArrays.checkOffsetAndCount(src.length, srcOffset, doubleCount); if (doubleCount > remaining()) { throw new BufferOverflowException(); } for (int i = srcOffset; i < srcOffset + doubleCount; ++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 (isReadOnly()) { throw new ReadOnlyBufferException(); } if (src == this) { throw new IllegalArgumentException("src == this"); } 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 buffers' * position, limit and mark are independent. */ public abstract DoubleBuffer slice(); }





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