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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;

import java.util.Arrays;

/**
 * A buffer of longs.
 * 

* A long buffer can be created in either of the following ways: *

    *
  • {@link #allocate(int) Allocate} a new long array and create a buffer * based on it;
  • *
  • {@link #wrap(long[]) Wrap} an existing long array to create a new * buffer;
  • *
  • Use {@link java.nio.ByteBuffer#asLongBuffer() ByteBuffer.asLongBuffer} * to create a long buffer based on a byte buffer.
  • *
*/ public abstract class LongBuffer extends Buffer implements Comparable { /** * Creates a long buffer based on a newly allocated long array. * * @param capacity * the capacity of the new buffer. * @return the created long buffer. * @throws IllegalArgumentException * if {@code capacity} is less than zero. */ public static LongBuffer allocate(int capacity) { if (capacity < 0) { throw new IllegalArgumentException("capacity < 0: " + capacity); } return new LongArrayBuffer(new long[capacity]); } /** * Creates a new long buffer by wrapping the given long array. *

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

* The new buffer's position will be {@code start}, limit will be * {@code start + longCount}, capacity will be the length of the array. * * @param array * the long 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 longCount * the length, must not be negative and not greater than * {@code array.length - start}. * @return the created long buffer. * @exception IndexOutOfBoundsException * if either {@code start} or {@code longCount} is invalid. */ public static LongBuffer wrap(long[] array, int start, int longCount) { Arrays.checkOffsetAndCount(array.length, start, longCount); LongBuffer buf = new LongArrayBuffer(array); buf.position = start; buf.limit = start + longCount; return buf; } LongBuffer(int capacity) { super(3, capacity, null); } public final long[] 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 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 LongBuffer asReadOnlyBuffer(); /** * Compacts this long buffer. *

* The remaining longs 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 LongBuffer compact(); /** * Compare the remaining longs of this buffer to another long buffer's * remaining longs. * * @param otherBuffer * another long buffer. * @return a negative value if this is less than {@code otherBuffer}; 0 if * this equals to {@code otherBuffer}; a positive value if this is * greater than {@code otherBuffer} * @exception ClassCastException * if {@code otherBuffer} is not a long buffer. */ public int compareTo(LongBuffer otherBuffer) { int compareRemaining = (remaining() < otherBuffer.remaining()) ? remaining() : otherBuffer.remaining(); int thisPos = position; int otherPos = otherBuffer.position; long thisLong, otherLong; while (compareRemaining > 0) { thisLong = get(thisPos); otherLong = otherBuffer.get(otherPos); if (thisLong != otherLong) { return thisLong < otherLong ? -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. The duplicated buffer's read-only property and byte order * are 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 LongBuffer duplicate(); /** * Checks whether this long buffer is equal to another object. *

* If {@code other} is not a long buffer then {@code false} is returned. Two * long buffers are equal if and only if their remaining longs are exactly * the same. Position, limit, capacity and mark are not considered. * * @param other * the object to compare with this long buffer. * @return {@code true} if this long buffer is equal to {@code other}, * {@code false} otherwise. */ @Override public boolean equals(Object other) { if (!(other instanceof LongBuffer)) { return false; } LongBuffer otherBuffer = (LongBuffer) 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 long at the current position and increase the position by 1. * * @return the long at the current position. * @exception BufferUnderflowException * if the position is equal or greater than limit. */ public abstract long get(); /** * Reads longs from the current position into the specified long array and * increases the position by the number of longs read. *

* Calling this method has the same effect as * {@code get(dst, 0, dst.length)}. * * @param dst * the destination long array. * @return this buffer. * @exception BufferUnderflowException * if {@code dst.length} is greater than {@code remaining()}. */ public LongBuffer get(long[] dst) { return get(dst, 0, dst.length); } /** * Reads longs from the current position into the specified long array, * starting from the specified offset, and increase the position by the * number of longs read. * * @param dst * the target long array. * @param dstOffset * the offset of the long array, must not be negative and not * greater than {@code dst.length}. * @param longCount * the number of longs 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 longCount} is invalid. * @exception BufferUnderflowException * if {@code longCount} is greater than {@code remaining()}. */ public LongBuffer get(long[] dst, int dstOffset, int longCount) { Arrays.checkOffsetAndCount(dst.length, dstOffset, longCount); if (longCount > remaining()) { throw new BufferUnderflowException(); } for (int i = dstOffset; i < dstOffset + longCount; ++i) { dst[i] = get(); } return this; } /** * Returns the long at the specified index; the position is not changed. * * @param index * the index, must not be negative and less than limit. * @return the long at the specified index. * @exception IndexOutOfBoundsException * if index is invalid. */ public abstract long 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 longs. */ @Override public int hashCode() { int myPosition = position; int hash = 0; long l; while (myPosition < limit) { l = 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 long 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 longs from/to * bytes. *

* If this buffer is not based on a byte buffer, then always return the * platform's native byte order. * * @return the byte order used by this buffer when converting longs from/to * bytes. */ public abstract ByteOrder order(); /** * Child class implements this method to realize {@code array()}. * * @return see {@code array()} */ abstract long[] protectedArray(); /** * Child class implements this method to realize {@code arrayOffset()}. * * @return see {@code arrayOffset()} */ abstract int protectedArrayOffset(); /** * Child class implements this method to realize {@code hasArray()}. * * @return see {@code hasArray()} */ abstract boolean protectedHasArray(); /** * Writes the given long to the current position and increases the position * by 1. * * @param l * the long 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 LongBuffer put(long l); /** * Writes longs from the given long array to the current position and * increases the position by the number of longs written. *

* Calling this method has the same effect as * {@code put(src, 0, src.length)}. * * @param src * the source long 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 LongBuffer put(long[] src) { return put(src, 0, src.length); } /** * Writes longs from the given long array, starting from the specified * offset, to the current position and increases the position by the number * of longs written. * * @param src * the source long array. * @param srcOffset * the offset of long array, must not be negative and not greater * than {@code src.length}. * @param longCount * the number of longs 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 longCount}. * @exception IndexOutOfBoundsException * if either {@code srcOffset} or {@code longCount} is invalid. * @exception ReadOnlyBufferException * if no changes may be made to the contents of this buffer. */ public LongBuffer put(long[] src, int srcOffset, int longCount) { Arrays.checkOffsetAndCount(src.length, srcOffset, longCount); if (longCount > remaining()) { throw new BufferOverflowException(); } for (int i = srcOffset; i < srcOffset + longCount; ++i) { put(src[i]); } return this; } /** * Writes all the remaining longs of the {@code src} long buffer to this * buffer's current position, and increases both buffers' position by the * number of longs copied. * * @param src * the source long 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 LongBuffer put(LongBuffer src) { if (isReadOnly()) { throw new ReadOnlyBufferException(); } if (src == this) { throw new IllegalArgumentException("src == this"); } if (src.remaining() > remaining()) { throw new BufferOverflowException(); } long[] contents = new long[src.remaining()]; src.get(contents); put(contents); return this; } /** * Writes a long to the specified index of this buffer; the position is not * changed. * * @param index * the index, must not be negative and less than the limit. * @param l * the long 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 LongBuffer put(int index, long l); /** * 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 * 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 LongBuffer slice(); }





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