/*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program 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.
*
* This program 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 at /legal/license.txt).
*
* 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 or visit www.sun.com if you need additional
* information or have any questions.
*/
package java.nio;
/**
* A short buffer.
*
* <p> This class is provided as part of the JSR 239 NIO Buffer
* building block. It is a subset of the
* <code>java.nio.ShortBuffer</code> class in Java(TM) Standard Edition
* version 1.4.2. Differences are noted in <b><i>bold italic</i></b>.
* The class documentation may make reference to classes that are not
* present in the building block.
*
* <p><b><i> I/O channels, marking and resetting, and read-only buffers
* are not supported. Allocation of non-direct short buffers,
* compaction, and duplication are not supported.
* The following methods are omitted:
*
* <ul>
* <li><code>ShortBuffer allocate(int capacity)</code></li>
* <li><code>ShortBuffer compact()</code></li>
* <li><code>ShortBuffer duplicate()</code></li>
* <li><code>Buffer mark()</code></li>
* <li><code>Buffer reset()</code></li>
* <li><code>boolean isReadOnly()</code></li>
* <li><code>ShortBuffer asReadOnlyBuffer()</code></li>
* </ul>
* </i></b>
*
* <p> This class defines four categories of operations upon
* short buffers:
*
* <ul>
*
* <li><p> Absolute and relative {@link #get() </code><i>get</i><code>} and
* {@link #put(short) </code><i>put</i><code>} methods that read and write
* single shorts; </p></li>
*
* <li><p> Relative {@link #get(short[]) </code><i>bulk get</i><code>}
* methods that transfer contiguous sequences of shorts from this buffer
* into an array;</li>
*
* <li><p> Relative {@link #put(short[]) </code><i>bulk put</i><code>}
* methods that transfer contiguous sequences of shorts from a
* short array or some other short
* buffer into this buffer; and </p></li>
*
* <li><p> Methods for compacting, duplicating, and {@link #slice
* slicing} a short buffer. <b><i>JSR 239 does
* not support compacting and duplicating buffers.</i></b> </p></li>
*
* </ul>
*
* <p> Short buffers can be created either by <i>allocation</i>, which
* allocates space for the buffer's content, by {@link #wrap(short[])
* </code><i>wrapping</i><code>} an existing short array into a
* buffer, or by creating a <a
* href="ByteBuffer.html#view"><i>view</i></a> of an existing byte
* buffer. <b><i>JSR 239 supports allocation of
* <code>ByteBuffer</code>s only.</i></b>
*
* <p> Like a byte buffer, a short buffer is either <a
* href="ByteBuffer.html#direct"><i>direct</i> or <i>non-direct</i></a>. A
* short buffer created via the <tt>wrap</tt> methods of this class will
* be non-direct. A short buffer created as a view of a byte buffer will
* be direct if, and only if, the byte buffer itself is direct. Whether or not
* a short buffer is direct may be determined by invoking the {@link
* #isDirect isDirect} method. </p>
*
* <p> Methods in this class that do not otherwise have a value to return are
* specified to return the buffer upon which they are invoked. This allows
* method invocations to be chained.
*/
public abstract class ShortBuffer extends Buffer implements Comparable {
ByteBufferImpl parent = null;
short[] array;
int arrayOffset;
boolean isDirect;
boolean disposed = false;
/**
* Constructs a new <code>ShortBuffer</code>.
*/
ShortBuffer() {}
/**
* Wraps a short array into a buffer.
*
* <p> The new buffer will be backed by the given short array;
* that is, modifications to the buffer will cause the array to be modified
* and vice versa. The new buffer's capacity will be
* <tt>array.length</tt>, its position will be <tt>offset</tt>, its limit
* will be <tt>offset + length</tt>, and its mark will be undefined. Its
* {@link #array </code>backing array<code>} will be the given array, and
* its {@link #arrayOffset </code>array offset<code>} will be zero. </p>
*
* @param array
* The array that will back the new buffer
*
* @param offset
* The offset of the subarray to be used; must be non-negative and
* no larger than <tt>array.length</tt>. The new buffer's position
* will be set to this value.
*
* @param length
* The length of the subarray to be used;
* must be non-negative and no larger than
* <tt>array.length - offset</tt>.
* The new buffer's limit will be set to <tt>offset + length</tt>.
*
* @return The new short buffer
*
* @throws IndexOutOfBoundsException
* If the preconditions on the <tt>offset</tt> and <tt>length</tt>
* parameters do not hold
*/
public static ShortBuffer wrap(short[] array, int offset, int length) {
if (offset < 0 || offset > array.length ||
length < 0 || length > array.length - offset) {
throw new IndexOutOfBoundsException();
}
ShortBufferImpl sbi =
new ShortBufferImpl(null, array.length, array, 0, false);
sbi.position(offset);
sbi.limit(offset + length);
return sbi;
}
/**
* Wraps a short array into a buffer.
*
* <p> The new buffer will be backed by the given short array;
* that is, modifications to the buffer will cause the array to be modified
* and vice versa. The new buffer's capacity and limit will be
* <tt>array.length</tt>, its position will be zero, and its mark will be
* undefined. Its {@link #array </code>backing array<code>} will be the
* given array, and its {@link #arrayOffset </code>array offset<code>} will
* be zero. </p>
*
* @param array
* The array that will back this buffer
*
* @return The new short buffer
*/
public static ShortBuffer wrap(short[] array) {
return wrap(array, 0, array.length);
}
/**
* Creates a new short buffer whose content is a shared
* subsequence of this buffer's content.
*
* <p> The content of the new buffer will start at this buffer's
* current position. Changes to this buffer's content will be
* visible in the new buffer, and vice versa; the two buffers'
* position, limit, and mark values will be independent. <b><i>JSR
* 239 does not support the mark.</i></b>
*
* <p> The new buffer's position will be zero, its capacity and
* its limit will be the number of shorts remaining in this
* buffer, and its mark will be undefined. The new buffer will be
* direct if, and only if, this buffer is direct, and it will be
* read-only if, and only if, this buffer is read-only. <b><i>JSR
* 239 does not support the mark or read-only buffers.</i></b>
* </p>
*
* @return The new short buffer.
*/
public abstract ShortBuffer slice();
/**
* Relative <i>get</i> method. Reads the short at this
* buffer's current position, and then increments the
* position. </p>
*
* @return The short at the buffer's current position.
*
* @throws BufferUnderflowException If the buffer's current
* position is not smaller than its limit.
*/
public abstract short get();
/**
* Relative <i>put</i> method <i>(optional
* operation)</i>.
*
* <p> Writes the given short into this buffer at the current
* position, and then increments the position. </p>
*
* @param s The short to be written.
*
* @return This buffer.
*
* @throws BufferOverflowException If this buffer's current
* position is not smaller than its limit.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*/
public abstract ShortBuffer put(short s);
/**
* Absolute <i>get</i> method. Reads the short at the given
* index. </p>
*
* @param index The index from which the short will be read.
*
* @return The short at the given index.
*
* @throws IndexOutOfBoundsException If <tt>index</tt> is negative
* or not smaller than the buffer's limit.
*/
public abstract short get(int index);
/**
* Absolute <i>put</i> method <i>(optional operation)</i>.
*
* <p> Writes the given short into this buffer at the given
* index. </p>
*
* @param index The index at which the short will be written.
*
* @param s The short value to be written.
*
* @return This buffer.
*
* @throws IndexOutOfBoundsException If <tt>index</tt> is negative
* or not smaller than the buffer's limit.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*/
public abstract ShortBuffer put(int index, short s);
/**
* Relative bulk <i>get</i> method.
*
* <p> This method transfers shorts from this buffer into the
* given destination array. If there are fewer shorts
* remaining in the buffer than are required to satisfy the
* request, that is, if
* <tt>length</tt> <tt>></tt> <tt>remaining()</tt>,
* then no shorts are transferred and a {@link
* BufferUnderflowException} is thrown.
*
* <p> Otherwise, this method copies <tt>length</tt> shorts
* from this buffer into the given array, starting at the current
* position of this buffer and at the given offset in the array.
* The position of this buffer is then incremented by
* <tt>length</tt>.
*
* <p> In other words, an invocation of this method of the form
* <tt>src.get(dst, off, len)</tt> has exactly the same
* effect as the loop
*
* <pre>
* for (int i = off; i < off + len; i++)
* dst[i] = src.get(); </pre>
*
* except that it first checks that there are sufficient
* shorts in this buffer and it is potentially much more
* efficient. </p>
*
* @param dst The array into which shorts are to be written.
*
* @param offset The offset within the array of the first
* short to be written; must be non-negative and no larger
* than <tt>dst.length</tt>.
*
* @param length The maximum number of shorts to be written
* to the given array; must be non-negative and no larger than
* <tt>dst.length - offset</tt>.
*
* @return This buffer.
*
* @throws BufferUnderflowException If there are fewer than
* <tt>length</tt> shorts remaining in this buffer.
*
* @throws IndexOutOfBoundsException If the preconditions on the
* <tt>offset</tt> and <tt>length</tt> parameters do not hold.
*/
public ShortBuffer get(short[] dst, int offset, int length) {
if (offset < 0 || offset > dst.length ||
length < 0 || length > dst.length - offset) {
throw new IndexOutOfBoundsException();
}
if (limit - position < length) {
throw new BufferUnderflowException();
}
int bytePtr = arrayOffset + (position << 1);
if (isDirect) {
ByteBufferImpl._getShorts(bytePtr, dst, offset, length);
} else if (array != null) {
System.arraycopy(array, arrayOffset + position,
dst, offset, length);
} else {
for (int i = 0; i < length; i++) {
dst[offset++] = parent.getShort(bytePtr);
bytePtr += 2;
}
}
position += length;
return this;
}
/**
* Relative bulk <i>get</i> method.
*
* <p> This method transfers shorts from this buffer into the
* given destination array. An invocation of this method of the
* form <tt>src.get(a)</tt> behaves in exactly the same way as the
* invocation
*
* <pre>
* src.get(a, 0, a.length) </pre>
*
* @return This buffer.
*
* @throws BufferUnderflowException If there are fewer than
* <tt>dst.length</tt> shorts remaining in this buffer.
*/
public ShortBuffer get(short[] dst) {
return get(dst, 0, dst.length);
}
/**
* Relative bulk <i>put</i> method <i>(optional
* operation)</i>.
*
* <p> This method transfers the shorts remaining in the
* given source buffer into this buffer. If there are more
* shorts remaining in the source buffer than in this buffer,
* that is, if
* <tt>src.remaining()</tt> <tt>></tt> <tt>remaining()</tt>,
* then no shorts are transferred and a {@link
* BufferOverflowException} is thrown.
*
* <p> Otherwise, this method copies
* <i>n</i> = <tt>src.remaining()</tt> shorts from
* the given buffer into this buffer, starting at each buffer's
* current position. The positions of both buffers are then
* incremented by <i>n</i>.
*
* <p> In other words, an invocation of this method of the form
* <tt>dst.put(src)</tt> has exactly the same effect as the loop
*
* <pre>
* while (src.hasRemaining())
* dst.put(src.get()); </pre>
*
* except that it first checks that there is sufficient space in
* this buffer and it is potentially much more efficient. </p>
*
* @param src The source buffer from which shorts are to be
* read; must not be this buffer.
*
* @return This buffer.
*
* @throws BufferOverflowException If there is insufficient space
* in this buffer for the remaining shorts in the source
* buffer.
*
* @throws IllegalArgumentException If the source buffer is this buffer.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*/
public ShortBuffer put(ShortBuffer src) {
if (src == this) {
throw new IllegalArgumentException();
}
ShortBufferImpl srci = (ShortBufferImpl)src;
int length = srci.limit - srci.position;
if (length > this.limit - this.position) {
throw new BufferOverflowException();
}
if (isDirect && srci.isDirect) {
ByteBufferImpl._copyBytes(srci.arrayOffset + (srci.position << 1),
this.arrayOffset + (this.position << 1),
(length << 1));
} else if (isDirect && !srci.isDirect) {
if (srci.array != null) {
ByteBufferImpl._putShorts(this.arrayOffset +
(this.position << 1),
srci.array,
srci.arrayOffset + srci.position,
length);
} else {
byte[] srcArray = srci.parent.array;
int srciArrayOffset = srci.parent.arrayOffset +
srci.arrayOffset +
(srci.position << 1);
ByteBufferImpl._putBytes(this.arrayOffset +
(this.position << 1),
srcArray,
srciArrayOffset,
2*length);
}
} else if (!isDirect && srci.isDirect) {
if (array != null) {
ByteBufferImpl._getShorts(srci.arrayOffset +
(srci.position << 1),
this.array,
this.arrayOffset + this.position,
length);
} else {
byte[] dstArray = parent.array;
int dstArrayOffset = parent.arrayOffset +
arrayOffset +
(position << 1);
ByteBufferImpl._getBytes(srci.arrayOffset +
(srci.position << 1),
dstArray,
dstArrayOffset,
2*length);
}
} else if (!isDirect && !srci.isDirect) {
if (array != null && srci.array != null) {
System.arraycopy(srci.array, srci.arrayOffset + srci.position,
this.array, this.arrayOffset + this.position,
length);
} else {
for (int i = 0; i < length; i++) {
put(i, srci.get(i));
}
}
}
srci.position += length;
this.position += length;
return this;
}
/**
* Relative bulk <i>put</i> method <i>(optional
* operation)</i>.
*
* <p> This method transfers shorts into this buffer from the
* given source array. If there are more shorts to be copied
* from the array than remain in this buffer, that is, if
* <tt>length</tt> <tt>></tt> <tt>remaining()</tt>,
* then no shorts are transferred and a {@link
* BufferOverflowException} is thrown.
*
* <p> Otherwise, this method copies <tt>length</tt> shorts
* from the given array into this buffer, starting at the given
* offset in the array and at the current position of this buffer.
* The position of this buffer is then incremented by
* <tt>length</tt>.
*
* <p> In other words, an invocation of this method of the form
* <tt>dst.put(src, off, len)</tt> has exactly the same
* effect as the loop
*
* <pre>
* for (int i = off; i < off + len; i++)
* dst.put(a[i]); </pre>
*
* except that it first checks that there is sufficient space in
* this buffer and it is potentially much more efficient. </p>
*
* @param src The array from which shorts are to be read.
*
* @param offset The offset within the array of the first
* short to be read; must be non-negative and no larger than
* <tt>array.length</tt>.
*
* @param length The number of shorts to be read from the
* given array; must be non-negative and no larger than
* <tt>array.length - offset</tt>.
*
* @return This buffer.
*
* @throws BufferOverflowException If there is insufficient space
* in this buffer.
*
* @throws IndexOutOfBoundsException If the preconditions on the
* <tt>offset</tt> and <tt>length</tt> parameters do not hold.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*/
public ShortBuffer put(short[] src, int offset, int length) {
if (offset < 0 || offset > src.length ||
length < 0 || length > src.length - offset) {
throw new IndexOutOfBoundsException();
}
if (length > limit - position) {
throw new BufferOverflowException();
}
int bytePtr = arrayOffset + (position << 1);
if (isDirect) {
ByteBufferImpl._putShorts(bytePtr, src, offset, length);
} else if (array != null) {
System.arraycopy(src, offset,
array, arrayOffset + position, length);
} else {
for (int i = 0; i < length; i++) {
parent.putShort(bytePtr, src[offset++]);
bytePtr += 2;
}
}
position += length;
return this;
}
/**
* Relative bulk <i>put</i> method <i>(optional operation)</i>.
*
* <p> This method transfers the entire content of the given
* source short array into this buffer. An invocation of
* this method of the form <tt>dst.put(a)</tt> behaves in exactly
* the same way as the invocation
*
* <pre>
* dst.put(a, 0, a.length) </pre>
*
* @return This buffer.
*
* @throws BufferOverflowException If there is insufficient space
* in this buffer.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*/
public final ShortBuffer put(short[] src) {
return put(src, 0, src.length);
}
/**
* Tells whether or not this buffer is backed by an accessible
* short array.
*
* <p> If this method returns <tt>true</tt> then the {@link
* #array() array} and {@link #arrayOffset() arrayOffset} methods
* may safely be invoked. </p>
*
* @return <tt>true</tt> if, and only if, this buffer is backed by
* an array and is not read-only. <b><i>JSR 239 does not support
* read-only buffers.</i></b>
*/
public final boolean hasArray() {
return array != null;
}
/**
* Returns the short array that backs this
* buffer <i>(optional operation)</i>.
*
* <p> Modifications to this buffer's content will cause the returned
* array's content to be modified, and vice versa.
*
* <p> Invoke the {@link #hasArray hasArray} method before
* invoking this method in order to ensure that this buffer has an
* accessible backing array. </p>
*
* @return The array that backs this buffer.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*
* @throws UnsupportedOperationException If this buffer is not
* backed by an accessible array.
*/
public final short[] array() {
if (array == null) {
throw new UnsupportedOperationException();
}
return array;
}
/**
* Returns the offset within this buffer's backing array of the
* first element of the buffer <i>(optional
* operation)</i>.
*
* <p> If this buffer is backed by an array then buffer position
* <i>p</i> corresponds to array index
* <i>p</i> + <tt>arrayOffset()</tt>.
*
* <p> Invoke the {@link #hasArray hasArray} method before
* invoking this method in order to ensure that this buffer has an
* accessible backing array. </p>
*
* @return The offset within this buffer's array of the first
* element of the buffer.
*
* @throws ReadOnlyBufferException If this buffer is
* read-only. <b><i>JSR 239 does not support read-only buffer or
* the <code>ReadOnlyBufferException</code> class.</i></b>
*
* @throws UnsupportedOperationException If this buffer is not
* backed by an accessible array.
*/
public final int arrayOffset() {
if (array == null) {
throw new UnsupportedOperationException();
}
return arrayOffset;
}
/**
* Tells whether or not this short buffer is direct. </p>
*
* @return <tt>true</tt> if, and only if, this buffer is direct.
*/
public abstract boolean isDirect();
/**
* Returns a string summarizing the state of this buffer.
*
* @return A summary string
*/
public String toString() {
return "java.nio.ShortBuffer[" +
"pos=" + position() +
"lim=" + limit() +
"cap=" + capacity() +
"]";
}
/**
* Returns the current hash code of this buffer.
*
* <p> The hash code of a short buffer depends only upon its remaining
* elements; that is, upon the elements from <tt>position()</tt> up to, and
* including, the element at <tt>limit()</tt> - <tt>1</tt>.
*
* <p> Because buffer hash codes are content-dependent, it is inadvisable
* to use buffers as keys in hash maps or similar data structures unless it
* is known that their contents will not change. </p>
*
* @return The current hash code of this buffer
*/
public int hashCode() {
int h = 1;
int p = position();
for (int i = limit() - 1; i >= p; i--)
h = 31 * h + (int)get(i);
return h;
}
/**
* Tells whether or not this buffer is equal to another object.
*
* <p> Two short buffers are equal if, and only if,
*
* <p><ol>
*
* <li><p> They have the same element type, </p></li>
*
* <li><p> They have the same number of remaining elements, and
* </p></li>
*
* <li><p> The two sequences of remaining elements, considered
* independently of their starting positions, are pointwise equal.
* </p></li>
*
* </ol>
*
* <p> A short buffer is not equal to any other type of object. </p>
*
* @param ob The object to which this buffer is to be compared.
*
* @return <tt>true</tt> if, and only if, this buffer is equal to the
* given object.
*/
public boolean equals(Object ob) {
if (!(ob instanceof ShortBuffer))
return false;
ShortBuffer that = (ShortBuffer)ob;
if (this.remaining() != that.remaining())
return false;
int p = this.position();
for (int i = this.limit() - 1, j = that.limit() - 1; i >= p; i--, j--) {
short v1 = this.get(i);
short v2 = that.get(j);
if (v1 != v2) {
if ((v1 != v1) && (v2 != v2)) // For float and double
continue;
return false;
}
}
return true;
}
/**
* Compares this buffer to another.
*
* <p> Two short buffers are compared by comparing their sequences of
* remaining elements lexicographically, without regard to the starting
* position of each sequence within its corresponding buffer.
*
* <p> A short buffer is not comparable to any other type of object.
*
* @return A negative integer, zero, or a positive integer as this buffer
* is less than, equal to, or greater than the given buffer.
* @throws ClassCastException If the argument is not a short buffer.
*/
public int compareTo(Object ob) {
ShortBuffer that = (ShortBuffer)ob;
int n = this.position() + Math.min(this.remaining(), that.remaining());
for (int i = this.position(), j = that.position(); i < n; i++, j++) {
short v1 = this.get(i);
short v2 = that.get(j);
if (v1 == v2)
continue;
if ((v1 != v1) && (v2 != v2)) // For float and double
continue;
if (v1 < v2)
return -1;
return +1;
}
return this.remaining() - that.remaining();
}
}
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