| /* ByteBuffer.java -- |
| Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.nio; |
| |
| /** |
| * @since 1.4 |
| */ |
| public abstract class ByteBuffer extends Buffer |
| implements Comparable |
| { |
| ByteOrder endian = ByteOrder.BIG_ENDIAN; |
| |
| int array_offset; |
| byte[] backing_buffer; |
| |
| ByteBuffer (int capacity, int limit, int position, int mark) |
| { |
| super (capacity, limit, position, mark); |
| } |
| |
| /** |
| * Allocates a new direct byte buffer. |
| */ |
| public static ByteBuffer allocateDirect (int capacity) |
| { |
| return DirectByteBufferImpl.allocate (capacity); |
| } |
| |
| /** |
| * Allocates a new <code>ByteBuffer</code> object with a given capacity. |
| */ |
| public static ByteBuffer allocate (int capacity) |
| { |
| return wrap(new byte[capacity], 0, capacity); |
| } |
| |
| /** |
| * Wraps a <code>byte</code> array into a <code>ByteBuffer</code> |
| * object. |
| * |
| * @exception IndexOutOfBoundsException If the preconditions on the offset |
| * and length parameters do not hold |
| */ |
| public static final ByteBuffer wrap (byte[] array, int offset, int length) |
| { |
| // FIXME: In GCJ and other implementations where arrays may not |
| // move we might consider, at least when offset==0: |
| // return new DirectByteBufferImpl(array, |
| // address_of_data(array) + offset, |
| // length, length, 0, false); |
| // This may be more efficient, mainly because we can then use the |
| // same logic for all ByteBuffers. |
| |
| return new ByteBufferImpl (array, 0, array.length, offset + length, offset, -1, false); |
| } |
| |
| /** |
| * Wraps a <code>byte</code> array into a <code>ByteBuffer</code> |
| * object. |
| */ |
| public static final ByteBuffer wrap (byte[] array) |
| { |
| return wrap (array, 0, array.length); |
| } |
| |
| /** |
| * This method transfers <code>byte</code>s from this buffer into the given |
| * destination array. Before the transfer, it checks if there are fewer than |
| * length <code>byte</code>s remaining in this buffer. |
| * |
| * @param dst The destination array |
| * @param offset The offset within the array of the first <code>byte</code> |
| * to be written; must be non-negative and no larger than dst.length. |
| * @param length The maximum number of bytes to be written to the given array; |
| * must be non-negative and no larger than dst.length - offset. |
| * |
| * @exception BufferUnderflowException If there are fewer than length |
| * <code>byte</code>s remaining in this buffer. |
| * @exception IndexOutOfBoundsException If the preconditions on the offset |
| * and length parameters do not hold. |
| */ |
| public ByteBuffer get (byte[] dst, int offset, int length) |
| { |
| checkArraySize(dst.length, offset, length); |
| checkForUnderflow(length); |
| |
| for (int i = offset; i < offset + length; i++) |
| { |
| dst [i] = get (); |
| } |
| |
| return this; |
| } |
| |
| /** |
| * This method transfers <code>byte</code>s from this buffer into the given |
| * destination array. |
| * |
| * @param dst The byte array to write into. |
| * |
| * @exception BufferUnderflowException If there are fewer than dst.length |
| * <code>byte</code>s remaining in this buffer. |
| */ |
| public ByteBuffer get (byte[] dst) |
| { |
| return get (dst, 0, dst.length); |
| } |
| |
| /** |
| * Writes the content of the the <code>ByteBUFFER</code> src |
| * into the buffer. Before the transfer, it checks if there is fewer than |
| * <code>src.remaining()</code> space remaining in this buffer. |
| * |
| * @param src The source data. |
| * |
| * @exception BufferOverflowException If there is insufficient space in this |
| * buffer for the remaining <code>byte</code>s in the source buffer. |
| * @exception IllegalArgumentException If the source buffer is this buffer. |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public ByteBuffer put (ByteBuffer src) |
| { |
| if (src == this) |
| throw new IllegalArgumentException (); |
| |
| checkForOverflow(src.remaining()); |
| |
| if (src.remaining () > 0) |
| { |
| byte[] toPut = new byte [src.remaining ()]; |
| src.get (toPut); |
| put (toPut); |
| } |
| |
| return this; |
| } |
| |
| /** |
| * Writes the content of the the <code>byte array</code> src |
| * into the buffer. Before the transfer, it checks if there is fewer than |
| * length space remaining in this buffer. |
| * |
| * @param src The array to copy into the buffer. |
| * @param offset The offset within the array of the first byte to be read; |
| * must be non-negative and no larger than src.length. |
| * @param length The number of bytes to be read from the given array; |
| * must be non-negative and no larger than src.length - offset. |
| * |
| * @exception BufferOverflowException If there is insufficient space in this |
| * buffer for the remaining <code>byte</code>s in the source array. |
| * @exception IndexOutOfBoundsException If the preconditions on the offset |
| * and length parameters do not hold |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public ByteBuffer put (byte[] src, int offset, int length) |
| { |
| checkArraySize(src.length, offset, length); |
| checkForOverflow(length); |
| |
| for (int i = offset; i < offset + length; i++) |
| put (src [i]); |
| |
| return this; |
| } |
| |
| /** |
| * Writes the content of the the <code>byte array</code> src |
| * into the buffer. |
| * |
| * @param src The array to copy into the buffer. |
| * |
| * @exception BufferOverflowException If there is insufficient space in this |
| * buffer for the remaining <code>byte</code>s in the source array. |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public final ByteBuffer put (byte[] src) |
| { |
| return put (src, 0, src.length); |
| } |
| |
| /** |
| * Tells whether ot not this buffer is backed by an accessible |
| * <code>byte</code> array. |
| */ |
| public final boolean hasArray () |
| { |
| return (backing_buffer != null |
| && !isReadOnly ()); |
| } |
| |
| /** |
| * Returns the <code>byte</code> array that backs this buffer. |
| * |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| * @exception UnsupportedOperationException If this buffer is not backed |
| * by an accessible array. |
| */ |
| public final byte[] array () |
| { |
| if (backing_buffer == null) |
| throw new UnsupportedOperationException (); |
| |
| checkIfReadOnly(); |
| |
| return backing_buffer; |
| } |
| |
| /** |
| * Returns the offset within this buffer's backing array of the first element. |
| * |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| * @exception UnsupportedOperationException If this buffer is not backed |
| * by an accessible array. |
| */ |
| public final int arrayOffset () |
| { |
| if (backing_buffer == null) |
| throw new UnsupportedOperationException (); |
| |
| checkIfReadOnly(); |
| |
| return array_offset; |
| } |
| |
| /** |
| * Calculates a hash code for this buffer. |
| * |
| * This is done with <code>int</code> arithmetic, |
| * where ** represents exponentiation, by this formula:<br> |
| * <code>s[position()] + 31 + (s[position()+1] + 30)*31**1 + ... + |
| * (s[limit()-1]+30)*31**(limit()-1)</code>. |
| * Where s is the buffer data. Note that the hashcode is dependent |
| * on buffer content, and therefore is not useful if the buffer |
| * content may change. |
| * |
| * @return the hash code |
| */ |
| public int hashCode () |
| { |
| int hashCode = get(position()) + 31; |
| int multiplier = 1; |
| for (int i = position() + 1; i < limit(); ++i) |
| { |
| multiplier *= 31; |
| hashCode += (get(i) + 30)*multiplier; |
| } |
| return hashCode; |
| } |
| |
| /** |
| * Checks if this buffer is equal to obj. |
| */ |
| public boolean equals (Object obj) |
| { |
| if (obj instanceof ByteBuffer) |
| { |
| return compareTo (obj) == 0; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Compares two <code>ByteBuffer</code> objects. |
| * |
| * @exception ClassCastException If obj is not an object derived from |
| * <code>ByteBuffer</code>. |
| */ |
| public int compareTo (Object obj) |
| { |
| ByteBuffer other = (ByteBuffer) obj; |
| |
| int num = Math.min(remaining(), other.remaining()); |
| int pos_this = position(); |
| int pos_other = other.position(); |
| |
| for (int count = 0; count < num; count++) |
| { |
| byte a = get(pos_this++); |
| byte b = other.get(pos_other++); |
| |
| if (a == b) |
| continue; |
| |
| if (a < b) |
| return -1; |
| |
| return 1; |
| } |
| |
| return remaining() - other.remaining(); |
| } |
| |
| /** |
| * Returns the byte order of this buffer. |
| */ |
| public final ByteOrder order () |
| { |
| return endian; |
| } |
| |
| /** |
| * Modifies this buffer's byte order. |
| */ |
| public final ByteBuffer order (ByteOrder endian) |
| { |
| this.endian = endian; |
| return this; |
| } |
| |
| /** |
| * Reads the <code>byte</code> at this buffer's current position, |
| * and then increments the position. |
| * |
| * @exception BufferUnderflowException If there are no remaining |
| * <code>byte</code>s in this buffer. |
| */ |
| public abstract byte get (); |
| |
| /** |
| * Writes the <code>byte</code> at this buffer's current position, |
| * and then increments the position. |
| * |
| * @exception BufferOverflowException If there no remaining |
| * <code>byte</code>s in this buffer. |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public abstract ByteBuffer put (byte b); |
| |
| /** |
| * Absolute get method. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit. |
| */ |
| public abstract byte get (int index); |
| |
| /** |
| * Absolute put method. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit. |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public abstract ByteBuffer put (int index, byte b); |
| |
| /** |
| * Compacts this buffer. |
| * |
| * @exception ReadOnlyBufferException If this buffer is read-only. |
| */ |
| public abstract ByteBuffer compact (); |
| |
| void shiftDown (int dst_offset, int src_offset, int count) |
| { |
| for (int i = 0; i < count; i++) |
| put(dst_offset + i, get(src_offset + i)); |
| } |
| |
| /** |
| * Tells whether or not this buffer is direct. |
| */ |
| public abstract boolean isDirect (); |
| |
| /** |
| * Creates a new <code>ByteBuffer</code> whose content is a shared |
| * subsequence of this buffer's content. |
| */ |
| public abstract ByteBuffer slice (); |
| |
| /** |
| * Creates a new <code>ByteBuffer</code> that shares this buffer's |
| * content. |
| */ |
| public abstract ByteBuffer duplicate (); |
| |
| /** |
| * Creates a new read-only <code>ByteBuffer</code> that shares this |
| * buffer's content. |
| */ |
| public abstract ByteBuffer asReadOnlyBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as a short buffer. |
| */ |
| public abstract ShortBuffer asShortBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as a char buffer. |
| */ |
| public abstract CharBuffer asCharBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as an integer buffer. |
| */ |
| public abstract IntBuffer asIntBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as a long buffer. |
| */ |
| public abstract LongBuffer asLongBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as a float buffer. |
| */ |
| public abstract FloatBuffer asFloatBuffer (); |
| |
| /** |
| * Creates a view of this byte buffer as a double buffer. |
| */ |
| public abstract DoubleBuffer asDoubleBuffer (); |
| |
| /** |
| * Relative get method for reading a character value. |
| * |
| * @exception BufferUnderflowException If there are fewer than two bytes |
| * remaining in this buffer. |
| */ |
| public abstract char getChar (); |
| |
| /** |
| * Relative put method for writing a character value. |
| * |
| * @exception BufferOverflowException If this buffer's current position is |
| * not smaller than its limit. |
| */ |
| public abstract ByteBuffer putChar (char value); |
| |
| /** |
| * Absolute get method for reading a character value. |
| * |
| * @exception IndexOutOfBoundsException If there are fewer than two bytes |
| * remaining in this buffer |
| */ |
| public abstract char getChar (int index); |
| |
| /** |
| * Absolute put method for writing a character value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus one. |
| */ |
| public abstract ByteBuffer putChar (int index, char value); |
| |
| /** |
| * Relative get method for reading a short value. |
| * |
| * @exception BufferUnderflowException If index is negative or not smaller |
| * than the buffer's limit, minus one. |
| */ |
| public abstract short getShort (); |
| |
| /** |
| * Relative put method for writing a short value. |
| * |
| * @exception BufferOverflowException If this buffer's current position is |
| * not smaller than its limit. |
| */ |
| public abstract ByteBuffer putShort (short value); |
| |
| /** |
| * Absolute get method for reading a short value. |
| * |
| * @exception IndexOutOfBoundsException If there are fewer than two bytes |
| * remaining in this buffer |
| */ |
| public abstract short getShort (int index); |
| |
| /** |
| * Absolute put method for writing a short value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus one. |
| */ |
| public abstract ByteBuffer putShort (int index, short value); |
| |
| /** |
| * Relative get method for reading an integer value. |
| * |
| * @exception BufferUnderflowException If there are fewer than four bytes |
| * remaining in this buffer. |
| */ |
| public abstract int getInt (); |
| |
| /** |
| * Relative put method for writing an integer value. |
| * |
| * @exception BufferOverflowException If this buffer's current position is |
| * not smaller than its limit. |
| */ |
| public abstract ByteBuffer putInt (int value); |
| |
| /** |
| * Absolute get method for reading an integer value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus three. |
| */ |
| public abstract int getInt (int index); |
| |
| /** |
| * Absolute put method for writing an integer value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus three. |
| */ |
| public abstract ByteBuffer putInt (int index, int value); |
| |
| /** |
| * Relative get method for reading a long value. |
| * |
| * @exception BufferUnderflowException If there are fewer than eight bytes |
| * remaining in this buffer. |
| */ |
| public abstract long getLong (); |
| |
| /** |
| * Relative put method for writing a long value. |
| * |
| * @exception BufferOverflowException If this buffer's current position is |
| * not smaller than its limit. |
| */ |
| public abstract ByteBuffer putLong (long value); |
| |
| /** |
| * Absolute get method for reading a long value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus seven. |
| */ |
| public abstract long getLong (int index); |
| |
| /** |
| * Absolute put method for writing a float value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus seven. |
| */ |
| public abstract ByteBuffer putLong (int index, long value); |
| |
| /** |
| * Relative get method for reading a float value. |
| * |
| * @exception BufferUnderflowException If there are fewer than four bytes |
| * remaining in this buffer. |
| */ |
| public abstract float getFloat (); |
| |
| /** |
| * Relative put method for writing a float value. |
| * |
| * @exception BufferOverflowException If there are fewer than four bytes |
| * remaining in this buffer. |
| */ |
| public abstract ByteBuffer putFloat (float value); |
| |
| /** |
| * Absolute get method for reading a float value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus three. |
| */ |
| public abstract float getFloat (int index); |
| |
| /** |
| * Relative put method for writing a float value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus three. |
| */ |
| public abstract ByteBuffer putFloat (int index, float value); |
| |
| /** |
| * Relative get method for reading a double value. |
| * |
| * @exception BufferUnderflowException If there are fewer than eight bytes |
| * remaining in this buffer. |
| */ |
| public abstract double getDouble (); |
| |
| /** |
| * Relative put method for writing a double value. |
| * |
| * @exception BufferOverflowException If this buffer's current position is |
| * not smaller than its limit. |
| */ |
| public abstract ByteBuffer putDouble (double value); |
| |
| /** |
| * Absolute get method for reading a double value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus seven. |
| */ |
| public abstract double getDouble (int index); |
| |
| /** |
| * Absolute put method for writing a double value. |
| * |
| * @exception IndexOutOfBoundsException If index is negative or not smaller |
| * than the buffer's limit, minus seven. |
| */ |
| public abstract ByteBuffer putDouble (int index, double value); |
| |
| /** |
| * Returns a string summarizing the state of this buffer. |
| */ |
| public String toString () |
| { |
| return getClass ().getName () + |
| "[pos=" + position () + |
| " lim=" + limit () + |
| " cap=" + capacity () + "]"; |
| } |
| } |