org.lwjgl
Class PointerBuffer

java.lang.Object
  extended by org.lwjgl.PointerBuffer
All Implemented Interfaces:
java.lang.Comparable

public class PointerBuffer
extends java.lang.Object
implements java.lang.Comparable

This class is a container for architecture independent pointer data. The interface mirrors the NIO LongBuffer API for convenience.

Author:
Spasi

Field Summary
protected  java.nio.ByteBuffer pointers
           
protected  java.nio.Buffer view
           
protected  java.nio.IntBuffer view32
           
protected  java.nio.LongBuffer view64
           
 
Constructor Summary
PointerBuffer(java.nio.ByteBuffer source)
          Creates a new PointerBuffer using the specified ByteBuffer as its pointer data source.
PointerBuffer(int capacity)
          Creates a new PointerBuffer with the specified capacity.
 
Method Summary
static PointerBuffer allocateDirect(int capacity)
          Allocates a new pointer buffer.
 PointerBuffer asReadOnlyBuffer()
          Creates a new, read-only pointer buffer that shares this buffer's content.
 int capacity()
          Returns this buffer's capacity.
 PointerBuffer clear()
          Clears this buffer.
 PointerBuffer compact()
          Compacts this buffer  (optional operation).
 int compareTo(java.lang.Object o)
          Compares this buffer to another.
 PointerBuffer duplicate()
          Creates a new pointer buffer that shares this buffer's content.
 boolean equals(java.lang.Object ob)
          Tells whether or not this buffer is equal to another object.
 PointerBuffer flip()
          Flips this buffer.
 long get()
          Relative get method.
 long get(int index)
          Absolute get method.
 PointerBuffer get(long[] dst)
          Relative bulk get method.
 PointerBuffer get(long[] dst, int offset, int length)
          Relative bulk get method.
 java.nio.ByteBuffer getBuffer()
          Returns the ByteBuffer that backs this PointerBuffer.
static int getPointerSize()
          Returns the pointer size in bytes, based on the underlying architecture.
 int hashCode()
          Returns the current hash code of this buffer.
 boolean hasRemaining()
          Tells whether there are any elements between the current position and the limit.
static boolean is64Bit()
          Returns true if the underlying architecture is 64bit.
 boolean isReadOnly()
           
 int limit()
          Returns this buffer's limit.
 PointerBuffer limit(int newLimit)
          Sets this buffer's limit.
 PointerBuffer mark()
          Sets this buffer's mark at its position.
protected  PointerBuffer newInstance(java.nio.ByteBuffer source)
          This method is used in slice and duplicate instead of normal object construction, so that subclasses can return themselves.
 java.nio.ByteOrder order()
          Retrieves this buffer's byte order.
 int position()
          Returns this buffer's position.
 PointerBuffer position(int newPosition)
          Sets this buffer's position.
 int positionByte()
          Returns this buffer's position, in bytes.
static void put(java.nio.ByteBuffer target, int index, long l)
          Convenience put on a target ByteBuffer.
static void put(java.nio.ByteBuffer target, long l)
          Convenience put on a target ByteBuffer.
 PointerBuffer put(int index, long l)
          Absolute put method  (optional operation).
 PointerBuffer put(int index, PointerWrapper pointer)
          Convenience put that accepts PointerWrapper objects.
 PointerBuffer put(long l)
          Relative put method  (optional operation).
 PointerBuffer put(long[] src)
          Relative bulk put method  (optional operation).
 PointerBuffer put(long[] src, int offset, int length)
          Relative bulk put method  (optional operation).
 PointerBuffer put(PointerBuffer src)
          Relative bulk put method  (optional operation).
 PointerBuffer put(PointerWrapper pointer)
          Convenience put that accepts PointerWrapper objects.
 int remaining()
          Returns the number of elements between the current position and the limit.
 int remainingByte()
          Returns the number of bytes between the current position and the limit.
 PointerBuffer reset()
          Resets this buffer's position to the previously-marked position.
 PointerBuffer rewind()
          Rewinds this buffer.
 PointerBuffer slice()
          Creates a new pointer buffer whose content is a shared subsequence of this buffer's content.
 java.lang.String toString()
          Returns a string summarizing the state of this buffer.
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

pointers

protected final java.nio.ByteBuffer pointers

view

protected final java.nio.Buffer view

view32

protected final java.nio.IntBuffer view32

view64

protected final java.nio.LongBuffer view64
Constructor Detail

PointerBuffer

public PointerBuffer(int capacity)
Creates a new PointerBuffer with the specified capacity.

Parameters:
capacity - the PointerBuffer size, in number of pointers

PointerBuffer

public PointerBuffer(java.nio.ByteBuffer source)
Creates a new PointerBuffer using the specified ByteBuffer as its pointer data source. This is useful for users that do their own memory management over a big ByteBuffer, instead of allocating many small ones.

Parameters:
source - the source buffer
Method Detail

getBuffer

public java.nio.ByteBuffer getBuffer()
Returns the ByteBuffer that backs this PointerBuffer.

Returns:
the pointer ByteBuffer

is64Bit

public static boolean is64Bit()
Returns true if the underlying architecture is 64bit.


getPointerSize

public static int getPointerSize()
Returns the pointer size in bytes, based on the underlying architecture.

Returns:
The pointer size in bytes

capacity

public final int capacity()
Returns this buffer's capacity.

Returns:
The capacity of this buffer

position

public final int position()
Returns this buffer's position.

Returns:
The position of this buffer

positionByte

public final int positionByte()
Returns this buffer's position, in bytes.

Returns:
The position of this buffer in bytes.

position

public final PointerBuffer position(int newPosition)
Sets this buffer's position. If the mark is defined and larger than the new position then it is discarded.

Parameters:
newPosition - The new position value; must be non-negative and no larger than the current limit
Returns:
This buffer
Throws:
java.lang.IllegalArgumentException - If the preconditions on newPosition do not hold

limit

public final int limit()
Returns this buffer's limit.

Returns:
The limit of this buffer

limit

public final PointerBuffer limit(int newLimit)
Sets this buffer's limit. If the position is larger than the new limit then it is set to the new limit. If the mark is defined and larger than the new limit then it is discarded.

Parameters:
newLimit - The new limit value; must be non-negative and no larger than this buffer's capacity
Returns:
This buffer
Throws:
java.lang.IllegalArgumentException - If the preconditions on newLimit do not hold

mark

public final PointerBuffer mark()
Sets this buffer's mark at its position.

Returns:
This buffer

reset

public final PointerBuffer reset()
Resets this buffer's position to the previously-marked position.

Invoking this method neither changes nor discards the mark's value.

Returns:
This buffer
Throws:
java.nio.InvalidMarkException - If the mark has not been set

clear

public final PointerBuffer clear()
Clears this buffer. The position is set to zero, the limit is set to the capacity, and the mark is discarded.

Invoke this method before using a sequence of channel-read or put operations to fill this buffer. For example:

 buf.clear();     // Prepare buffer for reading
 in.read(buf);    // Read data

This method does not actually erase the data in the buffer, but it is named as if it did because it will most often be used in situations in which that might as well be the case.

Returns:
This buffer

flip

public final PointerBuffer flip()
Flips this buffer. The limit is set to the current position and then the position is set to zero. If the mark is defined then it is discarded.

After a sequence of channel-read or put operations, invoke this method to prepare for a sequence of channel-write or relative get operations. For example:

 buf.put(magic);    // Prepend header
 in.read(buf);      // Read data into rest of buffer
 buf.flip();        // Flip buffer
 out.write(buf);    // Write header + data to channel

This method is often used in conjunction with the compact method when transferring data from one place to another.

Returns:
This buffer

rewind

public final PointerBuffer rewind()
Rewinds this buffer. The position is set to zero and the mark is discarded.

Invoke this method before a sequence of channel-write or get operations, assuming that the limit has already been set appropriately. For example:

 out.write(buf);    // Write remaining data
 buf.rewind();      // Rewind buffer
 buf.get(array);    // Copy data into array

Returns:
This buffer

remaining

public final int remaining()
Returns the number of elements between the current position and the limit.

Returns:
The number of elements remaining in this buffer

remainingByte

public final int remainingByte()
Returns the number of bytes between the current position and the limit.

Returns:
The number of bytes remaining in this buffer

hasRemaining

public final boolean hasRemaining()
Tells whether there are any elements between the current position and the limit.

Returns:
true if, and only if, there is at least one element remaining in this buffer

allocateDirect

public static PointerBuffer allocateDirect(int capacity)
Allocates a new pointer buffer.

The new buffer's position will be zero, its limit will be its capacity, and its mark will be undefined.

Parameters:
capacity - The new buffer's capacity, in pointers
Returns:
The new pointer buffer
Throws:
java.lang.IllegalArgumentException - If the capacity is a negative integer

newInstance

protected PointerBuffer newInstance(java.nio.ByteBuffer source)
This method is used in slice and duplicate instead of normal object construction, so that subclasses can return themselves.

Parameters:
source -
Returns:
A new PointerBuffer instance

slice

public PointerBuffer slice()
Creates a new pointer buffer whose content is a shared subsequence of this buffer's content.

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.

The new buffer's position will be zero, its capacity and its limit will be the number of longs 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.

Returns:
The new pointer buffer

duplicate

public PointerBuffer duplicate()
Creates a new pointer buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. 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.

The new buffer's capacity, limit and position will be identical to those of this buffer. 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.

Returns:
The new pointer buffer

asReadOnlyBuffer

public PointerBuffer asReadOnlyBuffer()
Creates a new, read-only pointer buffer that shares this buffer's content.

The content of the new buffer will be that of this buffer. Changes to this buffer's content will be visible in the new buffer; the new buffer itself, however, will be read-only and will not allow the shared content to be modified. The two buffers' position, limit, and mark values will be independent.

The new buffer's capacity, limit and position will be identical to those of this buffer.

If this buffer is itself read-only then this method behaves in exactly the same way as the duplicate method.

Returns:
The new, read-only pointer buffer

isReadOnly

public boolean isReadOnly()

get

public long get()
Relative get method. Reads the long at this buffer's current position, and then increments the position.

Returns:
The long at the buffer's current position
Throws:
java.nio.BufferUnderflowException - If the buffer's current position is not smaller than its limit

put

public PointerBuffer put(long l)
Relative put method  (optional operation).

Writes the given long into this buffer at the current position, and then increments the position.

Parameters:
l - The long to be written
Returns:
This buffer
Throws:
java.nio.BufferOverflowException - If this buffer's current position is not smaller than its limit
java.nio.ReadOnlyBufferException - If this buffer is read-only

put

public PointerBuffer put(PointerWrapper pointer)
Convenience put that accepts PointerWrapper objects.

See Also:
put(long)

put

public static void put(java.nio.ByteBuffer target,
                       long l)
Convenience put on a target ByteBuffer.

Parameters:
target - the target ByteBuffer
l - the long value to be written

get

public long get(int index)
Absolute get method. Reads the long at the given index.

Parameters:
index - The index from which the long will be read
Returns:
The long at the given index
Throws:
java.lang.IndexOutOfBoundsException - If index is negative or not smaller than the buffer's limit

put

public PointerBuffer put(int index,
                         long l)
Absolute put method  (optional operation).

Writes the given long into this buffer at the given index.

Parameters:
index - The index at which the long will be written
l - The long value to be written
Returns:
This buffer
Throws:
java.lang.IndexOutOfBoundsException - If index is negative or not smaller than the buffer's limit
java.nio.ReadOnlyBufferException - If this buffer is read-only

put

public PointerBuffer put(int index,
                         PointerWrapper pointer)
Convenience put that accepts PointerWrapper objects.

See Also:
put(int, long)

put

public static void put(java.nio.ByteBuffer target,
                       int index,
                       long l)
Convenience put on a target ByteBuffer.

Parameters:
target - the target ByteBuffer
index - the index at which the long will be written
l - the long value to be written

get

public PointerBuffer get(long[] dst,
                         int offset,
                         int length)
Relative bulk get method.

This method transfers longs from this buffer into the given destination array. If there are fewer longs remaining in the buffer than are required to satisfy the request, that is, if length > remaining(), then no longs are transferred and a BufferUnderflowException is thrown.

Otherwise, this method copies length longs 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 length.

In other words, an invocation of this method of the form src.get(dst, off, len) has exactly the same effect as the loop

     for (int i = off; i < off + len; i++)
         dst[i] = src.get(); 

except that it first checks that there are sufficient longs in this buffer and it is potentially much more efficient.

Parameters:
dst - The array into which longs are to be written
offset - The offset within the array of the first long to be written; must be non-negative and no larger than dst.length
length - The maximum number of longs to be written to the given array; must be non-negative and no larger than dst.length - offset
Returns:
This buffer
Throws:
java.nio.BufferUnderflowException - If there are fewer than length longs remaining in this buffer
java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold

get

public PointerBuffer get(long[] dst)
Relative bulk get method.

This method transfers longs from this buffer into the given destination array. An invocation of this method of the form src.get(a) behaves in exactly the same way as the invocation

     src.get(a, 0, a.length) 

Returns:
This buffer
Throws:
java.nio.BufferUnderflowException - If there are fewer than length longs remaining in this buffer

put

public PointerBuffer put(PointerBuffer src)
Relative bulk put method  (optional operation).

This method transfers the longs remaining in the given source buffer into this buffer. If there are more longs remaining in the source buffer than in this buffer, that is, if src.remaining() > remaining(), then no longs are transferred and a BufferOverflowException is thrown.

Otherwise, this method copies n = src.remaining() longs from the given buffer into this buffer, starting at each buffer's current position. The positions of both buffers are then incremented by n.

In other words, an invocation of this method of the form dst.put(src) has exactly the same effect as the loop

     while (src.hasRemaining())
         dst.put(src.get()); 

except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

Parameters:
src - The source buffer from which longs are to be read; must not be this buffer
Returns:
This buffer
Throws:
java.nio.BufferOverflowException - If there is insufficient space in this buffer for the remaining longs in the source buffer
java.lang.IllegalArgumentException - If the source buffer is this buffer
java.nio.ReadOnlyBufferException - If this buffer is read-only

put

public PointerBuffer put(long[] src,
                         int offset,
                         int length)
Relative bulk put method  (optional operation).

This method transfers longs into this buffer from the given source array. If there are more longs to be copied from the array than remain in this buffer, that is, if length > remaining(), then no longs are transferred and a BufferOverflowException is thrown.

Otherwise, this method copies length longs 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 length.

In other words, an invocation of this method of the form dst.put(src, off, len) has exactly the same effect as the loop

     for (int i = off; i < off + len; i++)
         dst.put(a[i]); 

except that it first checks that there is sufficient space in this buffer and it is potentially much more efficient.

Parameters:
src - The array from which longs are to be read
offset - The offset within the array of the first long to be read; must be non-negative and no larger than array.length
length - The number of longs to be read from the given array; must be non-negative and no larger than array.length - offset
Returns:
This buffer
Throws:
java.nio.BufferOverflowException - If there is insufficient space in this buffer
java.lang.IndexOutOfBoundsException - If the preconditions on the offset and length parameters do not hold
java.nio.ReadOnlyBufferException - If this buffer is read-only

put

public final PointerBuffer put(long[] src)
Relative bulk put method  (optional operation).

This method transfers the entire content of the given source long array into this buffer. An invocation of this method of the form dst.put(a) behaves in exactly the same way as the invocation

     dst.put(a, 0, a.length) 

Returns:
This buffer
Throws:
java.nio.BufferOverflowException - If there is insufficient space in this buffer
java.nio.ReadOnlyBufferException - If this buffer is read-only

compact

public PointerBuffer compact()
Compacts this buffer  (optional operation).

The longs between the buffer's current position and its limit, if any, are copied to the beginning of the buffer. That is, the long at index p = position() is copied to index zero, the long at index p + 1 is copied to index one, and so forth until the long at index limit() - 1 is copied to index n = limit() - 1 - p. The buffer's position is then set to n+1 and its limit is set to its capacity. The mark, if defined, is discarded.

The buffer's position is set to the number of longs copied, rather than to zero, so that an invocation of this method can be followed immediately by an invocation of another relative put method.

Returns:
This buffer
Throws:
java.nio.ReadOnlyBufferException - If this buffer is read-only

order

public java.nio.ByteOrder order()
Retrieves this buffer's byte order.

The byte order of a pointer buffer created by allocation or by wrapping an existing long array is the native order of the underlying hardware. The byte order of a pointer buffer created as a view of a byte buffer is that of the byte buffer at the moment that the view is created.

Returns:
This buffer's byte order

toString

public java.lang.String toString()
Returns a string summarizing the state of this buffer.

Overrides:
toString in class java.lang.Object
Returns:
A summary string

hashCode

public int hashCode()
Returns the current hash code of this buffer.

The hash code of a pointer buffer depends only upon its remaining elements; that is, upon the elements from position() up to, and including, the element at limit() - 1.

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.

Overrides:
hashCode in class java.lang.Object
Returns:
The current hash code of this buffer

equals

public boolean equals(java.lang.Object ob)
Tells whether or not this buffer is equal to another object.

Two pointer buffers are equal if, and only if,

  1. They have the same element type,

  2. They have the same number of remaining elements, and

  3. The two sequences of remaining elements, considered independently of their starting positions, are pointwise equal.

A pointer buffer is not equal to any other type of object.

Overrides:
equals in class java.lang.Object
Parameters:
ob - The object to which this buffer is to be compared
Returns:
true if, and only if, this buffer is equal to the given object

compareTo

public int compareTo(java.lang.Object o)
Compares this buffer to another.

Two pointer buffers are compared by comparing their sequences of remaining elements lexicographically, without regard to the starting position of each sequence within its corresponding buffer.

A pointer buffer is not comparable to any other type of object.

Specified by:
compareTo in interface java.lang.Comparable
Returns:
A negative integer, zero, or a positive integer as this buffer is less than, equal to, or greater than the given buffer


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