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com.sun.org.apache.xml.internal.utils

public Class SuballocatedByteVector

extends Object
Class Inheritance
A very simple table that stores a list of byte. Very similar API to our IntVector class (same API); different internal storage. This version uses an array-of-arrays solution. Read/write access is thus a bit slower than the simple IntVector, and basic storage is a trifle higher due to the top-level array -- but appending is O(1) fast rather than O(N**2) slow, which will swamp those costs in situations where long vectors are being built up. Known issues: Some methods are private because they haven't yet been tested properly. If an element has not been set (because we skipped it), its value will initially be 0. Shortening the vector does not clear old storage; if you then skip values and setElementAt a higher index again, you may see old data reappear in the truncated-and-restored section. Doing anything else would have performance costs.

Field Summary

Modifier and TypeField and Description
protected int
m_blocksize

Size of blocks to allocate

protected int
m_firstFree

Number of bytes in array

protected byte[][]
m_map

Array of arrays of bytes

protected byte[]
m_map0

"Shortcut" handle to m_map[0]

protected int
m_numblocks

Number of blocks to (over)allocate by

Constructor Summary

AccessConstructor and Description
public
SuballocatedByteVector()

Default constructor.

public
SuballocatedByteVector(int
Size of block to allocate
blocksize)

Construct a ByteVector, using the given block size.

public
SuballocatedByteVector(int
Size of block to allocate
blocksize, int increaseSize)

Construct a ByteVector, using the given block size.

Method Summary

Modifier and TypeMethod and Description
public void
addElement(byte
Byte to add to the list
value)

Append a byte onto the vector.

private void
addElements(byte
Byte to add to the list
value, int numberOfElements)

Append several byte values onto the vector.

private void
addElements(int numberOfElements)

Append several slots onto the vector, but do not set the values.

private boolean

Returns:

true if the object is in the list
contains(byte
object to look for
s)

Tell if the table contains the given node.

public byte

Returns:

value at given index. If that value wasn't previously set, the result is undefined for performance reasons. It may throw an exception (see below), may return zero, or (if setSize has previously been used) may return stale data.
elementAt(int
index of value to get
i)

Get the nth element.

public int

Returns:

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.
indexOf(byte
object to look for
elem, int
Index of where to begin search
index)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

public int

Returns:

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.
indexOf(byte
object to look for
elem)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

private void
insertElementAt(byte
Byte to insert
value, int
Index of where to insert
at)

Inserts the specified node in this vector at the specified index.

private int

Returns:

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.
lastIndexOf(byte
Object to look for
elem)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

public void
removeAllElements()

Wipe it out.

private boolean

Returns:

True if the byte was removed, false if it was not found
removeElement(byte
Byte to remove from array
s)

Removes the first occurrence of the argument from this vector.

private void
removeElementAt(int
index of where to remove a byte
at)

Deletes the component at the specified index.

public void
setElementAt(byte value, int
Index of where to set the object
at)

Sets the component at the specified index of this vector to be the specified object.

private void

Returns:

length of the list
setSize(int sz)

Set the length of the list.

public int

Returns:

length of the list
size()

Get the length of the list.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

m_blocksizeback to summary
protected int m_blocksize

Size of blocks to allocate

m_firstFreeback to summary
protected int m_firstFree

Number of bytes in array

m_mapback to summary
protected byte[][] m_map

Array of arrays of bytes

m_map0back to summary
protected byte[] m_map0

"Shortcut" handle to m_map[0]

m_numblocksback to summary
protected int m_numblocks

Number of blocks to (over)allocate by

Constructor Detail

SuballocatedByteVectorback to summary
public SuballocatedByteVector()

Default constructor. Note that the default block size is very small, for small lists.

SuballocatedByteVectorback to summary
public SuballocatedByteVector(int blocksize)

Construct a ByteVector, using the given block size.

Parameters
blocksize:int

Size of block to allocate

SuballocatedByteVectorback to summary
public SuballocatedByteVector(int blocksize, int increaseSize)

Construct a ByteVector, using the given block size.

Parameters
blocksize:int

Size of block to allocate

Method Detail

addElementback to summary
public void addElement(byte value)

Append a byte onto the vector.

Parameters
value:byte

Byte to add to the list

addElementsback to summary
private void addElements(byte value, int numberOfElements)

Append several byte values onto the vector.

Parameters
value:byte

Byte to add to the list

addElementsback to summary
private void addElements(int numberOfElements)

Append several slots onto the vector, but do not set the values.

Note

"Not Set" means the value is unspecified.

containsback to summary
private boolean contains(byte s)

Tell if the table contains the given node.

Parameters
s:byte

object to look for

Returns:boolean

true if the object is in the list

elementAtback to summary
public byte elementAt(int i)

Get the nth element. This is often at the innermost loop of an application, so performance is critical.

Parameters
i:int

index of value to get

Returns:byte

value at given index. If that value wasn't previously set, the result is undefined for performance reasons. It may throw an exception (see below), may return zero, or (if setSize has previously been used) may return stale data.

Exceptions
ArrayIndexOutOfBoundsException:
if the index was _clearly_ unreasonable (negative, or past the highest block).
NullPointerException:
if the index points to a block that could have existed (based on the highest index used) but has never had anything set into it. %REVIEW% Could add a catch to create the block in that case, or return 0. Try/Catch is _supposed_ to be nearly free when not thrown to. Do we believe that? Should we have a separate safeElementAt?
indexOfback to summary
public int indexOf(byte elem, int index)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

Parameters
elem:byte

object to look for

index:int

Index of where to begin search

Returns:int

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.

indexOfback to summary
public int indexOf(byte elem)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

Parameters
elem:byte

object to look for

Returns:int

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.

insertElementAtback to summary
private void insertElementAt(byte value, int at)

Inserts the specified node in this vector at the specified index. Each component in this vector with an index greater or equal to the specified index is shifted upward to have an index one greater than the value it had previously. Insertion may be an EXPENSIVE operation!

Parameters
value:byte

Byte to insert

at:int

Index of where to insert

lastIndexOfback to summary
private int lastIndexOf(byte elem)

Searches for the first occurence of the given argument, beginning the search at index, and testing for equality using the equals method.

Parameters
elem:byte

Object to look for

Returns:int

the index of the first occurrence of the object argument in this vector at position index or later in the vector; returns -1 if the object is not found.

removeAllElementsback to summary
public void removeAllElements()

Wipe it out.

removeElementback to summary
private boolean removeElement(byte s)

Removes the first occurrence of the argument from this vector. If the object is found in this vector, each component in the vector with an index greater or equal to the object's index is shifted downward to have an index one smaller than the value it had previously.

Parameters
s:byte

Byte to remove from array

Returns:boolean

True if the byte was removed, false if it was not found

removeElementAtback to summary
private void removeElementAt(int at)

Deletes the component at the specified index. Each component in this vector with an index greater or equal to the specified index is shifted downward to have an index one smaller than the value it had previously.

Parameters
at:int

index of where to remove a byte

setElementAtback to summary
public void setElementAt(byte value, int at)

Sets the component at the specified index of this vector to be the specified object. The previous component at that position is discarded. The index must be a value greater than or equal to 0 and less than the current size of the vector.

Parameters
at:int

Index of where to set the object

setSizeback to summary
private void setSize(int sz)

Set the length of the list.

Returns:void

length of the list

sizeback to summary
public int size()

Get the length of the list.

Returns:int

length of the list