| /* |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 1999-2003 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation and was |
| * originally based on software copyright (c) 1999, Lotus |
| * Development Corporation., http://www.lotus.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| */ |
| package org.apache.xml.utils; |
| |
| /** |
| * <meta name="usage" content="internal"/> |
| * 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. |
| */ |
| public class SuballocatedByteVector |
| { |
| /** Size of blocks to allocate */ |
| protected int m_blocksize; |
| |
| /** Number of blocks to (over)allocate by */ |
| protected int m_numblocks=32; |
| |
| /** Array of arrays of bytes */ |
| protected byte m_map[][]; |
| |
| /** Number of bytes in array */ |
| protected int m_firstFree = 0; |
| |
| /** "Shortcut" handle to m_map[0] */ |
| protected byte m_map0[]; |
| |
| /** |
| * Default constructor. Note that the default |
| * block size is very small, for small lists. |
| */ |
| public SuballocatedByteVector() |
| { |
| this(2048); |
| } |
| |
| /** |
| * Construct a ByteVector, using the given block size. |
| * |
| * @param blocksize Size of block to allocate |
| */ |
| public SuballocatedByteVector(int blocksize) |
| { |
| m_blocksize = blocksize; |
| m_map0=new byte[blocksize]; |
| m_map = new byte[m_numblocks][]; |
| m_map[0]=m_map0; |
| } |
| |
| /** |
| * Construct a ByteVector, using the given block size. |
| * |
| * @param blocksize Size of block to allocate |
| */ |
| public SuballocatedByteVector(int blocksize, int increaseSize) |
| { |
| // increaseSize not currently used. |
| this(blocksize); |
| } |
| |
| |
| /** |
| * Get the length of the list. |
| * |
| * @return length of the list |
| */ |
| public int size() |
| { |
| return m_firstFree; |
| } |
| |
| /** |
| * Set the length of the list. |
| * |
| * @return length of the list |
| */ |
| private void setSize(int sz) |
| { |
| if(m_firstFree<sz) |
| m_firstFree = sz; |
| } |
| |
| /** |
| * Append a byte onto the vector. |
| * |
| * @param value Byte to add to the list |
| */ |
| public void addElement(byte value) |
| { |
| if(m_firstFree<m_blocksize) |
| m_map0[m_firstFree++]=value; |
| else |
| { |
| int index=m_firstFree/m_blocksize; |
| int offset=m_firstFree%m_blocksize; |
| ++m_firstFree; |
| |
| if(index>=m_map.length) |
| { |
| int newsize=index+m_numblocks; |
| byte[][] newMap=new byte[newsize][]; |
| System.arraycopy(m_map, 0, newMap, 0, m_map.length); |
| m_map=newMap; |
| } |
| byte[] block=m_map[index]; |
| if(null==block) |
| block=m_map[index]=new byte[m_blocksize]; |
| block[offset]=value; |
| } |
| } |
| |
| /** |
| * Append several byte values onto the vector. |
| * |
| * @param value Byte to add to the list |
| */ |
| private void addElements(byte value, int numberOfElements) |
| { |
| if(m_firstFree+numberOfElements<m_blocksize) |
| for (int i = 0; i < numberOfElements; i++) |
| { |
| m_map0[m_firstFree++]=value; |
| } |
| else |
| { |
| int index=m_firstFree/m_blocksize; |
| int offset=m_firstFree%m_blocksize; |
| m_firstFree+=numberOfElements; |
| while( numberOfElements>0) |
| { |
| if(index>=m_map.length) |
| { |
| int newsize=index+m_numblocks; |
| byte[][] newMap=new byte[newsize][]; |
| System.arraycopy(m_map, 0, newMap, 0, m_map.length); |
| m_map=newMap; |
| } |
| byte[] block=m_map[index]; |
| if(null==block) |
| block=m_map[index]=new byte[m_blocksize]; |
| int copied=(m_blocksize-offset < numberOfElements) |
| ? m_blocksize-offset : numberOfElements; |
| numberOfElements-=copied; |
| while(copied-- > 0) |
| block[offset++]=value; |
| |
| ++index;offset=0; |
| } |
| } |
| } |
| |
| /** |
| * Append several slots onto the vector, but do not set the values. |
| * Note: "Not Set" means the value is unspecified. |
| * |
| * @param value Byte to add to the list |
| */ |
| private void addElements(int numberOfElements) |
| { |
| int newlen=m_firstFree+numberOfElements; |
| if(newlen>m_blocksize) |
| { |
| int index=m_firstFree%m_blocksize; |
| int newindex=(m_firstFree+numberOfElements)%m_blocksize; |
| for(int i=index+1;i<=newindex;++i) |
| m_map[i]=new byte[m_blocksize]; |
| } |
| m_firstFree=newlen; |
| } |
| |
| /** |
| * 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! |
| * |
| * @param value Byte to insert |
| * @param at Index of where to insert |
| */ |
| private void insertElementAt(byte value, int at) |
| { |
| if(at==m_firstFree) |
| addElement(value); |
| else if (at>m_firstFree) |
| { |
| int index=at/m_blocksize; |
| if(index>=m_map.length) |
| { |
| int newsize=index+m_numblocks; |
| byte[][] newMap=new byte[newsize][]; |
| System.arraycopy(m_map, 0, newMap, 0, m_map.length); |
| m_map=newMap; |
| } |
| byte[] block=m_map[index]; |
| if(null==block) |
| block=m_map[index]=new byte[m_blocksize]; |
| int offset=at%m_blocksize; |
| block[offset]=value; |
| m_firstFree=offset+1; |
| } |
| else |
| { |
| int index=at/m_blocksize; |
| int maxindex=m_firstFree+1/m_blocksize; |
| ++m_firstFree; |
| int offset=at%m_blocksize; |
| byte push; |
| |
| // ***** Easier to work down from top? |
| while(index<=maxindex) |
| { |
| int copylen=m_blocksize-offset-1; |
| byte[] block=m_map[index]; |
| if(null==block) |
| { |
| push=0; |
| block=m_map[index]=new byte[m_blocksize]; |
| } |
| else |
| { |
| push=block[m_blocksize-1]; |
| System.arraycopy(block, offset , block, offset+1, copylen); |
| } |
| block[offset]=value; |
| value=push; |
| offset=0; |
| ++index; |
| } |
| } |
| } |
| |
| /** |
| * Wipe it out. |
| */ |
| public void removeAllElements() |
| { |
| m_firstFree = 0; |
| } |
| |
| /** |
| * 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. |
| * |
| * @param s Byte to remove from array |
| * |
| * @return True if the byte was removed, false if it was not found |
| */ |
| private boolean removeElement(byte s) |
| { |
| int at=indexOf(s,0); |
| if(at<0) |
| return false; |
| removeElementAt(at); |
| return true; |
| } |
| |
| /** |
| * 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. |
| * |
| * @param at index of where to remove a byte |
| */ |
| private void removeElementAt(int at) |
| { |
| // No point in removing elements that "don't exist"... |
| if(at<m_firstFree) |
| { |
| int index=at/m_blocksize; |
| int maxindex=m_firstFree/m_blocksize; |
| int offset=at%m_blocksize; |
| |
| while(index<=maxindex) |
| { |
| int copylen=m_blocksize-offset-1; |
| byte[] block=m_map[index]; |
| if(null==block) |
| block=m_map[index]=new byte[m_blocksize]; |
| else |
| System.arraycopy(block, offset+1, block, offset, copylen); |
| if(index<maxindex) |
| { |
| byte[] next=m_map[index+1]; |
| if(next!=null) |
| block[m_blocksize-1]=(next!=null) ? next[0] : 0; |
| } |
| else |
| block[m_blocksize-1]=0; |
| offset=0; |
| ++index; |
| } |
| } |
| --m_firstFree; |
| } |
| |
| /** |
| * 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. |
| * |
| * @param node object to set |
| * @param index Index of where to set the object |
| */ |
| public void setElementAt(byte value, int at) |
| { |
| if(at<m_blocksize) |
| { |
| m_map0[at]=value; |
| return; |
| } |
| |
| int index=at/m_blocksize; |
| int offset=at%m_blocksize; |
| |
| if(index>=m_map.length) |
| { |
| int newsize=index+m_numblocks; |
| byte[][] newMap=new byte[newsize][]; |
| System.arraycopy(m_map, 0, newMap, 0, m_map.length); |
| m_map=newMap; |
| } |
| |
| byte[] block=m_map[index]; |
| if(null==block) |
| block=m_map[index]=new byte[m_blocksize]; |
| block[offset]=value; |
| |
| if(at>=m_firstFree) |
| m_firstFree=at+1; |
| } |
| |
| /** |
| * Get the nth element. This is often at the innermost loop of an |
| * application, so performance is critical. |
| * |
| * @param i index of value to get |
| * |
| * @return 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. |
| * |
| * @throw ArrayIndexOutOfBoundsException if the index was _clearly_ |
| * unreasonable (negative, or past the highest block). |
| * |
| * @throw 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? |
| */ |
| public byte elementAt(int i) |
| { |
| // %OPT% Does this really buy us anything? Test versus division for small, |
| // test _plus_ division for big docs. |
| if(i<m_blocksize) |
| return m_map0[i]; |
| |
| return m_map[i/m_blocksize][i%m_blocksize]; |
| } |
| |
| /** |
| * Tell if the table contains the given node. |
| * |
| * @param s object to look for |
| * |
| * @return true if the object is in the list |
| */ |
| private boolean contains(byte s) |
| { |
| return (indexOf(s,0) >= 0); |
| } |
| |
| /** |
| * Searches for the first occurence of the given argument, |
| * beginning the search at index, and testing for equality |
| * using the equals method. |
| * |
| * @param elem object to look for |
| * @param index Index of where to begin search |
| * @return 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. |
| */ |
| public int indexOf(byte elem, int index) |
| { |
| if(index>=m_firstFree) |
| return -1; |
| |
| int bindex=index/m_blocksize; |
| int boffset=index%m_blocksize; |
| int maxindex=m_firstFree/m_blocksize; |
| byte[] block; |
| |
| for(;bindex<maxindex;++bindex) |
| { |
| block=m_map[bindex]; |
| if(block!=null) |
| for(int offset=boffset;offset<m_blocksize;++offset) |
| if(block[offset]==elem) |
| return offset+bindex*m_blocksize; |
| boffset=0; // after first |
| } |
| // Last block may need to stop before end |
| int maxoffset=m_firstFree%m_blocksize; |
| block=m_map[maxindex]; |
| for(int offset=boffset;offset<maxoffset;++offset) |
| if(block[offset]==elem) |
| return offset+maxindex*m_blocksize; |
| |
| return -1; |
| } |
| |
| /** |
| * Searches for the first occurence of the given argument, |
| * beginning the search at index, and testing for equality |
| * using the equals method. |
| * |
| * @param elem object to look for |
| * @return 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. |
| */ |
| public int indexOf(byte elem) |
| { |
| return indexOf(elem,0); |
| } |
| |
| /** |
| * Searches for the first occurence of the given argument, |
| * beginning the search at index, and testing for equality |
| * using the equals method. |
| * |
| * @param elem Object to look for |
| * @return 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. |
| */ |
| private int lastIndexOf(byte elem) |
| { |
| int boffset=m_firstFree%m_blocksize; |
| for(int index=m_firstFree/m_blocksize; |
| index>=0; |
| --index) |
| { |
| byte[] block=m_map[index]; |
| if(block!=null) |
| for(int offset=boffset; offset>=0; --offset) |
| if(block[offset]==elem) |
| return offset+index*m_blocksize; |
| boffset=0; // after first |
| } |
| return -1; |
| } |
| |
| } |