/*
* Copyright (C) 2002-2011 XimpleWare, info@ximpleware.com
*
* This program 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 of the License, or
* (at your option) any later version.
*
* 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package com.ximpleware;
/**
* Fast object array implementation
*
*/
public class FastObjectBuffer implements IObjectBuffer {
/*
* bufferArrayList is a resizable array list of int buffers
*/
private final arrayList bufferArrayList;
/**
* Total capacity of the ObjectBuffer
*/
private int capacity;
/**
* Page size of the incremental growth of the object Buffer
*/
private final int pageSize;
/**
* Total number of objects in the IntBuffer
*/
protected int size;
private final int exp;
private final int r;
/**
* FastIntBuffer constructor comment.
*/
public FastObjectBuffer() {
size = 0;
capacity = 0;
pageSize = 1024;
exp = 10;
r = 1023;
bufferArrayList = new arrayList();
}
/**
* Constructor with adjustable buffer page size of the value bfz
*
* @param e
* int
*/
public FastObjectBuffer(final int e) {
if (e < 0) {
throw new IllegalArgumentException();
}
capacity = size = 0;
pageSize = 1 << e;
exp = e;
r = pageSize - 1;
bufferArrayList = new arrayList();
}
/**
* Append an object array to the end of this buffer instance
*
* @param obj_array
* Object[]
*/
public void append(final Object[] obj_array) {
if (obj_array == null) {
throw new NullPointerException();
}
// no additional buffer space needed
int lastBufferIndex;
Object[] lastBuffer;
if (bufferArrayList.size == 0) {
lastBuffer = new Object[pageSize];
bufferArrayList.add(lastBuffer);
lastBufferIndex = 0;
capacity = pageSize;
} else {
lastBufferIndex = Math.min((size >> exp),// +(((size&r)==0)? 0:1),
bufferArrayList.size - 1);
lastBuffer = (Object[]) bufferArrayList.get(lastBufferIndex);
}
if ((this.size + obj_array.length) < this.capacity) {
// get the last buffer from the bufferListArray
// obtain the starting offset in that buffer to which the data is to be copied
// update length
// System.arraycopy(input, 0, lastBuffer, size % pageSize, input.length);
if (this.size + obj_array.length < ((lastBufferIndex + 1) << exp)) {
System.arraycopy(obj_array, 0, lastBuffer, size & r, obj_array.length);
} else {
int offset = pageSize - (size & r);
// copy the first part
System.arraycopy(obj_array, 0, lastBuffer, size & r, offset);
// copy the middle part
final int l = obj_array.length - offset;
final int k = (l) >> exp;
int z;
for (z = 1; z <= k; z++) {
System.arraycopy(obj_array, offset, bufferArrayList.get(lastBufferIndex + z), 0, pageSize);
offset += pageSize;
}
// copy the last part
System.arraycopy(obj_array, offset, bufferArrayList.get(lastBufferIndex + z), 0, l & r);
}
size += obj_array.length;
return;
} else // new buffers needed
{
// compute the number of additional buffers needed
// int n =
// ((int) ((int_array.length + size) / pageSize))
// + (((int_array.length + size) % pageSize) > 0 ? 1 : 0)
// - (int) (capacity / pageSize);
final int n = ((obj_array.length + size) >> exp) + (((obj_array.length + size) & r) > 0 ? 1 : 0)
- (capacity >> exp);
// create these buffers
// add to bufferArrayList
// System.arraycopy(int_array, 0, lastBuffer, size % pageSize, capacity - size);
System.arraycopy(obj_array, 0, lastBuffer, size & r, capacity - size);
for (int i = 0; i < n; i++) {
final Object[] newBuffer = new Object[pageSize];
if (i < n - 1) {
// full copy
System.arraycopy(obj_array, pageSize * i + capacity - size, newBuffer, 0, pageSize);
} else {
// last page
System.arraycopy(obj_array, pageSize * i + capacity - size, newBuffer, 0, obj_array.length
+ this.size - capacity - pageSize * i);
}
bufferArrayList.add(newBuffer);
}
// update length
size += obj_array.length;
// update capacity
capacity += n * pageSize;
// update
}
}
/**
* Append a single object to the end of this buffer Instance
*
* @param obj
*/
final public void append(final Object obj) {
// Object[] lastBuffer;
// int lastBufferIndex;
/*
* if (bufferArrayList.size == 0) {
* lastBuffer = new Object[pageSize];
* bufferArrayList.add(lastBuffer);
* capacity = pageSize;
* } else {
* lastBufferIndex = Math.min((size>>exp),//+(((size&r)==0)? 0:1),
* bufferArrayList.size - 1);
* lastBuffer = (Object[]) bufferArrayList.oa[lastBufferIndex];
* //lastBuffer = (int[]) bufferArrayList.get(bufferArrayList.size() - 1);
* }
*/
if (this.size < this.capacity) {
// get the last buffer from the bufferListArray
// obtain the starting offset in that buffer to which the data is to be copied
// update length
// System.arraycopy(long_array, 0, lastBuffer, size % pageSize, long_array.length);
((Object[]) bufferArrayList.oa[bufferArrayList.size - 1])[size & r] = obj;
// lastBuffer[size % pageSize] = i;
size += 1;
} else // new buffers needed
{
final Object[] newBuffer = new Object[pageSize];
size++;
capacity += pageSize;
bufferArrayList.add(newBuffer);
newBuffer[0] = obj;
}
}
/**
* Returns the total allocated capacity of this buffer instance.
*
* @return int
*/
final public int getCapacity() {
return capacity;
}
/**
* Returns a single object array representing every object in this buffer instance
*
* @return Object[] (null if there isn't anything left in the buffer
* @param startingOffset
* int
* @param len
* int
* @return Object[]
*/
public Object[] getObjectArray(final int startingOffset, final int len) {
if (size <= 0 || startingOffset < 0) {
throw (new IllegalArgumentException());
}
if ((startingOffset + len) > size) {
throw (new IndexOutOfBoundsException());
}
final Object[] result = new Object[len]; // allocate result array
// int first_index = (int) (startingOffset / pageSize);
// int last_index = (int) ((startingOffset + len) / pageSize);
// if ((startingOffset + len) % pageSize == 0) {
// last_index--;
// }
final int first_index = startingOffset >> exp;
int last_index = (startingOffset + len) >> exp;
if (((startingOffset + len) & r) == 0) {
last_index--;
}
if (first_index == last_index) {
// to see if there is a need to go across buffer boundry
System.arraycopy((bufferArrayList.get(first_index)),
// startingOffset % pageSize,
startingOffset & r, result, 0, len);
} else {
int obj_array_offset = 0;
for (int i = first_index; i <= last_index; i++) {
final Object[] currentChunk = (Object[]) bufferArrayList.get(i);
if (i == first_index) // first section
{
System.arraycopy(currentChunk,
// startingOffset % pageSize,
startingOffset & r, result, 0,
// pageSize - (startingOffset % pageSize));
pageSize - (startingOffset & r));
// int_array_offset += pageSize - (startingOffset) % pageSize;
obj_array_offset += pageSize - (startingOffset & r);
} else if (i == last_index) // last sections
{
System.arraycopy(currentChunk, 0, result, obj_array_offset, len - obj_array_offset);
} else {
System.arraycopy(currentChunk, 0, result, obj_array_offset, pageSize);
obj_array_offset += pageSize;
}
}
}
return result;
}
/**
* Returns the page size of this buffer instance.
* Creation date: (7/17/03 6:38:02 PM)
*
* @return int
*/
public int getPageSize() {
return pageSize;
}
/**
* Get the object at the location specified by index.
*
* @return int
* @param index
* int
*/
@Override
public Object objectAt(final int index) {
if (index > size - 1) {
throw new IndexOutOfBoundsException();
}
// int pageNum = (int) index / pageSize;
final int pageNum = index >> exp;
// System.out.println("page Number is "+pageNum);
// int offset = index % pageSize;
final int offset = index & r;
return ((Object[]) bufferArrayList.get(pageNum))[offset];
}
/**
* Assigns a new int value to location index of the buffer instance.
*
* @param index
* int
* @param newValue
* int
*/
@Override
public void modifyEntry(final int index, final Object newValue) {
if (index > size - 1) {
throw new IndexOutOfBoundsException();
}
// ((int[]) bufferArrayList.get((int) (index / pageSize)))[index % pageSize] =
((Object[]) bufferArrayList.get((index >> exp)))[index & r] = newValue;
}
/**
* Returns the total number of objects in the buffer instance
*
* @return int
*/
@Override
public int size() {
return size;
}
/**
* Returns the object array corresponding to all objects in this buffer instance
*
* @return Object[] (null if the buffer is empty)
*/
public Object[] toObjectArray() {
if (size > 0) {
int s = size;
final Object[] resultArray = new Object[size];
// copy all the content int into the resultArray
int array_offset = 0;
for (int i = 0; s > 0; i++) {
System.arraycopy(bufferArrayList.get(i), 0, resultArray, array_offset, (s < pageSize) ? s : pageSize);
// (i == (bufferArrayList.size() - 1)) ? size() % pageSize : pageSize);
s = s - pageSize;
array_offset += pageSize;
}
return resultArray;
}
return null;
}
/**
* set the size of object buffer to zero, capacity
* untouched so object buffer can be reused without
* any unnecessary and additional allocation
*
*/
public void clear() {
size = 0;
}
}