Char Buffer
/*
* Copyright (c) 1998 - 2005 Versant Corporation
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Versant Corporation - initial API and implementation
*/
/**
* Fast StringBuffer replacement that allows direct access to the underlying
* char[]. This is based com.sosnoski.util.array.CharArray from
* Sosnoski Software Solutions, Inc.
*/
public final class CharBuf {
private char[] buf;
private int size;
public CharBuf() {
this(64);
}
public CharBuf(int capacity) {
buf = new char[capacity];
}
public CharBuf(String s) {
this(s.length());
append(s);
}
public CharBuf(CharBuf s) {
this(s.size);
size = s.size;
System.arraycopy(s.buf, 0, buf, 0, size);
}
public int size() {
return size;
}
public void clear() {
size = 0;
}
private void ensureCapacity(int len) {
if (size + len > buf.length) {
int n = buf.length * 3 / 2 + 1;
if (size + len > n) {
n = size + len;
}
char[] a = new char[n];
System.arraycopy(buf, 0, a, 0, size);
buf = a;
}
}
/**
* Append ch and return its index.
*/
public int append(char ch) {
ensureCapacity(size + 1);
int start = size;
buf[size++] = ch;
return start;
}
/**
* Append i and return its index.
*/
public int append(int i) {
return append(Integer.toString(i));
}
/**
* Append s and return its index.
*/
public int append(String s) {
return append(s.toCharArray());
}
/**
* Append a and return its index.
*/
public int append(char[] a) {
int n = a.length;
ensureCapacity(size + n);
int start = size;
System.arraycopy(a, 0, buf, size, n);
size += n;
return start;
}
/**
* Replace characters from i onwards with supplied characters. This does
* not do any error checking or make any attempt to expand the buffer
* for performance reasons.
*/
public void replace(int i, char[] text) {
System.arraycopy(text, 0, buf, i, text.length);
}
/**
* Replace characters from first to last - 1 with c. This does
* not do any error checking for performance reasons.
*/
public void replace(int first, int last, char c) {
for (int i = first; i < last; i++) {
buf[i] = c;
}
}
public String toString() {
return new String(buf, 0, size);
}
/**
* Constructs and returns a simple array containing the same data as held
* in a portion of this growable array.
*/
public char[] toArray(int offset, int length) {
char[] a = new char[length];
System.arraycopy(buf, offset, a, 0, length);
return a;
}
public void setSize(int sz) {
size = sz;
}
/**
* Construct a <code>String</code> from a portion of the character sequence
* present.
*/
public String toString(int offset, int length) {
return new String(buf, offset, length);
}
/**
* Insert the characters from a <code>char[]</code> into the array.
*/
public void insert(int offset, char[] text) {
adjust(offset, offset, text.length);
System.arraycopy(text, 0, buf, offset, text.length);
}
/**
* Insert the characters from a <code>String</code> into the array.
*/
public void insert(int offset, String text) {
adjust(offset, offset, text.length());
text.getChars(0, text.length(), buf, offset);
}
/**
* Replace a character range in the array with the characters from a
* <code>String</code>.
*/
public void replace(int from, int to, String text) {
adjust(from, to, text.length());
text.getChars(0, text.length(), buf, from);
}
/**
* Replace a character range in the array with the characters from a
* <code>char[]</code>.
*/
public void replace(int from, int to, char[] text) {
adjust(from, to, text.length);
System.arraycopy(text, 0, buf, from, text.length);
}
/**
* Adjust the characters in the array to make room for an insertion or
* replacement. Depending on the relative sizes of the range being
* replaced and the range being inserted, this may move characters past
* the start of the replacement range up or down in the array.
*
* @param from index number of first character to be replaced
* @param to index number past last character to be replaced
* @param length length of character range being inserted
*/
protected void adjust(int from, int to, int length) {
if (from >= 0 && to < size && from <= to) {
int change = from + length - to;
if (change > 0) {
ensureCapacity(size + change);
}
if (to < size){
System.arraycopy(buf, to, buf, to + change, size - to);
size += change;
}
} else {
throw new ArrayIndexOutOfBoundsException("Invalid remove range");
}
}
/**
* Set the value at an index position in the array.
*/
public void set(int index, char value) {
buf[index] = value;
}
/**
* Remove a range of value from the array. The index positions for values
* above the range removed are decreased by the number of values removed.
*
* @param from index number of first value to be removed
* @param to index number past last value to be removed
*/
public void remove(int from, int to) {
if (from >= 0 && to <= size && from <= to) {
if (to < size){
int change = from - to;
System.arraycopy(buf, to, buf, from, size - to);
size += change;
}
} else {
throw new ArrayIndexOutOfBoundsException("Invalid remove range");
}
}
}
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