/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.solr.internal.csv;
/**
* A simple StringBuffer replacement that aims to
* reduce copying as much as possible. The buffer
* grows as necessary.
* This class is not thread safe.
*/
public class CharBuffer {
private char[] c;
/**
* Actually used number of characters in the array.
* It is also the index at which
* a new character will be inserted into <code>c</code>.
*/
private int length;
/**
* Creates a new CharBuffer with an initial capacity of 32 characters.
*/
public CharBuffer() {
this(32);
}
/**
* Creates a new CharBuffer with an initial capacity
* of <code>length</code> characters.
*/
public CharBuffer(final int length) {
if (length == 0) {
throw new IllegalArgumentException("Can't create an empty CharBuffer");
}
this.c = new char[length];
}
/**
* Empties the buffer. The capacity still remains the same, so no memory is freed.
*/
public void clear() {
length = 0;
}
/**
* Returns the number of characters in the buffer.
* @return the number of characters
*/
public int length() {
return length;
}
/**
* Returns the current capacity of the buffer.
* @return the maximum number of characters that can be stored in this buffer without
* resizing it.
*/
public int capacity() {
return c.length;
}
/**
* Appends the contents of <code>cb</code> to the end of this CharBuffer.
* @param cb the CharBuffer to append or null
*/
public void append(final CharBuffer cb) {
if (cb == null) {
return;
}
provideCapacity(length + cb.length);
System.arraycopy(cb.c, 0, c, length, cb.length);
length += cb.length;
}
/**
* Appends <code>s</code> to the end of this CharBuffer.
* This method involves copying the new data once!
* @param s the String to append or null
*/
public void append(final String s) {
if (s == null) {
return;
}
append(s.toCharArray());
}
/**
* Appends <code>sb</code> to the end of this CharBuffer.
* This method involves copying the new data once!
* @param sb the StringBuffer to append or null
*/
public void append(final StringBuffer sb) {
if (sb == null) {
return;
}
provideCapacity(length + sb.length());
sb.getChars(0, sb.length(), c, length);
length += sb.length();
}
/**
* Appends <code>data</code> to the end of this CharBuffer.
* This method involves copying the new data once!
* @param data the char[] to append or null
*/
public void append(final char[] data) {
if (data == null) {
return;
}
provideCapacity(length + data.length);
System.arraycopy(data, 0, c, length, data.length);
length += data.length;
}
/**
* Appends a single character to the end of this CharBuffer.
* This method involves copying the new data once!
* @param data the char to append
*/
public void append(final char data) {
provideCapacity(length + 1);
c[length] = data;
length++;
}
/**
* Shrinks the capacity of the buffer to the current length if necessary.
* This method involves copying the data once!
*/
public void shrink() {
if (c.length == length) {
return;
}
char[] newc = new char[length];
System.arraycopy(c, 0, newc, 0, length);
c = newc;
}
/**
* Removes trailing whitespace.
*/
public void trimTrailingWhitespace() {
while (length>0 && Character.isWhitespace(c[length-1])) {
length--;
}
}
/**
* Returns the contents of the buffer as a char[]. The returned array may
* be the internal array of the buffer, so the caller must take care when
* modifying it.
* This method allows to avoid copying if the caller knows the exact capacity
* before.
*/
public char[] getCharacters() {
if (c.length == length) {
return c;
}
char[] chars = new char[length];
System.arraycopy(c, 0, chars, 0, length);
return chars;
}
/**
* Returns the character at the specified position.
*/
public char charAt(int pos) {
return c[pos];
}
/**
* Converts the contents of the buffer into a StringBuffer.
* This method involves copying the new data once!
*/
@Override
public String toString() {
return new String(c, 0, length);
}
/**
* Copies the data into a new array of at least <code>capacity</code> size.
*/
public void provideCapacity(final int capacity) {
if (c.length >= capacity) {
return;
}
int newcapacity = ((capacity*3)>>1) + 1;
char[] newc = new char[newcapacity];
System.arraycopy(c, 0, newc, 0, length);
c = newc;
}
}