CharArrayBuffer.java
/*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package com.foxinmy.weixin4j.util;
import java.io.Serializable;
import java.nio.CharBuffer;
import com.foxinmy.weixin4j.http.HTTP;
/**
* A resizable char array.
*
* @since 4.0
*/
public final class CharArrayBuffer implements CharSequence, Serializable {
private static final long serialVersionUID = -6208952725094867135L;
private char[] buffer;
private int len;
/**
* Creates an instance of {@link CharArrayBuffer} with the given initial
* capacity.
*
* @param capacity the capacity
*/
public CharArrayBuffer(final int capacity) {
super();
this.buffer = new char[capacity];
}
private void expand(final int newlen) {
final char newbuffer[] = new char[Math.max(this.buffer.length << 1, newlen)];
System.arraycopy(this.buffer, 0, newbuffer, 0, this.len);
this.buffer = newbuffer;
}
/**
* Appends {@code len} chars to this buffer from the given source
* array starting at index {@code off}. The capacity of the buffer
* is increased, if necessary, to accommodate all {@code len} chars.
*
* @param b the chars to be appended.
* @param off the index of the first char to append.
* @param len the number of chars to append.
* @throws IndexOutOfBoundsException if {@code off} is out of
* range, {@code len} is negative, or
* {@code off} + {@code len} is out of range.
*/
public void append(final char[] b, final int off, final int len) {
if (b == null) {
return;
}
if ((off < 0) || (off > b.length) || (len < 0) ||
((off + len) < 0) || ((off + len) > b.length)) {
throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);
}
if (len == 0) {
return;
}
final int newlen = this.len + len;
if (newlen > this.buffer.length) {
expand(newlen);
}
System.arraycopy(b, off, this.buffer, this.len, len);
this.len = newlen;
}
/**
* Appends chars of the given string to this buffer. The capacity of the
* buffer is increased, if necessary, to accommodate all chars.
*
* @param str the string.
*/
public void append(final String str) {
final String s = str != null ? str : "null";
final int strlen = s.length();
final int newlen = this.len + strlen;
if (newlen > this.buffer.length) {
expand(newlen);
}
s.getChars(0, strlen, this.buffer, this.len);
this.len = newlen;
}
/**
* Appends {@code len} chars to this buffer from the given source
* buffer starting at index {@code off}. The capacity of the
* destination buffer is increased, if necessary, to accommodate all
* {@code len} chars.
*
* @param b the source buffer to be appended.
* @param off the index of the first char to append.
* @param len the number of chars to append.
* @throws IndexOutOfBoundsException if {@code off} is out of
* range, {@code len} is negative, or
* {@code off} + {@code len} is out of range.
*/
public void append(final CharArrayBuffer b, final int off, final int len) {
if (b == null) {
return;
}
append(b.buffer, off, len);
}
/**
* Appends all chars to this buffer from the given source buffer starting
* at index {@code 0}. The capacity of the destination buffer is
* increased, if necessary, to accommodate all {@link #length()} chars.
*
* @param b the source buffer to be appended.
*/
public void append(final CharArrayBuffer b) {
if (b == null) {
return;
}
append(b.buffer,0, b.len);
}
/**
* Appends {@code ch} char to this buffer. The capacity of the buffer
* is increased, if necessary, to accommodate the additional char.
*
* @param ch the char to be appended.
*/
public void append(final char ch) {
final int newlen = this.len + 1;
if (newlen > this.buffer.length) {
expand(newlen);
}
this.buffer[this.len] = ch;
this.len = newlen;
}
/**
* Appends {@code len} bytes to this buffer from the given source
* array starting at index {@code off}. The capacity of the buffer
* is increased, if necessary, to accommodate all {@code len} bytes.
* <p>
* The bytes are converted to chars using simple cast.
*
* @param b the bytes to be appended.
* @param off the index of the first byte to append.
* @param len the number of bytes to append.
* @throws IndexOutOfBoundsException if {@code off} is out of
* range, {@code len} is negative, or
* {@code off} + {@code len} is out of range.
*/
public void append(final byte[] b, final int off, final int len) {
if (b == null) {
return;
}
if ((off < 0) || (off > b.length) || (len < 0) ||
((off + len) < 0) || ((off + len) > b.length)) {
throw new IndexOutOfBoundsException("off: "+off+" len: "+len+" b.length: "+b.length);
}
if (len == 0) {
return;
}
final int oldlen = this.len;
final int newlen = oldlen + len;
if (newlen > this.buffer.length) {
expand(newlen);
}
for (int i1 = off, i2 = oldlen; i2 < newlen; i1++, i2++) {
this.buffer[i2] = (char) (b[i1] & 0xff);
}
this.len = newlen;
}
/**
* Appends {@code len} bytes to this buffer from the given source
* array starting at index {@code off}. The capacity of the buffer
* is increased, if necessary, to accommodate all {@code len} bytes.
* <p>
* The bytes are converted to chars using simple cast.
*
* @param b the bytes to be appended.
* @param off the index of the first byte to append.
* @param len the number of bytes to append.
* @throws IndexOutOfBoundsException if {@code off} is out of
* range, {@code len} is negative, or
* {@code off} + {@code len} is out of range.
*/
public void append(final ByteArrayBuffer b, final int off, final int len) {
if (b == null) {
return;
}
append(b.buffer(), off, len);
}
/**
* Appends chars of the textual representation of the given object to this
* buffer. The capacity of the buffer is increased, if necessary, to
* accommodate all chars.
*
* @param obj the object.
*/
public void append(final Object obj) {
append(String.valueOf(obj));
}
/**
* Clears content of the buffer. The underlying char array is not resized.
*/
public void clear() {
this.len = 0;
}
/**
* Converts the content of this buffer to an array of chars.
*
* @return char array
*/
public char[] toCharArray() {
final char[] b = new char[this.len];
if (this.len > 0) {
System.arraycopy(this.buffer, 0, b, 0, this.len);
}
return b;
}
/**
* Returns the {@code char} value in this buffer at the specified
* index. The index argument must be greater than or equal to
* {@code 0}, and less than the length of this buffer.
*
* @param i the index of the desired char value.
* @return the char value at the specified index.
* @throws IndexOutOfBoundsException if {@code index} is
* negative or greater than or equal to {@link #length()}.
*/
@Override
public char charAt(final int i) {
return this.buffer[i];
}
/**
* Returns reference to the underlying char array.
*
* @return the char array.
*/
public char[] buffer() {
return this.buffer;
}
/**
* Returns the current capacity. The capacity is the amount of storage
* available for newly appended chars, beyond which an allocation will
* occur.
*
* @return the current capacity
*/
public int capacity() {
return this.buffer.length;
}
/**
* Returns the length of the buffer (char count).
*
* @return the length of the buffer
*/
@Override
public int length() {
return this.len;
}
/**
* Ensures that the capacity is at least equal to the specified minimum.
* If the current capacity is less than the argument, then a new internal
* array is allocated with greater capacity. If the {@code required}
* argument is non-positive, this method takes no action.
*
* @param required the minimum required capacity.
*/
public void ensureCapacity(final int required) {
if (required <= 0) {
return;
}
final int available = this.buffer.length - this.len;
if (required > available) {
expand(this.len + required);
}
}
/**
* Sets the length of the buffer. The new length value is expected to be
* less than the current capacity and greater than or equal to
* {@code 0}.
*
* @param len the new length
* @throws IndexOutOfBoundsException if the
* {@code len} argument is greater than the current
* capacity of the buffer or less than {@code 0}.
*/
public void setLength(final int len) {
if (len < 0 || len > this.buffer.length) {
throw new IndexOutOfBoundsException("len: "+len+" < 0 or > buffer len: "+this.buffer.length);
}
this.len = len;
}
/**
* Returns {@code true} if this buffer is empty, that is, its
* {@link #length()} is equal to {@code 0}.
* @return {@code true} if this buffer is empty, {@code false}
* otherwise.
*/
public boolean isEmpty() {
return this.len == 0;
}
/**
* Returns {@code true} if this buffer is full, that is, its
* {@link #length()} is equal to its {@link #capacity()}.
* @return {@code true} if this buffer is full, {@code false}
* otherwise.
*/
public boolean isFull() {
return this.len == this.buffer.length;
}
/**
* Returns the index within this buffer of the first occurrence of the
* specified character, starting the search at the specified
* {@code beginIndex} and finishing at {@code endIndex}.
* If no such character occurs in this buffer within the specified bounds,
* {@code -1} is returned.
* <p>
* There is no restriction on the value of {@code beginIndex} and
* {@code endIndex}. If {@code beginIndex} is negative,
* it has the same effect as if it were zero. If {@code endIndex} is
* greater than {@link #length()}, it has the same effect as if it were
* {@link #length()}. If the {@code beginIndex} is greater than
* the {@code endIndex}, {@code -1} is returned.
*
* @param ch the char to search for.
* @param from the index to start the search from.
* @param to the index to finish the search at.
* @return the index of the first occurrence of the character in the buffer
* within the given bounds, or {@code -1} if the character does
* not occur.
*/
public int indexOf(final int ch, final int from, final int to) {
int beginIndex = from;
if (beginIndex < 0) {
beginIndex = 0;
}
int endIndex = to;
if (endIndex > this.len) {
endIndex = this.len;
}
if (beginIndex > endIndex) {
return -1;
}
for (int i = beginIndex; i < endIndex; i++) {
if (this.buffer[i] == ch) {
return i;
}
}
return -1;
}
/**
* Returns the index within this buffer of the first occurrence of the
* specified character, starting the search at {@code 0} and finishing
* at {@link #length()}. If no such character occurs in this buffer within
* those bounds, {@code -1} is returned.
*
* @param ch the char to search for.
* @return the index of the first occurrence of the character in the
* buffer, or {@code -1} if the character does not occur.
*/
public int indexOf(final int ch) {
return indexOf(ch, 0, this.len);
}
/**
* Returns a substring of this buffer. The substring begins at the specified
* {@code beginIndex} and extends to the character at index
* {@code endIndex - 1}.
*
* @param beginIndex the beginning index, inclusive.
* @param endIndex the ending index, exclusive.
* @return the specified substring.
* @throws StringIndexOutOfBoundsException if the
* {@code beginIndex} is negative, or
* {@code endIndex} is larger than the length of this
* buffer, or {@code beginIndex} is larger than
* {@code endIndex}.
*/
public String substring(final int beginIndex, final int endIndex) {
if (beginIndex < 0) {
throw new IndexOutOfBoundsException("Negative beginIndex: " + beginIndex);
}
if (endIndex > this.len) {
throw new IndexOutOfBoundsException("endIndex: " + endIndex + " > length: " + this.len);
}
if (beginIndex > endIndex) {
throw new IndexOutOfBoundsException("beginIndex: " + beginIndex + " > endIndex: " + endIndex);
}
return new String(this.buffer, beginIndex, endIndex - beginIndex);
}
/**
* Returns a substring of this buffer with leading and trailing whitespace
* omitted. The substring begins with the first non-whitespace character
* from {@code beginIndex} and extends to the last
* non-whitespace character with the index lesser than
* {@code endIndex}.
*
* @param beginIndex the beginning index, inclusive.
* @param endIndex the ending index, exclusive.
* @return the specified substring.
* @throws IndexOutOfBoundsException if the
* {@code beginIndex} is negative, or
* {@code endIndex} is larger than the length of this
* buffer, or {@code beginIndex} is larger than
* {@code endIndex}.
*/
public String substringTrimmed(final int beginIndex, final int endIndex) {
if (beginIndex < 0) {
throw new IndexOutOfBoundsException("Negative beginIndex: " + beginIndex);
}
if (endIndex > this.len) {
throw new IndexOutOfBoundsException("endIndex: " + endIndex + " > length: " + this.len);
}
if (beginIndex > endIndex) {
throw new IndexOutOfBoundsException("beginIndex: " + beginIndex + " > endIndex: " + endIndex);
}
int beginIndex0 = beginIndex;
int endIndex0 = endIndex;
while (beginIndex0 < endIndex && HTTP.isWhitespace(this.buffer[beginIndex0])) {
beginIndex0++;
}
while (endIndex0 > beginIndex0 && HTTP.isWhitespace(this.buffer[endIndex0 - 1])) {
endIndex0--;
}
return new String(this.buffer, beginIndex0, endIndex0 - beginIndex0);
}
/**
* {@inheritDoc}
* @since 4.4
*/
@Override
public CharSequence subSequence(final int beginIndex, final int endIndex) {
if (beginIndex < 0) {
throw new IndexOutOfBoundsException("Negative beginIndex: " + beginIndex);
}
if (endIndex > this.len) {
throw new IndexOutOfBoundsException("endIndex: " + endIndex + " > length: " + this.len);
}
if (beginIndex > endIndex) {
throw new IndexOutOfBoundsException("beginIndex: " + beginIndex + " > endIndex: " + endIndex);
}
return CharBuffer.wrap(this.buffer, beginIndex, endIndex);
}
@Override
public String toString() {
return new String(this.buffer, 0, this.len);
}
}