/*
* Copyright 2008-2009 the original author or authors.
*
* Licensed 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 net.hasor.rsf.utils;
import java.io.*;
/**
* 使用InputStream读取Reader的工具类
* @version 2009-5-13
* @author 网络收集
*/
public class ReaderInputStream extends InputStream {
private Reader reader = null;
private ByteArrayOutputStream byteArrayOut = null;
private Writer writer = null;
private char[] chars = null;
private byte[] buffer = null;
private int index, length = 0;
//========================================================================================
/**
* 带Reader参数构造函数
* @param readerString - 要阅读的字符串。
*/
public ReaderInputStream(final String readerString) {
this.reader = new StringReader(readerString);
this.byteArrayOut = new ByteArrayOutputStream();
this.writer = new OutputStreamWriter(this.byteArrayOut);
this.chars = new char[1024];
}
/**
* 带Reader参数构造函数
* @param reader - InputStream使用的Reader
*/
public ReaderInputStream(final Reader reader) {
this.reader = reader;
this.byteArrayOut = new ByteArrayOutputStream();
this.writer = new OutputStreamWriter(this.byteArrayOut);
this.chars = new char[1024];
}
/**
* 带Reader和字符编码格式参数的构造函数
* @param reader - InputStream使用的Reader
* @param encoding - InputStream使用的字符编码格式.
* @throws UnsupportedEncodingException 如果字符编码格式不支持,则抛UnsupportedEncodingException异常
*/
public ReaderInputStream(final Reader reader, final String encoding) throws UnsupportedEncodingException {
this.reader = reader;
this.byteArrayOut = new ByteArrayOutputStream();
this.writer = new OutputStreamWriter(this.byteArrayOut, encoding);
this.chars = new char[1024];
}
//========================================================================================
/** @see InputStream#read() */
@Override
public int read() throws IOException {
if (this.index >= this.length) {
this.fillBuffer();
}
if (this.index >= this.length) {
return -1;
}
return 0xff & this.buffer[this.index++];
}
private void fillBuffer() throws IOException {
if (this.length < 0) {
return;
}
int numChars = this.reader.read(this.chars);
if (numChars < 0) {
this.length = -1;
} else {
this.byteArrayOut.reset();
this.writer.write(this.chars, 0, numChars);
this.writer.flush();
this.buffer = this.byteArrayOut.toByteArray();
this.length = this.buffer.length;
this.index = 0;
}
}
/** @see InputStream#read(byte[], int, int) */
@Override
public int read(final byte[] data, final int off, final int len) throws IOException {
if (this.index >= this.length) {
this.fillBuffer();
}
if (this.index >= this.length) {
return -1;
}
int amount = Math.min(len, this.length - this.index);
System.arraycopy(this.buffer, this.index, data, off, amount);
this.index += amount;
return amount;
}
/** @see InputStream#available() */
@Override
public int available() throws IOException {
return this.index < this.length ? this.length - this.index : this.length >= 0 && this.reader.ready() ? 1 : 0;
}
/** @see InputStream#close() */
@Override
public void close() throws IOException {
this.reader.close();
}
}