Mega Code Archive
A line reading wrapper that works with byte streams
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/*
* Copyright 2008-2009 SHOP.COM
*
* 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 com.shop.util;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
/**
* A line reading wrapper that works with byte streams. Has the same sematics as
* {@link BufferedReader}<br>
*
* @author Jordan Zimmerman
*/
public class LineReader extends InputStream {
public LineReader(InputStream in) {
fIn = in;
fBuffer = new StringBuilder();
fLastWasCR = false;
fPushbackChar = 0;
}
@Override
public synchronized int read() throws IOException {
if (fPushbackChar == 0) {
return streamRead();
} else {
return pushbackRead();
}
}
/**
* copied from {@link BufferedReader#readLine()}
*
* Reads a line of text. A line is considered to be terminated by any one of
* a line feed ('\n'), a carriage return ('\r'), or a carriage return
* followed immediately by a linefeed.
*
* @return A String containing the contents of the line, not including any
* line-termination characters, or null if the end of the stream has
* been reached
*
* @exception IOException
* If an I/O error occurs
*/
public synchronized String readLine() throws IOException {
fBuffer.setLength(0);
boolean eof = false;
for (;;) {
int b = read();
if (b == -1) {
eof = true;
break;
}
if (b == '\r') {
fLastWasCR = true;
break;
}
if (b == '\n') {
break;
}
fBuffer.append((char) (b & 0xFF));
}
return ((fBuffer.length() == 0) && eof) ? null : fBuffer.toString();
}
@Override
public synchronized void close() throws IOException {
super.close();
fBuffer = null;
fIn.close();
}
/**
* Push the given char so that the next() read will return this char
*
* @param c
* char to push back
*/
public synchronized void pushback(int c) {
fPushbackChar = c;
}
private int pushbackRead() {
int b = fPushbackChar;
fPushbackChar = 0;
return b;
}
private int streamRead() throws IOException {
int b = fIn.read();
if (fLastWasCR) {
fLastWasCR = false;
char c = (char) (b & 0xff);
if (c == '\n') {
return read();
}
}
return b;
}
private InputStream fIn;
private StringBuilder fBuffer;
private boolean fLastWasCR;
private int fPushbackChar;
}
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