001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.io.input; 018 019import static org.apache.commons.io.IOUtils.CR; 020import static org.apache.commons.io.IOUtils.EOF; 021import static org.apache.commons.io.IOUtils.LF; 022 023import java.io.IOException; 024import java.io.InputStream; 025 026/** 027 * A filtering input stream that ensures the content will have UNIX-style line endings, LF. 028 * 029 * @since 2.5 030 */ 031public class UnixLineEndingInputStream extends InputStream { 032 033 private boolean slashNSeen; 034 035 private boolean slashRSeen; 036 037 private boolean eofSeen; 038 039 private final InputStream target; 040 041 private final boolean ensureLineFeedAtEndOfFile; 042 043 /** 044 * Creates an input stream that filters another stream 045 * 046 * @param in The input stream to wrap 047 * @param ensureLineFeedAtEndOfFile true to ensure that the file ends with LF 048 */ 049 public UnixLineEndingInputStream(final InputStream in, final boolean ensureLineFeedAtEndOfFile) { 050 this.target = in; 051 this.ensureLineFeedAtEndOfFile = ensureLineFeedAtEndOfFile; 052 } 053 054 /** 055 * Reads the next item from the target, updating internal flags in the process 056 * @return the next int read from the target stream 057 * @throws IOException upon error 058 */ 059 private int readWithUpdate() throws IOException { 060 final int target = this.target.read(); 061 eofSeen = target == EOF; 062 if (eofSeen) { 063 return target; 064 } 065 slashNSeen = target == LF; 066 slashRSeen = target == CR; 067 return target; 068 } 069 070 /** 071 * {@inheritDoc} 072 */ 073 @Override 074 public int read() throws IOException { 075 final boolean previousWasSlashR = slashRSeen; 076 if (eofSeen) { 077 return eofGame(previousWasSlashR); 078 } 079 final int target = readWithUpdate(); 080 if (eofSeen) { 081 return eofGame(previousWasSlashR); 082 } 083 if (slashRSeen) { 084 return LF; 085 } 086 087 if (previousWasSlashR && slashNSeen) { 088 return read(); 089 } 090 091 return target; 092 } 093 094 /** 095 * Handles the EOF-handling at the end of the stream 096 * @param previousWasSlashR Indicates if the last seen was a \r 097 * @return The next char to output to the stream 098 */ 099 private int eofGame(final boolean previousWasSlashR) { 100 if (previousWasSlashR || !ensureLineFeedAtEndOfFile) { 101 return EOF; 102 } 103 if (!slashNSeen) { 104 slashNSeen = true; 105 return LF; 106 } 107 return EOF; 108 } 109 110 /** 111 * Closes the stream. Also closes the underlying stream. 112 * @throws IOException upon error 113 */ 114 @Override 115 public void close() throws IOException { 116 super.close(); 117 target.close(); 118 } 119 120 /** 121 * {@inheritDoc} 122 */ 123 @Override 124 public synchronized void mark(final int readlimit) { 125 throw UnsupportedOperationExceptions.mark(); 126 } 127}