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 Windows line endings, CRLF. 028 * 029 * @since 2.5 030 */ 031public class WindowsLineEndingInputStream extends InputStream { 032 033 private boolean slashRSeen; 034 035 private boolean slashNSeen; 036 037 private boolean injectSlashN; 038 039 private boolean eofSeen; 040 041 private final InputStream target; 042 043 private final boolean ensureLineFeedAtEndOfFile; 044 045 /** 046 * Creates an input stream that filters another stream 047 * 048 * @param in The input stream to wrap 049 * @param ensureLineFeedAtEndOfFile true to ensure that the file ends with CRLF 050 */ 051 public WindowsLineEndingInputStream(final InputStream in, final boolean ensureLineFeedAtEndOfFile) { 052 this.target = in; 053 this.ensureLineFeedAtEndOfFile = ensureLineFeedAtEndOfFile; 054 } 055 056 /** 057 * Reads the next item from the target, updating internal flags in the process 058 * @return the next int read from the target stream 059 * @throws IOException upon error 060 */ 061 private int readWithUpdate() throws IOException { 062 final int target = this.target.read(); 063 eofSeen = target == EOF; 064 if (eofSeen) { 065 return target; 066 } 067 slashRSeen = target == CR; 068 slashNSeen = target == LF; 069 return target; 070 } 071 072 /** 073 * {@inheritDoc} 074 */ 075 @Override 076 public int read() throws IOException { 077 if (eofSeen) { 078 return eofGame(); 079 } 080 if (injectSlashN) { 081 injectSlashN = false; 082 return LF; 083 } 084 final boolean prevWasSlashR = slashRSeen; 085 final int target = readWithUpdate(); 086 if (eofSeen) { 087 return eofGame(); 088 } 089 if ((target == LF) && !prevWasSlashR) { 090 injectSlashN = true; 091 return CR; 092 } 093 return target; 094 } 095 096 /** 097 * Handles the EOF-handling at the end of the stream 098 * @return The next char to output to the stream 099 */ 100 private int eofGame() { 101 if (!ensureLineFeedAtEndOfFile) { 102 return EOF; 103 } 104 if (!slashNSeen && !slashRSeen) { 105 slashRSeen = true; 106 return CR; 107 } 108 if (!slashNSeen) { 109 slashRSeen = false; 110 slashNSeen = true; 111 return LF; 112 } 113 return EOF; 114 } 115 116 /** 117 * Closes the stream. Also closes the underlying stream. 118 * @throws IOException upon error 119 */ 120 @Override 121 public void close() throws IOException { 122 super.close(); 123 target.close(); 124 } 125 126 /** 127 * {@inheritDoc} 128 */ 129 @Override 130 public synchronized void mark(final int readlimit) { 131 throw UnsupportedOperationExceptions.mark(); 132 } 133}