/*
    * 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.
   */
  package org.apache.maven.plugins.assembly.utils;
  
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * @author Kristian Rosenvold
   */
  class LinuxLineFeedInputStream extends InputStream {
  
      private final InputStream target;
  
      private final boolean ensureLineFeedAtEndOfFile;
  
      private boolean slashNSeen = false;
  
      private boolean slashRSeen = false;
  
      private boolean eofSeen = false;
  
      LinuxLineFeedInputStream(InputStream in, boolean ensureLineFeedAtEndOfFile) {
          this.target = in;
          this.ensureLineFeedAtEndOfFile = ensureLineFeedAtEndOfFile;
      }
  
      private int readWithUpdate() throws IOException {
          final int target = this.target.read();
          eofSeen = target == -1;
          if (eofSeen) {
              return target;
          }
          slashNSeen = target == '\n';
          slashRSeen = target == '\r';
          return target;
      }
  
      @Override
      public int read() throws IOException {
          boolean prevWasSlashR = slashRSeen;
          if (eofSeen) {
              return eofGame(prevWasSlashR);
          } else {
              int target = readWithUpdate();
              if (eofSeen) {
                  return eofGame(prevWasSlashR);
              }
              if (slashRSeen) {
                  return '\n';
              }
  
              if (prevWasSlashR && slashNSeen) { // Lone /r
                  return read();
              }
              return target;
          }
      }
  
      private int eofGame(boolean previousWasSlashR) {
          if (previousWasSlashR || !ensureLineFeedAtEndOfFile) {
              return -1;
          }
          if (!slashNSeen) {
              slashNSeen = true;
              return '\n';
          } else {
              return -1;
          }
      }
  
      @Override
      public void close() throws IOException {
          super.close();
          target.close();
      }
  
      @Override
      public synchronized void mark(int readlimit) {
          throw new UnsupportedOperationException("Mark not implemented yet");
      }
  }