gt:             if (this.inStream != System.in) {
context: /*
   *  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.
   *
   */
  
  /*
   * This package is based on the work done by Timothy Gerard Endres
   * (time@ice.com) to whom the Ant project is very grateful for his great code.
   */
  
  package yacy.utils.tar;
  
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.IOException;
  import java.util.Arrays;
  
  /**
   * The TarBuffer class implements the tar archive concept
   * of a buffered input stream. This concept goes back to the
   * days of blocked tape drives and special io devices. In the
   * Java universe, the only real function that this class
   * performs is to ensure that files have the correct "block"
   * size, or other tars will complain.
   * <p>
   * You should never have a need to access this class directly.
   * TarBuffers are created by Tar IO Streams.
   *
   */
  
  public class TarBuffer {
  
      /** Default record size */
      public static final int DEFAULT_RCDSIZE = (512);
  
      /** Default block size */
      public static final int DEFAULT_BLKSIZE = (DEFAULT_RCDSIZE * 20);
  
      private InputStream     inStream;
      private OutputStream    outStream;
      private byte[]          blockBuffer;
      private int             currBlkIdx;
      private int             currRecIdx;
      private int             blockSize;
      private int             recordSize;
      private int             recsPerBlock;
      private boolean         debug;
  
      /**
       * Constructor for a TarBuffer on an input stream.
       * @param inStream the input stream to use
       */
      public TarBuffer(InputStream inStream) {
          this(inStream, TarBuffer.DEFAULT_BLKSIZE);
      }
  
      /**
       * Constructor for a TarBuffer on an input stream.
       * @param inStream the input stream to use
       * @param blockSize the block size to use
       */
      public TarBuffer(InputStream inStream, int blockSize) {
          this(inStream, blockSize, TarBuffer.DEFAULT_RCDSIZE);
      }
  
      /**
       * Constructor for a TarBuffer on an input stream.
       * @param inStream the input stream to use
       * @param blockSize the block size to use
       * @param recordSize the record size to use
       */
      public TarBuffer(InputStream inStream, int blockSize, int recordSize) {
          this.inStream = inStream;
          this.outStream = null;
  
          this.initialize(blockSize, recordSize);
      }
  
      /**
       * Constructor for a TarBuffer on an output stream.
       * @param outStream the output stream to use
       */
      public TarBuffer(OutputStream outStream) {
          this(outStream, TarBuffer.DEFAULT_BLKSIZE);
      }
  
      /**
       * Constructor for a TarBuffer on an output stream.
       * @param outStream the output stream to use
       * @param blockSize the block size to use
       */
      public TarBuffer(OutputStream outStream, int blockSize) {
          this(outStream, blockSize, TarBuffer.DEFAULT_RCDSIZE);
      }
  
      /**
       * Constructor for a TarBuffer on an output stream.
       * @param outStream the output stream to use
       * @param blockSize the block size to use
       * @param recordSize the record size to use
       */
      public TarBuffer(OutputStream outStream, int blockSize, int recordSize) {
          this.inStream = null;
          this.outStream = outStream;
  
          this.initialize(blockSize, recordSize);
      }
  
      /**
       * Initialization common to all constructors.
       */
      private void initialize(int blockSize, int recordSize) {
          this.debug = false;
          this.blockSize = blockSize;
          this.recordSize = recordSize;
          this.recsPerBlock = (this.blockSize / this.recordSize);
          this.blockBuffer = new byte[this.blockSize];
  
          if (this.inStream != null) {
              this.currBlkIdx = -1;
              this.currRecIdx = this.recsPerBlock;
          } else {
              this.currBlkIdx = 0;
              this.currRecIdx = 0;
          }
      }
  
      /**
       * Get the TAR Buffer's block size. Blocks consist of multiple records.
       * @return the block size
       */
      public int getBlockSize() {
          return this.blockSize;
      }
  
      /**
       * Get the TAR Buffer's record size.
       * @return the record size
       */
      public int getRecordSize() {
          return this.recordSize;
      }
  
      /**
       * Set the debugging flag for the buffer.
       *
       * @param debug If true, print debugging output.
       */
      public void setDebug(boolean debug) {
          this.debug = debug;
      }
  
      /**
       * Determine if an archive record indicate End of Archive. End of
       * archive is indicated by a record that consists entirely of null bytes.
       *
       * @param record The record data to check.
       * @return true if the record data is an End of Archive
       */
      public boolean isEOFRecord(byte[] record) {
          for (int i = 0, sz = this.getRecordSize(); i < sz; ++i) {
              if (record[i] != 0) {
                  return false;
              }
          }
  
          return true;
      }
  
      /**
       * Skip over a record on the input stream.
       * @throws IOException on error
       */
      public void skipRecord() throws IOException {
          if (this.debug) {
              System.err.println("SkipRecord: recIdx = " + this.currRecIdx
                                 + " blkIdx = " + this.currBlkIdx);
          }
  
          if (this.inStream == null) {
              throw new IOException("reading (via skip) from an output buffer");
          }
  
          if (this.currRecIdx >= this.recsPerBlock) {
              if (!this.readBlock()) {
                  return;    // UNDONE
              }
          }
  
          this.currRecIdx++;
      }
  
      /**
       * Read a record from the input stream and return the data.
       *
       * @return The record data.
       * @throws IOException on error
       */
      public byte[] readRecord() throws IOException {
          if (this.debug) {
              System.err.println("ReadRecord: recIdx = " + this.currRecIdx
                                 + " blkIdx = " + this.currBlkIdx);
          }
  
          if (this.inStream == null) {
              throw new IOException("reading from an output buffer");
          }
  
          if (this.currRecIdx >= this.recsPerBlock) {
              if (!this.readBlock()) {
                  return null;
              }
          }
  
          byte[] result = new byte[this.recordSize];
  
          System.arraycopy(this.blockBuffer,
                           (this.currRecIdx * this.recordSize), result, 0,
                           this.recordSize);
  
          this.currRecIdx++;
  
          return result;
      }
  
      /**
       * @return false if End-Of-File, else true
       */
      private boolean readBlock() throws IOException {
          if (this.debug) {
              System.err.println("ReadBlock: blkIdx = " + this.currBlkIdx);
          }
  
          if (this.inStream == null) {
              throw new IOException("reading from an output buffer");
          }
  
          this.currRecIdx = 0;
  
          int offset = 0;
          int bytesNeeded = this.blockSize;
  
          while (bytesNeeded > 0) {
              long numBytes = this.inStream.read(this.blockBuffer, offset,
                                                 bytesNeeded);
  
              //
              // NOTE
              // We have fit EOF, and the block is not full!
              //
              // This is a broken archive. It does not follow the standard
              // blocking algorithm. However, because we are generous, and
              // it requires little effort, we will simply ignore the error
              // and continue as if the entire block were read. This does
              // not appear to break anything upstream. We used to return
              // false in this case.
              //
              // Thanks to 'Yohann.Roussel@alcatel.fr' for this fix.
              //
              if (numBytes == -1) {
                  if (offset == 0) {
                      // Ensure that we do not read gigabytes of zeros
                      // for a corrupt tar file.
                      // See http://issues.apache.org/bugzilla/show_bug.cgi?id=39924
                      return false;
                  }
                  // However, just leaving the unread portion of the buffer dirty does
                  // cause problems in some cases.  This problem is described in
                  // http://issues.apache.org/bugzilla/show_bug.cgi?id=29877
                  //
                  // The solution is to fill the unused portion of the buffer with zeros.
  
                  Arrays.fill(blockBuffer, offset, offset + bytesNeeded, (byte) 0);
  
                  break;
              }
  
              offset += numBytes;
              bytesNeeded -= numBytes;
  
              if (numBytes != this.blockSize) {
                  if (this.debug) {
                      System.err.println("ReadBlock: INCOMPLETE READ "
                                         + numBytes + " of " + this.blockSize
                                         + " bytes read.");
                  }
              }
          }
  
          this.currBlkIdx++;
  
          return true;
      }
  
      /**
       * Get the current block number, zero based.
       *
       * @return The current zero based block number.
       */
      public int getCurrentBlockNum() {
          return this.currBlkIdx;
      }
  
      /**
       * Get the current record number, within the current block, zero based.
       * Thus, current offset = (currentBlockNum * recsPerBlk) + currentRecNum.
       *
       * @return The current zero based record number.
       */
      public int getCurrentRecordNum() {
          return this.currRecIdx - 1;
      }
  
      /**
       * Write an archive record to the archive.
       *
       * @param record The record data to write to the archive.
       * @throws IOException on error
       */
      public void writeRecord(byte[] record) throws IOException {
          if (this.debug) {
              System.err.println("WriteRecord: recIdx = " + this.currRecIdx
                                 + " blkIdx = " + this.currBlkIdx);
          }
  
          if (this.outStream == null) {
              throw new IOException("writing to an input buffer");
          }
  
          if (record.length != this.recordSize) {
              throw new IOException("record to write has length '"
                                    + record.length
                                    + "' which is not the record size of '"
                                    + this.recordSize + "'");
          }
  
          if (this.currRecIdx >= this.recsPerBlock) {
              this.writeBlock();
          }
  
          System.arraycopy(record, 0, this.blockBuffer,
                           (this.currRecIdx * this.recordSize),
                           this.recordSize);
  
          this.currRecIdx++;
      }
  
      /**
       * Write an archive record to the archive, where the record may be
       * inside of a larger array buffer. The buffer must be "offset plus
       * record size" long.
       *
       * @param buf The buffer containing the record data to write.
       * @param offset The offset of the record data within buf.
       * @throws IOException on error
       */
      public void writeRecord(byte[] buf, int offset) throws IOException {
          if (this.debug) {
              System.err.println("WriteRecord: recIdx = " + this.currRecIdx
                                 + " blkIdx = " + this.currBlkIdx);
          }
  
          if (this.outStream == null) {
              throw new IOException("writing to an input buffer");
          }
  
          if ((offset + this.recordSize) > buf.length) {
              throw new IOException("record has length '" + buf.length
                                    + "' with offset '" + offset
                                    + "' which is less than the record size of '"
                                    + this.recordSize + "'");
          }
  
          if (this.currRecIdx >= this.recsPerBlock) {
              this.writeBlock();
          }
  
          System.arraycopy(buf, offset, this.blockBuffer,
                           (this.currRecIdx * this.recordSize),
                           this.recordSize);
  
          this.currRecIdx++;
      }
  
      /**
       * Write a TarBuffer block to the archive.
       */
      private void writeBlock() throws IOException {
          if (this.debug) {
              System.err.println("WriteBlock: blkIdx = " + this.currBlkIdx);
          }
  
          if (this.outStream == null) {
              throw new IOException("writing to an input buffer");
          }
  
          this.outStream.write(this.blockBuffer, 0, this.blockSize);
          this.outStream.flush();
  
          this.currRecIdx = 0;
          this.currBlkIdx++;
      }
  
      /**
       * Flush the current data block if it has any data in it.
       */
      private void flushBlock() throws IOException {
          if (this.debug) {
              System.err.println("TarBuffer.flushBlock() called.");
          }
  
          if (this.outStream == null) {
              throw new IOException("writing to an input buffer");
          }
  
          if (this.currRecIdx > 0) {
              this.writeBlock();
          }
      }
  
      /**
       * Close the TarBuffer. If this is an output buffer, also flush the
       * current block before closing.
       * @throws IOException on error
       */
      public synchronized void close() throws IOException {
          if (this.debug) {
              System.err.println("TarBuffer.closeBuffer().");
          }
  
          if (this.outStream != null) {
              this.flushBlock();
  
              if (this.outStream != System.out
                      && this.outStream != System.err) {
                  this.outStream.close();
  
                  this.outStream = null;
              }
          } else if (this.inStream != null) {
  