content: /*
   * 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 mf.org.apache.xerces.impl.io;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.Reader;
  import java.util.Locale;
  
  import mf.org.apache.xerces.impl.msg.XMLMessageFormatter;
  import mf.org.apache.xerces.util.MessageFormatter;
  
  
  /**
   * A simple ASCII byte reader. This is an optimized reader for reading
   * byte streams that only contain 7-bit ASCII characters.
   *
   * @author Andy Clark, IBM
   * @version $Id: ASCIIReader.java 718095 2008-11-16 20:00:14Z mrglavas $
   * @xerces.internal
   */
  public final class ASCIIReader
          extends Reader {
  
      //
      // Constants
      //
  
      /**
       * Default byte buffer size (2048).
       */
      public static final int DEFAULT_BUFFER_SIZE = 2048;
  
      //
      // Data
      //
  
      /**
       * Input stream.
       */
      protected final InputStream fInputStream;
  
      /**
       * Byte buffer.
       */
      protected final byte[] fBuffer;
  
      // message formatter; used to produce localized
      // exception messages
      private final MessageFormatter fFormatter;
  
      //Locale to use for messages
      private final Locale fLocale;
  
      //
      // Constructors
      //
  
      /**
       * Constructs an ASCII reader from the specified input stream
       * using the default buffer size.
       *
       * @param inputStream      The input stream.
       * @param messageFormatter the MessageFormatter to use to message reporting.
       * @param locale           the Locale for which messages are to be reported
       */
      public ASCIIReader(InputStream inputStream, MessageFormatter messageFormatter,
                         Locale locale) {
          this(inputStream, DEFAULT_BUFFER_SIZE, messageFormatter, locale);
      } // <init>(InputStream, MessageFormatter, Locale)
  
      /**
       * Constructs an ASCII reader from the specified input stream
       * and buffer size.
       *
       * @param inputStream      The input stream.
       * @param size             The initial buffer size.
       * @param messageFormatter the MessageFormatter to use to message reporting.
       * @param locale           the Locale for which messages are to be reported
       */
      public ASCIIReader(InputStream inputStream, int size,
                         MessageFormatter messageFormatter, Locale locale) {
          this(inputStream, new byte[size], messageFormatter, locale);
      } // <init>(InputStream, int, MessageFormatter, Locale)
  
      /**
       * Constructs an ASCII reader from the specified input stream and buffer.
       *
       * @param inputStream      The input stream.
       * @param buffer           The byte buffer.
       * @param messageFormatter the MessageFormatter to use to message reporting.
       * @param locale           the Locale for which messages are to be reported
       */
      public ASCIIReader(InputStream inputStream, byte[] buffer,
                         MessageFormatter messageFormatter, Locale locale) {
          fInputStream = inputStream;
          fBuffer = buffer;
          fFormatter = messageFormatter;
          fLocale = locale;
      } // <init>(InputStream, byte[], MessageFormatter, Locale)
  
      //
      // Reader methods
      //
  
      /**
       * Read a single character.  This method will block until a character is
       * available, an I/O error occurs, or the end of the stream is reached.
       * <p/>
       * <p> Subclasses that intend to support efficient single-character input
       * should override this method.
       *
       * @return The character read, as an integer in the range 0 to 127
       * (<tt>0x00-0x7f</tt>), or -1 if the end of the stream has
       * been reached
       * @throws IOException If an I/O error occurs
       */
      @Override
      public int read() throws IOException {
          int b0 = fInputStream.read();
          if (b0 >= 0x80) {
              throw new MalformedByteSequenceException(fFormatter,
                      fLocale, XMLMessageFormatter.XML_DOMAIN,
                      "InvalidASCII", new Object[]{Integer.toString(b0)});
          }
          return b0;
      } // read():int
  
      /**
       * Read characters into a portion of an array.  This method will block
       * until some input is available, an I/O error occurs, or the end of the
       * stream is reached.
       *
       * @param ch     Destination buffer
       * @param offset Offset at which to start storing characters
       * @param length Maximum number of characters to read
       * @return The number of characters read, or -1 if the end of the
       * stream has been reached
       * @throws IOException If an I/O error occurs
       */
      @Override
      public int read(char ch[], int offset, int length) throws IOException {
          if (length > fBuffer.length) {
              length = fBuffer.length;
          }
          int count = fInputStream.read(fBuffer, 0, length);
          for (int i = 0; i < count; i++) {
              int b0 = fBuffer[i];
              if (b0 < 0) {
                  throw new MalformedByteSequenceException(fFormatter,
                          fLocale, XMLMessageFormatter.XML_DOMAIN,
                          "InvalidASCII", new Object[]{Integer.toString(b0 & 0x0FF)});
              }
              ch[offset + i] = (char) b0;
          }
          return count;
      } // read(char[],int,int)
  
      /**
       * Skip characters.  This method will block until some characters are
       * available, an I/O error occurs, or the end of the stream is reached.
       *
       * @param n The number of characters to skip
       * @return The number of characters actually skipped
       * @throws IOException If an I/O error occurs
       */
      @Override
      public long skip(long n) throws IOException {
          return fInputStream.skip(n);
      } // skip(long):long
  
      /**
       * Tell whether this stream is ready to be read.
       *
       * @return True if the next read() is guaranteed not to block for input,
       * false otherwise.  Note that returning false does not guarantee that the
       * next read will block.
       * @throws IOException If an I/O error occurs
       */
      @Override
      public boolean ready() throws IOException {
          return false;
      } // ready()
  
      /**
       * Tell whether this stream supports the mark() operation.
       */
      @Override
      public boolean markSupported() {
          return fInputStream.markSupported();
      } // markSupported()
  
      /**
       * Mark the present position in the stream.  Subsequent calls to reset()
       * will attempt to reposition the stream to this point.  Not all
       * character-input streams support the mark() operation.
       *
       * @param readAheadLimit Limit on the number of characters that may be
       *                       read while still preserving the mark.  After
       *                       reading this many characters, attempting to
       *                       reset the stream may fail.
       * @throws IOException If the stream does not support mark(),
       *                     or if some other I/O error occurs
       */
      @Override
      public void mark(int readAheadLimit) throws IOException {
          fInputStream.mark(readAheadLimit);
      } // mark(int)
  
      /**
       * Reset the stream.  If the stream has been marked, then attempt to
       * reposition it at the mark.  If the stream has not been marked, then
       * attempt to reset it in some way appropriate to the particular stream,
       * for example by repositioning it to its starting point.  Not all
       * character-input streams support the reset() operation, and some support
       * reset() without supporting mark().
       *
       * @throws IOException If the stream has not been marked,
       *                     or if the mark has been invalidated,
       *                     or if the stream does not support reset(),
       *                     or if some other I/O error occurs
       */
      @Override
      public void reset() throws IOException {
          fInputStream.reset();
      } // reset()
  
      /**
       * Close the stream.  Once a stream has been closed, further read(),
       * ready(), mark(), or reset() invocations will throw an IOException.
       * Closing a previously-closed stream, however, has no effect.
       *
       * @throws IOException If an I/O error occurs
       */
      @Override
      public void close() throws IOException {
          fInputStream.close();
      } // close()
  
  } // class ASCIIReader
  