content: /*
   *  This file is part of AndroidIDE.
   *
   *  AndroidIDE is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
   *  (at your option) any later version.
   *
   *  AndroidIDE is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * reserved comment block
   * DO NOT REMOVE OR ALTER!
   */
  /*
   * Copyright 2000-2002,2004 The Apache Software Foundation.
   *
   * Licensed 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 jaxp.sun.org.apache.xerces.internal.impl.io;
  
  import java.io.InputStream;
  import java.io.IOException;
  import java.io.Reader;
  
  import jaxp.sun.xml.internal.stream.util.BufferAllocator;
  import jaxp.sun.xml.internal.stream.util.ThreadLocalBufferAllocator;
  
  /**
   * Reader for UCS-2 and UCS-4 encodings.
   * (i.e., encodings from ISO-10646-UCS-(2|4)).
   *
   * @xerces.internal
   *
   * @author Neil Graham, IBM
   *
   */
  public class UCSReader extends Reader {
  
      //
      // Constants
      //
  
      /** Default byte buffer size (8192, larger than that of ASCIIReader
       * since it's reasonable to surmise that the average UCS-4-encoded
       * file should be 4 times as large as the average ASCII-encoded file).
       */
      public static final int DEFAULT_BUFFER_SIZE = 8192;
  
      public static final short UCS2LE = 1;
      public static final short UCS2BE = 2;
      public static final short UCS4LE = 4;
      public static final short UCS4BE = 8;
  
      //
      // Data
      //
  
      /** Input stream. */
      protected InputStream fInputStream;
  
      /** Byte buffer. */
      protected byte[] fBuffer;
  
      // what kind of data we're dealing with
      protected short fEncoding;
  
      //
      // Constructors
      //
  
      /**
       * Constructs an ASCII reader from the specified input stream
       * using the default buffer size.  The Endian-ness and whether this is
       * UCS-2 or UCS-4 needs also to be known in advance.
       *
       * @param inputStream The input stream.
       * @param encoding One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.
       */
      public UCSReader(InputStream inputStream, short encoding) {
          this(inputStream, DEFAULT_BUFFER_SIZE, encoding);
      } // <init>(InputStream, short)
  
      /**
       * Constructs an ASCII reader from the specified input stream
       * and buffer size.  The Endian-ness and whether this is
       * UCS-2 or UCS-4 needs also to be known in advance.
       *
       * @param inputStream The input stream.
       * @param size        The initial buffer size.
       * @param encoding One of UCS2LE, UCS2BE, UCS4LE or UCS4BE.
       */
      public UCSReader(InputStream inputStream, int size, short encoding) {
          fInputStream = inputStream;
          BufferAllocator ba = ThreadLocalBufferAllocator.getBufferAllocator();
          fBuffer = ba.getByteBuffer(size);
          if (fBuffer == null) {
              fBuffer = new byte[size];
          }
          fEncoding = encoding;
      } // <init>(InputStream,int,short)
  
      //
      // 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> 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
       *
       * @exception  IOException  If an I/O error occurs
       */
      public int read() throws IOException {
          int b0 = fInputStream.read() & 0xff;
          if (b0 == 0xff)
              return -1;
          int b1 = fInputStream.read() & 0xff;
          if (b1 == 0xff)
              return -1;
          if(fEncoding >=4) {
              int b2 = fInputStream.read() & 0xff;
              if (b2 == 0xff)
                  return -1;
              int b3 = fInputStream.read() & 0xff;
              if (b3 == 0xff)
                  return -1;
              System.err.println("b0 is " + (b0 & 0xff) + " b1 " + (b1 & 0xff) + " b2 " + (b2 & 0xff) + " b3 " + (b3 & 0xff));
              if (fEncoding == UCS4BE)
                  return (b0<<24)+(b1<<16)+(b2<<8)+b3;
              else
                  return (b3<<24)+(b2<<16)+(b1<<8)+b0;
          } else { // UCS-2
              if (fEncoding == UCS2BE)
                  return (b0<<8)+b1;
              else
                  return (b1<<8)+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
       *
       * @exception  IOException  If an I/O error occurs
       */
      public int read(char ch[], int offset, int length) throws IOException {
          int byteLength = length << ((fEncoding >= 4)?2:1);
          if (byteLength > fBuffer.length) {
              byteLength = fBuffer.length;
          }
          int count = fInputStream.read(fBuffer, 0, byteLength);
          if(count == -1) return -1;
          // try and make count be a multiple of the number of bytes we're looking for
          if(fEncoding >= 4) { // BigEndian
              // this looks ugly, but it avoids an if at any rate...
              int numToRead = (4 - (count & 3) & 3);
              for(int i=0; i<numToRead; i++) {
                  int charRead = fInputStream.read();
                  if(charRead == -1) { // end of input; something likely went wrong!A  Pad buffer with nulls.
                      for (int j = i;j<numToRead; j++)
                          fBuffer[count+j] = 0;
                      break;
                  } else {
                      fBuffer[count+i] = (byte)charRead;
                  }
              }
              count += numToRead;
          } else {
              int numToRead = count & 1;
              if(numToRead != 0) {
                  count++;
                  int charRead = fInputStream.read();
                  if(charRead == -1) { // end of input; something likely went wrong!A  Pad buffer with nulls.
                      fBuffer[count] = 0;
                  } else {
                      fBuffer[count] = (byte)charRead;
                  }
              }
          }
  
          // now count is a multiple of the right number of bytes
          int numChars = count >> ((fEncoding >= 4)?2:1);
          int curPos = 0;
          for (int i = 0; i < numChars; i++) {
              int b0 = fBuffer[curPos++] & 0xff;
              int b1 = fBuffer[curPos++] & 0xff;
              if(fEncoding >=4) {
                  int b2 = fBuffer[curPos++] & 0xff;
                  int b3 = fBuffer[curPos++] & 0xff;
                  if (fEncoding == UCS4BE)
                      ch[offset+i] = (char)((b0<<24)+(b1<<16)+(b2<<8)+b3);
                  else
                      ch[offset+i] = (char)((b3<<24)+(b2<<16)+(b1<<8)+b0);
              } else { // UCS-2
                  if (fEncoding == UCS2BE)
                      ch[offset+i] = (char)((b0<<8)+b1);
                  else
                      ch[offset+i] = (char)((b1<<8)+b0);
              }
          }
          return numChars;
      } // 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
       *
       * @exception  IOException  If an I/O error occurs
       */
      public long skip(long n) throws IOException {
          // charWidth will represent the number of bits to move
          // n leftward to get num of bytes to skip, and then move the result rightward
          // to get num of chars effectively skipped.
          // The trick with &'ing, as with elsewhere in this dcode, is
          // intended to avoid an expensive use of / that might not be optimized
          // away.
          int charWidth = (fEncoding >=4)?2:1;
          long bytesSkipped = fInputStream.skip(n<<charWidth);
          if((bytesSkipped & (charWidth | 1)) == 0) return bytesSkipped >> charWidth;
          return (bytesSkipped >> charWidth) + 1;
      } // 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.
       *
       * @exception  IOException  If an I/O error occurs
       */
      public boolean ready() throws IOException {
              return false;
      } // ready()
  
      /**
       * Tell whether this stream supports the mark() operation.
       */
      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.
       *
       * @exception  IOException  If the stream does not support mark(),
       *                          or if some other I/O error occurs
       */
      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().
       *
       * @exception  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
       */
      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.
       *
       * @exception  IOException  If an I/O error occurs
       */
       public void close() throws IOException {
           BufferAllocator ba = ThreadLocalBufferAllocator.getBufferAllocator();
           ba.returnByteBuffer(fBuffer);
           fBuffer = null;
           fInputStream.close();
       } // close()
  
  } // class UCSReader
  