datainputstream.java

专业汽车级嵌入式操作系统OSEK的源代码

/*
 * @(#)DataInputStream.java   1.00 01/12/14
 *
 * Adapted from the original Sun Microsystems code for leJOS.
 * @author Brian Bagnall
 */

package java.io;

public class DataInputStream extends InputStream {
    
   protected InputStream  in;
    
   public DataInputStream(InputStream in) {
      this.in = in;
   }
   
   /**
   * Reads the next byte of data from this input stream. The value 
   * byte is returned as an <code>int</code> in the range 
   * <code>0</code> to <code>255</code>. If no byte is available 
   * because the end of the stream has been reached, the value 
   * <code>-1</code> is returned. This method blocks until input data 
   * is available, the end of the stream is detected, or an exception 
   * is thrown. 
   * <p>
   * This method
   * simply performs <code>in.read()</code> and returns the result.
   *
   * @return     the next byte of data, or <code>-1</code> if the end of the
   *             stream is reached.
   * @exception  IOException  if an I/O error occurs.
   * @see        java.io.FilterInputStream#in
   */
   public int read() throws IOException {
      return in.read();
   }
    
   public final int read(byte b[]) throws IOException {
      return in.read(b, 0, b.length);
   }

   public final int read(byte b[], int off, int len) throws IOException {
      return in.read(b, off, len);
   }
/*
   public final void readFully(byte b[]) throws IOException {
      readFully(b, 0, b.length);
   }
*/
/*   public final void readFully(byte b[], int off, int len) throws IOException {
	  if (len < 0)
	     throw new IOException();

    	int n = 0;
    	while (n < len) {
         int count = in.read(b, off + n, len - n);
    	   if (count < 0)
    		   throw new IOException();
    	   n += count;
      }
   }
*/
/*   public final int skipBytes(int n) throws IOException {

      int total = 0;
      int cur = 0;
      
      while ((total<n) && ((cur = (int) in.skip(n-total)) > 0)) {
         total += cur;
      }
      return total;
   }
*/
   public final boolean readBoolean() throws IOException {
      int ch = in.read();
      if (ch < 0)
         throw new IOException();
      return (ch != 0);
   }

   public final byte readByte() throws IOException {
      int ch = in.read();
      if (ch < 0)
         throw new IOException();
      return (byte)(ch);
   }
/*
   public final int readUnsignedByte() throws IOException {
	   int ch = in.read();
	   if (ch < 0)
	      throw new IOException();
	   return ch;
   }
*/
   public final short readShort() throws IOException {
      int ch1 = in.read();
      int ch2 = in.read();
      if ((ch1 | ch2) < 0)
         throw new IOException();
      return (short)((ch1 << 8) + (ch2 << 0));
   }
   /*
   public final int readUnsignedShort() throws IOException {
      InputStream in = this.in;
      int ch1 = in.read();
      int ch2 = in.read();
      if ((ch1 | ch2) < 0)
         throw new IOException();
      return (ch1 << 8) + (ch2 << 0);
   }
   */
   
   public final char readChar() throws IOException {
      InputStream in = this.in;
      int ch1 = in.read();
      int ch2 = in.read();
      if ((ch1 | ch2) < 0)
         throw new IOException();
      return (char)((ch1 << 8) + (ch2 << 0));
   }

   public final int readInt() throws IOException {
      int ch1 = in.read();
      int ch2 = in.read();
      int ch3 = in.read();
      int ch4 = in.read();
      if ((ch1 | ch2 | ch3 | ch4) < 0)
         throw new IOException();
      return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
   }
/*
   public final long readLong() throws IOException {
      InputStream in = this.in;
      return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
   }
   */

   public final float readFloat() throws IOException {
      return Float.intBitsToFloat(readInt());
   }

/*
   public final double readDouble() throws IOException {
      return Double.longBitsToDouble(readLong());
   }*/
}