Program: 24378
Project: 24378
Buggy source:
/** 
 * Reads up to <code>len</code> bytes of data into an array of bytes from this input stream. If <code>pos</code> equals <code>count</code>, then <code>-1</code> is returned to indicate end of file. Otherwise, the number <code>k</code> of bytes read is equal to the smaller of <code>len</code> and <code>count-pos</code>. If <code>k</code> is positive, then bytes <code>buf[pos]</code> through <code>buf[pos+k-1]</code> are copied into <code>b[off]</code> through <code>b[off+k-1]</code> in the manner performed by <code>System.arraycopy</code>. The value <code>k</code> is added into <code>pos</code> and <code>k</code> is returned. <p> This <code>read</code> method cannot block.
 * @param b the buffer into which the data is read.
 * @param off the start offset in the destination array <code>b</code>
 * @param len the maximum number of bytes read.
 * @return the total number of bytes read into the buffer, or<code>-1</code> if there is no more data because the end of the stream has been reached.
 * @exception NullPointerException If <code>b</code> is <code>null</code>.
 * @exception IndexOutOfBoundsException If <code>off</code> is negative,<code>len</code> is negative, or <code>len</code> is greater than <code>b.length - off</code>
 */
public int read(byte b[],int off,int len){
  if (b == null) {
    throw new NullPointerException();
  }
 else   if (off < 0 || len < 0 || len > b.length - off) {
    throw new IndexOutOfBoundsException();
  }
  if (pos >= count) {
    return -1;
  }
  if (pos + len > count) {
    len=count - pos;
  }
  if (len <= 0) {
    return 0;
  }
  System.arraycopy(buffer,pos,b,off,len);
  pos+=len;
  return len;
}

Fixed version (ground truth):
/** 
 * Reads up to <code>len</code> bytes of data into an array of bytes from this input stream. If <code>pos</code> equals <code>count</code>, then <code>-1</code> is returned to indicate end of file. Otherwise, the number <code>k</code> of bytes read is equal to the smaller of <code>len</code> and <code>count-pos</code>. If <code>k</code> is positive, then bytes <code>buf[pos]</code> through <code>buf[pos+k-1]</code> are copied into <code>b[off]</code> through <code>b[off+k-1]</code> in the manner performed by <code>System.arraycopy</code>. The value <code>k</code> is added into <code>pos</code> and <code>k</code> is returned. <p> This <code>read</code> method cannot block.
 * @param b the buffer into which the data is read.
 * @param off the start offset in the destination array <code>b</code>
 * @param len the maximum number of bytes read.
 * @return the total number of bytes read into the buffer, or<code>-1</code> if there is no more data because the end of the stream has been reached.
 * @exception NullPointerException If <code>b</code> is <code>null</code>.
 * @exception IndexOutOfBoundsException If <code>off</code> is negative,<code>len</code> is negative, or <code>len</code> is greater than <code>b.length - off</code>
 */
public int read(byte b[],int off,int len){
  if (b == null) {
    throw new NullPointerException();
  }
 else   if (off < 0 || len < 0 || len > b.length - off) {
    throw new IndexOutOfBoundsException();
  }
  if (pos - offsetStart >= count) {
    return -1;
  }
  if (pos + len - offsetStart > count) {
    len=count - pos + offsetStart;
  }
  if (len <= 0) {
    return 0;
  }
  System.arraycopy(buffer,pos,b,off,len);
  pos+=len;
  return len;
}