diff src/org/tn5250j/framework/tn5250/Stream5250.java @ 3:e8d2a24e85c6 tn5250

adding tn5250 files
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 12:11:10 -0700
parents
children 77ac18bc1b2f
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tn5250j/framework/tn5250/Stream5250.java	Thu May 22 12:11:10 2014 -0700
@@ -0,0 +1,173 @@
+/**
+ * Title: tn5250J
+ * Copyright:   Copyright (c) 2001
+ * Company:
+ * @author  Kenneth J. Pouncey
+ * @version 0.4
+ *
+ * Description:
+ *
+ * This program 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 2, or (at your option)
+ * any later version.
+ *
+ * This program 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 this software; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307 USA
+ *
+ */
+package org.tn5250j.framework.tn5250;
+
+public class Stream5250 {
+
+    public int streamSize;
+    public int opCode;
+    public int dataStart;
+    public int pos;
+    public byte buffer[];
+
+    public Stream5250(byte abyte0[]) {
+        buffer = abyte0;
+        // size without end of record 0xFF 0xEF
+        streamSize = (abyte0[0] & 0xff) << 8 | abyte0[1] & 0xff;
+        opCode = abyte0[9];
+        dataStart = 6 + abyte0[6];
+        pos = dataStart;
+    }
+
+    public Stream5250() {
+       buffer = null;
+       streamSize = 0;
+       opCode = 0;
+       dataStart = 0;
+       pos = dataStart;
+   }
+
+    /**
+     * This method takes a byte array and initializes the object information
+     *    to be used.
+     * 
+     * @param abyte0
+     */
+    public void initialize(byte abyte0[]) {
+       
+     buffer = abyte0;
+     // size without end of record 0xFF 0xEF
+     streamSize = (abyte0[0] & 0xff) << 8 | abyte0[1] & 0xff;
+     opCode = abyte0[9];
+     dataStart = 6 + abyte0[6];
+     pos = dataStart;
+       
+    }
+    
+    public final int getOpCode() {
+        return opCode;
+    }
+
+    public final byte getNextByte()
+        throws Exception  {
+        if(buffer == null || pos > buffer.length)
+            throw new Exception("Buffer length exceeded: " + pos);
+        else
+            return buffer[pos++];
+    }
+
+    public final void setPrevByte()
+        throws Exception {
+        if(pos == 0) {
+            throw new Exception("Index equals zero.");
+        }
+        else {
+            pos--;
+            return;
+      }
+   }
+
+   /**
+    * Returns where we are in the buffer
+    * @return position in the buffer
+    */
+   public final int getCurrentPos() {
+      return pos;
+   }
+
+   public final byte getByteOffset(int off)
+        throws Exception  {
+
+        if(buffer == null || (pos + off ) > buffer.length)
+            throw new Exception("Buffer length exceeded: " + pos);
+        else
+            return buffer[pos + off];
+
+   }
+
+   public final boolean size() {
+      return pos >= streamSize;
+   }
+
+
+   /**
+    * Determines if any more bytes are available in the buffer to be processed.
+    * @return yes or no
+    */
+   public final boolean hasNext() {
+
+//      return pos >= buffer.length;
+      return pos < streamSize;
+   }
+
+   /**
+    * This routine will retrieve a segment based on the first two bytes being
+    * the length of the segment.
+    *
+    * @return a new byte array containing the bytes of the segment.
+    * @throws Exception
+    */
+   public final byte[] getSegment() throws Exception {
+
+      // The first two bytes contain the length of the segment.
+      int length = ((buffer[pos] & 0xff )<< 8 | (buffer[pos+1] & 0xff));
+      // allocate space for it.
+      byte[] segment = new byte[length];
+
+      getSegment(segment,length,true);
+
+      return segment;
+   }
+
+
+   /**
+    * This routine will retrieve a byte array based on the first two bytes being
+    * the length of the segment.
+    *
+    * @param segment - byte array
+    * @param length - length of segment to return
+    * @param adjustPos - adjust the position of the buffer to the end of the seg
+    *                      ment
+    * @throws Exception
+    */
+   public final void getSegment(byte[] segment, int length, boolean adjustPos)
+               throws Exception {
+
+      // If the length is larger than what is available throw an exception
+      if((pos + length ) > buffer.length)
+            throw new Exception("Buffer length exceeded: start " + pos
+                                 + " length " + length);
+      // use the system array copy to move the bytes from the buffer
+      //    to the allocated byte array
+      System.arraycopy(buffer,pos,segment,0,length);
+
+      // update the offset to be after the segment so the next byte can be read
+      if (adjustPos)
+         pos +=length;
+
+   }
+
+}