lazy unpacking of the table contents. Only done when required - usually when a MethodGen built for a Method (i.e. we are going to weave it).

bcel-builder/src/org/aspectj/apache/bcel/classfile/LineNumberTable.java

@@ -62,12 +62,20 @@ import  java.io.*;
  * purposes. This attribute is used by the <em>Code</em> attribute. It
  * contains pairs of PCs and line numbers.
  *
- * @version $Id: LineNumberTable.java,v 1.2 2004/11/19 16:45:18 aclement Exp $
+ * @version $Id: LineNumberTable.java,v 1.3 2006/02/07 15:15:42 aclement Exp $
  * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
  * @see     Code
- * @see LineNumber
+ *
+ * changes:
+ *   asc Feb06 Made unpacking lazy
  */
 public final class LineNumberTable extends Attribute {
+  
+	
+  // if 'isInPackedState' then this data needs unpacking
+  private boolean isInPackedState = false;
+  private byte[]  data; 
+  
   private int          line_number_table_length;
   private LineNumber[] line_number_table; // Table of line/numbers pairs
 
@@ -76,8 +84,7 @@ public final class LineNumberTable extends Attribute {
    * references (shallow copy). Use copy() for a physical copy.
    */
   public LineNumberTable(LineNumberTable c) {
-    this(c.getNameIndex(), c.getLength(), c.getLineNumberTable(),
-	 c.getConstantPool());
+    this(c.getNameIndex(), c.getLength(), c.getLineNumberTable(), c.getConstantPool());
   }
 
   /*
@@ -87,11 +94,10 @@ public final class LineNumberTable extends Attribute {
    * @param constant_pool Array of constants
    */
   public LineNumberTable(int name_index, int length,
-			 LineNumber[] line_number_table,
-			 ConstantPool constant_pool)
-  {
+			 LineNumber[] line_number_table, ConstantPool constant_pool) {
     super(Constants.ATTR_LINE_NUMBER_TABLE, name_index, length, constant_pool);
     setLineNumberTable(line_number_table);
+    isInPackedState=false;
   }
    
   /**
@@ -105,13 +111,32 @@ public final class LineNumberTable extends Attribute {
   LineNumberTable(int name_index, int length, DataInputStream file,
 		  ConstantPool constant_pool) throws IOException
   {
-    this(name_index, length, (LineNumber[])null, constant_pool);
-    line_number_table_length = (file.readUnsignedShort());
-    line_number_table = new LineNumber[line_number_table_length];
+    this(name_index, length, (LineNumber[])null, constant_pool);  
+    data = new byte[length];
+    int byteReads = file.read(data);
+    isInPackedState = true;
+    // assert(bytesRead==length)
+  }
+  
+  // Unpacks the byte array into the table
+  private void unpack() {
+	  if (!isInPackedState) return;
 
-    for(int i=0; i < line_number_table_length; i++)
-      line_number_table[i] = new LineNumber(file);
-  }    
+	  try {
+  	    ByteArrayInputStream bs = new ByteArrayInputStream(data);
+		DataInputStream dis = new DataInputStream(bs);
+		line_number_table_length = (dis.readUnsignedShort());
+		line_number_table = new LineNumber[line_number_table_length];
+		for (int i=0; i < line_number_table_length; i++)
+		  line_number_table[i] = new LineNumber(dis);
+	    dis.close();
+	    data = null; // throw it away now
+      } catch (IOException e) {
+		throw new RuntimeException("Unpacking of LineNumberTable attribute failed");
+	  }
+	  isInPackedState=false;
+  }
+  
   /**
    * Called by objects that are traversing the nodes of the tree implicitely
    * defined by the contents of a Java class. I.e., the hierarchy of methods,
@@ -120,8 +145,10 @@ public final class LineNumberTable extends Attribute {
    * @param v Visitor object
    */
   public void accept(Visitor v) {
+	unpack();
     v.visitLineNumberTable(this);
   }    
+  
   /**
    * Dump line number table attribute to file stream in binary format.
    *
@@ -131,20 +158,26 @@ public final class LineNumberTable extends Attribute {
   public final void dump(DataOutputStream file) throws IOException
   {
     super.dump(file);
-    file.writeShort(line_number_table_length);
-    for(int i=0; i < line_number_table_length; i++)
-      line_number_table[i].dump(file);
+    if (isInPackedState) {
+      file.write(data);
+    } else {
+	    file.writeShort(line_number_table_length);
+	    for(int i=0; i < line_number_table_length; i++)
+	      line_number_table[i].dump(file);
+    }
   }    
    
   /**
    * @return Array of (pc offset, line number) pairs.
    */  
-  public final LineNumber[] getLineNumberTable() { return line_number_table; }    
+  public final LineNumber[] getLineNumberTable() { unpack();return line_number_table; }    
 
   /**
    * @param line_number_table.
    */
   public final void setLineNumberTable(LineNumber[] line_number_table) {
+	this.data = null;
+	this.isInPackedState=false;
     this.line_number_table = line_number_table;
 
     line_number_table_length = (line_number_table == null)? 0 :
@@ -155,6 +188,7 @@ public final class LineNumberTable extends Attribute {
    * @return String representation.
    */ 
   public final String toString() {
+	unpack();
     StringBuffer buf  = new StringBuffer();
     StringBuffer line = new StringBuffer();
 
@@ -183,6 +217,7 @@ public final class LineNumberTable extends Attribute {
    * @return corresponding line in source code
    */
   public int getSourceLine(int pos) {
+	  unpack();
     int l = 0, r = line_number_table_length-1;
 
     if(r < 0) // array is empty
@@ -226,6 +261,7 @@ public final class LineNumberTable extends Attribute {
    * @return deep copy of this attribute
    */
   public Attribute copy(ConstantPool constant_pool) {
+	  unpack();
     LineNumberTable c = (LineNumberTable)clone();
 
     c.line_number_table = new LineNumber[line_number_table_length];
@@ -236,5 +272,5 @@ public final class LineNumberTable extends Attribute {
     return c;
   }
 
-  public final int getTableLength() { return line_number_table_length; }
+  public final int getTableLength() { unpack();return line_number_table_length; }
 }