Diff of /jakarta/bcel/trunk/src/java/org/apache/bcel/generic/LocalVariableInstruction.java

Parent Directory | Revision Log | Patch

--- jakarta/bcel/trunk/src/java/org/apache/bcel/generic/LocalVariableInstruction.java	2006/03/15 11:30:53	386055
+++ jakarta/bcel/trunk/src/java/org/apache/bcel/generic/LocalVariableInstruction.java	2006/03/15 11:31:56	386056
@@ -13,7 +13,7 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License. 
  *
- */ 
+ */
 package org.apache.bcel.generic;
 
 import java.io.DataOutputStream;
@@ -27,163 +27,176 @@ import org.apache.bcel.util.ByteSequence
  * @version $Id$
  * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
  */
-public abstract class LocalVariableInstruction extends Instruction
-  implements TypedInstruction, IndexedInstruction {
-  protected int     n         = -1; // index of referenced variable
-  private short     c_tag     = -1; // compact version, such as ILOAD_0
-  private short     canon_tag = -1; // canonical tag such as ILOAD
-
-  private final boolean wide() { return n > Constants.MAX_BYTE; }
-
-  /**
-   * Empty constructor needed for the Class.newInstance() statement in
-   * Instruction.readInstruction(). Not to be used otherwise.
-   * tag and length are defined in readInstruction and initFromFile, respectively.
-   */
-  LocalVariableInstruction(short canon_tag, short c_tag) {
-    super();
-    this.canon_tag = canon_tag;
-    this.c_tag     = c_tag;
-  }
-
-  /**
-   * Empty constructor needed for the Class.newInstance() statement in
-   * Instruction.readInstruction(). Also used by IINC()!
-   */
-  LocalVariableInstruction() {
-  }
-
-  /**
-   * @param opcode Instruction opcode
-   * @param c_tag Instruction number for compact version, ALOAD_0, e.g.
-   * @param n local variable index (unsigned short)
-   */
-  protected LocalVariableInstruction(short opcode, short c_tag, int n) {
-    super(opcode, (short)2);
-
-    this.c_tag = c_tag;
-    canon_tag  = opcode;
-
-    setIndex(n);
-  }
-
-  /**
-   * Dump instruction as byte code to stream out.
-   * @param out Output stream
-   */
-  public void dump(DataOutputStream out) throws IOException {
-    if(wide()) // Need WIDE prefix ?
-      out.writeByte(Constants.WIDE);
-
-    out.writeByte(opcode);
-
-    if(length > 1) { // Otherwise ILOAD_n, instruction, e.g.
-      if(wide())
-	out.writeShort(n);
-      else
-	out.writeByte(n);
-    }
-  }
-
-  /**
-   * Long output format:
-   *
-   * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]" 
-   * "("&lt;length of instruction&gt;")" "&lt;"&lt; local variable index&gt;"&gt;"
-   *
-   * @param verbose long/short format switch
-   * @return mnemonic for instruction
-   */
-  public String toString(boolean verbose) {
-    if(((opcode >= Constants.ILOAD_0) &&
-	(opcode <= Constants.ALOAD_3)) ||
-       ((opcode >= Constants.ISTORE_0) &&
-	(opcode <= Constants.ASTORE_3)))
-      return super.toString(verbose);
-    else
-      return super.toString(verbose) + " " + n;
-  }
-
-  /**
-   * Read needed data (e.g. index) from file.
-   * PRE: (ILOAD <= tag <= ALOAD_3) || (ISTORE <= tag <= ASTORE_3)
-   */
-  protected void initFromFile(ByteSequence bytes, boolean wide)
-    throws IOException
-  {
-    if(wide) {
-      n         = bytes.readUnsignedShort();
-      length    = 4;
-    } else if(((opcode >= Constants.ILOAD) &&
-	       (opcode <= Constants.ALOAD)) ||
-	      ((opcode >= Constants.ISTORE) &&
-	       (opcode <= Constants.ASTORE))) {
-      n      = bytes.readUnsignedByte();
-      length = 2;
-    } else if(opcode <= Constants.ALOAD_3) { // compact load instruction such as ILOAD_2
-      n      = (opcode - Constants.ILOAD_0) % 4;
-      length = 1;
-    } else { // Assert ISTORE_0 <= tag <= ASTORE_3
-      n      = (opcode - Constants.ISTORE_0) % 4;
-      length = 1;
-    }
- }
-
-  /**
-   * @return local variable index  referred by this instruction.
-   */
-  public final int getIndex() { return n; }
-
-  /**
-   * Set the local variable index
-   */
-  public void setIndex(int n) { 
-    if((n < 0) || (n > Constants.MAX_SHORT))
-      throw new ClassGenException("Illegal value: " + n);
-
-    this.n = n;
-
-    if(n >= 0 && n <= 3) { // Use more compact instruction xLOAD_n
-      opcode = (short)(c_tag + n);
-      length = 1;
-    } else {
-      opcode = canon_tag;
-      
-      if(wide()) // Need WIDE prefix ?
-	length = 4;
-      else
-	length = 2;
-    }
-  }
-
-  /** @return canonical tag for instruction, e.g., ALOAD for ALOAD_0
-   */
-  public short getCanonicalTag() {
-    return canon_tag;
-  }
-
-  /**
-   * Returns the type associated with the instruction - 
-   * in case of ALOAD or ASTORE Type.OBJECT is returned.
-   * This is just a bit incorrect, because ALOAD and ASTORE
-   * may work on every ReferenceType (including Type.NULL) and
-   * ASTORE may even work on a ReturnaddressType .
-   * @return type associated with the instruction
-   */
-  public Type getType(ConstantPoolGen cp) {
-    switch(canon_tag) {
-    case Constants.ILOAD: case Constants.ISTORE: 
-      return Type.INT;
-    case Constants.LLOAD: case Constants.LSTORE: 
-      return Type.LONG;
-    case Constants.DLOAD: case Constants.DSTORE: 
-      return Type.DOUBLE;
-    case Constants.FLOAD: case Constants.FSTORE: 
-      return Type.FLOAT;
-    case Constants.ALOAD: case Constants.ASTORE:
-      return Type.OBJECT;
+public abstract class LocalVariableInstruction extends Instruction implements TypedInstruction,
+        IndexedInstruction {
+
+    protected int n = -1; // index of referenced variable
+    private short c_tag = -1; // compact version, such as ILOAD_0
+    private short canon_tag = -1; // canonical tag such as ILOAD
+
+
+    private final boolean wide() {
+        return n > Constants.MAX_BYTE;
+    }
+
+
+    /**
+     * Empty constructor needed for the Class.newInstance() statement in
+     * Instruction.readInstruction(). Not to be used otherwise.
+     * tag and length are defined in readInstruction and initFromFile, respectively.
+     */
+    LocalVariableInstruction(short canon_tag, short c_tag) {
+        super();
+        this.canon_tag = canon_tag;
+        this.c_tag = c_tag;
+    }
+
+
+    /**
+     * Empty constructor needed for the Class.newInstance() statement in
+     * Instruction.readInstruction(). Also used by IINC()!
+     */
+    LocalVariableInstruction() {
+    }
+
+
+    /**
+     * @param opcode Instruction opcode
+     * @param c_tag Instruction number for compact version, ALOAD_0, e.g.
+     * @param n local variable index (unsigned short)
+     */
+    protected LocalVariableInstruction(short opcode, short c_tag, int n) {
+        super(opcode, (short) 2);
+        this.c_tag = c_tag;
+        canon_tag = opcode;
+        setIndex(n);
+    }
+
+
+    /**
+     * Dump instruction as byte code to stream out.
+     * @param out Output stream
+     */
+    public void dump( DataOutputStream out ) throws IOException {
+        if (wide()) {
+            out.writeByte(Constants.WIDE);
+        }
+        out.writeByte(opcode);
+        if (length > 1) { // Otherwise ILOAD_n, instruction, e.g.
+            if (wide()) {
+                out.writeShort(n);
+            } else {
+                out.writeByte(n);
+            }
+        }
+    }
+
+
+    /**
+     * Long output format:
+     *
+     * &lt;name of opcode&gt; "["&lt;opcode number&gt;"]" 
+     * "("&lt;length of instruction&gt;")" "&lt;"&lt; local variable index&gt;"&gt;"
+     *
+     * @param verbose long/short format switch
+     * @return mnemonic for instruction
+     */
+    public String toString( boolean verbose ) {
+        if (((opcode >= Constants.ILOAD_0) && (opcode <= Constants.ALOAD_3))
+                || ((opcode >= Constants.ISTORE_0) && (opcode <= Constants.ASTORE_3))) {
+            return super.toString(verbose);
+        } else {
+            return super.toString(verbose) + " " + n;
+        }
+    }
+
+
+    /**
+     * Read needed data (e.g. index) from file.
+     * PRE: (ILOAD <= tag <= ALOAD_3) || (ISTORE <= tag <= ASTORE_3)
+     */
+    protected void initFromFile( ByteSequence bytes, boolean wide ) throws IOException {
+        if (wide) {
+            n = bytes.readUnsignedShort();
+            length = 4;
+        } else if (((opcode >= Constants.ILOAD) && (opcode <= Constants.ALOAD))
+                || ((opcode >= Constants.ISTORE) && (opcode <= Constants.ASTORE))) {
+            n = bytes.readUnsignedByte();
+            length = 2;
+        } else if (opcode <= Constants.ALOAD_3) { // compact load instruction such as ILOAD_2
+            n = (opcode - Constants.ILOAD_0) % 4;
+            length = 1;
+        } else { // Assert ISTORE_0 <= tag <= ASTORE_3
+            n = (opcode - Constants.ISTORE_0) % 4;
+            length = 1;
+        }
+    }
+
+
+    /**
+     * @return local variable index  referred by this instruction.
+     */
+    public final int getIndex() {
+        return n;
+    }
+
+
+    /**
+     * Set the local variable index
+     */
+    public void setIndex( int n ) {
+        if ((n < 0) || (n > Constants.MAX_SHORT)) {
+            throw new ClassGenException("Illegal value: " + n);
+        }
+        this.n = n;
+        if (n >= 0 && n <= 3) { // Use more compact instruction xLOAD_n
+            opcode = (short) (c_tag + n);
+            length = 1;
+        } else {
+            opcode = canon_tag;
+            if (wide()) {
+                length = 4;
+            } else {
+                length = 2;
+            }
+        }
+    }
+
+
+    /** @return canonical tag for instruction, e.g., ALOAD for ALOAD_0
+     */
+    public short getCanonicalTag() {
+        return canon_tag;
+    }
+
 
-    default: throw new ClassGenException("Oops: unknown case in switch" + canon_tag);
+    /**
+     * Returns the type associated with the instruction - 
+     * in case of ALOAD or ASTORE Type.OBJECT is returned.
+     * This is just a bit incorrect, because ALOAD and ASTORE
+     * may work on every ReferenceType (including Type.NULL) and
+     * ASTORE may even work on a ReturnaddressType .
+     * @return type associated with the instruction
+     */
+    public Type getType( ConstantPoolGen cp ) {
+        switch (canon_tag) {
+            case Constants.ILOAD:
+            case Constants.ISTORE:
+                return Type.INT;
+            case Constants.LLOAD:
+            case Constants.LSTORE:
+                return Type.LONG;
+            case Constants.DLOAD:
+            case Constants.DSTORE:
+                return Type.DOUBLE;
+            case Constants.FLOAD:
+            case Constants.FSTORE:
+                return Type.FLOAT;
+            case Constants.ALOAD:
+            case Constants.ASTORE:
+                return Type.OBJECT;
+            default:
+                throw new ClassGenException("Oops: unknown case in switch" + canon_tag);
+        }
     }
-  }
 }