bundles/org.apache.tomcat/src/org/apache/tomcat/util/bcel/classfile/ConstantPool.java - rap/org.apache.tomcat - Git at Google

 /*
  *  Licensed to the Apache Software Foundation (ASF) under one or more
  *  contributor license agreements.  See the NOTICE file distributed with
  *  this work for additional information regarding copyright ownership.
  *  The ASF licenses this file to You under the Apache License, Version 2.0
  *  (the "License"); you may not use this file except in compliance with
  *  the License.  You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  *  Unless required by applicable law or agreed to in writing, software
  *  distributed under the License is distributed on an "AS IS" BASIS,
  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  *
  */
 package org.apache.tomcat.util.bcel.classfile;

 import java.io.DataInputStream;
 import java.io.IOException;
 import java.io.Serializable;

 import org.apache.tomcat.util.bcel.Constants;

 /**
  * This class represents the constant pool, i.e., a table of constants, of
  * a parsed classfile. It may contain null references, due to the JVM
  * specification that skips an entry after an 8-byte constant (double,
  * long) entry.  Those interested in generating constant pools
  * programatically should see <a href="../generic/ConstantPoolGen.html">
  * ConstantPoolGen</a>.

  * @version $Id: ConstantPool.java,v 1.1 2011/06/28 21:08:24 rherrmann Exp $
  * @see     Constant
  * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
  */
 public class ConstantPool implements Cloneable, Serializable {

     private static final long serialVersionUID = -6765503791185687014L;
     private int constant_pool_count;
     private Constant[] constant_pool;


     /**
      * Read constants from given file stream.
      *
      * @param file Input stream
      * @throws IOException
      * @throws ClassFormatException
      */
     ConstantPool(DataInputStream file) throws IOException, ClassFormatException {
         byte tag;
         constant_pool_count = file.readUnsignedShort();
         constant_pool = new Constant[constant_pool_count];
         /* constant_pool[0] is unused by the compiler and may be used freely
          * by the implementation.
          */
         for (int i = 1; i < constant_pool_count; i++) {
             constant_pool[i] = Constant.readConstant(file);
             /* Quote from the JVM specification:
              * "All eight byte constants take up two spots in the constant pool.
              * If this is the n'th byte in the constant pool, then the next item
              * will be numbered n+2"
              *
              * Thus we have to increment the index counter.
              */
             tag = constant_pool[i].getTag();
             if ((tag == Constants.CONSTANT_Double) || (tag == Constants.CONSTANT_Long)) {
                 i++;
             }
         }
     }


     /**
      * Resolve constant to a string representation.
      *
      * @param  c Constant to be printed
      * @return String representation
      */
     public String constantToString( Constant c ) throws ClassFormatException {
         String str;
         int i;
         byte tag = c.getTag();
         switch (tag) {
             case Constants.CONSTANT_Class:
                 i = ((ConstantClass) c).getNameIndex();
                 c = getConstant(i, Constants.CONSTANT_Utf8);
                 str = Utility.compactClassName(((ConstantUtf8) c).getBytes(), false);
                 break;
             case Constants.CONSTANT_String:
                 i = ((ConstantString) c).getStringIndex();
                 c = getConstant(i, Constants.CONSTANT_Utf8);
                 str = "\"" + escape(((ConstantUtf8) c).getBytes()) + "\"";
                 break;
             case Constants.CONSTANT_Utf8:
                 str = ((ConstantUtf8) c).getBytes();
                 break;
             case Constants.CONSTANT_Double:
                 str = String.valueOf(((ConstantDouble) c).getBytes());
                 break;
             case Constants.CONSTANT_Float:
                 str = String.valueOf(((ConstantFloat) c).getBytes());
                 break;
             case Constants.CONSTANT_Long:
                 str = String.valueOf(((ConstantLong) c).getBytes());
                 break;
             case Constants.CONSTANT_Integer:
                 str = String.valueOf(((ConstantInteger) c).getBytes());
                 break;
             case Constants.CONSTANT_NameAndType:
                 str = (constantToString(((ConstantNameAndType) c).getNameIndex(),
                         Constants.CONSTANT_Utf8)
                         + " " + constantToString(((ConstantNameAndType) c).getSignatureIndex(),
                         Constants.CONSTANT_Utf8));
                 break;
             case Constants.CONSTANT_InterfaceMethodref:
             case Constants.CONSTANT_Methodref:
             case Constants.CONSTANT_Fieldref:
                 str = (constantToString(((ConstantCP) c).getClassIndex(), Constants.CONSTANT_Class)
                         + "." + constantToString(((ConstantCP) c).getNameAndTypeIndex(),
                         Constants.CONSTANT_NameAndType));
                 break;
             default: // Never reached
                 throw new RuntimeException("Unknown constant type " + tag);
         }
         return str;
     }


     private static final String escape( String str ) {
         int len = str.length();
         StringBuffer buf = new StringBuffer(len + 5);
         char[] ch = str.toCharArray();
         for (int i = 0; i < len; i++) {
             switch (ch[i]) {
                 case '\n':
                     buf.append("\\n");
                     break;
                 case '\r':
                     buf.append("\\r");
                     break;
                 case '\t':
                     buf.append("\\t");
                     break;
                 case '\b':
                     buf.append("\\b");
                     break;
                 case '"':
                     buf.append("\\\"");
                     break;
                 default:
                     buf.append(ch[i]);
             }
         }
         return buf.toString();
     }


     /**
      * Retrieve constant at `index' from constant pool and resolve it to
      * a string representation.
      *
      * @param  index of constant in constant pool
      * @param  tag expected type
      * @return String representation
      */
     public String constantToString( int index, byte tag ) throws ClassFormatException {
         Constant c = getConstant(index, tag);
         return constantToString(c);
     }


     /**
      * Get constant from constant pool.
      *
      * @param  index Index in constant pool
      * @return Constant value
      * @see    Constant
      */
     public Constant getConstant( int index ) {
         if (index >= constant_pool.length || index < 0) {
             throw new ClassFormatException("Invalid constant pool reference: " + index
                     + ". Constant pool size is: " + constant_pool.length);
         }
         return constant_pool[index];
     }


     /**
      * Get constant from constant pool and check whether it has the
      * expected type.
      *
      * @param  index Index in constant pool
      * @param  tag Tag of expected constant, i.e., its type
      * @return Constant value
      * @see    Constant
      * @throws  ClassFormatException
      */
     public Constant getConstant( int index, byte tag ) throws ClassFormatException {
         Constant c;
         c = getConstant(index);
         if (c == null) {
             throw new ClassFormatException("Constant pool at index " + index + " is null.");
         }
         if (c.getTag() != tag) {
             throw new ClassFormatException("Expected class `" + Constants.CONSTANT_NAMES[tag]
                     + "' at index " + index + " and got " + c);
         }
         return c;
     }


     /**
      * Get string from constant pool and bypass the indirection of
      * `ConstantClass' and `ConstantString' objects. I.e. these classes have
      * an index field that points to another entry of the constant pool of
      * type `ConstantUtf8' which contains the real data.
      *
      * @param  index Index in constant pool
      * @param  tag Tag of expected constant, either ConstantClass or ConstantString
      * @return Contents of string reference
      * @see    ConstantClass
      * @see    ConstantString
      * @throws  ClassFormatException
      */
     public String getConstantString( int index, byte tag ) throws ClassFormatException {
         Constant c;
         int i;
         c = getConstant(index, tag);
         /* This switch() is not that elegant, since the two classes have the
          * same contents, they just differ in the name of the index
          * field variable.
          * But we want to stick to the JVM naming conventions closely though
          * we could have solved these more elegantly by using the same
          * variable name or by subclassing.
          */
         switch (tag) {
             case Constants.CONSTANT_Class:
                 i = ((ConstantClass) c).getNameIndex();
                 break;
             case Constants.CONSTANT_String:
                 i = ((ConstantString) c).getStringIndex();
                 break;
             default:
                 throw new RuntimeException("getConstantString called with illegal tag " + tag);
         }
         // Finally get the string from the constant pool
         c = getConstant(i, Constants.CONSTANT_Utf8);
         return ((ConstantUtf8) c).getBytes();
     }


     /**
      * @return Length of constant pool.
      */
     public int getLength() {
         return constant_pool_count;
     }


     /**
      * @return String representation.
      */
     @Override
     public String toString() {
         StringBuffer buf = new StringBuffer();
         for (int i = 1; i < constant_pool_count; i++) {
             buf.append(i).append(")").append(constant_pool[i]).append("\n");
         }
         return buf.toString();
     }


 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*
	*/
	package org.apache.tomcat.util.bcel.classfile;

	import java.io.DataInputStream;
	import java.io.IOException;
	import java.io.Serializable;

	import org.apache.tomcat.util.bcel.Constants;

	/**
	* This class represents the constant pool, i.e., a table of constants, of
	* a parsed classfile. It may contain null references, due to the JVM
	* specification that skips an entry after an 8-byte constant (double,
	* long) entry. Those interested in generating constant pools
	* programatically should see <a href="../generic/ConstantPoolGen.html">
	* ConstantPoolGen</a>.

	* @version $Id: ConstantPool.java,v 1.1 2011/06/28 21:08:24 rherrmann Exp $
	* @see Constant
	* @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
	*/
	public class ConstantPool implements Cloneable, Serializable {

	private static final long serialVersionUID = -6765503791185687014L;
	private int constant_pool_count;
	private Constant[] constant_pool;


	/**
	* Read constants from given file stream.
	*
	* @param file Input stream
	* @throws IOException
	* @throws ClassFormatException
	*/
	ConstantPool(DataInputStream file) throws IOException, ClassFormatException {
	byte tag;
	constant_pool_count = file.readUnsignedShort();
	constant_pool = new Constant[constant_pool_count];
	/* constant_pool[0] is unused by the compiler and may be used freely
	* by the implementation.
	*/
	for (int i = 1; i < constant_pool_count; i++) {
	constant_pool[i] = Constant.readConstant(file);
	/* Quote from the JVM specification:
	* "All eight byte constants take up two spots in the constant pool.
	* If this is the n'th byte in the constant pool, then the next item
	* will be numbered n+2"
	*
	* Thus we have to increment the index counter.
	*/
	tag = constant_pool[i].getTag();
	if ((tag == Constants.CONSTANT_Double) \|\| (tag == Constants.CONSTANT_Long)) {
	i++;
	}
	}
	}


	/**
	* Resolve constant to a string representation.
	*
	* @param c Constant to be printed
	* @return String representation
	*/
	public String constantToString( Constant c ) throws ClassFormatException {
	String str;
	int i;
	byte tag = c.getTag();
	switch (tag) {
	case Constants.CONSTANT_Class:
	i = ((ConstantClass) c).getNameIndex();
	c = getConstant(i, Constants.CONSTANT_Utf8);
	str = Utility.compactClassName(((ConstantUtf8) c).getBytes(), false);
	break;
	case Constants.CONSTANT_String:
	i = ((ConstantString) c).getStringIndex();
	c = getConstant(i, Constants.CONSTANT_Utf8);
	str = "\"" + escape(((ConstantUtf8) c).getBytes()) + "\"";
	break;
	case Constants.CONSTANT_Utf8:
	str = ((ConstantUtf8) c).getBytes();
	break;
	case Constants.CONSTANT_Double:
	str = String.valueOf(((ConstantDouble) c).getBytes());
	break;
	case Constants.CONSTANT_Float:
	str = String.valueOf(((ConstantFloat) c).getBytes());
	break;
	case Constants.CONSTANT_Long:
	str = String.valueOf(((ConstantLong) c).getBytes());
	break;
	case Constants.CONSTANT_Integer:
	str = String.valueOf(((ConstantInteger) c).getBytes());
	break;
	case Constants.CONSTANT_NameAndType:
	str = (constantToString(((ConstantNameAndType) c).getNameIndex(),
	Constants.CONSTANT_Utf8)
	+ " " + constantToString(((ConstantNameAndType) c).getSignatureIndex(),
	Constants.CONSTANT_Utf8));
	break;
	case Constants.CONSTANT_InterfaceMethodref:
	case Constants.CONSTANT_Methodref:
	case Constants.CONSTANT_Fieldref:
	str = (constantToString(((ConstantCP) c).getClassIndex(), Constants.CONSTANT_Class)
	+ "." + constantToString(((ConstantCP) c).getNameAndTypeIndex(),
	Constants.CONSTANT_NameAndType));
	break;
	default: // Never reached
	throw new RuntimeException("Unknown constant type " + tag);
	}
	return str;
	}


	private static final String escape( String str ) {
	int len = str.length();
	StringBuffer buf = new StringBuffer(len + 5);
	char[] ch = str.toCharArray();
	for (int i = 0; i < len; i++) {
	switch (ch[i]) {
	case '\n':
	buf.append("\\n");
	break;
	case '\r':
	buf.append("\\r");
	break;
	case '\t':
	buf.append("\\t");
	break;
	case '\b':
	buf.append("\\b");
	break;
	case '"':
	buf.append("\\\"");
	break;
	default:
	buf.append(ch[i]);
	}
	}
	return buf.toString();
	}


	/**
	* Retrieve constant at `index' from constant pool and resolve it to
	* a string representation.
	*
	* @param index of constant in constant pool
	* @param tag expected type
	* @return String representation
	*/
	public String constantToString( int index, byte tag ) throws ClassFormatException {
	Constant c = getConstant(index, tag);
	return constantToString(c);
	}


	/**
	* Get constant from constant pool.
	*
	* @param index Index in constant pool
	* @return Constant value
	* @see Constant
	*/
	public Constant getConstant( int index ) {
	if (index >= constant_pool.length \|\| index < 0) {
	throw new ClassFormatException("Invalid constant pool reference: " + index
	+ ". Constant pool size is: " + constant_pool.length);
	}
	return constant_pool[index];
	}


	/**
	* Get constant from constant pool and check whether it has the
	* expected type.
	*
	* @param index Index in constant pool
	* @param tag Tag of expected constant, i.e., its type
	* @return Constant value
	* @see Constant
	* @throws ClassFormatException
	*/
	public Constant getConstant( int index, byte tag ) throws ClassFormatException {
	Constant c;
	c = getConstant(index);
	if (c == null) {
	throw new ClassFormatException("Constant pool at index " + index + " is null.");
	}
	if (c.getTag() != tag) {
	throw new ClassFormatException("Expected class `" + Constants.CONSTANT_NAMES[tag]
	+ "' at index " + index + " and got " + c);
	}
	return c;
	}


	/**
	* Get string from constant pool and bypass the indirection of
	* `ConstantClass' and `ConstantString' objects. I.e. these classes have
	* an index field that points to another entry of the constant pool of
	* type `ConstantUtf8' which contains the real data.
	*
	* @param index Index in constant pool
	* @param tag Tag of expected constant, either ConstantClass or ConstantString
	* @return Contents of string reference
	* @see ConstantClass
	* @see ConstantString
	* @throws ClassFormatException
	*/
	public String getConstantString( int index, byte tag ) throws ClassFormatException {
	Constant c;
	int i;
	c = getConstant(index, tag);
	/* This switch() is not that elegant, since the two classes have the
	* same contents, they just differ in the name of the index
	* field variable.
	* But we want to stick to the JVM naming conventions closely though
	* we could have solved these more elegantly by using the same
	* variable name or by subclassing.
	*/
	switch (tag) {
	case Constants.CONSTANT_Class:
	i = ((ConstantClass) c).getNameIndex();
	break;
	case Constants.CONSTANT_String:
	i = ((ConstantString) c).getStringIndex();
	break;
	default:
	throw new RuntimeException("getConstantString called with illegal tag " + tag);
	}
	// Finally get the string from the constant pool
	c = getConstant(i, Constants.CONSTANT_Utf8);
	return ((ConstantUtf8) c).getBytes();
	}


	/**
	* @return Length of constant pool.
	*/
	public int getLength() {
	return constant_pool_count;
	}


	/**
	* @return String representation.
	*/
	@Override
	public String toString() {
	StringBuffer buf = new StringBuffer();
	for (int i = 1; i < constant_pool_count; i++) {
	buf.append(i).append(")").append(constant_pool[i]).append("\n");
	}
	return buf.toString();
	}


	}