/*
 *  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 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>.

 * @see     Constant
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 */
public class ConstantPool {

    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 {
        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.
             */
            if (constant_pool[i] != null) {
                byte tag = constant_pool[i].getTag();
                if ((tag == Constants.CONSTANT_Double) || (tag == Constants.CONSTANT_Long)) {
                    i++;
                }
            }
        }
    }


    /**
     * 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
     * @throws  ClassFormatException
     */
    public String getConstantString( int index, byte tag ) throws ClassFormatException {
        Constant c = getConstant(index, tag);

        if (Constants.CONSTANT_Class != tag) {
            throw new RuntimeException("getConstantString called with illegal tag " + tag);
        }

        int i = ((ConstantClass) c).getNameIndex();

        // Finally get the string from the constant pool
        c = getConstant(i, Constants.CONSTANT_Utf8);
        return ((ConstantUtf8) c).getBytes();
    }
}

@@ -1471,44 +1471,13 @@
 ate 
+f
 in
-t constant_pool_count;%0A    private
+al
  Con
@@ -1747,32 +1747,36 @@
 ption %7B%0A        
+int 
 constant_pool_co

Remove constant_pool_count field. The field is never read, and its value is known from the length of constant_pool array created in constructor.