package openejb.shade.org.apache.bcel.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

import  openejb.shade.org.apache.bcel.Constants;
import  openejb.shade.org.apache.bcel.generic.ConstantPoolGen;
import  java.io.*;

/**
 * This class represents the constant pool, i.e., a table of constants.
 * It may contain null references, due to the JVM specification that skips
 * an entry after an 8-byte constant (double, long) entry.
 *
 * @version $Id$
 * @see     Constant
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 */
public class ConstantPool implements Cloneable, Node {
    private int        constant_pool_count;
    private Constant[] constant_pool;

    /**
     * @param constant_pool Array of constants
     */
    public ConstantPool(Constant[] constant_pool)
    {
        setConstantPool(constant_pool);
    }

    /**
     * Read constants from given file stream.
     *
     * @param file Input stream
     * @throw IOException
     * @throw ClassFormatError
     */
    ConstantPool(DataInputStream file) throws IOException, ClassFormatError
    {
        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++;
        }
    }

    /**
     * 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,
     * fields, attributes, etc. spawns a tree of objects.
     *
     * @param v Visitor object
     */
    public void accept(Visitor v) {
        v.visitConstantPool(this);
    }

    /**
     * Resolve constant to a string representation.
     *
     * @param  constant Constant to be printed
     * @return String representation
     */
    public String constantToString(Constant c)
            throws ClassFormatError
    {
        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 = "" + ((ConstantDouble)c).getBytes();  break;
            case Constants.CONSTANT_Float:   str = "" + ((ConstantFloat)c).getBytes();   break;
            case Constants.CONSTANT_Long:    str = "" + ((ConstantLong)c).getBytes();    break;
            case Constants.CONSTANT_Integer: str = "" + ((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 ClassFormatError
    {
        Constant c = getConstant(index, tag);
        return constantToString(c);
    }

    /**
     * Dump constant pool to file stream in binary format.
     *
     * @param file Output file stream
     * @throw IOException
     */
    public void dump(DataOutputStream file) throws IOException
    {
        /*
         * Constants over the size of the constant pool shall not be written out.
         * This is a redundant measure as the ConstantPoolGen should have already
         * reported an error back in the situation.
         */
        int size = constant_pool_count < ConstantPoolGen.CONSTANT_POOL_SIZE - 1 ?
                   constant_pool_count : ConstantPoolGen.CONSTANT_POOL_SIZE - 1;

        file.writeShort(size);

        for(int i=1; i < size; i++)
            if(constant_pool[i] != null)
                constant_pool[i].dump(file);
    }

    /**
     * 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 ClassFormatError("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
     * @throw  ClassFormatError
     */
    public Constant getConstant(int index, byte tag)
            throws ClassFormatError
    {
        Constant c;

        c = getConstant(index);

        if(c == null)
            throw new ClassFormatError("Constant pool at index " + index + " is null.");

        if(c.getTag() == tag)
            return c;
        else
            throw new ClassFormatError("Expected class `" + Constants.CONSTANT_NAMES[tag] +
                    "' at index " + index + " and got " + c);
    }

    /**
     * @return Array of constants.
     * @see    Constant
     */
    public Constant[] getConstantPool() { return constant_pool;  }
    /**
     * 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
     * @throw  ClassFormatError
     */
    public String getConstantString(int index, byte tag)
            throws ClassFormatError
    {
        Constant c;
        int    i;
        String   s;

        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;
    }

    /**
     * @param constant Constant to set
     */
    public void setConstant(int index, Constant constant) {
        constant_pool[index] = constant;
    }

    /**
     * @param constant_pool
     */
    public void setConstantPool(Constant[] constant_pool) {
        this.constant_pool = constant_pool;
        constant_pool_count = (constant_pool == null)? 0 : constant_pool.length;
    }
    /**
     * @return String representation.
     */
    public String toString() {
        StringBuffer buf = new StringBuffer();

        for(int i=1; i < constant_pool_count; i++)
            buf.append(i + ")" + constant_pool[i] + "\n");

        return buf.toString();
    }

    /**
     * @return deep copy of this constant pool
     */
    public ConstantPool copy() {
        ConstantPool c = null;

        try {
            c = (ConstantPool)clone();
        } catch(CloneNotSupportedException e) {}

        c.constant_pool = new Constant[constant_pool_count];

        for(int i=1; i < constant_pool_count; i++) {
            if(constant_pool[i] != null)
                c.constant_pool[i] = constant_pool[i].copy();
        }

        return c;
    }
}
