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	/*
	* reserved comment block
	* DO NOT REMOVE OR ALTER!
	*/
	/*
	* 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 com.sun.org.apache.bcel.internal.classfile;

	import java.io.DataInput;
	import java.io.DataOutputStream;
	import java.io.IOException;

	import com.sun.org.apache.bcel.internal.Const;

	/**
	* 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 1749603 2016-06-21 20:50:19Z ggregory $
	* @see Constant
	* @see com.sun.org.apache.bcel.internal.generic.ConstantPoolGen
	*/
	public class ConstantPool implements Cloneable, Node {

	private Constant[] constant_pool;


	/**
	* @param constant_pool Array of constants
	*/
	public ConstantPool(final Constant[] constant_pool) {
	this.constant_pool = constant_pool;
	}


	/**
	* Read constants from given input stream.
	*
	* @param input Input stream
	* @throws IOException
	* @throws ClassFormatException
	*/
	public ConstantPool(final DataInput input) throws IOException, ClassFormatException {
	byte tag;
	final int constant_pool_count = input.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(input);
	/* 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 == Const.CONSTANT_Double) \|\| (tag == Const.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
	*/
	@Override
	public void accept( final Visitor v ) {
	v.visitConstantPool(this);
	}


	/**
	* 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;
	final byte tag = c.getTag();
	switch (tag) {
	case Const.CONSTANT_Class:
	i = ((ConstantClass) c).getNameIndex();
	c = getConstant(i, Const.CONSTANT_Utf8);
	str = Utility.compactClassName(((ConstantUtf8) c).getBytes(), false);
	break;
	case Const.CONSTANT_String:
	i = ((ConstantString) c).getStringIndex();
	c = getConstant(i, Const.CONSTANT_Utf8);
	str = "\"" + escape(((ConstantUtf8) c).getBytes()) + "\"";
	break;
	case Const.CONSTANT_Utf8:
	str = ((ConstantUtf8) c).getBytes();
	break;
	case Const.CONSTANT_Double:
	str = String.valueOf(((ConstantDouble) c).getBytes());
	break;
	case Const.CONSTANT_Float:
	str = String.valueOf(((ConstantFloat) c).getBytes());
	break;
	case Const.CONSTANT_Long:
	str = String.valueOf(((ConstantLong) c).getBytes());
	break;
	case Const.CONSTANT_Integer:
	str = String.valueOf(((ConstantInteger) c).getBytes());
	break;
	case Const.CONSTANT_NameAndType:
	str = constantToString(((ConstantNameAndType) c).getNameIndex(),
	Const.CONSTANT_Utf8)
	+ ":" + constantToString(((ConstantNameAndType) c).getSignatureIndex(),
	Const.CONSTANT_Utf8);
	break;
	case Const.CONSTANT_InterfaceMethodref:
	case Const.CONSTANT_Methodref:
	case Const.CONSTANT_Fieldref:
	str = constantToString(((ConstantCP) c).getClassIndex(), Const.CONSTANT_Class)
	+ "." + constantToString(((ConstantCP) c).getNameAndTypeIndex(),
	Const.CONSTANT_NameAndType);
	break;
	case Const.CONSTANT_MethodHandle:
	// Note that the ReferenceIndex may point to a Fieldref, Methodref or
	// InterfaceMethodref - so we need to peek ahead to get the actual type.
	final ConstantMethodHandle cmh = (ConstantMethodHandle) c;
	str = Const.getMethodHandleName(cmh.getReferenceKind())
	+ " " + constantToString(cmh.getReferenceIndex(),
	getConstant(cmh.getReferenceIndex()).getTag());
	break;
	case Const.CONSTANT_MethodType:
	final ConstantMethodType cmt = (ConstantMethodType) c;
	str = constantToString(cmt.getDescriptorIndex(), Const.CONSTANT_Utf8);
	break;
	case Const.CONSTANT_InvokeDynamic:
	final ConstantInvokeDynamic cid = (ConstantInvokeDynamic) c;
	str = cid.getBootstrapMethodAttrIndex()
	+ ":" + constantToString(cid.getNameAndTypeIndex(),
	Const.CONSTANT_NameAndType);
	break;
	default: // Never reached
	throw new RuntimeException("Unknown constant type " + tag);
	}
	return str;
	}


	private static String escape( final String str ) {
	final int len = str.length();
	final StringBuilder buf = new StringBuilder(len + 5);
	final 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( final int index, final byte tag ) throws ClassFormatException {
	final Constant c = getConstant(index, tag);
	return constantToString(c);
	}


	/**
	* Dump constant pool to file stream in binary format.
	*
	* @param file Output file stream
	* @throws IOException
	*/
	public void dump( final DataOutputStream file ) throws IOException {
	file.writeShort(constant_pool.length);
	for (int i = 1; i < constant_pool.length; 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( final 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( final int index, final 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 `" + Const.getConstantName(tag)
	+ "' at index " + index + " and got " + c);
	}
	return 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
	* @throws ClassFormatException
	*/
	public String getConstantString( final int index, final 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 Const.CONSTANT_Class:
	i = ((ConstantClass) c).getNameIndex();
	break;
	case Const.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, Const.CONSTANT_Utf8);
	return ((ConstantUtf8) c).getBytes();
	}


	/**
	* @return Length of constant pool.
	*/
	public int getLength() {
	return constant_pool == null ? 0 : constant_pool.length;
	}


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


	/**
	* @param constant_pool
	*/
	public void setConstantPool( final Constant[] constant_pool ) {
	this.constant_pool = constant_pool;
	}


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


	/**
	* @return deep copy of this constant pool
	*/
	public ConstantPool copy() {
	ConstantPool c = null;
	try {
	c = (ConstantPool) clone();
	c.constant_pool = new Constant[constant_pool.length];
	for (int i = 1; i < constant_pool.length; i++) {
	if (constant_pool[i] != null) {
	c.constant_pool[i] = constant_pool[i].copy();
	}
	}
	} catch (final CloneNotSupportedException e) {
	// TODO should this throw?
	}
	return c;
	}
	}

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