/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2005 INRIA, France Telecom
 * 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. Neither the name of the copyright holders nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND 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.
 */
package clojure.asm;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

/**
 * A Java type. This class can be used to make it easier to manipulate type and
 * method descriptors.
 *
 * @author Eric Bruneton
 * @author Chris Nokleberg
 */
public class Type{

/**
 * The sort of the <tt>void</tt> type. See {@link #getSort getSort}.
 */
public final static int VOID = 0;

/**
 * The sort of the <tt>boolean</tt> type. See {@link #getSort getSort}.
 */
public final static int BOOLEAN = 1;

/**
 * The sort of the <tt>char</tt> type. See {@link #getSort getSort}.
 */
public final static int CHAR = 2;

/**
 * The sort of the <tt>byte</tt> type. See {@link #getSort getSort}.
 */
public final static int BYTE = 3;

/**
 * The sort of the <tt>short</tt> type. See {@link #getSort getSort}.
 */
public final static int SHORT = 4;

/**
 * The sort of the <tt>int</tt> type. See {@link #getSort getSort}.
 */
public final static int INT = 5;

/**
 * The sort of the <tt>float</tt> type. See {@link #getSort getSort}.
 */
public final static int FLOAT = 6;

/**
 * The sort of the <tt>long</tt> type. See {@link #getSort getSort}.
 */
public final static int LONG = 7;

/**
 * The sort of the <tt>double</tt> type. See {@link #getSort getSort}.
 */
public final static int DOUBLE = 8;

/**
 * The sort of array reference types. See {@link #getSort getSort}.
 */
public final static int ARRAY = 9;

/**
 * The sort of object reference type. See {@link #getSort getSort}.
 */
public final static int OBJECT = 10;

/**
 * The <tt>void</tt> type.
 */
public final static Type VOID_TYPE = new Type(VOID);

/**
 * The <tt>boolean</tt> type.
 */
public final static Type BOOLEAN_TYPE = new Type(BOOLEAN);

/**
 * The <tt>char</tt> type.
 */
public final static Type CHAR_TYPE = new Type(CHAR);

/**
 * The <tt>byte</tt> type.
 */
public final static Type BYTE_TYPE = new Type(BYTE);

/**
 * The <tt>short</tt> type.
 */
public final static Type SHORT_TYPE = new Type(SHORT);

/**
 * The <tt>int</tt> type.
 */
public final static Type INT_TYPE = new Type(INT);

/**
 * The <tt>float</tt> type.
 */
public final static Type FLOAT_TYPE = new Type(FLOAT);

/**
 * The <tt>long</tt> type.
 */
public final static Type LONG_TYPE = new Type(LONG);

/**
 * The <tt>double</tt> type.
 */
public final static Type DOUBLE_TYPE = new Type(DOUBLE);

// ------------------------------------------------------------------------
// Fields
// ------------------------------------------------------------------------

/**
 * The sort of this Java type.
 */
private final int sort;

/**
 * A buffer containing the descriptor of this Java type. This field is only
 * used for reference types.
 */
private char[] buf;

/**
 * The offset of the descriptor of this Java type in {@link #buf buf}. This
 * field is only used for reference types.
 */
private int off;

/**
 * The length of the descriptor of this Java type.
 */
private int len;

// ------------------------------------------------------------------------
// Constructors
// ------------------------------------------------------------------------

/**
 * Constructs a primitive type.
 *
 * @param sort the sort of the primitive type to be constructed.
 */
private Type(final int sort){
	this.sort = sort;
	this.len = 1;
}

/**
 * Constructs a reference type.
 *
 * @param sort the sort of the reference type to be constructed.
 * @param buf  a buffer containing the descriptor of the previous type.
 * @param off  the offset of this descriptor in the previous buffer.
 * @param len  the length of this descriptor.
 */
private Type(final int sort, final char[] buf, final int off, final int len){
	this.sort = sort;
	this.buf = buf;
	this.off = off;
	this.len = len;
}

/**
 * Returns the Java type corresponding to the given type descriptor.
 *
 * @param typeDescriptor a type descriptor.
 * @return the Java type corresponding to the given type descriptor.
 */
public static Type getType(final String typeDescriptor){
	return getType(typeDescriptor.toCharArray(), 0);
}

/**
 * Returns the Java type corresponding to the given class.
 *
 * @param c a class.
 * @return the Java type corresponding to the given class.
 */
public static Type getType(final Class c){
	if(c.isPrimitive())
		{
		if(c == Integer.TYPE)
			{
			return INT_TYPE;
			}
		else if(c == Void.TYPE)
			{
			return VOID_TYPE;
			}
		else if(c == Boolean.TYPE)
			{
			return BOOLEAN_TYPE;
			}
		else if(c == Byte.TYPE)
			{
			return BYTE_TYPE;
			}
		else if(c == Character.TYPE)
			{
			return CHAR_TYPE;
			}
		else if(c == Short.TYPE)
			{
			return SHORT_TYPE;
			}
		else if(c == Double.TYPE)
			{
			return DOUBLE_TYPE;
			}
		else if(c == Float.TYPE)
			{
			return FLOAT_TYPE;
			}
		else /* if (c == Long.TYPE) */
			{
			return LONG_TYPE;
			}
		}
	else
		{
		return getType(getDescriptor(c));
		}
}

/**
 * Returns the {@link Type#OBJECT} type for the given internal class name.
 * This is a shortcut method for <code>Type.getType("L"+name+";")</code>.
 * <i>Note that opposed to {@link Type#getType(String)}, this method takes
 * internal class names and not class descriptor.</i>
 *
 * @param name an internal class name.
 * @return the the {@link Type#OBJECT} type for the given class name.
 */
public static Type getObjectType(String name){
	int l = name.length();
	char[] buf = new char[l + 2];
	buf[0] = 'L';
	buf[l + 1] = ';';
	name.getChars(0, l, buf, 1);
	return new Type(OBJECT, buf, 0, l + 2);
}

/**
 * Returns the Java types corresponding to the argument types of the given
 * method descriptor.
 *
 * @param methodDescriptor a method descriptor.
 * @return the Java types corresponding to the argument types of the given
 *         method descriptor.
 */
public static Type[] getArgumentTypes(final String methodDescriptor){
	char[] buf = methodDescriptor.toCharArray();
	int off = 1;
	int size = 0;
	while(true)
		{
		char car = buf[off++];
		if(car == ')')
			{
			break;
			}
		else if(car == 'L')
			{
			while(buf[off++] != ';')
				{
				}
			++size;
			}
		else if(car != '[')
			{
			++size;
			}
		}
	Type[] args = new Type[size];
	off = 1;
	size = 0;
	while(buf[off] != ')')
		{
		args[size] = getType(buf, off);
		off += args[size].len;
		size += 1;
		}
	return args;
}

/**
 * Returns the Java types corresponding to the argument types of the given
 * method.
 *
 * @param method a method.
 * @return the Java types corresponding to the argument types of the given
 *         method.
 */
public static Type[] getArgumentTypes(final Method method){
	Class[] classes = method.getParameterTypes();
	Type[] types = new Type[classes.length];
	for(int i = classes.length - 1; i >= 0; --i)
		{
		types[i] = getType(classes[i]);
		}
	return types;
}

/**
 * Returns the Java type corresponding to the return type of the given
 * method descriptor.
 *
 * @param methodDescriptor a method descriptor.
 * @return the Java type corresponding to the return type of the given
 *         method descriptor.
 */
public static Type getReturnType(final String methodDescriptor){
	char[] buf = methodDescriptor.toCharArray();
	return getType(buf, methodDescriptor.indexOf(')') + 1);
}

/**
 * Returns the Java type corresponding to the return type of the given
 * method.
 *
 * @param method a method.
 * @return the Java type corresponding to the return type of the given
 *         method.
 */
public static Type getReturnType(final Method method){
	return getType(method.getReturnType());
}

/**
 * Returns the Java type corresponding to the given type descriptor.
 *
 * @param buf a buffer containing a type descriptor.
 * @param off the offset of this descriptor in the previous buffer.
 * @return the Java type corresponding to the given type descriptor.
 */
private static Type getType(final char[] buf, final int off){
	int len;
	switch(buf[off])
		{
		case'V':
			return VOID_TYPE;
		case'Z':
			return BOOLEAN_TYPE;
		case'C':
			return CHAR_TYPE;
		case'B':
			return BYTE_TYPE;
		case'S':
			return SHORT_TYPE;
		case'I':
			return INT_TYPE;
		case'F':
			return FLOAT_TYPE;
		case'J':
			return LONG_TYPE;
		case'D':
			return DOUBLE_TYPE;
		case'[':
			len = 1;
			while(buf[off + len] == '[')
				{
				++len;
				}
			if(buf[off + len] == 'L')
				{
				++len;
				while(buf[off + len] != ';')
					{
					++len;
					}
				}
			return new Type(ARRAY, buf, off, len + 1);
			// case 'L':
		default:
			len = 1;
			while(buf[off + len] != ';')
				{
				++len;
				}
			return new Type(OBJECT, buf, off, len + 1);
		}
}

// ------------------------------------------------------------------------
// Accessors
// ------------------------------------------------------------------------

/**
 * Returns the sort of this Java type.
 *
 * @return {@link #VOID VOID}, {@link #BOOLEAN BOOLEAN},
 *         {@link #CHAR CHAR}, {@link #BYTE BYTE}, {@link #SHORT SHORT},
 *         {@link #INT INT}, {@link #FLOAT FLOAT}, {@link #LONG LONG},
 *         {@link #DOUBLE DOUBLE}, {@link #ARRAY ARRAY} or
 *         {@link #OBJECT OBJECT}.
 */
public int getSort(){
	return sort;
}

/**
 * Returns the number of dimensions of this array type. This method should
 * only be used for an array type.
 *
 * @return the number of dimensions of this array type.
 */
public int getDimensions(){
	int i = 1;
	while(buf[off + i] == '[')
		{
		++i;
		}
	return i;
}

/**
 * Returns the type of the elements of this array type. This method should
 * only be used for an array type.
 *
 * @return Returns the type of the elements of this array type.
 */
public Type getElementType(){
	return getType(buf, off + getDimensions());
}

/**
 * Returns the name of the class corresponding to this type.
 *
 * @return the fully qualified name of the class corresponding to this type.
 */
public String getClassName(){
	switch(sort)
		{
		case VOID:
			return "void";
		case BOOLEAN:
			return "boolean";
		case CHAR:
			return "char";
		case BYTE:
			return "byte";
		case SHORT:
			return "short";
		case INT:
			return "int";
		case FLOAT:
			return "float";
		case LONG:
			return "long";
		case DOUBLE:
			return "double";
		case ARRAY:
			StringBuffer b = new StringBuffer(getElementType().getClassName());
			for(int i = getDimensions(); i > 0; --i)
				{
				b.append("[]");
				}
			return b.toString();
			// case OBJECT:
		default:
			return new String(buf, off + 1, len - 2).replace('/', '.');
		}
}

/**
 * Returns the internal name of the class corresponding to this object type.
 * The internal name of a class is its fully qualified name, where '.' are
 * replaced by '/'. This method should only be used for an object type.
 *
 * @return the internal name of the class corresponding to this object type.
 */
public String getInternalName(){
	return new String(buf, off + 1, len - 2);
}

// ------------------------------------------------------------------------
// Conversion to type descriptors
// ------------------------------------------------------------------------

/**
 * Returns the descriptor corresponding to this Java type.
 *
 * @return the descriptor corresponding to this Java type.
 */
public String getDescriptor(){
	StringBuffer buf = new StringBuffer();
	getDescriptor(buf);
	return buf.toString();
}

/**
 * Returns the descriptor corresponding to the given argument and return
 * types.
 *
 * @param returnType    the return type of the method.
 * @param argumentTypes the argument types of the method.
 * @return the descriptor corresponding to the given argument and return
 *         types.
 */
public static String getMethodDescriptor(
		final Type returnType,
		final Type[] argumentTypes){
	StringBuffer buf = new StringBuffer();
	buf.append('(');
	for(int i = 0; i < argumentTypes.length; ++i)
		{
		argumentTypes[i].getDescriptor(buf);
		}
	buf.append(')');
	returnType.getDescriptor(buf);
	return buf.toString();
}

/**
 * Appends the descriptor corresponding to this Java type to the given
 * string buffer.
 *
 * @param buf the string buffer to which the descriptor must be appended.
 */
private void getDescriptor(final StringBuffer buf){
	switch(sort)
		{
		case VOID:
			buf.append('V');
			return;
		case BOOLEAN:
			buf.append('Z');
			return;
		case CHAR:
			buf.append('C');
			return;
		case BYTE:
			buf.append('B');
			return;
		case SHORT:
			buf.append('S');
			return;
		case INT:
			buf.append('I');
			return;
		case FLOAT:
			buf.append('F');
			return;
		case LONG:
			buf.append('J');
			return;
		case DOUBLE:
			buf.append('D');
			return;
			// case ARRAY:
			// case OBJECT:
		default:
			buf.append(this.buf, off, len);
		}
}

// ------------------------------------------------------------------------
// Direct conversion from classes to type descriptors,
// without intermediate Type objects
// ------------------------------------------------------------------------

/**
 * Returns the internal name of the given class. The internal name of a
 * class is its fully qualified name, where '.' are replaced by '/'.
 *
 * @param c an object class.
 * @return the internal name of the given class.
 */
public static String getInternalName(final Class c){
	return c.getName().replace('.', '/');
}

/**
 * Returns the descriptor corresponding to the given Java type.
 *
 * @param c an object class, a primitive class or an array class.
 * @return the descriptor corresponding to the given class.
 */
public static String getDescriptor(final Class c){
	StringBuffer buf = new StringBuffer();
	getDescriptor(buf, c);
	return buf.toString();
}

/**
 * Returns the descriptor corresponding to the given constructor.
 *
 * @param c a {@link Constructor Constructor} object.
 * @return the descriptor of the given constructor.
 */
public static String getConstructorDescriptor(final Constructor c){
	Class[] parameters = c.getParameterTypes();
	StringBuffer buf = new StringBuffer();
	buf.append('(');
	for(int i = 0; i < parameters.length; ++i)
		{
		getDescriptor(buf, parameters[i]);
		}
	return buf.append(")V").toString();
}

/**
 * Returns the descriptor corresponding to the given method.
 *
 * @param m a {@link Method Method} object.
 * @return the descriptor of the given method.
 */
public static String getMethodDescriptor(final Method m){
	Class[] parameters = m.getParameterTypes();
	StringBuffer buf = new StringBuffer();
	buf.append('(');
	for(int i = 0; i < parameters.length; ++i)
		{
		getDescriptor(buf, parameters[i]);
		}
	buf.append(')');
	getDescriptor(buf, m.getReturnType());
	return buf.toString();
}

/**
 * Appends the descriptor of the given class to the given string buffer.
 *
 * @param buf the string buffer to which the descriptor must be appended.
 * @param c   the class whose descriptor must be computed.
 */
private static void getDescriptor(final StringBuffer buf, final Class c){
	Class d = c;
	while(true)
		{
		if(d.isPrimitive())
			{
			char car;
			if(d == Integer.TYPE)
				{
				car = 'I';
				}
			else if(d == Void.TYPE)
				{
				car = 'V';
				}
			else if(d == Boolean.TYPE)
				{
				car = 'Z';
				}
			else if(d == Byte.TYPE)
				{
				car = 'B';
				}
			else if(d == Character.TYPE)
				{
				car = 'C';
				}
			else if(d == Short.TYPE)
				{
				car = 'S';
				}
			else if(d == Double.TYPE)
				{
				car = 'D';
				}
			else if(d == Float.TYPE)
				{
				car = 'F';
				}
			else /* if (d == Long.TYPE) */
				{
				car = 'J';
				}
			buf.append(car);
			return;
			}
		else if(d.isArray())
			{
			buf.append('[');
			d = d.getComponentType();
			}
		else
			{
			buf.append('L');
			String name = d.getName();
			int len = name.length();
			for(int i = 0; i < len; ++i)
				{
				char car = name.charAt(i);
				buf.append(car == '.' ? '/' : car);
				}
			buf.append(';');
			return;
			}
		}
}

// ------------------------------------------------------------------------
// Corresponding size and opcodes
// ------------------------------------------------------------------------

/**
 * Returns the size of values of this type.
 *
 * @return the size of values of this type, i.e., 2 for <tt>long</tt> and
 *         <tt>double</tt>, and 1 otherwise.
 */
public int getSize(){
	return sort == LONG || sort == DOUBLE ? 2 : 1;
}

/**
 * Returns a JVM instruction opcode adapted to this Java type.
 *
 * @param opcode a JVM instruction opcode. This opcode must be one of ILOAD,
 *               ISTORE, IALOAD, IASTORE, IADD, ISUB, IMUL, IDIV, IREM, INEG, ISHL,
 *               ISHR, IUSHR, IAND, IOR, IXOR and IRETURN.
 * @return an opcode that is similar to the given opcode, but adapted to
 *         this Java type. For example, if this type is <tt>float</tt> and
 *         <tt>opcode</tt> is IRETURN, this method returns FRETURN.
 */
public int getOpcode(final int opcode){
	if(opcode == Opcodes.IALOAD || opcode == Opcodes.IASTORE)
		{
		switch(sort)
			{
			case BOOLEAN:
			case BYTE:
				return opcode + 5;
			case CHAR:
				return opcode + 6;
			case SHORT:
				return opcode + 7;
			case INT:
				return opcode;
			case FLOAT:
				return opcode + 2;
			case LONG:
				return opcode + 1;
			case DOUBLE:
				return opcode + 3;
				// case ARRAY:
				// case OBJECT:
			default:
				return opcode + 4;
			}
		}
	else
		{
		switch(sort)
			{
			case VOID:
				return opcode + 5;
			case BOOLEAN:
			case CHAR:
			case BYTE:
			case SHORT:
			case INT:
				return opcode;
			case FLOAT:
				return opcode + 2;
			case LONG:
				return opcode + 1;
			case DOUBLE:
				return opcode + 3;
				// case ARRAY:
				// case OBJECT:
			default:
				return opcode + 4;
			}
		}
}

// ------------------------------------------------------------------------
// Equals, hashCode and toString
// ------------------------------------------------------------------------

/**
 * Tests if the given object is equal to this type.
 *
 * @param o the object to be compared to this type.
 * @return <tt>true</tt> if the given object is equal to this type.
 */
public boolean equals(final Object o){
	if(this == o)
		{
		return true;
		}
	if(!(o instanceof Type))
		{
		return false;
		}
	Type t = (Type) o;
	if(sort != t.sort)
		{
		return false;
		}
	if(sort == Type.OBJECT || sort == Type.ARRAY)
		{
		if(len != t.len)
			{
			return false;
			}
		for(int i = off, j = t.off, end = i + len; i < end; i++, j++)
			{
			if(buf[i] != t.buf[j])
				{
				return false;
				}
			}
		}
	return true;
}

/**
 * Returns a hash code value for this type.
 *
 * @return a hash code value for this type.
 */
public int hashCode(){
	int hc = 13 * sort;
	if(sort == Type.OBJECT || sort == Type.ARRAY)
		{
		for(int i = off, end = i + len; i < end; i++)
			{
			hc = 17 * (hc + buf[i]);
			}
		}
	return hc;
}

/**
 * Returns a string representation of this type.
 *
 * @return the descriptor of this type.
 */
public String toString(){
	return getDescriptor();
}
}