/***
 * ASM: a very small and fast Java bytecode manipulation framework
 * Copyright (c) 2000-2007 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 alterrs.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 static final int VOID = 0;

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

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

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

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

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

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

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

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

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

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

	/**
	 * The <tt>void</tt> type.
	 */
	public static final Type VOID_TYPE = new Type(VOID, null, ('V' << 24)
			| (5 << 16) | (0 << 8) | 0, 1);

	/**
	 * The <tt>boolean</tt> type.
	 */
	public static final Type BOOLEAN_TYPE = new Type(BOOLEAN, null, ('Z' << 24)
			| (0 << 16) | (5 << 8) | 1, 1);

	/**
	 * The <tt>char</tt> type.
	 */
	public static final Type CHAR_TYPE = new Type(CHAR, null, ('C' << 24)
			| (0 << 16) | (6 << 8) | 1, 1);

	/**
	 * The <tt>byte</tt> type.
	 */
	public static final Type BYTE_TYPE = new Type(BYTE, null, ('B' << 24)
			| (0 << 16) | (5 << 8) | 1, 1);

	/**
	 * The <tt>short</tt> type.
	 */
	public static final Type SHORT_TYPE = new Type(SHORT, null, ('S' << 24)
			| (0 << 16) | (7 << 8) | 1, 1);

	/**
	 * The <tt>int</tt> type.
	 */
	public static final Type INT_TYPE = new Type(INT, null, ('I' << 24)
			| (0 << 16) | (0 << 8) | 1, 1);

	/**
	 * The <tt>float</tt> type.
	 */
	public static final Type FLOAT_TYPE = new Type(FLOAT, null, ('F' << 24)
			| (2 << 16) | (2 << 8) | 1, 1);

	/**
	 * The <tt>long</tt> type.
	 */
	public static final Type LONG_TYPE = new Type(LONG, null, ('J' << 24)
			| (1 << 16) | (1 << 8) | 2, 1);

	/**
	 * The <tt>double</tt> type.
	 */
	public static final Type DOUBLE_TYPE = new Type(DOUBLE, null, ('D' << 24)
			| (3 << 16) | (3 << 8) | 2, 1);

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

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

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

	/**
	 * The offset of the internal name of this Java type in {@link #buf buf} or,
	 * for primitive types, the size, descriptor and getOpcode offsets for this
	 * type (byte 0 contains the size, byte 1 the descriptor, byte 2 the offset
	 * for IALOAD or IASTORE, byte 3 the offset for all other instructions).
	 */
	private final int off;

	/**
	 * The length of the internal name of this Java type.
	 */
	private final int len;

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

	/**
	 * 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 internal name.
	 * 
	 * @param internalName
	 *            an internal name.
	 * @return the Java type corresponding to the given internal name.
	 */
	public static Type getObjectType(final String internalName) {
		char[] buf = internalName.toCharArray();
		return new Type(buf[0] == '[' ? ARRAY : OBJECT, buf, 0, buf.length);
	}

	/**
	 * 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 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 + (args[size].sort == OBJECT ? 2 : 0);
			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());
	}

	/**
	 * Computes the size of the arguments and of the return value of a method.
	 * 
	 * @param desc
	 *            the descriptor of a method.
	 * @return the size of the arguments of the method (plus one for the
	 *         implicit this argument), argSize, and the size of its return
	 *         value, retSize, packed into a single int i =
	 *         <tt>(argSize << 2) | retSize</tt> (argSize is therefore equal to
	 *         <tt>i >> 2</tt>, and retSize to <tt>i & 0x03</tt>).
	 */
	public static int getArgumentsAndReturnSizes(final String desc) {
		int n = 1;
		int c = 1;
		while (true) {
			char car = desc.charAt(c++);
			if (car == ')') {
				car = desc.charAt(c);
				return n << 2
						| (car == 'V' ? 0 : (car == 'D' || car == 'J' ? 2 : 1));
			} else if (car == 'L') {
				while (desc.charAt(c++) != ';') {
				}
				n += 1;
			} else if (car == '[') {
				while ((car = desc.charAt(c)) == '[') {
					++c;
				}
				if (car == 'D' || car == 'J') {
					n -= 1;
				}
			} else if (car == 'D' || car == 'J') {
				n += 2;
			} else {
				n += 1;
			}
		}
	}

	/**
	 * 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 + 1, 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, len).replace('/', '.');
		}
	}

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

	// ------------------------------------------------------------------------
	// 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) {
		if (this.buf == null) {
			// descriptor is in byte 3 of 'off' for primitive types (buf ==
			// null)
			buf.append((char) ((off & 0xFF000000) >>> 24));
		} else if (sort == ARRAY) {
			buf.append(this.buf, off, len);
		} else { // sort == OBJECT
			buf.append('L');
			buf.append(this.buf, off, len);
			buf.append(';');
		}
	}

	// ------------------------------------------------------------------------
	// 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, as returned by Class.getName(), where
	 * '.' are replaced by '/'.
	 * 
	 * @param c
	 *            an object or array 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>, 0 for <tt>void</tt> and 1 otherwise.
	 */
	public int getSize() {
		// the size is in byte 0 of 'off' for primitive types (buf == null)
		return buf == null ? (off & 0xFF) : 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) {
			// the offset for IALOAD or IASTORE is in byte 1 of 'off' for
			// primitive types (buf == null)
			return opcode + (buf == null ? (off & 0xFF00) >> 8 : 4);
		} else {
			// the offset for other instructions is in byte 2 of 'off' for
			// primitive types (buf == null)
			return opcode + (buf == null ? (off & 0xFF0000) >> 16 : 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 == OBJECT || sort == 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 == OBJECT || sort == 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();
	}
}
