/***
 * 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.optimizer;

import alterrs.asm.ClassWriter;

/**
 * A constant pool item.
 * 
 * @author Eric Bruneton
 */
class Constant {

	/**
	 * Type of this constant pool item. A single class is used to represent all
	 * constant pool item types, in order to minimize the bytecode size of this
	 * package. The value of this field is I, J, F, D, S, s, C, T, G, M, or N
	 * (for Constant Integer, Long, Float, Double, STR, UTF8, Class, NameType,
	 * Fieldref, Methodref, or InterfaceMethodref constant pool items
	 * respectively).
	 */
	char type;

	/**
	 * Value of this item, for an integer item.
	 */
	int intVal;

	/**
	 * Value of this item, for a long item.
	 */
	long longVal;

	/**
	 * Value of this item, for a float item.
	 */
	float floatVal;

	/**
	 * Value of this item, for a double item.
	 */
	double doubleVal;

	/**
	 * First part of the value of this item, for items that do not hold a
	 * primitive value.
	 */
	String strVal1;

	/**
	 * Second part of the value of this item, for items that do not hold a
	 * primitive value.
	 */
	String strVal2;

	/**
	 * Third part of the value of this item, for items that do not hold a
	 * primitive value.
	 */
	String strVal3;

	/**
	 * The hash code value of this constant pool item.
	 */
	int hashCode;

	Constant() {
	}

	Constant(final Constant i) {
		type = i.type;
		intVal = i.intVal;
		longVal = i.longVal;
		floatVal = i.floatVal;
		doubleVal = i.doubleVal;
		strVal1 = i.strVal1;
		strVal2 = i.strVal2;
		strVal3 = i.strVal3;
		hashCode = i.hashCode;
	}

	/**
	 * Sets this item to an integer item.
	 * 
	 * @param intVal
	 *            the value of this item.
	 */
	void set(final int intVal) {
		this.type = 'I';
		this.intVal = intVal;
		this.hashCode = 0x7FFFFFFF & (type + intVal);
	}

	/**
	 * Sets this item to a long item.
	 * 
	 * @param longVal
	 *            the value of this item.
	 */
	void set(final long longVal) {
		this.type = 'J';
		this.longVal = longVal;
		this.hashCode = 0x7FFFFFFF & (type + (int) longVal);
	}

	/**
	 * Sets this item to a float item.
	 * 
	 * @param floatVal
	 *            the value of this item.
	 */
	void set(final float floatVal) {
		this.type = 'F';
		this.floatVal = floatVal;
		this.hashCode = 0x7FFFFFFF & (type + (int) floatVal);
	}

	/**
	 * Sets this item to a double item.
	 * 
	 * @param doubleVal
	 *            the value of this item.
	 */
	void set(final double doubleVal) {
		this.type = 'D';
		this.doubleVal = doubleVal;
		this.hashCode = 0x7FFFFFFF & (type + (int) doubleVal);
	}

	/**
	 * Sets this item to an item that do not hold a primitive value.
	 * 
	 * @param type
	 *            the type of this item.
	 * @param strVal1
	 *            first part of the value of this item.
	 * @param strVal2
	 *            second part of the value of this item.
	 * @param strVal3
	 *            third part of the value of this item.
	 */
	void set(final char type, final String strVal1, final String strVal2,
			final String strVal3) {
		this.type = type;
		this.strVal1 = strVal1;
		this.strVal2 = strVal2;
		this.strVal3 = strVal3;
		switch (type) {
		case 's':
		case 'S':
		case 'C':
			hashCode = 0x7FFFFFFF & (type + strVal1.hashCode());
			return;
		case 'T':
			hashCode = 0x7FFFFFFF & (type + strVal1.hashCode()
					* strVal2.hashCode());
			return;
			// case 'G':
			// case 'M':
			// case 'N':
		default:
			hashCode = 0x7FFFFFFF & (type + strVal1.hashCode()
					* strVal2.hashCode() * strVal3.hashCode());
		}
	}

	void write(final ClassWriter cw) {
		switch (type) {
		case 'I':
			cw.newConst(new Integer(intVal));
			break;
		case 'J':
			cw.newConst(new Long(longVal));
			break;
		case 'F':
			cw.newConst(new Float(floatVal));
			break;
		case 'D':
			cw.newConst(new Double(doubleVal));
			break;
		case 'S':
			cw.newConst(strVal1);
			break;
		case 's':
			cw.newUTF8(strVal1);
			break;
		case 'C':
			cw.newClass(strVal1);
			break;
		case 'T':
			cw.newNameType(strVal1, strVal2);
			break;
		case 'G':
			cw.newField(strVal1, strVal2, strVal3);
			break;
		case 'M':
			cw.newMethod(strVal1, strVal2, strVal3, false);
			break;
		case 'N':
			cw.newMethod(strVal1, strVal2, strVal3, true);
			break;
		}
	}

	public boolean equals(final Object o) {
		if (!(o instanceof Constant)) {
			return false;
		}
		Constant c = (Constant) o;
		if (c.type == type) {
			switch (type) {
			case 'I':
				return c.intVal == intVal;
			case 'J':
				return c.longVal == longVal;
			case 'F':
				return Float.compare(c.floatVal, floatVal) == 0;
			case 'D':
				return Double.compare(c.doubleVal, doubleVal) == 0;
			case 's':
			case 'S':
			case 'C':
				return c.strVal1.equals(strVal1);
			case 'T':
				return c.strVal1.equals(strVal1) && c.strVal2.equals(strVal2);
				// case 'G':
				// case 'M':
				// case 'N':
			default:
				return c.strVal1.equals(strVal1) && c.strVal2.equals(strVal2)
						&& c.strVal3.equals(strVal3);
			}
		}
		return false;
	}

	public int hashCode() {
		return hashCode;
	}
}
