package org.eclipse.jdt.internal.compiler.classfmt;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import org.eclipse.jdt.internal.compiler.env.*;

import org.eclipse.jdt.internal.compiler.impl.*;
import org.eclipse.jdt.internal.compiler.codegen.*;
import org.eclipse.jdt.internal.compiler.util.*;

public class FieldInfo extends ClassFileStruct implements AttributeNamesConstants, IBinaryField {
	private Constant constant;
	private boolean isDeprecated;
	private int[] constantPoolOffsets;
	private int accessFlags;
	private char[] name;
	private char[] signature;
	private int attributeBytes;
/**
 * @param classFileBytes byte[]
 * @param offsets int[]
 * @param offset int
 */
public FieldInfo (byte classFileBytes[], int offsets[], int offset) throws ClassFormatException {
	super(classFileBytes, offset);
	constantPoolOffsets = offsets;
	accessFlags = -1;
	int attributesCount = u2At(6);
	int readOffset = 8;
	for (int i = 0; i < attributesCount; i++) {
		readOffset += (6 + u4At(readOffset + 2));
	}
	attributeBytes = readOffset;
}
/**
 * Return the constant of the field.
 * Return org.eclipse.jdt.internal.compiler.Constant.NotAConstant if there is none.
 * @return org.eclipse.jdt.internal.compiler.Constant
 */
public Constant getConstant() {
	if (constant == null) {
		// read constant
		readConstantAttribute();
	}
	return constant;
}
/**
 * Answer an int whose bits are set according the access constants
 * defined by the VM spec.
 * Set the AccDeprecated and AccSynthetic bits if necessary
 * @return int
 */
public int getModifiers() {
	if (accessFlags == -1) {
		// compute the accessflag. Don't forget the deprecated attribute
		accessFlags = u2At(0);
		readDeprecatedAttributes();
		if (isDeprecated) {
			accessFlags |= AccDeprecated;
		}
		if (isSynthetic()) {
			accessFlags |= AccSynthetic;
		}
	}
	return accessFlags;
}
/**
 * Answer the name of the field.
 * @return char[]
 */
public char[] getName() {
	if (name == null) {
		// read the name
		int utf8Offset = constantPoolOffsets[u2At(2)] - structOffset;
		name = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
	}
	return name;
}
/**
 * Answer the resolved name of the receiver's type in the
 * class file format as specified in section 4.3.2 of the Java 2 VM spec.
 *
 * For example:
 *   - java.lang.String is Ljava/lang/String;
 *   - an int is I
 *   - a 2 dimensional array of strings is [[Ljava/lang/String;
 *   - an array of floats is [F
 * @return char[]
 */
public char[] getTypeName() {
	if (signature == null) {
		// read the signature
		int utf8Offset = constantPoolOffsets[u2At(4)] - structOffset;
		signature = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
	}
	return signature;
}
/**
 * Return a wrapper that contains the constant of the field.
 * Throws a java.ibm.compiler.java.classfmt.ClassFormatException in case the signature is 
 * incompatible with the constant tag.
 * 
 * @exception java.ibm.compiler.java.classfmt.ClassFormatException
 * @return java.lang.Object
 */
public Object getWrappedConstantValue() throws ClassFormatException {

	int attributesCount = u2At(6);
	int readOffset = 8;
	for (int i = 0; i < attributesCount; i++) {
		int utf8Offset = constantPoolOffsets[u2At(8)] - structOffset;
		char[] attributeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
		if (CharOperation
			.equals(attributeName, ConstantValueName)) {
			// read the right constant
			int relativeOffset = constantPoolOffsets[u2At(14)] - structOffset;
			switch (u1At(relativeOffset)) {
				case IntegerTag :
					return new Integer(i4At(relativeOffset + 1));
				case FloatTag :
					return new Float(floatAt(relativeOffset + 1));
				case DoubleTag :
					return new Double(doubleAt(relativeOffset + 1));
				case LongTag :
					return new Long(i8At(relativeOffset + 1));
				case StringTag :
					utf8Offset = constantPoolOffsets[u2At(relativeOffset + 1)] - structOffset;
					return String.valueOf(utf8At(utf8Offset + 3, u2At(utf8Offset + 1)));
			}
		}
		readOffset += (6 + u4At(readOffset + 2));
	}
	return null;
}
/**
 * Return true if the field has a constant value attribute, false otherwise.
 * @return boolean
 */
public boolean hasConstant() {
	int attributesCount = u2At(6);
	int readOffset = 8;
	boolean isConstant = false;
	for (int i = 0; i < attributesCount; i++) {
		int utf8Offset = constantPoolOffsets[u2At(8)] - structOffset;
		char[] attributeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
		if (CharOperation.equals(attributeName, ConstantValueName)) {
			isConstant = true;
		}
		readOffset += (6 + u4At(readOffset + 2));
	}
	return isConstant;
}
/**
 * Return true if the field is a synthetic field, false otherwise.
 * @return boolean
 */
private boolean isSynthetic() {
	int attributesCount = u2At(6);
	int readOffset = 8;
	boolean isSynthetic = false;
	for (int i = 0; i < attributesCount; i++) {
		int utf8Offset = constantPoolOffsets[u2At(8)] - structOffset;
		char[] attributeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
		if (CharOperation.equals(attributeName, SyntheticName)) {
			isSynthetic = true;
		}
		readOffset += (6 + u4At(readOffset + 2));
	}
	return isSynthetic;
}
private void readConstantAttribute() {
	int attributesCount = u2At(6);
	int readOffset = 8;
	boolean isConstant = false;
	for (int i = 0; i < attributesCount; i++) {
		int utf8Offset = constantPoolOffsets[u2At(8)] - structOffset;
		char[] attributeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
		if (CharOperation
			.equals(attributeName, ConstantValueName)) {
			isConstant = true;
			// read the right constant
			int relativeOffset = constantPoolOffsets[u2At(14)] - structOffset;
			switch (u1At(relativeOffset)) {
				case IntegerTag :
					char[] sign = getTypeName();
					if (sign.length == 1) {
						switch (sign[0]) {
							case 'Z' : // boolean constant
								constant = new BooleanConstant(i4At(relativeOffset + 1) == 1);
								break;
							case 'I' : // integer constant
								constant = new IntConstant(i4At(relativeOffset + 1));
								break;
							case 'C' : // char constant
								constant = new CharConstant((char) i4At(relativeOffset + 1));
								break;
							case 'B' : // byte constant
								constant = new ByteConstant((byte) i4At(relativeOffset + 1));
								break;
							case 'S' : // short constant
								constant = new ShortConstant((short) i4At(relativeOffset + 1));
								break;
							default:
								constant = Constant.NotAConstant;                   
						}
					} else {
						constant = Constant.NotAConstant;
					}
					break;
				case FloatTag :
					constant = new FloatConstant(floatAt(relativeOffset + 1));
					break;
				case DoubleTag :
					constant = new DoubleConstant(doubleAt(relativeOffset + 1));
					break;
				case LongTag :
					constant = new LongConstant(i8At(relativeOffset + 1));
					break;
				case StringTag :
					utf8Offset = constantPoolOffsets[u2At(relativeOffset + 1)] - structOffset;
					constant = 
						new StringConstant(
							String.valueOf(utf8At(utf8Offset + 3, u2At(utf8Offset + 1)))); 
					break;
			}
		}
		readOffset += (6 + u4At(readOffset + 2));
	}
	if (!isConstant) {
		constant = Constant.NotAConstant;
	}
}
private void readDeprecatedAttributes() {
	int attributesCount = u2At(6);
	int readOffset = 8;
	for (int i = 0; i < attributesCount; i++) {
		int utf8Offset = constantPoolOffsets[u2At(readOffset)] - structOffset;
		char[] attributeName = utf8At(utf8Offset + 3, u2At(utf8Offset + 1));
		if (CharOperation.equals(attributeName, DeprecatedName)) {
			isDeprecated = true;
		}
		readOffset += (6 + u4At(readOffset + 2));
	}
}
/**
 * Answer the size of the receiver in bytes.
 * 
 * @return int
 */
public int sizeInBytes() {
	return attributeBytes;
}
public void throwFormatException() throws ClassFormatException {
	throw new ClassFormatException(ClassFormatException.ErrBadFieldInfo);
}
public String toString() {
	StringBuffer buffer = new StringBuffer(this.getClass().getName());
	int modifiers = getModifiers();
	return buffer
		.append("{"/*nonNLS*/)
		.append(
			((modifiers & AccDeprecated) != 0 ? "deprecated "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0001) == 1 ? "public "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0002) == 0x0002 ? "private "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0004) == 0x0004 ? "protected "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0008) == 0x000008 ? "static "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0010) == 0x0010 ? "final "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0040) == 0x0040 ? "volatile "/*nonNLS*/ : ""/*nonNLS*/)
				+ ((modifiers & 0x0080) == 0x0080 ? "transient "/*nonNLS*/ : ""/*nonNLS*/))
		.append(getTypeName())
		.append(" "/*nonNLS*/)
		.append(getName())
		.append(" "/*nonNLS*/)
		.append(getConstant())
		.append("}"/*nonNLS*/)
		.toString(); 
}
}