package org.aspectj.apache.bcel.classfile;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import org.aspectj.apache.bcel.Constants;

public class AttributeUtils {

    public static Attribute[] readAttributes(DataInputStream dataInputstream, ConstantPool cpool) {
	    try {
		    int length = dataInputstream.readUnsignedShort();
		    if (length==0) return Attribute.NoAttributes;
		    Attribute[] attrs       = new Attribute[length];
		    for (int i=0; i < length; i++)
			    attrs[i] = Attribute.readAttribute(dataInputstream, cpool);
		    return attrs;
	    } catch (IOException e) {
		    throw new ClassFormatException("IOException whilst reading set of attributes: "+e.toString());
	    }
    }
	  
	/** Write (serialize) a set of attributes into a specified output stream */
	public static void writeAttributes(Attribute[] attributes,DataOutputStream file) throws IOException {
		if (attributes==null) {
			file.writeShort(0);
		} else {
			file.writeShort(attributes.length);
	        for(int i=0; i < attributes.length; i++)
	          attributes[i].dump(file);
		}
	}

	public static Attribute[] copy(Attribute[] attributes, ConstantPool constant_pool) {
		if (attributes==null || attributes.length==0) return Attribute.NoAttributes;
		Attribute[] attrs = new Attribute[attributes.length];
		for (int i = 0; i < attributes.length; i++) {
			attrs[i] = attributes[i].copy(constant_pool);			
		}
		return attrs;
	}

	public static Signature getSignatureAttribute(Attribute[] attributes) {
	    for(int i=0; i < attributes.length; i++) {
	      if (attributes[i].tag==Constants.ATTR_SIGNATURE) return ((Signature)attributes[i]);
	    }
		return null;
	}

	public static Code getCodeAttribute(Attribute[] attributes) {
	    for(int i=0; i < attributes.length; i++) {
		      if (attributes[i].tag==Constants.ATTR_CODE) { return ((Code)attributes[i]);}
	    }
		return null;
	}

	public static ExceptionTable getExceptionTableAttribute(Attribute[] attributes) {
	    for(int i=0; i < attributes.length; i++) {
		      if (attributes[i].tag==Constants.ATTR_EXCEPTIONS) { return ((ExceptionTable)attributes[i]);}
	    }
		return null;
	}

	public static ConstantValue getConstantValueAttribute(Attribute[] attributes) {
	    for(int i=0; i < attributes.length; i++) {
	        if(attributes[i].getTag() == Constants.ATTR_CONSTANT_VALUE) return (ConstantValue)attributes[i];
		} 
		return null;
	}

	public static void accept(Attribute[] attributes,ClassVisitor visitor) {
		for(int i=0; i < attributes.length; i++)
			attributes[i].accept(visitor);
	}

	public static boolean hasSyntheticAttribute(Attribute[] attributes) {
		for (int i = 0; i < attributes.length; i++) {
			if (attributes[i].tag==Constants.ATTR_SYNTHETIC) {
				return true;
			}
		}
		return false;
	}

	public static SourceFile getSourceFileAttribute(Attribute[] attributes) {
	    for(int i=0; i < attributes.length; i++) {
		      if (attributes[i].tag==Constants.ATTR_SOURCE_FILE) { return ((SourceFile)attributes[i]);}
	    }
		return null;
	}

}