package org.aspectj.apache.bcel.classfile;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  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. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

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

import org.apache.bcel.Constants;

/**
 * This class is derived from <em>Attribute</em> and represents a reference to
 * a <href="http://wwwipd.ira.uka.de/~pizza/gj/">GJ</a> attribute.
 * 
 * @version $Id: Signature.java,v 1.2 2006-07-05 15:22:56 ebruneton Exp $
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @see Attribute
 */
public final class Signature extends Attribute {
    private int signature_index;

    /**
     * Initialize from another object. Note that both objects use the same
     * references (shallow copy). Use clone() for a physical copy.
     * 
     * @param c
     */
    public Signature(final Signature c) {
        this(c.getNameIndex(),
                c.getLength(),
                c.getSignatureIndex(),
                c.getConstantPool());
    }

    /**
     * Construct object from file stream.
     * 
     * @param name_index Index in constant pool to CONSTANT_Utf8
     * @param length Content length in bytes
     * @param file Input stream
     * @param constant_pool Array of constants
     * @throws IOException
     */
    Signature(
        final int name_index,
        final int length,
        final DataInputStream file,
        final ConstantPool constant_pool) throws IOException
    {
        this(name_index, length, file.readUnsignedShort(), constant_pool);
    }

    /**
     * @param name_index Index in constant pool to CONSTANT_Utf8
     * @param length Content length in bytes
     * @param constant_pool Array of constants
     * @param signature_index Index in constant pool to CONSTANT_Utf8
     */
    public Signature(
        final int name_index,
        final int length,
        final int signature_index,
        final ConstantPool constant_pool)
    {
        super(Constants.ATTR_SIGNATURE, name_index, length, constant_pool);
        this.signature_index = signature_index;
    }

    /**
     * Called by objects that are traversing the nodes of the tree implicitely
     * defined by the contents of a Java class. I.e., the hierarchy of methods,
     * fields, attributes, etc. spawns a tree of objects.
     * 
     * @param v Visitor object
     */
    @Override
    public void accept(final Visitor v) {
        // System.err.println("Visiting non-standard Signature object");
        // v.visitSignature(this);
    }

    /**
     * Dump source file attribute to file stream in binary format.
     * 
     * @param file Output file stream
     * @throws IOException
     */
    @Override
    public final void dump(final DataOutputStream file) throws IOException {
        super.dump(file);
        file.writeShort(signature_index);
    }

    /**
     * @return Index in constant pool of source file name.
     */
    public final int getSignatureIndex() {
        return signature_index;
    }

    /**
     * @param signature_index
     */
    public final void setSignatureIndex(final int signature_index) {
        this.signature_index = signature_index;
    }

    /**
     * @return GJ signature.
     */
    public final String getSignature() {
        ConstantUtf8 c = (ConstantUtf8) constant_pool.getConstant(signature_index,
                Constants.CONSTANT_Utf8);
        return c.getBytes();
    }

    /**
     * Extends ByteArrayInputStream to make 'unreading' chars possible.
     */
    private static final class MyByteArrayInputStream extends
            ByteArrayInputStream
    {
        MyByteArrayInputStream(final String data) {
            super(data.getBytes());
        }

        final int mark() {
            return pos;
        }

        final String getData() {
            return new String(buf);
        }

        final void reset(final int p) {
            pos = p;
        }

        final void unread() {
            if (pos > 0) {
                pos--;
            }
        }
    }

    private static boolean identStart(final int ch) {
        return ch == 'T' || ch == 'L';
    }

    // private static boolean identPart(int ch) {
    // return ch == '/' || ch == ';';
    // }

    private static final void matchIdent(
        final MyByteArrayInputStream in,
        final StringBuffer buf)
    {
        int ch;

        if ((ch = in.read()) == -1) {
            throw new RuntimeException("Illegal signature: " + in.getData()
                    + " no ident, reaching EOF");
        }

        // System.out.println("return from ident:" + (char)ch);

        if (!identStart(ch)) {
            StringBuffer buf2 = new StringBuffer();

            int count = 1;
            while (Character.isJavaIdentifierPart((char) ch)) {
                buf2.append((char) ch);
                count++;
                ch = in.read();
            }

            if (ch == ':') { // Ok, formal parameter
                in.skip("Ljava/lang/Object".length());
                buf.append(buf2);

                ch = in.read();
                in.unread();
                // System.out.println("so far:" + buf2 + ":next:" +(char)ch);
            } else {
                for (int i = 0; i < count; i++) {
                    in.unread();
                }
            }

            return;
        }

        StringBuffer buf2 = new StringBuffer();
        ch = in.read();

        do {
            buf2.append((char) ch);
            ch = in.read();
            // System.out.println("within ident:"+ (char)ch);

        } while (ch != -1
                && (Character.isJavaIdentifierPart((char) ch) || ch == '/'));

        buf.append(buf2.toString().replace('/', '.'));

        // System.out.println("regular return ident:"+ (char)ch + ":" + buf2);

        if (ch != -1) {
            in.unread();
        }
    }

    private static final void matchGJIdent(
        final MyByteArrayInputStream in,
        final StringBuffer buf)
    {
        int ch;

        matchIdent(in, buf);

        ch = in.read();
        if (ch == '<' || ch == '(') { // Parameterized or method
            // System.out.println("Enter <");
            buf.append((char) ch);
            matchGJIdent(in, buf);

            while ((ch = in.read()) != '>' && ch != ')') { // List of
                // parameters
                if (ch == -1) {
                    throw new RuntimeException("Illegal signature: "
                            + in.getData() + " reaching EOF");
                }

                // System.out.println("Still no >");
                buf.append(", ");
                in.unread();
                matchGJIdent(in, buf); // Recursive call
            }

            // System.out.println("Exit >");

            buf.append((char) ch);
        } else {
            in.unread();
        }

        ch = in.read();
        if (identStart(ch)) {
            in.unread();
            matchGJIdent(in, buf);
        } else if (ch == ')') {
            in.unread();
            return;
        } else if (ch != ';') {
            throw new RuntimeException("Illegal signature: " + in.getData()
                    + " read " + (char) ch);
        }
    }

    public static String translate(final String s) {
        // System.out.println("Sig:" + s);
        StringBuffer buf = new StringBuffer();

        matchGJIdent(new MyByteArrayInputStream(s), buf);

        return buf.toString();
    }

    public static final boolean isFormalParameterList(final String s) {
        return s.startsWith("<") && s.indexOf(':') > 0;
    }

    public static final boolean isActualParameterList(final String s) {
        return s.startsWith("L") && s.endsWith(">;");
    }

    /**
     * @return String representation
     */
    @Override
    public final String toString() {
        String s = getSignature();

        return "Signature(" + s + ")";
    }

    /**
     * @param constant_pool
     * @return deep copy of this attribute
     */
    @Override
    public Attribute copy(final ConstantPool constant_pool) {
        return (Signature) clone();
    }
}