/*

 * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.tools.classfile;

import java.io.IOException;

/**

 * See JVMS, section 4.4.

 *

 *  <p><b>This is NOT part of any supported API.

 *  If you write code that depends on this, you do so at your own risk.

 *  This code and its internal interfaces are subject to change or

 *  deletion without notice.</b>

 */

public class Descriptor {

    public static class InvalidDescriptor extends DescriptorException {

        private static final long serialVersionUID = 1L;

        InvalidDescriptor(String desc) {

            this.desc = desc;

            this.index = -1;

        }

        InvalidDescriptor(String desc, int index) {

            this.desc = desc;

            this.index = index;

        }

        @Override

        public String getMessage() {

            // i18n

            if (index == -1)

                return "invalid descriptor \"" + desc + "\"";

            else

                return "descriptor is invalid at offset " + index + " in \"" + desc + "\"";

        }

        public final String desc;

        public final int index;

    }

    public Descriptor(ClassReader cr) throws IOException {

        this(cr.readUnsignedShort());

    }

    public Descriptor(int index) {

        this.index = index;

    }

    public String getValue(ConstantPool constant_pool) throws ConstantPoolException {

        return constant_pool.getUTF8Value(index);

    }

    public int getParameterCount(ConstantPool constant_pool)

            throws ConstantPoolException, InvalidDescriptor {

        String desc = getValue(constant_pool);

        int end = desc.indexOf(")");

        if (end == -1)

            throw new InvalidDescriptor(desc);

        parse(desc, 0, end + 1);

        return count;

    }

    public String getParameterTypes(ConstantPool constant_pool)

            throws ConstantPoolException, InvalidDescriptor {

        String desc = getValue(constant_pool);

        int end = desc.indexOf(")");

        if (end == -1)

            throw new InvalidDescriptor(desc);

        return parse(desc, 0, end + 1);

    }

    public String getReturnType(ConstantPool constant_pool)

            throws ConstantPoolException, InvalidDescriptor {

        String desc = getValue(constant_pool);

        int end = desc.indexOf(")");

        if (end == -1)

            throw new InvalidDescriptor(desc);

        return parse(desc, end + 1, desc.length());

    }

    public String getFieldType(ConstantPool constant_pool)

            throws ConstantPoolException, InvalidDescriptor {

        String desc = getValue(constant_pool);

        return parse(desc, 0, desc.length());

    }

    private String parse(String desc, int start, int end)

            throws InvalidDescriptor {

        int p = start;

        StringBuilder sb = new StringBuilder();

        int dims = 0;

        count = 0;

        while (p < end) {

            String type;

            char ch;

            switch (ch = desc.charAt(p++)) {

                case '(':

                    sb.append('(');

                    continue;

                case ')':

                    sb.append(')');

                    continue;

                case '[':

                    dims++;

                    continue;

                case 'B':

                    type = "byte";

                    break;

                case 'C':

                    type = "char";

                    break;

                case 'D':

                    type = "double";

                    break;

                case 'F':

                    type = "float";

                    break;

                case 'I':

                    type = "int";

                    break;

                case 'J':

                    type = "long";

                    break;

                case 'L':

                    int sep = desc.indexOf(';', p);

                    if (sep == -1)

                        throw new InvalidDescriptor(desc, p - 1);

                    type = desc.substring(p, sep).replace('/', '.');

                    p = sep + 1;

                    break;

                case 'S':

                    type = "short";

                    break;

                case 'Z':

                    type = "boolean";

                    break;

                case 'V':

                    type = "void";

                    break;

                default:

                    throw new InvalidDescriptor(desc, p - 1);

            }

            if (sb.length() > 1 && sb.charAt(0) == '(')

                sb.append(", ");

            sb.append(type);

            for ( ; dims > 0; dims-- )

                sb.append("[]");

            count++;

        }

        return sb.toString();

    }

    public final int index;

    private int count;

}