/*
 * 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.
 
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.
/**
 * 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;
}