001/*
002 * BridJ - Dynamic and blazing-fast native interop for Java.
003 * http://bridj.googlecode.com/
004 *
005 * Copyright (c) 2010-2013, Olivier Chafik (http://ochafik.com/)
006 * All rights reserved.
007 *
008 * Redistribution and use in source and binary forms, with or without
009 * modification, are permitted provided that the following conditions are met:
010 * 
011 *     * Redistributions of source code must retain the above copyright
012 *       notice, this list of conditions and the following disclaimer.
013 *     * Redistributions in binary form must reproduce the above copyright
014 *       notice, this list of conditions and the following disclaimer in the
015 *       documentation and/or other materials provided with the distribution.
016 *     * Neither the name of Olivier Chafik nor the
017 *       names of its contributors may be used to endorse or promote products
018 *       derived from this software without specific prior written permission.
019 * 
020 * THIS SOFTWARE IS PROVIDED BY OLIVIER CHAFIK AND CONTRIBUTORS ``AS IS'' AND ANY
021 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
022 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
023 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS BE LIABLE FOR ANY
024 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
025 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
026 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
027 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
028 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
029 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
030 */
031package org.bridj.ann;
032
033import java.lang.annotation.ElementType;
034import java.lang.annotation.Retention;
035import java.lang.annotation.RetentionPolicy;
036import java.lang.annotation.Target;
037
038/**
039 * Indicate the index of a structure field (in Java, the order of methods and
040 * fields is unspecified so you need to order them explicitely).<br>
041 * For C++ structs, the index is absolute : it must take into account the fields
042 * in parent classes (unlike {@link Virtual}, which virtual table offset is
043 * relative to the declared class).
044 *
045 * @author ochafik
046 */
047@Retention(RetentionPolicy.RUNTIME)
048@Target({ElementType.FIELD, ElementType.METHOD})
049public @interface Field {
050
051    /**
052     * Index of the field in a struct (first field has index 0).<br>
053     * Fields of parent structures must be taken into account (if parent struct
054     * has 2 fields, first field of sub-struct has index 2).<br>
055     * If more than one field are given the same index, this will produce an
056     * union at that index.
057     */
058    int value();
059
060    /**
061     * Absolute index of the field from the start of the struct
062     */
063    //int offset() default Integer.MIN_VALUE;
064    /**
065     * Declare that this field shares its space with another (the two or more
066     * fields are in an union).<br>
067     * The unionWith index must be the index of the first field of the union.
068     */
069    int unionWith() default -1;
070}