org.graalvm.nativeimage.c.struct.CField Maven / Gradle / Ivy
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/*
* Copyright (c) 2013, 2017, 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
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package org.graalvm.nativeimage.c.struct;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.graalvm.word.LocationIdentity;
import org.graalvm.word.WordBase;
/**
* Denotes a method as a field access of a {@link CStruct C struct}.
*
* If the method has a non-void return type, it is a get-method of the field. Calls of the method
* are replaced with a memory read. The possible signatures are
* {@code FieldType getFieldName([IntType index], [LocationIdentity locationIdentity]);}
*
* If the method has the return type void, it is a set-method of the field. Calls of the method are
* replaced with a memory write. The possible signatures are
* {@code void setFieldName([IntType index], FieldType value, [LocationIdentity locationIdentity]);}
*
* The receiver is the pointer to the struct that is accessed, i.e., the base address of the memory
* access.
*
* The {@code FieldType} must be the Java-equivalent of the C type used in the C struct. The
* additional annotations {@link AllowNarrowingCast} or {@link AllowWideningCast} can be used to
* relax the strict type requirements.
*
* The optional parameter {@code index} (always the first parameter when it is present) denotes an
* index, i.e., the receiver is treated as an array of the struct. The type must be a primitive
* integer type or a {@link WordBase word type}. Address arithmetic is used to scale the index with
* the size of the struct.
*
* The optional parameter {@code locationIdentity} specifies the {@link LocationIdentity} to be used
* for the memory access. Two memory accesses with two different location identities are guaranteed
* to not alias. The parameter cannot be used together with the {@link UniqueLocationIdentity}
* annotation, which is another way of providing a location identity for the memory access.
*
* Multiple accessor methods, with different signatures according to the rules of allowed
* signatures, are allowed for a single field.
*
* @since 1.0
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface CField {
/**
* Specifies the field name inside the {@link CStruct C struct}. If no name is provided, the
* method name is used as the field name. A possible "get" or "set" prefix of the method name is
* removed.
*
* @since 1.0
*/
String value() default "";
}