org.graalvm.nativeimage.c.struct.CPointerTo Maven / Gradle / Ivy
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* 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.
*
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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.PointerBase;
import org.graalvm.word.WordBase;
/**
* Denotes Java interface that imports a C pointer type. The interface must extend
* {@link PointerBase}, i.e., it is a word type. There is never a Java class that implements the
* interface.
*
* If the method has a non-void return type that is not the annotated interface, it is a read-method
* of the pointer. Calls of the method are replaced with a memory read. The possible signatures are
* {@code ValueType read([IntType index], [LocationIdentity locationIdentity]);}
*
* If the method has the return type void, it is a write-method of the pointer. Calls of the method
* are replaced with a memory write. The possible signatures are
* {@code void write([IntType index], ValueType value, [LocationIdentity locationIdentity]);}
*
* If the return type of the method is the annotated interface, it is an address computation for an
* array access. Calls of the method are replaced with address arithmetic. The possible signatures
* are {@code PointerType addressOf(IntType index);}
*
* The receiver is the pointer that is accessed, i.e., the base address of the memory access.
*
* The {@code ValueType} must be the Java-equivalent of the C type used in the pointer definition.
*
* 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 pointers. 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 value type.
*
* 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.
*/
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface CPointerTo {
/**
* The value type, as a reference to a Java interface that is either annotated with
* {@link CStruct} or {@link CPointerTo}.
*
* Exactly one of the properties {@link #value()} and {@link CPointerTo#nameOfCType()} must be
* specified.
*/
Class value() default WordBase.class;
/**
* The value type, as C type name.
*
* Exactly one of the properties {@link #value()} and {@link CPointerTo#nameOfCType()} must be
* specified.
*/
String nameOfCType() default "";
}