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package org.graalvm.nativeimage;

import org.graalvm.nativeimage.impl.UnmanagedMemorySupport;
import org.graalvm.word.PointerBase;
import org.graalvm.word.UnsignedWord;
import org.graalvm.word.WordFactory;

Contains static methods that allow allocate/free of unmanaged memory, i.e., memory that is not
under the control of the garbage collector. In a typical C environment, these are the malloc/free
functions of the standard C library, however this class makes no assumptions or guarantees about
how the memory is managed. In particular, it is not allowed to free memory returned by these
allocation function directly using the standard C library (or vice versa).
Since:
19.0/**
 * Contains static methods that allow allocate/free of unmanaged memory, i.e., memory that is not
 * under the control of the garbage collector. In a typical C environment, these are the malloc/free
 * functions of the standard C library, however this class makes no assumptions or guarantees about
 * how the memory is managed. In particular, it is not allowed to free memory returned by these
 * allocation function directly using the standard C library (or vice versa).
 *
 * @since 19.0
 */
public final class UnmanagedMemory {

    private UnmanagedMemory() {
    }

    
Allocates size bytes of unmanaged memory. The content of the memory is undefined. 
 If size is 0, the method is allowed but not required to return the null pointer. This method never returns a the null pointer, but instead throws a OutOfMemoryError when allocation fails. 
Since:
19.0/**
     * Allocates {@code size} bytes of unmanaged memory. The content of the memory is undefined.
     * <p>
     * If {@code size} is 0, the method is allowed but not required to return the null pointer. This
     * method never returns a the null pointer, but instead throws a {@link OutOfMemoryError} when
     * allocation fails.
     *
     * @since 19.0
     */
    public static <T extends PointerBase> T malloc(UnsignedWord size) {
        T result = ImageSingletons.lookup(UnmanagedMemorySupport.class).malloc(size);
        if (result.isNull()) {
            throw new OutOfMemoryError("malloc of unmanaged memory");
        }
        return result;
    }

    
Allocates size bytes of unmanaged memory. The content of the memory is undefined. 
 If size is 0, the method is allowed but not required to return the null pointer. This method never returns a the null pointer, but instead throws a OutOfMemoryError when allocation fails. 
Since:
19.0/**
     * Allocates {@code size} bytes of unmanaged memory. The content of the memory is undefined.
     * <p>
     * If {@code size} is 0, the method is allowed but not required to return the null pointer. This
     * method never returns a the null pointer, but instead throws a {@link OutOfMemoryError} when
     * allocation fails.
     *
     * @since 19.0
     */
    public static <T extends PointerBase> T malloc(int size) {
        return malloc(WordFactory.unsigned(size));
    }

    
Allocates size bytes of unmanaged memory. The content of the memory is set to 0. 
 If size is 0, the method is allowed but not required to return the null pointer. This method never returns a the null pointer, but instead throws a OutOfMemoryError when allocation fails. 
Since:
19.0/**
     * Allocates {@code size} bytes of unmanaged memory. The content of the memory is set to 0.
     * <p>
     * If {@code size} is 0, the method is allowed but not required to return the null pointer. This
     * method never returns a the null pointer, but instead throws a {@link OutOfMemoryError} when
     * allocation fails.
     *
     * @since 19.0
     */
    public static <T extends PointerBase> T calloc(UnsignedWord size) {
        T result = ImageSingletons.lookup(UnmanagedMemorySupport.class).calloc(size);
        if (result.isNull()) {
            throw new OutOfMemoryError("calloc of unmanaged memory");
        }
        return result;
    }

    
Allocates size bytes of unmanaged memory. The content of the memory is set to 0. 
 If size is 0, the method is allowed but not required to return the null pointer. This method never returns a the null pointer, but instead throws a OutOfMemoryError when allocation fails. 
Since:
19.0/**
     * Allocates {@code size} bytes of unmanaged memory. The content of the memory is set to 0.
     * <p>
     * If {@code size} is 0, the method is allowed but not required to return the null pointer. This
     * method never returns a the null pointer, but instead throws a {@link OutOfMemoryError} when
     * allocation fails.
     *
     * @since 19.0
     */
    public static <T extends PointerBase> T calloc(int size) {
        return calloc(WordFactory.unsigned(size));
    }

    
Changes the size of the provided unmanaged memory to size bytes of unmanaged memory. If the new size is larger than the old size, the content of the additional memory is undefined. 
 If size is 0, the method is allowed but not required to return the null pointer. This method never returns a the null pointer, but instead throws a OutOfMemoryError when allocation fails. 
Since:
19.0/**
     * Changes the size of the provided unmanaged memory to {@code size} bytes of unmanaged memory.
     * If the new size is larger than the old size, the content of the additional memory is
     * undefined.
     * <p>
     * If {@code size} is 0, the method is allowed but not required to return the null pointer. This
     * method never returns a the null pointer, but instead throws a {@link OutOfMemoryError} when
     * allocation fails.
     *
     * @since 19.0
     */
    public static <T extends PointerBase> T realloc(T ptr, UnsignedWord size) {
        T result = ImageSingletons.lookup(UnmanagedMemorySupport.class).realloc(ptr, size);
        if (result.isNull()) {
            throw new OutOfMemoryError("realloc of unmanaged memory");
        }
        return result;
    }

    
Frees unmanaged memory that was previously allocated using methods of this class.
Since:
19.0/**
     * Frees unmanaged memory that was previously allocated using methods of this class.
     *
     * @since 19.0
     */
    public static void free(PointerBase ptr) {
        ImageSingletons.lookup(UnmanagedMemorySupport.class).free(ptr);
    }
}