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95 lines
3.7 KiB
Java
95 lines
3.7 KiB
Java
/*
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* Copyright (c) 2019, 2025, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.lang.invoke;
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import java.lang.foreign.MemoryLayout;
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import java.lang.foreign.MemorySegment;
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import java.util.Objects;
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import jdk.internal.foreign.AbstractMemorySegmentImpl;
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import jdk.internal.misc.ScopedMemoryAccess;
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import jdk.internal.vm.annotation.ForceInline;
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/**
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* A var handle that accesses primitive values in a memory segment.
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*/
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final class SegmentVarHandle extends VarHandle {
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// Common implementation fields for the VarForms
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static final boolean BE = MethodHandleStatics.UNSAFE.isBigEndian();
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static final ScopedMemoryAccess SCOPED_MEMORY_ACCESS = ScopedMemoryAccess.getScopedMemoryAccess();
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/** endianness **/
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final boolean be;
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/** The layout the accessed segment must be compatible with. */
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final MemoryLayout enclosing;
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/** The offset value, if is constant. vform decides if offset is constant or variable. */
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final long offset;
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SegmentVarHandle(VarForm form, boolean be, MemoryLayout enclosing, long offset, boolean exact) {
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super(form, exact);
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this.be = be;
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this.enclosing = enclosing;
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this.offset = offset;
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}
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@Override
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final MethodType accessModeTypeUncached(VarHandle.AccessType accessType) {
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var getType = vform.methodType_table[0]; // erased, but our value type is erase-compatible
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return getType.parameterCount() == 2
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? accessType.accessModeType(MemorySegment.class, getType.returnType(), long.class)
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: accessType.accessModeType(MemorySegment.class, getType.returnType(), long.class, long.class);
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}
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@Override
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public SegmentVarHandle withInvokeExactBehavior() {
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return hasInvokeExactBehavior() ?
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this :
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new SegmentVarHandle(vform, be, enclosing, offset, true);
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}
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@Override
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public SegmentVarHandle withInvokeBehavior() {
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return !hasInvokeExactBehavior() ?
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this :
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new SegmentVarHandle(vform, be, enclosing, offset, false);
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}
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// Common implementation methods for the VarForms
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@ForceInline
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static long offset(AbstractMemorySegmentImpl bb, long base, long offset) {
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long segment_base = bb.unsafeGetOffset();
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return segment_base + base + offset;
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}
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@ForceInline
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AbstractMemorySegmentImpl checkSegment(Object obb, long base, boolean ro) {
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AbstractMemorySegmentImpl oo = (AbstractMemorySegmentImpl) Objects.requireNonNull(obb);
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oo.checkEnclosingLayout(base, this.enclosing, ro);
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return oo;
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}
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}
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