Add Negation (#1804)

Author: yukoba

byte-buddy-dep/src/main/java/net/bytebuddy/implementation/bytecode/Negation.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2014 - Present Rafael Winterhalter
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.bytebuddy.implementation.bytecode;
+
+import net.bytebuddy.implementation.Implementation;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+/**
+ * A stack manipulation that negates a number on the operand stack.
+ */
+public enum Negation implements StackManipulation {
+
+    /**
+     * Negates an integer or an integer-compatible value.
+     */
+    INTEGER(Opcodes.INEG),
+
+    /**
+     * Negates a long.
+     */
+    LONG(Opcodes.LNEG),
+
+    /**
+     * Negates a float.
+     */
+    FLOAT(Opcodes.FNEG),
+
+    /**
+     * Negates a double.
+     */
+    DOUBLE(Opcodes.DNEG);
+
+    /**
+     * The opcode to apply.
+     */
+    private final int opcode;
+
+    /**
+     * Creates a new negation.
+     *
+     * @param opcode The opcode to apply.
+     */
+    Negation(int opcode) {
+        this.opcode = opcode;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public boolean isValid() {
+        return true;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public Size apply(MethodVisitor methodVisitor, Implementation.Context implementationContext) {
+        methodVisitor.visitInsn(opcode);
+        return StackManipulation.Size.ZERO;
+    }
+}

byte-buddy-dep/src/test/java/net/bytebuddy/implementation/bytecode/NegationTest.java

@@ -0,0 +1,62 @@
+package net.bytebuddy.implementation.bytecode;
+
+import net.bytebuddy.implementation.Implementation;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.MethodRule;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnit;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+
+@RunWith(Parameterized.class)
+public class NegationTest {
+
+    @Parameterized.Parameters
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][]{
+                {Negation.INTEGER, Opcodes.INEG},
+                {Negation.LONG, Opcodes.LNEG},
+                {Negation.FLOAT, Opcodes.FNEG},
+                {Negation.DOUBLE, Opcodes.DNEG}
+        });
+    }
+
+    private final StackManipulation stackManipulation;
+
+    private final int opcodes;
+
+    public NegationTest(StackManipulation stackManipulation, int opcodes) {
+        this.stackManipulation = stackManipulation;
+        this.opcodes = opcodes;
+    }
+
+    @Rule
+    public MethodRule mockitoRule = MockitoJUnit.rule().silent();
+
+    @Mock
+    private MethodVisitor methodVisitor;
+
+    @Mock
+    private Implementation.Context implementationContext;
+
+    @Test
+    public void testNegation() {
+        StackManipulation.Size size = stackManipulation.apply(methodVisitor, implementationContext);
+        assertThat(size.getMaximalSize(), is(0));
+        assertThat(size.getSizeImpact(), is(0));
+        verify(methodVisitor).visitInsn(opcodes);
+        verifyNoMoreInteractions(methodVisitor);
+        verifyNoMoreInteractions(implementationContext);
+    }
+}