io.datakernel.codegen.PredicateDefCmp.java Source code

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Here is the source code for io.datakernel.codegen.PredicateDefCmp.java

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/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * 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 io.datakernel.codegen;

import io.datakernel.codegen.utils.Preconditions;
import org.objectweb.asm.Label;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.GeneratorAdapter;
import org.objectweb.asm.commons.Method;

import static io.datakernel.codegen.PredicateDefCmp.Operation.*;
import static io.datakernel.codegen.Utils.isPrimitiveType;
import static org.objectweb.asm.Type.BOOLEAN_TYPE;
import static org.objectweb.asm.Type.INT_TYPE;

/**
 * Defines methods for comparing functions
 */
public final class PredicateDefCmp implements PredicateDef {
    private Expression left;
    private Expression right;
    private Operation operation = EQ;

    public enum Operation {
        EQ(GeneratorAdapter.EQ, "=="), NE(GeneratorAdapter.NE, "!="), LT(GeneratorAdapter.LT,
                "<"), GT(GeneratorAdapter.GT, ">"), LE(GeneratorAdapter.LE, "<="), GE(GeneratorAdapter.GE, ">=");

        private final int opCode;
        private final String symbol;

        Operation(int opCode, String symbol) {
            this.opCode = opCode;
            this.symbol = symbol;
        }

        public static Operation operation(String symbol) {
            for (Operation operation : values()) {
                if (operation.symbol.equals(symbol)) {
                    return operation;
                }
            }
            throw new IllegalArgumentException();
        }
    }

    PredicateDefCmp(Operation operation, Expression left, Expression right) {
        this.left = left;
        this.right = right;
        this.operation = operation;
    }

    @Override
    public final Type type(Context ctx) {
        return BOOLEAN_TYPE;
    }

    @Override
    public Type load(Context ctx) {
        GeneratorAdapter g = ctx.getGeneratorAdapter();
        Label labelTrue = new Label();
        Label labelExit = new Label();

        Type leftFieldType = left.type(ctx);
        Preconditions.check(leftFieldType.equals(right.type(ctx)));
        left.load(ctx);
        right.load(ctx);

        if (isPrimitiveType(leftFieldType)) {
            g.ifCmp(leftFieldType, operation.opCode, labelTrue);
        } else {
            if (operation == EQ || operation == NE) {
                g.invokeVirtual(leftFieldType,
                        new Method("equals", BOOLEAN_TYPE, new Type[] { Type.getType(Object.class) }));
                g.push(operation == EQ);
                g.ifCmp(BOOLEAN_TYPE, GeneratorAdapter.EQ, labelTrue);
            } else {
                g.invokeVirtual(leftFieldType,
                        new Method("compareTo", INT_TYPE, new Type[] { Type.getType(Object.class) }));
                if (operation == LT) {
                    g.ifZCmp(GeneratorAdapter.LT, labelTrue);
                } else if (operation == GT) {
                    g.ifZCmp(GeneratorAdapter.GT, labelTrue);
                } else if (operation == LE) {
                    g.ifZCmp(GeneratorAdapter.LE, labelTrue);
                } else if (operation == GE) {
                    g.ifZCmp(GeneratorAdapter.GE, labelTrue);
                }
            }
        }

        g.push(false);
        g.goTo(labelExit);

        g.mark(labelTrue);
        g.push(true);

        g.mark(labelExit);

        return BOOLEAN_TYPE;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o)
            return true;
        if (o == null || getClass() != o.getClass())
            return false;

        PredicateDefCmp that = (PredicateDefCmp) o;

        if (left != null ? !left.equals(that.left) : that.left != null)
            return false;
        if (operation != that.operation)
            return false;
        if (right != null ? !right.equals(that.right) : that.right != null)
            return false;

        return true;
    }

    @Override
    public int hashCode() {
        int result = left != null ? left.hashCode() : 0;
        result = 31 * result + (right != null ? right.hashCode() : 0);
        result = 31 * result + (operation != null ? operation.hashCode() : 0);
        return result;
    }

    public int getOperationOpCode() {
        return operation.opCode;
    }
}