org.formulacompiler.compiler.internal.bytecode.CacheCompiler.java Source code

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Here is the source code for org.formulacompiler.compiler.internal.bytecode.CacheCompiler.java

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/*
 * Copyright (c) 2006-2009 by Abacus Research AG, Switzerland.
 * All rights reserved.
 *
 * This file is part of the Abacus Formula Compiler (AFC).
 *
 * For commercial licensing, please contact sales(at)formulacompiler.com.
 *
 * AFC is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * AFC 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with AFC.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.formulacompiler.compiler.internal.bytecode;

import org.formulacompiler.compiler.CompilerException;
import org.objectweb.asm.ClassWriter;
import org.objectweb.asm.Label;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.commons.GeneratorAdapter;

abstract class CacheCompiler {
    private final SectionCompiler section;
    private final GeneratorAdapter mv;
    private final Type type;
    private final String cachedIndicatorName;
    private final String cacheName;

    CacheCompiler(SectionCompiler _section, GeneratorAdapter _mv, String _baseName, Type _type) {
        this.section = _section;
        this.mv = _mv;
        this.cachedIndicatorName = "h$" + _baseName;
        this.cacheName = "c$" + _baseName;
        this.type = _type;
    }

    abstract void compileValue() throws CompilerException;

    void compile() throws CompilerException {
        // private boolean h$<x>
        cw().visitField(Opcodes.ACC_PRIVATE, this.cachedIndicatorName, Type.BOOLEAN_TYPE.getDescriptor(), null,
                null).visitEnd();

        // private <type> c$<x>
        cw().visitField(Opcodes.ACC_PRIVATE, this.cacheName, this.type.getDescriptor(), null, null).visitEnd();

        // if (!h$<x>) {
        final Label skipCachedComputation = mv().newLabel();
        mv().loadThis();
        mv().getField(classType(), this.cachedIndicatorName, Type.BOOLEAN_TYPE);
        mv().visitJumpInsn(Opcodes.IFNE, skipCachedComputation);

        // c$<x> = <value>;
        mv().loadThis();
        compileValue();
        mv().putField(classType(), this.cacheName, this.type);

        // h$<x> = true;
        mv().loadThis();
        mv().push(true);
        mv().putField(classType(), this.cachedIndicatorName, Type.BOOLEAN_TYPE);

        // }
        // return c$<x>;
        mv().mark(skipCachedComputation);
        mv().loadThis();
        mv().getField(classType(), this.cacheName, this.type);

        // In reset(), do:
        if (this.section.hasReset()) {
            // h$<x> = false;
            final GeneratorAdapter r = this.section.resetter();
            r.loadThis();
            r.push(false);
            r.putField(classType(), this.cachedIndicatorName, Type.BOOLEAN_TYPE);
        }
    }

    private Type classType() {
        return this.section.classType();
    }

    private ClassWriter cw() {
        return this.section.cw();
    }

    private GeneratorAdapter mv() {
        return this.mv;
    }
}