io.activej.serializer.def.impl.EnumSerializerDef Maven / Gradle / Ivy

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/*
 * Copyright (C) 2020 ActiveJ 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.activej.serializer.def.impl;

import io.activej.codegen.expression.Expression;
import io.activej.codegen.expression.Variable;
import io.activej.common.annotation.ExposedInternals;
import io.activej.serializer.CompatibilityLevel;
import io.activej.serializer.def.AbstractSerializerDef;
import io.activej.serializer.def.SerializerDef;
import io.activej.serializer.def.SerializerDefWithNullable;
import io.activej.serializer.def.SerializerDefs;

import static io.activej.codegen.expression.Expressions.*;
import static io.activej.serializer.CompatibilityLevel.LEVEL_3;
import static io.activej.serializer.def.SerializerExpressions.*;

@ExposedInternals
public final class EnumSerializerDef extends AbstractSerializerDef implements SerializerDefWithNullable {
	public final Class> enumType;
	public final boolean nullable;

	public EnumSerializerDef(Class> enumType, boolean nullable) {
		this.enumType = enumType;
		this.nullable = nullable;
	}

	@Override
	public Class getEncodeType() {
		return enumType;
	}

	@Override
	public Expression encode(StaticEncoders staticEncoders, Expression buf, Variable pos, Expression value, int version, CompatibilityLevel compatibilityLevel) {
		Expression ordinal = call(cast(value, Enum.class), "ordinal");
		if (isSmallEnum()) {
			return !nullable ?
				writeByte(buf, pos, cast(ordinal, byte.class)) :
				ifNull(value,
					writeByte(buf, pos, value((byte) 0)),
					writeByte(buf, pos, cast(add(ordinal, value(1)), byte.class)));
		} else {
			return !nullable ?
				writeVarInt(buf, pos, ordinal) :
				ifNull(value,
					writeByte(buf, pos, value((byte) 0)),
					writeVarInt(buf, pos, add(ordinal, value((byte) 1))));
		}
	}

	@Override
	public Expression decode(StaticDecoders staticDecoders, Expression in, int version, CompatibilityLevel compatibilityLevel) {
		return isSmallEnum() ?
			let(readByte(in), b ->
				!nullable ?
					arrayGet(staticCall(enumType, "values"), b) :
					ifEq(b, value((byte) 0),
						nullRef(enumType),
						arrayGet(staticCall(enumType, "values"), dec(b)))) :
			let(readVarInt(in), value ->
				!nullable ?
					arrayGet(staticCall(enumType, "values"), value) :
					ifEq(value, value(0),
						nullRef(enumType),
						arrayGet(staticCall(enumType, "values"), dec(value))));
	}

	private boolean isSmallEnum() {
		int size = enumType.getEnumConstants().length + (nullable ? 1 : 0);
		if (size >= 16384) throw new IllegalArgumentException();
		return size <= Byte.MAX_VALUE;
	}

	@Override
	public SerializerDef ensureNullable(CompatibilityLevel compatibilityLevel) {
		if (compatibilityLevel.getLevel() < LEVEL_3.getLevel()) {
			return SerializerDefs.ofNullable(this);
		}
		return new EnumSerializerDef(enumType, true);
	}
}