/*
 * Copyright (C) 2024 The Android Open Source Project
 *
 * 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 android.net.apf;

import com.android.internal.annotations.VisibleForTesting;

import java.util.Objects;

/**
 * APFv6 assembler/generator. A tool for generating an APFv6 program.
 *
 * @hide
 */
public final class ApfV6Generator extends ApfV6GeneratorBase<ApfV6Generator> {
    /**
     * Returns true if we support the specified {@code version}, otherwise false.
     */
    public static boolean supportsVersion(int version) {
        return version >= APF_VERSION_6;
    }

    /**
     * Creates an ApfV6Generator instance which emits instructions for APFv6.
     */
    public ApfV6Generator(int maximumApfProgramSize) throws IllegalInstructionException {
        this(new byte[0], maximumApfProgramSize);
    }

    @Override
    void updateExceptionBufferSize(int programSize) throws IllegalInstructionException {
        mInstructions.get(1).updateExceptionBufferSize(
                mMaximumApfProgramSize - ApfCounterTracker.Counter.totalSize() - programSize);
    }

    /**
     * Creates an ApfV6Generator instance which emits instructions APFv6.
     * Initializes the data region with {@code bytes}.
     */
    @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
    public ApfV6Generator(byte[] bytes, int maximumApfProgramSize)
            throws IllegalInstructionException {
        super(maximumApfProgramSize);
        Objects.requireNonNull(bytes);
        addData(bytes);
        addExceptionBuffer(0);
    }
}