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1 /*
2  * Copyright (C) 2024 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 package android.net.apf;
17 
18 import com.android.internal.annotations.VisibleForTesting;
19 
20 import java.util.Objects;
21 
22 /**
23  * APFv6 assembler/generator. A tool for generating an APFv6 program.
24  *
25  * @hide
26  */
27 public final class ApfV6Generator extends ApfV6GeneratorBase<ApfV6Generator> {
28     /**
29      * Returns true if we support the specified {@code version}, otherwise false.
30      */
supportsVersion(int version)31     public static boolean supportsVersion(int version) {
32         return version >= APF_VERSION_6;
33     }
34 
35     /**
36      * Creates an ApfV6Generator instance which emits instructions for APFv6.
37      */
ApfV6Generator(int maximumApfProgramSize)38     public ApfV6Generator(int maximumApfProgramSize) throws IllegalInstructionException {
39         this(new byte[0], maximumApfProgramSize);
40     }
41 
42     @Override
updateExceptionBufferSize(int programSize)43     void updateExceptionBufferSize(int programSize) throws IllegalInstructionException {
44         mInstructions.get(1).updateExceptionBufferSize(
45                 mMaximumApfProgramSize - ApfCounterTracker.Counter.totalSize() - programSize);
46     }
47 
48     /**
49      * Creates an ApfV6Generator instance which emits instructions APFv6.
50      * Initializes the data region with {@code bytes}.
51      */
52     @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
ApfV6Generator(byte[] bytes, int maximumApfProgramSize)53     public ApfV6Generator(byte[] bytes, int maximumApfProgramSize)
54             throws IllegalInstructionException {
55         super(maximumApfProgramSize);
56         Objects.requireNonNull(bytes);
57         addData(bytes);
58         addExceptionBuffer(0);
59     }
60 }
61