UA-.NETStandard/fuzzing/Opc.Ua.PubSub.Fuzz/FuzzableCode.cs

/* ========================================================================
 * Copyright (c) 2005-2026 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
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 * obtaining a copy of this software and associated documentation
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using System;
using System.IO;
using Opc.Ua.PubSub.Diagnostics;
using Opc.Ua.PubSub.Encoding;
using Opc.Ua.PubSub.MetaData;

namespace Opc.Ua.Fuzzing
{
    /// <summary>
    /// Shared helpers for PubSub fuzz targets.
    /// </summary>
    public static partial class FuzzableCode
    {
        private const int MaxFuzzInputBytes = 1024 * 1024;

        /// <summary>
        /// Prints information about the fuzzer target.
        /// </summary>
        public static void FuzzInfo()
        {
            Console.WriteLine("OPC UA PubSub fuzzer for UADP, UADP chunk reassembly and JSON decode.");
        }

        internal static PubSubNetworkMessageContext NewContext()
        {
            return new PubSubNetworkMessageContext(
                ServiceMessageContext.CreateEmpty(null!),
                new DataSetMetaDataRegistry(),
                new PubSubDiagnostics(PubSubDiagnosticsLevel.Low),
                TimeProvider.System);
        }

        internal static byte[] CopyCapped(ReadOnlySpan<byte> input)
        {
            return input.Length <= MaxFuzzInputBytes
                ? input.ToArray()
                : input[..MaxFuzzInputBytes].ToArray();
        }

        internal static byte[] ReadCapped(Stream stream)
        {
            using var memoryStream = new MemoryStream();
            byte[] buffer = new byte[4096];
            int remaining = MaxFuzzInputBytes;
            while (remaining > 0)
            {
                int read = stream.Read(buffer, 0, Math.Min(buffer.Length, remaining));
                if (read == 0)
                {
                    break;
                }

                memoryStream.Write(buffer, 0, read);
                remaining -= read;
            }

            return memoryStream.ToArray();
        }

        internal static bool IsExpected(Exception ex)
        {
            if (ex is ServiceResultException or InvalidOperationException or ArgumentException or
                FormatException or IOException or OverflowException)
            {
                return true;
            }

            return false;
        }
    }
}