C# BlobReader.ReadUInt16方法代码示例

        public static ILResult GetInstructions(BlobReader reader)
        {
            var instructions = ImmutableArray.CreateBuilder<Instruction>();
            List<int[]> switches = null;

            while (reader.RemainingBytes > 0)
            {
                ushort pos = (ushort)reader.Offset;
                byte op0 = reader.ReadByte();
                InstrCode code = (InstrCode)(op0 == 0xFE ? unchecked(0xFE00 + reader.ReadByte()) : op0);
                OperandType opType = code.GetOperandType();

                ulong operand = 0;
                if (code == InstrCode.Switch)
                {
                    if (switches == null)
                        switches = new List<int[]>();

                    operand = (ulong)switches.Count;
                    uint branchCount = reader.ReadUInt32();
                    int[] branches = new int[branchCount];
                    for (int i = 0; i < branchCount; i++)
                    {
                        branches[i] = reader.ReadInt32();
                    }
                    switches.Add(branches);
                }
                else
                {
                    byte operandSize = opType.GetOperandSize();
                    operand = operandSize == 8 ? reader.ReadUInt64()
                        : operandSize == 4 ? reader.ReadUInt32()
                        : operandSize == 2 ? reader.ReadUInt16()
                        : operandSize == 1 ? (ulong)reader.ReadByte()
                        : 0;
                }

                instructions.Add(new Instruction(pos, code, opType, operand));
            }

            return new ILResult
            {
                Instructions = instructions.ToImmutable(),
                Switches = switches?.ToArray()
            };
        }

        /// <summary>
        /// Reads stream headers described in Ecma-335 24.2.2 Stream header
        /// </summary>
        private StreamHeader[] ReadStreamHeaders(ref BlobReader memReader)
        {
            // storage header:
            memReader.ReadUInt16();
            int streamCount = memReader.ReadInt16();

            var streamHeaders = new StreamHeader[streamCount];
            for (int i = 0; i < streamHeaders.Length; i++)
            {
                if (memReader.RemainingBytes < COR20Constants.MinimumSizeofStreamHeader)
                {
                    throw new BadImageFormatException(MetadataResources.StreamHeaderTooSmall);
                }

                streamHeaders[i].Offset = memReader.ReadUInt32();
                streamHeaders[i].Size = memReader.ReadInt32();
                streamHeaders[i].Name = memReader.ReadUtf8NullTerminated();
                bool aligned = memReader.TryAlign(4);

                if (!aligned || memReader.RemainingBytes == 0)
                {
                    throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForStreamHeaderName);
                }
            }

            return streamHeaders;
        }

        /// <summary>
        /// Looks like this function reads beginning of the header described in
        /// Ecma-335 24.2.1 Metadata root
        /// </summary>
        private void ReadMetadataHeader(ref BlobReader memReader)
        {
            if (memReader.RemainingBytes < COR20Constants.MinimumSizeofMetadataHeader)
            {
                throw new BadImageFormatException(MetadataResources.MetadataHeaderTooSmall);
            }

            this.metadataHeader.Signature = memReader.ReadUInt32();
            if (this.metadataHeader.Signature != COR20Constants.COR20MetadataSignature)
            {
                throw new BadImageFormatException(MetadataResources.MetadataSignature);
            }

            this.metadataHeader.MajorVersion = memReader.ReadUInt16();
            this.metadataHeader.MinorVersion = memReader.ReadUInt16();
            this.metadataHeader.ExtraData = memReader.ReadUInt32();
            this.metadataHeader.VersionStringSize = memReader.ReadInt32();
            if (memReader.RemainingBytes < this.metadataHeader.VersionStringSize)
            {
                throw new BadImageFormatException(MetadataResources.NotEnoughSpaceForVersionString);
            }

            int numberOfBytesRead;
            this.metadataHeader.VersionString = memReader.GetMemoryBlockAt(0, this.metadataHeader.VersionStringSize).PeekUtf8NullTerminated(0, null, utf8Decoder, out numberOfBytesRead, '\0');
            memReader.SkipBytes(this.metadataHeader.VersionStringSize);
            this.metadataKind = GetMetadataKind(metadataHeader.VersionString);
        }

        internal static ImmutableArray<DebugDirectoryEntry> ReadDebugDirectoryEntries(BlobReader reader)
        {
            int entryCount = reader.Length / DebugDirectoryEntry.Size;
            var builder = ImmutableArray.CreateBuilder<DebugDirectoryEntry>(entryCount);
            for (int i = 0; i < entryCount; i++)
            {
                // Reserved, must be zero.
                int characteristics = reader.ReadInt32();
                if (characteristics != 0)
                {
                    throw new BadImageFormatException(SR.InvalidDebugDirectoryEntryCharacteristics);
                }

                uint stamp = reader.ReadUInt32();
                ushort majorVersion = reader.ReadUInt16();
                ushort minorVersion = reader.ReadUInt16();

                var type = (DebugDirectoryEntryType)reader.ReadInt32();

                int dataSize = reader.ReadInt32();
                int dataRva = reader.ReadInt32();
                int dataPointer = reader.ReadInt32();

                builder.Add(new DebugDirectoryEntry(stamp, majorVersion, minorVersion, type, dataSize, dataRva, dataPointer));
            }

            return builder.MoveToImmutable();
        }

        /// <summary>
        /// Looks like this function reads beginning of the header described in
        /// ECMA-335 24.2.1 Metadata root
        /// </summary>
        private void ReadMetadataHeader(ref BlobReader memReader, out string versionString)
        {
            if (memReader.RemainingBytes < COR20Constants.MinimumSizeofMetadataHeader)
            {
                throw new BadImageFormatException(SR.MetadataHeaderTooSmall);
            }

            uint signature = memReader.ReadUInt32();
            if (signature != COR20Constants.COR20MetadataSignature)
            {
                throw new BadImageFormatException(SR.MetadataSignature);
            }

            // major version
            memReader.ReadUInt16();

            // minor version
            memReader.ReadUInt16();

            // reserved:
            memReader.ReadUInt32();

            int versionStringSize = memReader.ReadInt32();
            if (memReader.RemainingBytes < versionStringSize)
            {
                throw new BadImageFormatException(SR.NotEnoughSpaceForVersionString);
            }

            int numberOfBytesRead;
            versionString = memReader.GetMemoryBlockAt(0, versionStringSize).PeekUtf8NullTerminated(0, null, UTF8Decoder, out numberOfBytesRead, '\0');
            memReader.SkipBytes(versionStringSize);
        }

        private object ReadAndTranslateValue(ref BlobReader sigReader, SignatureTypeCode typeCode, out bool isEnumTypeCode)
        {
            switch (typeCode)
            {
                case SignatureTypeCode.Boolean:
                    isEnumTypeCode = true;
                    return (short)(sigReader.ReadBoolean() ? 1 : 0);

                case SignatureTypeCode.Char:
                    isEnumTypeCode = true;
                    return (ushort)sigReader.ReadChar();

                case SignatureTypeCode.SByte:
                    isEnumTypeCode = true;
                    return (short)sigReader.ReadSByte();

                case SignatureTypeCode.Byte:
                    isEnumTypeCode = true;
                    return (short)sigReader.ReadByte();

                case SignatureTypeCode.Int16:
                    isEnumTypeCode = true;
                    return sigReader.ReadInt16();

                case SignatureTypeCode.UInt16:
                    isEnumTypeCode = true;
                    return sigReader.ReadUInt16();

                case SignatureTypeCode.Int32:
                    isEnumTypeCode = true;
                    return sigReader.ReadInt32();

                case SignatureTypeCode.UInt32:
                    isEnumTypeCode = true;
                    return sigReader.ReadUInt32();

                case SignatureTypeCode.Int64:
                    isEnumTypeCode = true;
                    return sigReader.ReadInt64();

                case SignatureTypeCode.UInt64:
                    isEnumTypeCode = true;
                    return sigReader.ReadUInt64();

                case SignatureTypeCode.Single:
                    isEnumTypeCode = false;
                    return sigReader.ReadSingle();

                case SignatureTypeCode.Double:
                    isEnumTypeCode = false;
                    return sigReader.ReadDouble();

                case SignatureTypeCode.String:
                    isEnumTypeCode = false;

                    if (sigReader.RemainingBytes == 1)
                    {
                        if (sigReader.ReadByte() != 0xff)
                        {
                            throw new BadImageFormatException();
                        }

                        return NullReferenceValue;
                    }

                    if (sigReader.RemainingBytes % 2 != 0)
                    {
                        throw new BadImageFormatException();
                    }

                    return sigReader.ReadUTF16(sigReader.RemainingBytes);

                case SignatureTypeCode.Object:
                    // null reference
                    isEnumTypeCode = false;
                    return NullReferenceValue;

                default:
                    throw new BadImageFormatException();
            }
        }

        /// <summary>
        /// Reads all Debug Directory table entries.
        /// </summary>
        /// <exception cref="BadImageFormatException">Bad format of the entry.</exception>
        public unsafe ImmutableArray<DebugDirectoryEntry> ReadDebugDirectory()
        {
            var debugDirectory = PEHeaders.PEHeader.DebugTableDirectory;
            if (debugDirectory.Size == 0)
            {
                return ImmutableArray<DebugDirectoryEntry>.Empty;
            }

            int position;
            if (!PEHeaders.TryGetDirectoryOffset(debugDirectory, out position))
            {
                throw new BadImageFormatException(SR.InvalidDirectoryRVA);
            }

            const int entrySize = 0x1c;

            if (debugDirectory.Size % entrySize != 0)
            {
                throw new BadImageFormatException(SR.InvalidDirectorySize);
            }

            using (AbstractMemoryBlock block = _peImage.GetMemoryBlock(position, debugDirectory.Size))
            {
                var reader = new BlobReader(block.Pointer, block.Size);

                int entryCount = debugDirectory.Size / entrySize;
                var builder = ImmutableArray.CreateBuilder<DebugDirectoryEntry>(entryCount);
                for (int i = 0; i < entryCount; i++)
                {
                    // Reserved, must be zero.
                    int characteristics = reader.ReadInt32();
                    if (characteristics != 0)
                    {
                        throw new BadImageFormatException(SR.InvalidDebugDirectoryEntryCharacteristics);
                    }

                    uint stamp = reader.ReadUInt32();
                    ushort majorVersion = reader.ReadUInt16();
                    ushort minorVersion = reader.ReadUInt16();

                    var type = (DebugDirectoryEntryType)reader.ReadInt32();

                    int dataSize = reader.ReadInt32();
                    int dataRva = reader.ReadInt32();
                    int dataPointer = reader.ReadInt32();

                    builder.Add(new DebugDirectoryEntry(stamp, majorVersion, minorVersion, type, dataSize, dataRva, dataPointer));
                }

                return builder.MoveToImmutable();
            }
        }

        public static MethodBodyBlock Create(BlobReader reader)
        {
            int startOffset = reader.Offset;
            int ilSize;

            // Error need to check if the Memory Block is empty. This is calse for all the calls...
            byte headByte = reader.ReadByte();
            if ((headByte & ILFormatMask) == ILTinyFormat)
            {
                // tiny IL can't have locals so technically this shouldn't matter,
                // but false is consistent with other metadata readers and helps
                // for use cases involving comparing our output with theirs.
                const bool initLocalsForTinyIL = false;

                ilSize = headByte >> ILTinyFormatSizeShift;
                return new MethodBodyBlock(
                    initLocalsForTinyIL,
                    8,
                    default(StandaloneSignatureHandle),
                    reader.GetMemoryBlockAt(0, ilSize),
                    ImmutableArray<ExceptionRegion>.Empty,
                    1 + ilSize // header + IL
                );
            }

            if ((headByte & ILFormatMask) != ILFatFormat)
            {
                throw new BadImageFormatException(string.Format(MetadataResources.InvalidMethodHeader1, headByte));
            }

            // FatILFormat
            byte headByte2 = reader.ReadByte();
            if ((headByte2 >> ILFatFormatHeaderSizeShift) != ILFatFormatHeaderSize)
            {
                throw new BadImageFormatException(string.Format(MetadataResources.InvalidMethodHeader2, headByte, headByte2));
            }

            bool localsInitialized = (headByte & ILInitLocals) == ILInitLocals;
            bool hasExceptionHandlers = (headByte & ILMoreSects) == ILMoreSects;

            ushort maxStack = reader.ReadUInt16();
            ilSize = reader.ReadInt32();

            int localSignatureToken = reader.ReadInt32();
            StandaloneSignatureHandle localSignatureHandle;
            if (localSignatureToken == 0)
            {
                localSignatureHandle = default(StandaloneSignatureHandle);
            }
            else if ((localSignatureToken & TokenTypeIds.TokenTypeMask) == TokenTypeIds.Signature)
            {
                localSignatureHandle = StandaloneSignatureHandle.FromRowId((uint)localSignatureToken & TokenTypeIds.RIDMask);
            }
            else
            {
                throw new BadImageFormatException(string.Format(MetadataResources.InvalidLocalSignatureToken, unchecked((uint)localSignatureToken)));
            }

            var ilBlock = reader.GetMemoryBlockAt(0, ilSize);
            reader.SkipBytes(ilSize);

            ImmutableArray<ExceptionRegion> exceptionHandlers;
            if (hasExceptionHandlers)
            {
                reader.Align(4);
                byte sehHeader = reader.ReadByte();
                if ((sehHeader & SectEHTable) != SectEHTable)
                {
                    throw new BadImageFormatException(string.Format(MetadataResources.InvalidSehHeader, sehHeader));
                }

                bool sehFatFormat = (sehHeader & SectFatFormat) == SectFatFormat;
                int dataSize = reader.ReadByte();
                if (sehFatFormat)
                {
                    dataSize += reader.ReadUInt16() << 8;
                    exceptionHandlers = ReadFatExceptionHandlers(ref reader, dataSize / 24);
                }
                else
                {
                    reader.SkipBytes(2); // skip over reserved field
                    exceptionHandlers = ReadSmallExceptionHandlers(ref reader, dataSize / 12);
                }
            }
            else
            {
                exceptionHandlers = ImmutableArray<ExceptionRegion>.Empty;
            }

            return new MethodBodyBlock(
                localsInitialized,
                maxStack,
                localSignatureHandle,
                ilBlock,
                exceptionHandlers,
                reader.Offset - startOffset);
        }

        private static ImmutableArray<ExceptionRegion> ReadSmallExceptionHandlers(ref BlobReader memReader, int count)
        {
            var result = new ExceptionRegion[count];
            for (int i = 0; i < result.Length; i++)
            {
                var kind = (ExceptionRegionKind)memReader.ReadUInt16();
                var tryOffset = memReader.ReadUInt16();
                var tryLength = memReader.ReadByte();
                var handlerOffset = memReader.ReadUInt16();
                var handlerLength = memReader.ReadByte();
                var classTokenOrFilterOffset = memReader.ReadInt32();
                result[i] = new ExceptionRegion(kind, tryOffset, tryLength, handlerOffset, handlerLength, classTokenOrFilterOffset);
            }

            return ImmutableArray.Create(result);
        }

 private static int ReadReference(ref BlobReader reader, bool smallRefSize)
 {
     return smallRefSize ? reader.ReadUInt16() : reader.ReadInt32();
 }