ParkanPlayground/X86Disassembler/PE/OptionalHeader.cs

namespace X86Disassembler.PE
{
    /// <summary>
    /// Represents the Optional header of a PE file
    /// </summary>
    public class OptionalHeader
    {
        // Optional Header Magic values
        private const ushort PE32_MAGIC = 0x10B;           // 32-bit executable
        private const ushort PE32PLUS_MAGIC = 0x20B;       // 64-bit executable
        
        // Standard fields
        public ushort Magic;                  // Magic number (PE32 or PE32+)
        public byte MajorLinkerVersion;       // Major linker version
        public byte MinorLinkerVersion;       // Minor linker version
        public uint SizeOfCode;               // Size of code section
        public uint SizeOfInitializedData;    // Size of initialized data section
        public uint SizeOfUninitializedData;  // Size of uninitialized data section
        public uint AddressOfEntryPoint;      // Address of entry point
        public uint BaseOfCode;               // Base of code section
        public uint BaseOfData;               // Base of data section (PE32 only)
        
        // Windows-specific fields
        public object ImageBase;              // Image base address (uint for PE32, ulong for PE32+)
        public uint SectionAlignment;         // Section alignment
        public uint FileAlignment;            // File alignment
        public ushort MajorOperatingSystemVersion; // Major OS version
        public ushort MinorOperatingSystemVersion; // Minor OS version
        public ushort MajorImageVersion;      // Major image version
        public ushort MinorImageVersion;      // Minor image version
        public ushort MajorSubsystemVersion;  // Major subsystem version
        public ushort MinorSubsystemVersion;  // Minor subsystem version
        public uint Win32VersionValue;        // Win32 version value
        public uint SizeOfImage;              // Size of image
        public uint SizeOfHeaders;            // Size of headers
        public uint CheckSum;                 // Checksum
        public ushort Subsystem;              // Subsystem
        public ushort DllCharacteristics;     // DLL characteristics
        public object SizeOfStackReserve;     // Size of stack reserve (uint for PE32, ulong for PE32+)
        public object SizeOfStackCommit;      // Size of stack commit (uint for PE32, ulong for PE32+)
        public object SizeOfHeapReserve;      // Size of heap reserve (uint for PE32, ulong for PE32+)
        public object SizeOfHeapCommit;       // Size of heap commit (uint for PE32, ulong for PE32+)
        public uint LoaderFlags;              // Loader flags
        public uint NumberOfRvaAndSizes;      // Number of RVA and sizes
        
        public DataDirectory[] DataDirectories; // Data directories
        
        /// <summary>
        /// Initializes a new instance of the OptionalHeader class
        /// </summary>
        public OptionalHeader()
        {
            // Initialize object fields to avoid nullability warnings
            ImageBase = 0u; // Default to 32-bit value
            SizeOfStackReserve = 0u;
            SizeOfStackCommit = 0u;
            SizeOfHeapReserve = 0u;
            SizeOfHeapCommit = 0u;
            
            // Initialize array to avoid nullability warning
            DataDirectories = new DataDirectory[0];
        }
        
        /// <summary>
        /// Determines if the PE file is 64-bit based on the Magic value
        /// </summary>
        /// <returns>True if the PE file is 64-bit, false otherwise</returns>
        public bool Is64Bit()
        {
            return Magic == PE32PLUS_MAGIC;
        }
    }
}