using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace ArchiveUnpack
{

    /// <summary>
    /// Dos头-64字节（byte）
    /// </summary>
    public struct DosHeader
    {
        public short e_magic;           //DOS头的标识，为4Dh和5Ah。分别为字母MZ
        public short e_cblp;
        public short e_cp;
        public short e_crlc;
        public short e_cparhdr;
        public short e_minalloc;
        public short e_maxalloc;
        public short e_ss;
        public short e_sp;
        public short e_csum;
        public short e_ip;
        public short e_cs;
        public short e_lfarlc;
        public short e_ovno;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 4)]
        public short[] e_res;
        public short e_oemid;
        public short e_oeminfo;
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 10)]
        public short[] e_res2;
        public Int32 e_lfanew;             //指向IMAGE_NT_HEADERS的所在
    }

    public struct NtHeader
    {
        /// <summary>
        /// PE字符
        /// </summary>
        public Int32 Signature;     
        public FileHeader FileHeader;
        public OptionHeader OptionalHeader;
    }

    public struct FileHeader
    {
        public short Machine;                   //运行平台
        public short NumberOfSections;          //文件的区块数目
        public Int32 TimeDateStamp;                //文件创建日期和时间
        public Int32 PointerToSymbolTable;     //指向符号表（用于调试）
        public Int32 NumberOfSymbols;          //符号表中符号个数（用于调试）
        public short SizeOfOptionalHeader;      //IMAGE_OPTIONAL_HEADER32结构大小
        public short Characteristics;
    }

    /// <summary>
    /// 可选映像头
    /// </summary>
    public struct OptionHeader
    {
        public short Magic;                         //标志字
        public byte MajorLinkerVersion;                //链接器主版本号
        public byte MinorLinkerVersion;                //链接器次版本号
        public Int32 SizeOfCode;                       //所有含有代码表的总大小
        public Int32 SizeOfInitializedData;            //所有初始化数据表总大小
        public Int32 SizeOfUninitializedData;      //所有未初始化数据表总大小
        public Int32 AddressOfEntryPoint;          //程序执行入口RVA
        public Int32 BaseOfCode;                       //代码表其实RVA
        public Int32 BaseOfData;                       //数据表其实RVA
        public Int32 ImageBase;                        //程序默认装入基地址
        public Int32 SectionAlignment;             //内存中表的对齐值
        public Int32 FileAlignment;                    //文件中表的对齐值
        public short MajorOperatingSystemVersion;   //操作系统主版本号
        public short MinorOperatingSystemVersion;   //操作系统次版本号
        public short MajorImageVersion;             //用户自定义主版本号
        public short MinorImageVersion;             //用户自定义次版本号
        public short MajorSubsystemVersion;         //所需要子系统主版本号
        public short MinorSubsystemVersion;         //所需要子系统次版本号
        public Int32 Win32VersionValue;                //保留，通常设置为0
        public Int32 SizeOfImage;                  //映像装入内存后的总大小
        public Int32 SizeOfHeaders;                    //DOS头、PE头、区块表总大小
        public Int32 CheckSum;                     //映像校验和
        public short Subsystem;                     //文件子系统
        public short DllCharacteristics;                //显示DLL特性的旗标
        public Int32 SizeOfStackReserve;               //初始化堆栈大小
        public Int32 SizeOfStackCommit;                //初始化实际提交堆栈大小
        public Int32 SizeOfHeapReserve;                //初始化保留堆栈大小
        public Int32 SizeOfHeapCommit;             //初始化实际保留堆栈大小
        public Int32 LoaderFlags;                  //与调试相关，默认值为0
        public Int32 NumberOfRvaAndSizes;          //数据目录表的项数

        /// <summary>
        /// 数据目录（128字节，共16个表）
        /// </summary>
        [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
        public DataDirectory[] DataDirectory;
    }


    public struct DataDirectory
    {
        public Int32 VirtualAddress;           //数据块的起始RVA
        public Int32 Size;                 //数据块的长度
    }

    /// <summary>
    /// 节表头(实测只有32字节)
    /// </summary>
    public struct SectionHeader
    {
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 8)]
        public string Name;                        //8个字节的块名
         
        //public Int32 PhysicalAddress;        //物理地址，可能读入内存后会存在(实测中没有)
        public Int32 VirtualSize;                //区块尺寸</span>
        public Int32 VirtualAddress;       //区块的RVA地址
        public Int32 SizeOfRawData;        //在文件中对齐后的尺寸
        public Int32 PointerToRawData;     //在文件中偏移
        public Int32 PointerToRelocations; //在OBJ文件中使用，重定位的偏移
        public Int32 PointerToLinenumbers; //行号表的偏移（供调试使用地）
        public short NumberOfRelocations;   //在OBJ文件中使用，重定位项数目 (EFF中没有看到，可能打包DLL后也没有)
        public short NumberOfLinenumbers;   //行号表中行号的数目
        public Int32 Characteristics;      //区块属性如可读，可写，可执行等
    }

    public struct CLRHeader
    {
        public Int32 cb;
        public short MajorRuntimeVersion;
        public short MinorRuntimeVersion;
        //符号表和开始信息
        public DataDirectory MetaData;
        Int32 Flags;
        Int32 EntryPointToken;
        Int32 EntryPointRVA;
        //绑定信息
        public DataDirectory Resource;
        public DataDirectory StrongNameSignature;
        //常规的定位和绑定信息
        public DataDirectory CodeMagagerTable;
        public DataDirectory VTableFixups;
        public DataDirectory ExprotAddressTableJumps;

        public DataDirectory MagageNativeHeader;
    }

    public struct MetaData
    {
        /// <summary>
        /// 固定的ASCII码，BSJB
        /// </summary>
        public Int32 lSignature;

        /// <summary>
        /// 元数据的主版本，一般为1
        /// </summary>
        public short iMajorVersion;

        /// <summary>
        /// 元数据的副版本，一般为1
        /// </summary>
        public short iMinorVersion;

        /// <summary>
        /// 保留字节
        /// </summary>
        public Int32 iExtraData;

        /// <summary>
        /// 接下来版本字符串的长度，包含尾部0，且按4字节对齐
        /// </summary>
        public Int32 iLength;

        /// <summary>
        /// UTF8格式的编译环境版本号
        /// </summary>
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 11)]
        //public byte[] iVersionString;
        public string iVersionString;

        /// <summary>
        /// 保留为0
        /// </summary>
        public byte fFlags;

        /// <summary>
        /// 无意义字节（对齐用）
        /// </summary>
        public byte padding;

        /// <summary>
        /// NStream的个数（流的个数）
        /// </summary>
        public short iStreams;
    }

    public struct NStreamHeader
    {
        /// <summary>
        /// 该流的存储位置相对于MetaData   Root的偏移
        /// </summary>
        public Int32 iOffset;

        /// <summary>
        /// 该流占多少字节
        /// </summary>
        public Int32 iSize;

        /// <summary>
        /// 流的名称，与4字节对齐
        /// </summary>
        public char[] rcName;
    }

    public struct NStreamData
    {
        /// <summary>
        /// 保留字节，为0
        /// </summary>
        public Int32 Reserved;

        /// <summary>
        /// 元数据表的主版本号，于.NET主版本号一致
        /// </summary>
        public byte Major;

        /// <summary>
        /// 元数据的副版本号，一般为0
        /// </summary>
        public byte Minor;

        /// <summary>
        /// Heap中定义数据时的索引的大小，为0表示16位索引值，若堆中数据超出16位数据表示范围，则使用32位索引值。01代表strings堆，02h代表GUID堆04h代表blob堆
        /// </summary>
        public byte Heaps;

        /// <summary>
        /// 所有元数据表中记录最大索引值，在运行时有.NET计算，文件中通常为1
        /// </summary>
        public byte Rid;

        /// <summary>
        /// 8字节长度的掩码，每个为代表一个表，为1表示该表有效，为0表示该表无效
        /// </summary>
        public Int64 MaskValid;

        /// <summary>
        /// 8字节长度的掩码，每个为代表一个表，为1表示该表已排序，反之为0
        /// </summary>
        public Int64 Sorted;
    }

    public class PEFormat
    {
        /// <summary>
        /// 64字节
        /// </summary>
        protected DosHeader _DosHeader;

        /// <summary>
        /// 一般也是64字节
        /// </summary>
        protected byte[] _DosStub;


        protected NtHeader _NtHeader;

        /// <summary>
        /// 节表块(最后一个必为一个全空节头)
        /// </summary>
        protected SectionHeader[] _SetctionBlocks;

        /// <summary>
        /// 节段总数
        /// </summary>
        public int SectionCount
        {
            get
            {
                return _NtHeader.FileHeader.NumberOfSections + 1;
            }
        }
    }
}