Extracting Icons from EXE/DLL and Icon Manipulation

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using BYTE = System.Byte;
using WORD = System.Int16;
using DWORD = System.Int32;

namespace TAFactory.IconPack
{
    /// <summary>
    /// Presents an Icon Directory.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Size=6)]
    public struct IconDir
    {
        public WORD Reserved;   // Reserved (must be 0)
        public WORD Type;       // Resource Type (1 for icons)
        public WORD Count;      // How many images?

        /// <summary>
        /// Converts the current TAFactory.IconPack.IconDir into TAFactory.IconPack.GroupIconDir.
        /// </summary>
        /// <returns>TAFactory.IconPack.GroupIconDir</returns>
        public GroupIconDir ToGroupIconDir()
        {
            GroupIconDir grpDir = new GroupIconDir();
            grpDir.Reserved = this.Reserved;
            grpDir.Type = this.Type;
            grpDir.Count = this.Count;
            return grpDir;
        }
    }

    /// <summary>
    /// Presents an Icon Directory Entry.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Size=16)]
    public struct IconDirEntry
    {
        public BYTE  Width;          // Width, in pixels, of the image
        public BYTE  Height;         // Height, in pixels, of the image
        public BYTE  ColorCount;     // Number of colors in image (0 if >=8bpp)
        public BYTE  Reserved;       // Reserved ( must be 0)
        public WORD  Planes;         // Color Planes
        public WORD  BitCount;       // Bits per pixel
        public DWORD BytesInRes;     // How many bytes in this resource?
        public DWORD ImageOffset;    // Where in the file is this image?

        /// <summary>
        /// Converts the current TAFactory.IconPack.IconDirEntry into TAFactory.IconPack.GroupIconDirEntry.
        /// </summary>
        /// <param name="id">The resource identifier.</param>
        /// <returns>TAFactory.IconPack.GroupIconDirEntry</returns>
        public GroupIconDirEntry ToGroupIconDirEntry(int id)
        {
            GroupIconDirEntry grpEntry = new GroupIconDirEntry();
            grpEntry.Width = this.Width;
            grpEntry.Height = this.Height;
            grpEntry.ColorCount = this.ColorCount;
            grpEntry.Reserved = this.Reserved;
            grpEntry.Planes = this.Planes;
            grpEntry.BitCount = this.BitCount;
            grpEntry.BytesInRes = this.BytesInRes;
            grpEntry.ID = (short)id;
            return grpEntry;
        }
    }

    /// <summary>
    /// Presents a Group Icon Directory.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Size=6)]
    public struct GroupIconDir
    {
        public WORD Reserved;   // Reserved (must be 0)
        public WORD Type;       // Resource Type (1 for icons)
        public WORD Count;      // How many images?

        /// <summary>
        /// Converts the current TAFactory.IconPack.GroupIconDir into TAFactory.IconPack.IconDir.
        /// </summary>
        /// <returns>TAFactory.IconPack.IconDir</returns>
        public IconDir ToIconDir()
        {
            IconDir dir = new IconDir();
            dir.Reserved = this.Reserved;
            dir.Type = this.Type;
            dir.Count = this.Count;
            return dir;
        }
    }

    /// <summary>
    /// Presents a Group Icon Directory Entry.
    /// </summary>
    [StructLayout(LayoutKind.Sequential, Size=14)]
    public struct GroupIconDirEntry
    {
        public BYTE  Width;          // Width, in pixels, of the image
        public BYTE  Height;         // Height, in pixels, of the image
        public BYTE  ColorCount;     // Number of colors in image (0 if >=8bpp)
        public BYTE  Reserved;       // Reserved ( must be 0)
        public WORD  Planes;         // Color Planes
        public WORD  BitCount;       // Bits per pixel
        public DWORD BytesInRes;     // How many bytes in this resource?
        public WORD  ID;             // the ID

        /// <summary>
        /// Converts the current TAFactory.IconPack.GroupIconDirEntry into TAFactory.IconPack.IconDirEntry.
        /// </summary>
        /// <param name="id">The resource identifier.</param>
        /// <returns>TAFactory.IconPack.IconDirEntry</returns>
        public IconDirEntry ToIconDirEntry(int imageOffiset)
        {
            IconDirEntry entry = new IconDirEntry();
            entry.Width = this.Width;
            entry.Height = this.Height;
            entry.ColorCount = this.ColorCount;
            entry.Reserved = this.Reserved;
            entry.Planes = this.Planes;
            entry.BitCount = this.BitCount;
            entry.BytesInRes = this.BytesInRes;
            entry.ImageOffset = imageOffiset;
            return entry;
        }
    }
}