IniFile.cs

// **************************
// *** IniFile class V1.0    ***
// **************************
// *** (C)2009 S.T.A. snc ***
// **************************
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text;
using System.Threading;

namespace CreateMissing
{

	internal class IniFile
	{

#region "Declarations"

		// *** Lock for thread-safe access to file and local cache ***
		private readonly Lock m_Lock = new();

		// *** File name ***
		private string m_FileName = null;
		internal string FileName
		{
			get
			{
				return m_FileName;
			}
		}

		// *** Lazy loading flag ***
		private bool m_Lazy = false;

		// *** Local cache ***
		private readonly Dictionary<string, Dictionary<string, string>> m_Sections = [];

		// *** Local cache modified flag ***
		private bool m_CacheModified = false;

#endregion

#region "Methods"

		// *** Constructor ***
		public IniFile(string FileName)
		{
			Initialize(FileName, false);
		}

		public IniFile(string FileName, bool Lazy)
		{
			Initialize(FileName, Lazy);
		}

		// *** Initialization ***
		private void Initialize (string FileName, bool Lazy)
		{
			m_FileName = FileName;
			m_Lazy = Lazy;
			if (!m_Lazy) Refresh();
		}

		// *** Read file contents into local cache ***
		internal void Refresh()
		{
			lock (m_Lock)
			{
				FileStream fs = null;
				StreamReader sr = null;
				try
				{
					// *** Clear local cache ***
					m_Sections.Clear();

					// *** Open the INI file ***
					try
					{
						fs = new FileStream(m_FileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
						sr = new StreamReader(fs);
					}
					catch (FileNotFoundException)
					{
						return;
					}

					// *** Read up the file content ***
					Dictionary<string, string> CurrentSection = null;
					string s;
					while ((s = sr.ReadLine()) != null)
					{
						s = s.Trim();

						// *** Check for section names ***
						if (s.StartsWith('[') && s.EndsWith(']'))
						{
							if (s.Length > 2)
							{
								string SectionName = s[1..^1];

								// *** Only first occurrence of a section is loaded ***
								if (m_Sections.ContainsKey(SectionName))
								{
									CurrentSection = null;
								}
								else
								{
									CurrentSection = [];
									m_Sections.Add(SectionName,CurrentSection);
								}
							}
						}
						else if (CurrentSection != null)
						{
							// *** Check for key+value pair ***
							int i;
							if ((i=s.IndexOf('=')) > 0)
							{
								int j = s.Length - i - 1;
								string Key = s[..i].Trim();
								if (Key.Length  > 0)
								{
									// *** Only first occurrence of a key is loaded ***
									if (!CurrentSection.ContainsKey(Key))
									{
										string Value = (j > 0) ? (s.Substring(i+1,j).Trim()) : (string.Empty);
										CurrentSection.Add(Key,Value);
									}
								}
							}
						}
					}
				}
				finally
				{
					// *** Cleanup: close file ***
					if (sr != null) sr.Close();
					if (fs != null) fs.Close();
					sr = null;
					fs = null;
				}
			}
		}

		// *** Flush local cache content ***
		internal void Flush()
		{
			lock(m_Lock)
			{
				// *** If local cache was not modified, exit ***
				if (!m_CacheModified) return;
				m_CacheModified=false;

				// *** Open the file ***
				using StreamWriter sw = new StreamWriter(m_FileName);

				// *** Cycle on all sections ***
				bool First = false;
				foreach (KeyValuePair<string, Dictionary<string, string>> SectionPair in m_Sections)
				{
					Dictionary<string, string> Section = SectionPair.Value;
					if (First) sw.WriteLine();
					First = true;

					// *** Write the section name ***
					sw.Write('[');
					sw.Write(SectionPair.Key);
					sw.WriteLine(']');

					// *** Cycle on all key+value pairs in the section ***
					foreach (KeyValuePair<string, string> ValuePair in Section)
					{
						// *** Write the key+value pair ***
						sw.Write(ValuePair.Key);
						sw.Write('=');
						sw.WriteLine(ValuePair.Value);
					}
				}
			}
		}

		// *** Read a value from local cache ***
		internal string GetValue(string SectionName, string Key, string DefaultValue)
		{
			// *** Lazy loading ***
			if (m_Lazy)
			{
				m_Lazy = false;
				Refresh();
			}

			lock (m_Lock)
			{
				// *** Check if the section exists ***
				Dictionary<string, string> Section;
				if (!m_Sections.TryGetValue(SectionName, out Section)) return DefaultValue;

				// *** Check if the key exists ***
				string Value;
				if (!Section.TryGetValue(Key, out Value)) return DefaultValue;

				// *** Check if the value is blank ***
				if (string.IsNullOrWhiteSpace(Value)) return DefaultValue;

				// *** Return the found value ***
				return Value;
			}
		}

		// *** Insert or modify a value in local cache ***
		internal void SetValue(string SectionName, string Key, string Value)
		{
			// *** Lazy loading ***
			if (m_Lazy)
			{
				m_Lazy = false;
				Refresh();
			}

			lock (m_Lock)
			{
				// *** Flag local cache modification ***
				m_CacheModified = true;

				// *** Check if the section exists ***
				Dictionary<string, string> Section;
				if (!m_Sections.TryGetValue(SectionName, out Section))
				{
					// *** If it doesn't, add it ***
					Section = [];
					m_Sections.Add(SectionName,Section);
				}

				// *** Modify the value ***
				Section.Remove(Key);
				Section.Add(Key, Value);
			}
		}

		internal bool ValueExists(string SectionName, string Key)
		{
			// *** Lazy loading ***
			if (m_Lazy)
			{
				m_Lazy = false;
				Refresh();
			}

			lock (m_Lock)
			{
				// *** Check if the section exists ***
				Dictionary<string, string> Section;
				if (!m_Sections.TryGetValue(SectionName, out Section)) return false;

				// *** Check if the key exists ***
				return Section.TryGetValue(Key, out _);
			}
		}

			// *** Encode byte array ***
		private static string EncodeByteArray(byte[] Value)
		{
			if (Value == null) return null;

			StringBuilder sb = new StringBuilder();
			foreach (byte b in Value)
			{
				string hex = Convert.ToString(b,16);
				int l = hex.Length;
				if (l > 2)
				{
					sb.Append(hex.AsSpan(l-2,2));
				}
				else
				{
					if (l < 2) sb.Append('0');
					sb.Append(hex);
				}
			}
			return sb.ToString();
		}

		// *** Decode byte array ***
		private static byte[] DecodeByteArray(string Value)
		{
			if (Value == null) return null;

			int l = Value.Length;
			if (l < 2) return [];

			l /= 2;
			byte[] Result = new byte[l];
			for (int i=0; i<l; i++) Result[i] = Convert.ToByte(Value.Substring(i*2,2),16);
			return Result;
		}

		// *** Getters for various types ***
		internal bool GetValue(string SectionName, string Key, bool DefaultValue)
		{
			string StringValue=GetValue(SectionName, Key, DefaultValue.ToString(System.Globalization.CultureInfo.InvariantCulture));
			int Value;
			if (int.TryParse(StringValue, out Value)) return (Value != 0);
			return DefaultValue;
		}

		internal int GetValue(string SectionName, string Key, int DefaultValue)
		{
			string StringValue=GetValue(SectionName, Key, DefaultValue.ToString(CultureInfo.InvariantCulture));
			int Value;
			if (int.TryParse(StringValue, NumberStyles.Any, CultureInfo.InvariantCulture, out Value)) return Value;
			return DefaultValue;
		}

		internal double GetValue(string SectionName, string Key, double DefaultValue)
		{
			string StringValue=GetValue(SectionName, Key, DefaultValue.ToString(CultureInfo.InvariantCulture));
			double Value;
			if (double.TryParse(StringValue, NumberStyles.Any, CultureInfo.InvariantCulture, out Value)) return Value;
			return DefaultValue;
		}

		internal byte[] GetValue(string SectionName, string Key, byte[] DefaultValue)
		{
			string StringValue = GetValue(SectionName, Key, EncodeByteArray(DefaultValue));
			try
			{
				return DecodeByteArray(StringValue);
			}
			catch (FormatException)
			{
				return DefaultValue;
			}
		}

		internal DateTime GetValue(string SectionName, string Key, DateTime DefaultValue)
		{
			string StringValue = GetValue(SectionName, Key, DefaultValue.ToString(CultureInfo.InvariantCulture));
			DateTime Value;
			if (DateTime.TryParse(StringValue, out Value)) return Value;
			return DefaultValue;
		}

		// *** Setters for various types ***
		internal void SetValue(string SectionName, string Key, bool Value)
		{
			SetValue(SectionName, Key, (Value) ? ("1") : ("0"));
		}

		internal void SetValue(string SectionName, string Key, int Value)
		{
			SetValue(SectionName, Key, Value.ToString(CultureInfo.InvariantCulture));
		}

		internal void SetValue(string SectionName, string Key, double Value)
		{
			SetValue(SectionName, Key, Value.ToString("G17", CultureInfo.InvariantCulture));
		}

		internal void SetValue(string SectionName, string Key, byte[] Value)
		{
			SetValue(SectionName, Key, EncodeByteArray(Value));
		}

		internal void SetValue(string SectionName, string Key, DateTime Value)
		{
			// write datetimes in ISO 8601 ("sortable")
			SetValue(SectionName, Key, Value.ToString("s"));
		}

		#endregion
	}

}