Distinguish IO extensions and helpers

SabreTools.IO/IOExtensions.cs

@@ -0,0 +1,132 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+namespace SabreTools.IO
+{
+    /// <summary>
+    /// Methods around path operations
+    /// </summary>
+    public static class IOExtensions
+    {
+        /// <summary>
+        /// Ensure the output directory is a proper format and can be created
+        /// </summary>
+        /// <param name="dir">Directory to check</param>
+        /// <param name="create">True if the directory should be created, false otherwise (default)</param>
+        /// <param name="temp">True if this is a temp directory, false otherwise</param>
+        /// <returns>Full path to the directory</returns>
+        public static string Ensure(this string dir, bool create = false, bool temp = false)
+        {
+            // If the output directory is invalid
+            if (string.IsNullOrWhiteSpace(dir))
+            {
+                if (temp)
+                    dir = Path.GetTempPath();
+                else
+                    dir = Environment.CurrentDirectory;
+            }
+
+            // Get the full path for the output directory
+            dir = Path.GetFullPath(dir);
+
+            // If we're creating the output folder, do so
+            if (create)
+                Directory.CreateDirectory(dir);
+
+            return dir;
+        }
+
+        /// <summary>
+        /// Determines a text file's encoding by analyzing its byte order mark (BOM).
+        /// Defaults to ASCII when detection of the text file's endianness fails.
+        /// </summary>
+        /// <param name="filename">The text file to analyze.</param>
+        /// <returns>The detected encoding.</returns>
+        /// <link>http://stackoverflow.com/questions/3825390/effective-way-to-find-any-files-encoding</link>
+        public static Encoding GetEncoding(this string filename)
+        {
+            if (string.IsNullOrEmpty(filename))
+                return Encoding.Default;
+
+            if (!File.Exists(filename))
+                return Encoding.Default;
+
+            // Try to open the file
+            try
+            {
+                FileStream file = File.OpenRead(filename);
+                if (file == null)
+                    return Encoding.Default;
+
+                // Read the BOM
+                var bom = new byte[4];
+                file.Read(bom, 0, 4);
+                file.Dispose();
+
+                // Analyze the BOM
+                if (bom[0] == 0x2b && bom[1] == 0x2f && bom[2] == 0x76) return Encoding.UTF7;
+                if (bom[0] == 0xef && bom[1] == 0xbb && bom[2] == 0xbf) return Encoding.UTF8;
+                if (bom[0] == 0xff && bom[1] == 0xfe) return Encoding.Unicode; //UTF-16LE
+                if (bom[0] == 0xfe && bom[1] == 0xff) return Encoding.BigEndianUnicode; //UTF-16BE
+                if (bom[0] == 0 && bom[1] == 0 && bom[2] == 0xfe && bom[3] == 0xff) return Encoding.UTF32;
+                return Encoding.Default;
+            }
+            catch
+            {
+                return Encoding.Default;
+            }
+        }
+
+        /// <summary>
+        /// Get the extension from the path, if possible
+        /// </summary>
+        /// <param name="path">Path to get extension from</param>
+        /// <returns>Extension, if possible</returns>
+        public static string GetNormalizedExtension(this string path)
+        {
+            // Check null or empty first
+            if (string.IsNullOrWhiteSpace(path))
+                return null;
+
+            // Get the extension from the path, if possible
+            string ext = Path.GetExtension(path)?.ToLowerInvariant();
+
+            // Check if the extension is null or empty
+            if (string.IsNullOrWhiteSpace(ext))
+                return null;
+
+            // Make sure that extensions are valid
+            ext = ext.TrimStart('.');
+
+            return ext;
+        }
+    
+        /// <summary>
+        /// Get all empty folders within a root folder
+        /// </summary>
+        /// <param name="root">Root directory to parse</param>
+        /// <returns>IEumerable containing all directories that are empty, an empty enumerable if the root is empty, null otherwise</returns>
+        public static List<string> ListEmpty(this string root)
+        {
+            // Check null or empty first
+            if (string.IsNullOrEmpty(root))
+                return null;
+
+            // Then, check if the root exists
+            if (!Directory.Exists(root))
+                return null;
+
+            // If it does and it is empty, return a blank enumerable
+            if (Directory.EnumerateFileSystemEntries(root, "*", SearchOption.AllDirectories).Count() == 0)
+                return new List<string>();
+
+            // Otherwise, get the complete list
+            return Directory.EnumerateDirectories(root, "*", SearchOption.AllDirectories)
+                .Where(dir => Directory.EnumerateFileSystemEntries(dir, "*", SearchOption.AllDirectories).Count() == 0)
+                .ToList();
+        }
+    }
+}