Add BrotliCalc command line argument parsing

BrotliCalc/Arguments.cs

@@ -0,0 +1,76 @@
+using System;
+using System.IO;
+using BrotliLib.Numbers;
+
+namespace BrotliCalc{
+    static class Arguments{
+        public static void Read(string[] args){
+            for(int index = 0; index < args.Length;){
+                string key = args[index];
+                string value = index + 1 < args.Length ? args[index + 1] : null;
+
+                index += ProcessArgument(key, value);
+            }
+        }
+
+        private static int ProcessArgument(string key, string value){
+            switch(key){
+                case "-help":
+                    static void Print(string arg, string description){
+                        Console.WriteLine();
+                        Console.ForegroundColor = ConsoleColor.White;
+                        Console.Write(" ");
+                        Console.WriteLine(arg);
+                        Console.ForegroundColor = ConsoleColor.Gray;
+                        Console.Write("  ");
+                        Console.WriteLine(description);
+                    }
+
+                    Console.WriteLine("BrotliCalc arguments");
+                    Console.WriteLine("--------------------");
+
+
+                    Environment.Exit(0);
+                    return 1;
+
+                default:
+                    throw new ArgumentException($"Unknown argument {key}");
+            }
+        }
+
+        // Parsing
+
+        private static int ParseInt(string key, string value, IntRange range = default /* IntRange.Any */){
+            if (value == null){
+                throw new ArgumentException($"Missing value for argument {key}");
+            }
+            else if (!int.TryParse(value, out int result)){
+                throw new FormatException($"Value of argument {key} must be a number");
+            }
+            else if (!range.Contains(result)){
+                throw new ArgumentException($"Value of argument {key} must be in the range {range}");
+            }
+            else{
+                return result;
+            }
+        }
+
+        private static string ParseFolder(string key, string value){
+            if (value == null || !Directory.Exists(value)){
+                throw new ArgumentException($"Folder specified by argument {key} does not exist: {value ?? "<missing>"}");
+            }
+            else{
+                return value;
+            }
+        }
+
+        private static string ParseFile(string key, string value){
+            if (value == null || !File.Exists(value)){
+                throw new ArgumentException($"File specified by argument {key} does not exist: {value ?? "<missing>"}");
+            }
+            else{
+                return value;
+            }
+        }
+    }
+}

BrotliCalc/Program.cs

@@ -18,10 +18,21 @@ namespace BrotliCalc{
             new CmdBenchReserializeRebuild()
         };
 
-        private static void Main(){
+        private static void Main(string[] args){
             Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
             Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
 
+            try{
+                Arguments.Read(args);
+            }catch(Exception e){
+                Console.ForegroundColor = ConsoleColor.Red;
+                Console.WriteLine("Error parsing the arguments:");
+                Console.ForegroundColor = ConsoleColor.Gray;
+                Console.WriteLine(e.Message);
+                Debug.Print(e.ToString());
+                return;
+            }
+
             Console.ForegroundColor = ConsoleColor.White;
             Console.WriteLine("Available commands:");
             Console.WriteLine();
@@ -73,9 +84,9 @@ namespace BrotliCalc{
                 }
 
                 IntRange range = command.ArgumentCount;
-                string[] args = ParseCommandArguments(input.ElementAtOrDefault(1) ?? string.Empty);
+                string[] arguments = ParseCommandArguments(input.ElementAtOrDefault(1) ?? string.Empty);
 
-                if (!range.Contains(args.Length)){
+                if (!range.Contains(arguments.Length)){
                     if (range.First == range.Last){
                         Console.WriteLine($"Command requires exactly {range.First} argument(s).");
                     }
@@ -93,7 +104,7 @@ namespace BrotliCalc{
                     Console.ForegroundColor = ConsoleColor.White;
 
                     var stopwatch = Stopwatch.StartNew();
-                    var result = command.Process(args);
+                    var result = command.Process(arguments);
                     stopwatch.Stop();
 
                     Console.WriteLine(result);