Renamed FloatImpl to SingleImpl.

source/Cosmos.System2_Plugs/System/SingleImpl.cs

@@ -1,16 +1,117 @@
 using System;
 using Cosmos.Common;
-using IL2CPU.API;
+using System.Collections.Generic;
 using IL2CPU.API.Attribs;
 
 namespace Cosmos.System_Plugs.System
 {
     [Plug(Target = typeof(float))]
     public static class SingleImpl
-    { 
+    {
         public static string ToString(ref float aThis)
         {
             return StringHelper.GetNumberString(aThis);
         }
+
+        public static float Parse(string s)
+        {
+            //Format of Float string: [whitespace][sign][integral-digits[,]]integral-digits[.[fractional-digits]][E[sign]exponential-digits][whitespace]
+
+            //Validate input
+            if (s is null) throw new ArgumentNullException("s can not be null");
+
+            //Remove leading whitespaces
+            while (s.Length != 0 && (s[0] == ' ' || s[0] == '\n' || s[0] == '\t'))
+            {
+                s = s.Substring(1);
+            }
+
+            //Check that string is not finished too early
+            if (s.Length == 0) throw new FormatException();
+
+            //Check for sign
+            short sign = 1;
+            if (s[0] == '-')
+            {
+                s = s.Substring(1);
+                sign = -1;
+            }
+            else if (s[0] == '+') s = s.Substring(1);
+
+            //Check that string is not finished too early
+            if (s.Length == 0) throw new FormatException();
+
+            //Read in number
+
+            List<int> internalDigits = new List<int>();
+            List<int> fractionalDigits = new List<int>();
+
+            bool foundDecimal = false;
+
+            //Iterate until fully parsed or an E/Whitespace is found
+            //Assume english standard, so . == decimal seperator and , == thousands seperator
+            while (s.Length != 0)
+            {
+                char active = s[0];
+                if (active == 'E' || active == 'e' || active == ' ' || active == '\n' || active == '\t') break;
+
+                s = s.Substring(1);
+                if (active == '.') foundDecimal = true;
+                else if (active == ',') continue;
+                else if (active >= '0' && active <= '9')
+                {
+                    if (foundDecimal) fractionalDigits.Add(int.Parse(active.ToString()));
+                    else internalDigits.Add(int.Parse(active.ToString()));
+                }
+                else
+                {
+                    throw new FormatException();
+                }
+            }
+
+            //Iterate through rest of string
+            float multiplier = 0;
+            while (s.Length != 0)
+            {
+                //Check for exponential notation i.e. 8.1E10 = 8.1 * 10^10 + Whitespaces
+                //E can only be followed by integers
+                if (s[0] == 'E' || s[0] == 'e')
+                {
+                    multiplier = float.Parse(s.Substring(1));
+                    break;
+                }
+                else if (s[0] == ' ' || s[0] == '\n' || s[0] == '\t') s = s.Substring(1);
+                else throw new FormatException();
+            }
+
+            //Create float
+            float parsed = 0;
+            for (int i = 0; i < internalDigits.Count; i++)
+            {
+                parsed += internalDigits[i] * (float)Math.Pow(10, (internalDigits.Count - (i + 1)));
+            }
+            for (int i = 0; i < fractionalDigits.Count; i++)
+            {
+                parsed += fractionalDigits[i] * (float)Math.Pow(10, -1 * (i + 1));
+            }
+            parsed *= (float)Math.Pow(10, multiplier);
+            parsed *= sign;
+
+            return parsed;
+        }
+
+        public static bool TryParse(string s, out float result)
+        {
+            try
+            {
+                result = Parse(s);
+                return true;
+            }
+            catch (Exception)
+            {
+                result = 0;
+                return false;
+            }
+        }
     }
 }