Fixed formatting negative durations, rounding. Bump version

Author: andersnm

README.md

@@ -41,10 +41,12 @@ Fraction | 0/0       |double|Convert.ToDouble()
 Exponent | \#0.0E+0  |double|Convert.ToDouble()
 Date/Time| hh\:mm    |DateTime|Convert.ToDateTime()
 Duration | \[hh\]\:mm|TimeSpan|Cast to TimeSpan
-General  | General   |(any)|Convert.ToString()
+General  | General   |(any)|CompatibleConvert.ToString()
 Text     | ;;;"Text: "@|string|Convert.ToString()
 
-In case of errors, `Format()` returns the value from `Convert.ToString()`.
+In case of errors, `Format()` returns the value from `CompatibleConvert.ToString()`.
+
+`CompatibleConvert.ToString()` formats floats and doubles with explicit precision, or falls back to `Convert.ToString()` for any other types.
 
 ## TODO/notes
 

src/ExcelNumberFormat/ExcelNumberFormat.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFrameworks>net20;netstandard1.0;netstandard2.0</TargetFrameworks>
-    <VersionPrefix>1.0.9</VersionPrefix>
+    <VersionPrefix>1.0.10</VersionPrefix>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <Description>.NET library to parse ECMA-376 number format strings and format values like Excel and other spreadsheet softwares.</Description>

src/ExcelNumberFormat/Formatter.cs

@@ -77,7 +77,7 @@ private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, Cul
             // The timeSpan input is then truncated to the remainder fraction, which is used to format mm and/or ss.
             var result = new StringBuilder();
             var containsMilliseconds = false;
-            for (var i = tokens.Count-1; i >= 0; i--)
+            for (var i = tokens.Count - 1; i >= 0; i--)
             {
                 if (tokens[i].StartsWith(".0"))
                 {
@@ -98,16 +98,9 @@ private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, Cul
                 }
                 else if (token.StartsWith("s", StringComparison.OrdinalIgnoreCase))
                 {
-                    var value = timeSpan.Seconds;
-                    if (!containsMilliseconds)
-                    {
-                        var roundedMilliseconds = GetRoundedMilliseconds(timeSpan);
-                        
-                        if (roundedMilliseconds >= 500)
-                        {
-                            value += 1;
-                        }
-                    }
+                    // If format does not include ms, then include ms in seconds and round before printing
+                    var formatMs = containsMilliseconds ? 0 : timeSpan.Milliseconds / 1000D;
+                    var value = (int)Math.Round(timeSpan.Seconds + formatMs, 0, MidpointRounding.AwayFromZero);
                     var digits = token.Length;
                     result.Append(value.ToString("D" + digits));
                 }
@@ -116,24 +109,24 @@ private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, Cul
                     var value = (int)timeSpan.TotalHours;
                     var digits = token.Length - 2;
                     result.Append(value.ToString("D" + digits));
-                    timeSpan = TimeSpan.FromHours(timeSpan.TotalHours - value);
+                    timeSpan = new TimeSpan(0, 0, Math.Abs(timeSpan.Minutes), Math.Abs(timeSpan.Seconds), Math.Abs(timeSpan.Milliseconds));
                 }
                 else if (token.StartsWith("[m", StringComparison.OrdinalIgnoreCase))
                 {
                     var value = (int)timeSpan.TotalMinutes;
                     var digits = token.Length - 2;
                     result.Append(value.ToString("D" + digits));
-                    timeSpan = TimeSpan.FromMinutes(timeSpan.TotalMinutes - value);
+                    timeSpan = new TimeSpan(0, 0, 0, Math.Abs(timeSpan.Seconds), Math.Abs(timeSpan.Milliseconds));
                 }
                 else if (token.StartsWith("[s", StringComparison.OrdinalIgnoreCase))
                 {
                     var value = (int)timeSpan.TotalSeconds;
                     var digits = token.Length - 2;
                     result.Append(value.ToString("D" + digits));
-                    timeSpan = TimeSpan.FromSeconds(timeSpan.TotalSeconds - value);
+                    timeSpan = new TimeSpan(0, 0, 0, 0, Math.Abs(timeSpan.Milliseconds));
                 }
                 else if (token.StartsWith(".0")) {
-                    var value = GetRoundedMilliseconds(timeSpan);
+                    var value = timeSpan.Milliseconds;
                     var digits = token.Length - 1;
                     result.Append("." + value.ToString("D" + digits));
                 }
@@ -146,17 +139,6 @@ private static string FormatTimeSpan(TimeSpan timeSpan, List<string> tokens, Cul
             return result.ToString();
         }
 
-        /// <summary>
-        /// In .Net Core 3.0, TimeSpan is stored with microseconds. As a result, 31:44.500 may be presented as 31:44.499999,
-        /// and TimeSpan.Microseconds will return 499 instead of 500. This method returns a number of microseconds rounded
-        /// to a whole.
-        /// </summary>
-        private static int GetRoundedMilliseconds(TimeSpan timeSpan)
-        {
-            var milliseconds = timeSpan.TotalMilliseconds - (int)timeSpan.TotalSeconds * 1000;
-            return (int)Math.Round(milliseconds);
-        }
-
         private static string FormatDate(DateTime date, List<string> tokens, CultureInfo culture)
         {
             var containsAmPm = ContainsAmPm(tokens);

test/ExcelNumberFormat.Tests/Class1.cs

@@ -153,6 +153,11 @@ public void TestTimeSpan()
             Test(new TimeSpan(1, 2, 31, 45), "[hh]:mm:ss", "26:31:45");
             Test(new TimeSpan(1, 2, 31, 44, 500), "[hh]:mm:ss", "26:31:45");
             Test(new TimeSpan(1, 2, 31, 44, 500), "[hh]:mm:ss.000", "26:31:44.500");
+
+            Test(new TimeSpan(-1, -2, -31, -45), "[hh]:mm:ss", "-26:31:45");
+            Test(new TimeSpan(0, -2, -31, -45), "[hh]:mm:ss", "-02:31:45");
+            Test(new TimeSpan(0, -2, -31, -44, -500), "[hh]:mm:ss", "-02:31:45");
+            Test(new TimeSpan(0, -2, -31, -44, -500), "[hh]:mm:ss.000", "-02:31:44.500");
         }
 
         void Test(object value, string format, string expected)