Completed Int32 APIs (#2353)

src/System.Memory.Polyfill/System/Numbers.cs

@@ -0,0 +1,54 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Globalization;
+
+namespace System
+{
+    public static partial class Int32Polyfill
+    {
+        public static bool TryParse(ReadOnlySpan<char> s, out int value)
+        {
+#if NETCOREAPP2_1
+            return int.TryParse(s, out value);
+#else
+            return int.TryParse(s.ToString(), out value);
+#endif
+        }
+
+        public static bool TryParse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider provider, out int value)
+        {
+#if NETCOREAPP2_1
+            return int.TryParse(s, style, provider, out value);
+#else
+            return int.TryParse(s.ToString(), style, provider, out value);
+#endif
+        } 
+
+        public static int Parse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider provider = null)
+        {
+#if NETCOREAPP2_1
+            return int.Parse(s, style, provider);
+#else
+            return int.Parse(s.ToString(), style, provider);
+#endif
+        }
+
+        public static bool TryFormat(this int value, Span<char> destination, out int charsWritten, ReadOnlySpan<char> format = default, IFormatProvider provider = null)
+        {
+#if NETCOREAPP2_1
+            return value.TryFormat(destination, out charsWritten, format, provider);
+#else
+            var str = value.ToString(format.ToString(), provider);
+            if (str.AsSpan().TryCopyTo(destination))
+            {
+                charsWritten = str.Length;
+                return true;
+            }
+            charsWritten = 0;
+            return false;
+#endif
+        }
+    }
+}

tests/System.Memory.Polyfill.Tests/Int32.cs

@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System.IO;
+using System.Globalization;
 using Xunit;
 
 namespace System.Polyfill.Tests
@@ -15,5 +15,33 @@ public void Int32TryParse()
             Assert.True(Int32Polyfill.TryParse(span, out int value));
             Assert.Equal(int.MaxValue, value);
         }
+
+        [Fact]
+        public void Int32TryParseCulture()
+        {
+            var culture = CultureInfo.CreateSpecificCulture("pl-PL");
+            var formatted = (" " + int.MaxValue.ToString("N", culture));
+            Assert.True(Int32Polyfill.TryParse(formatted.AsSpan(), NumberStyles.AllowLeadingWhite | NumberStyles.AllowDecimalPoint | NumberStyles.AllowThousands, culture, out int value));
+            Assert.Equal(int.MaxValue, value);
+        }
+
+        [Fact]
+        public void Int32ParseCulture()
+        {
+            var culture = CultureInfo.CreateSpecificCulture("pl-PL");
+            var formatted = (" " + int.MaxValue.ToString("N", culture));
+            var value = Int32Polyfill.Parse(formatted.AsSpan(), NumberStyles.AllowLeadingWhite | NumberStyles.AllowDecimalPoint | NumberStyles.AllowThousands, culture);
+            Assert.Equal(int.MaxValue, value);
+        }
+
+        [Fact]
+        public void Int32TryFormat()
+        {
+            var culture = CultureInfo.CreateSpecificCulture("pl-PL");
+            var buffer = new char[100];
+            Assert.True(int.MinValue.TryFormat(buffer.AsSpan(), out int written, "N".AsSpan(), culture));
+            var result = buffer.AsSpan(0, written).ToString();
+            Assert.Equal(int.MinValue.ToString("N", culture), result);
+        }
     }
 }