Expose IUtf8SpanParsable and implement it on the primitive numeric ty…

…pes (#86875)

* Expose IUtf8SpanParsable

* Have INumberBase implement IUtf8SpanParsable

* Deduplicate some floating-point parsing logic

* Refactoring the primitive parsing logic to support UTF-8

* Updating the primitive numeric types to include UTF-8 parsing support

* Adding tests covering the new UTF-8 parsing support

* Ensure that tests don't try to capture a span in lambda

* Ensure that MatchChars does the right thing

* Account for the switch from string to ROSpan<TChar> for currSymbol

* Ensure EqualsIgnoreCaseUtf8_Scalar handles the remaining elements correctly

* Allow alloc-free conversion for the UTF8 parsing fallback paths

* Remove unnecessary attributes and ensure trailing elements are correctly handled

* Fix the handling of UTF8 as per the feedback

* Fix a slightly broken merge

* Ensure the lengths are properly checked on the ASCII path

* Ensure that length is defined for 32-bit

* Responding to PR feedback and allow invalid sequences to self match

* Fixing a copy/paste error

* Fixing a build failure due to not assigning the out parameter

src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems

@@ -330,6 +330,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.Icu.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.Invariant.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.Nls.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.Utf8.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.WebAssembly.cs" Condition="'$(TargetsBrowser)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareInfo.OSX.cs" Condition="'$(IsOSXLike)' == 'true'" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\CompareOptions.cs" />
@@ -375,6 +376,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\NumberFormatInfo.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\NumberStyles.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\Ordinal.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\Ordinal.Utf8.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\OrdinalCasing.Icu.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\PersianCalendar.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Globalization\RegionInfo.cs" />
@@ -510,6 +512,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\ISpanFormattable.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IUtfChar.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\IUtf8SpanFormattable.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\IUtf8SpanParsable.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Lazy.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\LazyOfTTMetadata.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\LoaderOptimization.cs" />
@@ -526,7 +529,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryDebugView.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Globalization.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Globalization.Utf8.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Trim.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Trim.Utf8.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MethodAccessException.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MidpointRounding.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MissingFieldException.cs" />

src/libraries/System.Private.CoreLib/src/System/Buffers/Text/Utf8Parser/Utf8Parser.Float.cs

@@ -33,7 +33,7 @@ public static unsafe bool TryParse(ReadOnlySpan<byte> source, out float value, o
 
             if (TryParseNormalAsFloatingPoint(source, ref number, out bytesConsumed, standardFormat))
             {
-                value = Number.NumberToSingle(ref number);
+                value = Number.NumberToFloat<float>(ref number);
                 return true;
             }
 
@@ -66,7 +66,7 @@ public static unsafe bool TryParse(ReadOnlySpan<byte> source, out double value,
 
             if (TryParseNormalAsFloatingPoint(source, ref number, out bytesConsumed, standardFormat))
             {
-                value = Number.NumberToDouble(ref number);
+                value = Number.NumberToFloat<double>(ref number);
                 return true;
             }
 

src/libraries/System.Private.CoreLib/src/System/Byte.cs

@@ -108,13 +108,19 @@ public static byte Parse(string s, NumberStyles style, IFormatProvider? provider
         public static byte Parse(ReadOnlySpan<char> s, NumberStyles style = NumberStyles.Integer, IFormatProvider? provider = null)
         {
             NumberFormatInfo.ValidateParseStyleInteger(style);
-            return Number.ParseBinaryInteger<byte>(s, style, NumberFormatInfo.GetInstance(provider));
+            return Number.ParseBinaryInteger<char, byte>(s, style, NumberFormatInfo.GetInstance(provider));
         }
 
         public static bool TryParse([NotNullWhen(true)] string? s, out byte result) => TryParse(s, NumberStyles.Integer, provider: null, out result);
 
         public static bool TryParse(ReadOnlySpan<char> s, out byte result) => TryParse(s, NumberStyles.Integer, provider: null, out result);
 
+        /// <summary>Tries to convert a UTF-8 character span containing the string representation of a number to its 8-bit unsigned integer equivalent.</summary>
+        /// <param name="utf8Text">A span containing the UTF-8 characters representing the number to convert.</param>
+        /// <param name="result">When this method returns, contains the 8-bit unsigned integer value equivalent to the number contained in <paramref name="utf8Text" /> if the conversion succeeded, or zero if the conversion failed. This parameter is passed uninitialized; any value originally supplied in result will be overwritten.</param>
+        /// <returns><c>true</c> if <paramref name="utf8Text" /> was converted successfully; otherwise, false.</returns>
+        public static bool TryParse(ReadOnlySpan<byte> utf8Text, out byte result) => TryParse(utf8Text, NumberStyles.Integer, provider: null, out result);
+
         public static bool TryParse([NotNullWhen(true)] string? s, NumberStyles style, IFormatProvider? provider, out byte result)
         {
             NumberFormatInfo.ValidateParseStyleInteger(style);
@@ -124,7 +130,7 @@ public static bool TryParse([NotNullWhen(true)] string? s, NumberStyles style, I
                 result = 0;
                 return false;
             }
-            return Number.TryParseBinaryInteger(s, style, NumberFormatInfo.GetInstance(provider), out result) == Number.ParsingStatus.OK;
+            return Number.TryParseBinaryInteger(s.AsSpan(), style, NumberFormatInfo.GetInstance(provider), out result) == Number.ParsingStatus.OK;
         }
 
         public static bool TryParse(ReadOnlySpan<char> s, NumberStyles style, IFormatProvider? provider, out byte result)
@@ -1151,6 +1157,30 @@ static bool INumberBase<byte>.TryConvertToTruncating<TOther>(byte value, [MaybeN
         /// <inheritdoc cref="IUnaryPlusOperators{TSelf, TResult}.op_UnaryPlus(TSelf)" />
         static byte IUnaryPlusOperators<byte, byte>.operator +(byte value) => (byte)(+value);
 
+        //
+        // IUtf8SpanParsable
+        //
+
+        /// <inheritdoc cref="INumberBase{TSelf}.Parse(ReadOnlySpan{byte}, NumberStyles, IFormatProvider?)" />
+        public static byte Parse(ReadOnlySpan<byte> utf8Text, NumberStyles style = NumberStyles.Integer, IFormatProvider? provider = null)
+        {
+            NumberFormatInfo.ValidateParseStyleInteger(style);
+            return Number.ParseBinaryInteger<byte, byte>(utf8Text, style, NumberFormatInfo.GetInstance(provider));
+        }
+
+        /// <inheritdoc cref="INumberBase{TSelf}.TryParse(ReadOnlySpan{byte}, NumberStyles, IFormatProvider?, out TSelf)" />
+        public static bool TryParse(ReadOnlySpan<byte> utf8Text, NumberStyles style, IFormatProvider? provider, out byte result)
+        {
+            NumberFormatInfo.ValidateParseStyleInteger(style);
+            return Number.TryParseBinaryInteger(utf8Text, style, NumberFormatInfo.GetInstance(provider), out result) == Number.ParsingStatus.OK;
+        }
+
+        /// <inheritdoc cref="IUtf8SpanParsable{TSelf}.Parse(ReadOnlySpan{byte}, IFormatProvider?)" />
+        public static byte Parse(ReadOnlySpan<byte> utf8Text, IFormatProvider? provider) => Parse(utf8Text, NumberStyles.Integer, provider);
+
+        /// <inheritdoc cref="IUtf8SpanParsable{TSelf}.TryParse(ReadOnlySpan{byte}, IFormatProvider?, out TSelf)" />
+        public static bool TryParse(ReadOnlySpan<byte> utf8Text, IFormatProvider? provider, out byte result) => TryParse(utf8Text, NumberStyles.Integer, provider, out result);
+
         //
         // IUtfChar
         //
@@ -1161,6 +1191,8 @@ static bool INumberBase<byte>.TryConvertToTruncating<TOther>(byte value, [MaybeN
         static byte IUtfChar<byte>.CastFrom(uint value) => (byte)value;
         static byte IUtfChar<byte>.CastFrom(ulong value) => (byte)value;
 
+        static uint IUtfChar<byte>.CastToUInt32(byte value) => value;
+
         //
         // IBinaryIntegerParseAndFormatInfo
         //

src/libraries/System.Private.CoreLib/src/System/Char.cs

@@ -1993,6 +1993,8 @@ static bool INumberBase<char>.TryConvertToTruncating<TOther>(char value, [MaybeN
         static char IUtfChar<char>.CastFrom(uint value) => (char)value;
         static char IUtfChar<char>.CastFrom(ulong value) => (char)value;
 
+        static uint IUtfChar<char>.CastToUInt32(char value) => value;
+
         //
         // IBinaryIntegerParseAndFormatInfo
         //

src/libraries/System.Private.CoreLib/src/System/Decimal.DecCalc.cs

@@ -196,7 +196,7 @@ private static void UInt64x64To128(ulong a, ulong b, ref DecCalc result)
                     high++;
 
                 if (high > uint.MaxValue)
-                    Number.ThrowOverflowException(TypeCode.Decimal);
+                    Number.ThrowOverflowException(SR.Overflow_Decimal);
                 result.Low64 = low;
                 result.High = (uint)high;
             }
@@ -681,7 +681,7 @@ private static unsafe int ScaleResult(Buf24* bufRes, uint hiRes, int scale)
                 return scale;
 
 ThrowOverflow:
-                Number.ThrowOverflowException(TypeCode.Decimal);
+                Number.ThrowOverflowException(SR.Overflow_Decimal);
                 return 0;
             }
 
@@ -725,7 +725,7 @@ private static unsafe uint DivByConst(uint* result, uint hiRes, out uint quotien
             private static int OverflowUnscale(ref Buf12 bufQuo, int scale, bool sticky)
             {
                 if (--scale < 0)
-                    Number.ThrowOverflowException(TypeCode.Decimal);
+                    Number.ThrowOverflowException(SR.Overflow_Decimal);
 
                 Debug.Assert(bufQuo.U2 == 0);
 
@@ -837,7 +837,7 @@ private static int SearchScale(ref Buf12 bufQuo, int scale)
                 // positive if it isn't already.
                 //
                 if (curScale + scale < 0)
-                    Number.ThrowOverflowException(TypeCode.Decimal);
+                    Number.ThrowOverflowException(SR.Overflow_Decimal);
 
                 return curScale;
             }
@@ -1107,7 +1107,7 @@ internal static unsafe void DecAddSub(ref DecCalc d1, ref DecCalc d2, bool sign)
                     // Divide the value by 10, dropping the scale factor.
                     //
                     if ((flags & ScaleMask) == 0)
-                        Number.ThrowOverflowException(TypeCode.Decimal);
+                        Number.ThrowOverflowException(SR.Overflow_Decimal);
                     flags -= 1 << ScaleShift;
 
                     const uint den = 10;
@@ -1534,7 +1534,7 @@ internal static void VarDecFromR4(float input, out DecCalc result)
                     return; // result should be zeroed out
 
                 if (exp > 96)
-                    Number.ThrowOverflowException(TypeCode.Decimal);
+                    Number.ThrowOverflowException(SR.Overflow_Decimal);
 
                 uint flags = 0;
                 if (input < 0)
@@ -1701,7 +1701,7 @@ internal static void VarDecFromR8(double input, out DecCalc result)
                     return; // result should be zeroed out
 
                 if (exp > 96)
-                    Number.ThrowOverflowException(TypeCode.Decimal);
+                    Number.ThrowOverflowException(SR.Overflow_Decimal);
 
                 uint flags = 0;
                 if (input < 0)
@@ -2170,7 +2170,7 @@ internal static unsafe void VarDecDiv(ref DecCalc d1, ref DecCalc d2)
                 }
 
 ThrowOverflow:
-                Number.ThrowOverflowException(TypeCode.Decimal);
+                Number.ThrowOverflowException(SR.Overflow_Decimal);
             }
 
             /// <summary>