Unify parsing part of BigInteger with CoreLib

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

@@ -580,7 +580,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\Number.Dragon4.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Number.Formatting.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Number.Grisu3.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\Number.NumberBuffer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Number.NumberToFloatingPointBits.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Number.Parsing.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\Numerics\BitOperations.cs" />
@@ -1420,6 +1419,12 @@
     <Compile Include="$(CommonPath)System\NotImplemented.cs">
       <Link>Common\System\NotImplemented.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)System\Number.NumberBuffer.cs">
+      <Link>System\Number.NumberBuffer.cs</Link>
+    </Compile>
+    <Compile Include="$(CommonPath)System\Number.Parsing.Common.cs">
+      <Link>System\Number.Parsing.Common.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)System\Numerics\Crc32ReflectedTable.cs">
       <Link>Common\System\Numerics\Crc32ReflectedTable.cs</Link>
     </Compile>

src/libraries/System.Private.CoreLib/src/System/Number.Parsing.cs

@@ -1361,17 +1361,6 @@ private static bool TrailingZeros<TChar>(ReadOnlySpan<TChar> value, int index)
             return null;
         }
 
-        private static bool IsWhite(uint ch) => (ch == 0x20) || ((ch - 0x09) <= (0x0D - 0x09));
-
-        private static bool IsDigit(uint ch) => (ch - '0') <= 9;
-
-        internal enum ParsingStatus
-        {
-            OK,
-            Failed,
-            Overflow
-        }
-
         [DoesNotReturn]
         internal static void ThrowOverflowOrFormatException<TChar, TInteger>(ParsingStatus status, ReadOnlySpan<TChar> value)
             where TChar : unmanaged, IUtfChar<TChar>

src/libraries/System.Runtime.Numerics/src/System.Runtime.Numerics.csproj

@@ -17,21 +17,24 @@
     <Compile Include="System\Numerics\BigIntegerCalculator.SquMul.cs" />
     <Compile Include="System\Numerics\BigIntegerCalculator.Utils.cs" />
     <Compile Include="System\Numerics\BigInteger.cs" />
-    <Compile Include="System\Numerics\BigNumber.cs" />
+    <Compile Include="System\Number.BigInteger.cs" />
     <Compile Include="System\Numerics\NumericsHelpers.cs" />
     <Compile Include="System\Numerics\Complex.cs" />
     <Compile Include="System\Globalization\FormatProvider.BigInteger.cs" />
+    <Compile Include="System\Globalization\FormatProvider.Number.cs" />
     <Compile Include="System\Globalization\FormatProvider.NumberBuffer.cs" />
     <Compile Include="Properties\InternalsVisibleTo.cs" />
   </ItemGroup>
 
   <ItemGroup>
-    <Compile Include="$(CommonPath)System\Globalization\FormatProvider.Number.cs"
-             Link="System\Globalization\FormatProvider.Number.cs" />
     <Compile Include="$(CommonPath)System\Text\ValueStringBuilder.cs"
              Link="CoreLib\System\Text\ValueStringBuilder.cs" />
     <Compile Include="$(CommonPath)System\HexConverter.cs"
              Link="Common\System\HexConverter.cs" />
+    <Compile Include="$(CommonPath)System\Number.NumberBuffer.cs"
+             Link="Common\System\Number.NumberBuffer.cs" />
+    <Compile Include="$(CommonPath)System\Number.Parsing.Common.cs"
+             Link="Common\System\Number.Parsing.Common.cs" />
   </ItemGroup>
 
   <ItemGroup>

src/libraries/System.Runtime.Numerics/src/System/Globalization/FormatProvider.BigInteger.cs

@@ -1,7 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Security;
 using System.Text;
 
 namespace System.Globalization
@@ -32,43 +31,5 @@ internal static void FormatBigInteger(ref ValueStringBuilder sb, int precision,
                 }
             }
         }
-
-        internal static bool TryStringToBigInteger(
-            ReadOnlySpan<char> s,
-            NumberStyles styles,
-            NumberFormatInfo numberFormatInfo,
-            StringBuilder receiver,  // Receives the decimal digits
-            out int precision,
-            out int scale,
-            out bool sign
-            )
-        {
-            FormatProvider.Number.NumberBuffer numberBuffer = default;
-
-            unsafe
-            {
-                // Note: because we passed a non-null StringBuilder (receiver) to TryStringToNumber, it streams the digits into
-                // that instead of numberBuffer.digits. This is quite important since numberBuffer.digits is a fixed-buffer size
-                // and BigNumbers can have an arbitrary number of digits.
-                //
-                // Just in case a bug is ever introduced into TryStringToNumber that violates this, set the pointer that numberBuffer.digits returns
-                // to something that will AV.
-                numberBuffer.overrideDigits = (char*)0x1;
-            }
-            if (!Number.TryStringToNumber(s, styles, ref numberBuffer, receiver, numberFormatInfo, parseDecimal: false))
-            {
-                precision = default(int);
-                scale = default(int);
-                sign = default(bool);
-                return false;
-            }
-            else
-            {
-                precision = numberBuffer.precision;
-                scale = numberBuffer.scale;
-                sign = numberBuffer.sign;
-                return true;
-            }
-        }
     }
 }