Clean up in Number.Formatting.cs (#110955)

Author: EgorBo

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

@@ -268,11 +268,11 @@ internal static partial class Number
             300;
 #endif
         /// <summary>Lazily-populated cache of strings for uint values in the range [0, <see cref="SmallNumberCacheLength"/>).</summary>
-        private static readonly string[] s_smallNumberCache = new string[SmallNumberCacheLength];
+        private static readonly string?[] s_smallNumberCache = new string[SmallNumberCacheLength];
 
         // Optimizations using "TwoDigits" inspired by:
         // https://engineering.fb.com/2013/03/15/developer-tools/three-optimization-tips-for-c/
-        private static readonly byte[] TwoDigitsCharsAsBytes =
+        private static ReadOnlySpan<byte> TwoDigitsCharsAsBytes =>
             MemoryMarshal.AsBytes<char>("00010203040506070809" +
                                         "10111213141516171819" +
                                         "20212223242526272829" +
@@ -282,9 +282,9 @@ internal static partial class Number
                                         "60616263646566676869" +
                                         "70717273747576777879" +
                                         "80818283848586878889" +
-                                        "90919293949596979899").ToArray();
-        private static readonly byte[] TwoDigitsBytes =
-                                       ("00010203040506070809"u8 +
+                                        "90919293949596979899");
+        private static ReadOnlySpan<byte> TwoDigitsBytes =>
+                                        "00010203040506070809"u8 +
                                         "10111213141516171819"u8 +
                                         "20212223242526272829"u8 +
                                         "30313233343536373839"u8 +
@@ -293,7 +293,7 @@ internal static partial class Number
                                         "60616263646566676869"u8 +
                                         "70717273747576777879"u8 +
                                         "80818283848586878889"u8 +
-                                        "90919293949596979899"u8).ToArray();
+                                        "90919293949596979899"u8;
 
         public static unsafe string FormatDecimal(decimal value, ReadOnlySpan<char> format, NumberFormatInfo info)
         {
@@ -387,9 +387,8 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
 
             int maxDigits = precision;
 
-            switch (fmt)
+            switch (fmt | 0x20)
             {
-                case 'C':
                 case 'c':
                     {
                         // The currency format uses the precision specifier to indicate the number of
@@ -404,7 +403,6 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
                         break;
                     }
 
-                case 'E':
                 case 'e':
                     {
                         // The exponential format uses the precision specifier to indicate the number of
@@ -423,9 +421,7 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
                         break;
                     }
 
-                case 'F':
                 case 'f':
-                case 'N':
                 case 'n':
                     {
                         // The fixed-point and number formats use the precision specifier to indicate the number
@@ -440,7 +436,6 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
                         break;
                     }
 
-                case 'G':
                 case 'g':
                     {
                         // The general format uses the precision specifier to indicate the number of significant
@@ -457,7 +452,6 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
                         break;
                     }
 
-                case 'P':
                 case 'p':
                     {
                         // The percent format uses the precision specifier to indicate the number of
@@ -476,7 +470,6 @@ private static int GetFloatingPointMaxDigitsAndPrecision(char fmt, ref int preci
                         break;
                     }
 
-                case 'R':
                 case 'r':
                     {
                         // The roundtrip format ignores the precision specifier and always returns the shortest
@@ -1579,7 +1572,7 @@ internal static unsafe void WriteTwoDigits<TChar>(uint value, TChar* ptr) where
 
             Unsafe.CopyBlockUnaligned(
                 ref *(byte*)ptr,
-                ref Unsafe.Add(ref MemoryMarshal.GetArrayDataReference(typeof(TChar) == typeof(char) ? TwoDigitsCharsAsBytes : TwoDigitsBytes), (uint)sizeof(TChar) * 2 * value),
+                ref Unsafe.Add(ref MemoryMarshal.GetReference(typeof(TChar) == typeof(char) ? TwoDigitsCharsAsBytes : TwoDigitsBytes), (uint)sizeof(TChar) * 2 * value),
                 (uint)sizeof(TChar) * 2);
         }
 
@@ -1595,7 +1588,7 @@ internal static unsafe void WriteFourDigits<TChar>(uint value, TChar* ptr) where
 
             (value, uint remainder) = Math.DivRem(value, 100);
 
-            ref byte charsArray = ref MemoryMarshal.GetArrayDataReference(typeof(TChar) == typeof(char) ? TwoDigitsCharsAsBytes : TwoDigitsBytes);
+            ref byte charsArray = ref MemoryMarshal.GetReference(typeof(TChar) == typeof(char) ? TwoDigitsCharsAsBytes : TwoDigitsBytes);
 
             Unsafe.CopyBlockUnaligned(
                 ref *(byte*)ptr,
@@ -1677,7 +1670,7 @@ internal static unsafe void WriteDigits<TChar>(uint value, TChar* ptr, int count
             return bufferEnd;
         }
 
-        internal static unsafe string UInt32ToDecStr(uint value)
+        internal static string UInt32ToDecStr(uint value)
         {
             // For small numbers, consult a lazily-populated cache.
             if (value < SmallNumberCacheLength)
@@ -2540,102 +2533,6 @@ private static unsafe bool TryUInt128ToDecStr<TChar>(UInt128 value, int digits,
             return false;
         }
 
-        private static ulong ExtractFractionAndBiasedExponent(double value, out int exponent)
-        {
-            ulong bits = BitConverter.DoubleToUInt64Bits(value);
-            ulong fraction = (bits & 0xFFFFFFFFFFFFF);
-            exponent = ((int)(bits >> 52) & 0x7FF);
-
-            if (exponent != 0)
-            {
-                // For normalized value, according to https://en.wikipedia.org/wiki/Double-precision_floating-point_format
-                // value = 1.fraction * 2^(exp - 1023)
-                //       = (1 + mantissa / 2^52) * 2^(exp - 1023)
-                //       = (2^52 + mantissa) * 2^(exp - 1023 - 52)
-                //
-                // So f = (2^52 + mantissa), e = exp - 1075;
-
-                fraction |= (1UL << 52);
-                exponent -= 1075;
-            }
-            else
-            {
-                // For denormalized value, according to https://en.wikipedia.org/wiki/Double-precision_floating-point_format
-                // value = 0.fraction * 2^(1 - 1023)
-                //       = (mantissa / 2^52) * 2^(-1022)
-                //       = mantissa * 2^(-1022 - 52)
-                //       = mantissa * 2^(-1074)
-                // So f = mantissa, e = -1074
-                exponent = -1074;
-            }
-
-            return fraction;
-        }
-
-        private static ushort ExtractFractionAndBiasedExponent(Half value, out int exponent)
-        {
-            ushort bits = BitConverter.HalfToUInt16Bits(value);
-            ushort fraction = (ushort)(bits & 0x3FF);
-            exponent = ((int)(bits >> 10) & 0x1F);
-
-            if (exponent != 0)
-            {
-                // For normalized value, according to https://en.wikipedia.org/wiki/Half-precision_floating-point_format
-                // value = 1.fraction * 2^(exp - 15)
-                //       = (1 + mantissa / 2^10) * 2^(exp - 15)
-                //       = (2^10 + mantissa) * 2^(exp - 15 - 10)
-                //
-                // So f = (2^10 + mantissa), e = exp - 25;
-
-                fraction |= (ushort)(1U << 10);
-                exponent -= 25;
-            }
-            else
-            {
-                // For denormalized value, according to https://en.wikipedia.org/wiki/Half-precision_floating-point_format
-                // value = 0.fraction * 2^(1 - 15)
-                //       = (mantissa / 2^10) * 2^(-14)
-                //       = mantissa * 2^(-14 - 10)
-                //       = mantissa * 2^(-24)
-                // So f = mantissa, e = -24
-                exponent = -24;
-            }
-
-            return fraction;
-        }
-
-        private static uint ExtractFractionAndBiasedExponent(float value, out int exponent)
-        {
-            uint bits = BitConverter.SingleToUInt32Bits(value);
-            uint fraction = (bits & 0x7FFFFF);
-            exponent = ((int)(bits >> 23) & 0xFF);
-
-            if (exponent != 0)
-            {
-                // For normalized value, according to https://en.wikipedia.org/wiki/Single-precision_floating-point_format
-                // value = 1.fraction * 2^(exp - 127)
-                //       = (1 + mantissa / 2^23) * 2^(exp - 127)
-                //       = (2^23 + mantissa) * 2^(exp - 127 - 23)
-                //
-                // So f = (2^23 + mantissa), e = exp - 150;
-
-                fraction |= (1U << 23);
-                exponent -= 150;
-            }
-            else
-            {
-                // For denormalized value, according to https://en.wikipedia.org/wiki/Single-precision_floating-point_format
-                // value = 0.fraction * 2^(1 - 127)
-                //       = (mantissa / 2^23) * 2^(-126)
-                //       = mantissa * 2^(-126 - 23)
-                //       = mantissa * 2^(-149)
-                // So f = mantissa, e = -149
-                exponent = -149;
-            }
-
-            return fraction;
-        }
-
         private static ulong ExtractFractionAndBiasedExponent<TNumber>(TNumber value, out int exponent)
             where TNumber : unmanaged, IBinaryFloatParseAndFormatInfo<TNumber>
         {