Fix parsing of trailing zeros: TryParseNumber

src/libraries/System.Formats.Cbor/tests/Writer/CborWriterTests.Tag.cs

@@ -158,7 +158,7 @@ public static void WriteInteger_SingleValue_HappyPath(string valueString, string
  [InlineData("1", "c4820001")]
  [InlineData("-1", "c4820020")]
  [InlineData("1.1", "c482200b")]
- [InlineData("1.000", "c482221903e8")]
+ [InlineData("1.000", "c4820001")]
  [InlineData("273.15", "c48221196ab3")]
  [InlineData("79228162514264337593543950335", "c48200c24cffffffffffffffffffffffff")] // decimal.MaxValue
  [InlineData("7922816251426433759354395033.5", "c48220c24cffffffffffffffffffffffff")]

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

@@ -70,6 +70,28 @@ public void CheckConsistency()
 
  Debug.Assert(numDigits == DigitsCount, "Null terminator found in unexpected location in Number");
  Debug.Assert(numDigits < Digits.Length, "Null terminator not found in Number");
+
+ uint totalDigits = (uint)(DigitsCount);
+ uint positiveExponent = (uint)(Math.Max(0, Scale));
+ uint integerDigitsPresent = Math.Min(positiveExponent, totalDigits);
+ uint fractionalDigitsPresent = totalDigits - integerDigitsPresent;
+
+ // Verify that the fractional part does not have any trailing zeros
+ int numberOfTrailingZeros = 0;
+ for (int i = DigitsCount - (int)fractionalDigitsPresent; i < DigitsCount; i++)
+ {
+ byte digit = Digits[i];
+ if (digit == 0)
+ {
+ numberOfTrailingZeros++;
+ }
+ else
+ {
+ numberOfTrailingZeros = 0;
+ }
+ }
+ Debug.Assert(numberOfTrailingZeros == 0, "Fractional part should not have trailing zeros");
+
 #endif // DEBUG
  }
 

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

@@ -324,6 +324,7 @@ private static unsafe bool TryParseNumber(ref char* str, char* strEnd, NumberSty
  int digCount = 0;
  int digEnd = 0;
  int maxDigCount = number.Digits.Length - 1;
+ int numberOfTrailingZeros = 0;
 
  while (true)
  {
@@ -357,6 +358,18 @@ private static unsafe bool TryParseNumber(ref char* str, char* strEnd, NumberSty
  {
  number.Scale++;
  }
+ else if (digCount < maxDigCount)
+ {
+ // Handle a case like "53.0". We need to ignore trailing zeros in the fractional part, so we keep a count of the number of trailing zeros and update digCount later
+ if (ch == '0')
+ {
+ numberOfTrailingZeros++;
+ }
+ else
+ {
+ numberOfTrailingZeros = 0;
+ }
+ }
  state |= StateNonZero;
  }
  else if ((state & StateDecimal) != 0)
@@ -381,8 +394,15 @@ private static unsafe bool TryParseNumber(ref char* str, char* strEnd, NumberSty
  }
 
  bool negExp = false;
- number.DigitsCount = digEnd;
+ number.DigitsCount = digEnd - numberOfTrailingZeros;
  number.Digits[digEnd] = (byte)('\0');
+ if (numberOfTrailingZeros != 0)
+ {
+ for (int i = digEnd - numberOfTrailingZeros; i < digEnd; i++)
+ {
+ number.Digits[i] = (byte)('\0');
+ }
+ }
  if ((state & StateDigits) != 0)
  {
  if ((ch == 'E' || ch == 'e') && ((styles & NumberStyles.AllowExponent) != 0))

src/libraries/System.Runtime/tests/System/DecimalTests.cs

@@ -766,6 +766,7 @@ public static void Negate(decimal d, decimal expected)
  public static IEnumerable<object[]> Parse_Valid_TestData()
  {
  NumberStyles defaultStyle = NumberStyles.Number;
+ NumberFormatInfo invariantFormat = NumberFormatInfo.InvariantInfo;
 
  NumberFormatInfo emptyFormat = NumberFormatInfo.CurrentInfo;
 
@@ -788,6 +789,7 @@ public static IEnumerable<object[]> Parse_Valid_TestData()
  yield return new object[] { " 123 ", defaultStyle, null, 123m };
  yield return new object[] { (567.89m).ToString(), defaultStyle, null, 567.89m };
  yield return new object[] { (-567.89m).ToString(), defaultStyle, null, -567.89m };
+ yield return new object[] { "0.6666666666666666666666666666500000000000000000000000000000000000000000000000000000000000000", defaultStyle, invariantFormat, 0.6666666666666666666666666666m };
 
  yield return new object[] { "79228162514264337593543950335", defaultStyle, null, 79228162514264337593543950335m };
  yield return new object[] { "-79228162514264337593543950335", defaultStyle, null, -79228162514264337593543950335m };

src/libraries/System.Runtime/tests/System/DoubleTests.cs

@@ -272,6 +272,13 @@ public static IEnumerable<object[]> Parse_Valid_TestData()
  yield return new object[] { (567.89).ToString(), defaultStyle, null, 567.89 };
  yield return new object[] { (-567.89).ToString(), defaultStyle, null, -567.89 };
  yield return new object[] { "1E23", defaultStyle, null, 1E23 };
+ yield return new object[] { "9007199254740997.0", defaultStyle, invariantFormat, 9007199254740996.0 };
+ yield return new object[] { "5.005", defaultStyle, invariantFormat, 5.005 };
+ yield return new object[] { "5.050", defaultStyle, invariantFormat, 5.05 };
+ yield return new object[] { "5005.0", defaultStyle, invariantFormat, 5005.0 };
+ yield return new object[] { "50050.0", defaultStyle, invariantFormat, 50050.0 };
+ yield return new object[] { "5005", defaultStyle, invariantFormat, 5005.0 };
+ yield return new object[] { "50050", defaultStyle, invariantFormat, 50050.0 };
 
  yield return new object[] { (123.1).ToString(), NumberStyles.AllowDecimalPoint, null, 123.1 };
  yield return new object[] { (1000.0).ToString("N0"), NumberStyles.AllowThousands, null, 1000.0 };