mfbt/decimal/floor-ceiling.patch

   1 diff --git a/mfbt/decimal/Decimal.cpp b/mfbt/decimal/Decimal.cpp
   2 --- a/mfbt/decimal/Decimal.cpp
   3 +++ b/mfbt/decimal/Decimal.cpp
   4 @@ -618,26 +618,26 @@ Decimal::AlignedOperands Decimal::alignO
   5  Decimal Decimal::ceiling() const
   6  {
   7      if (isSpecial())
   8          return *this;
   9
  10      if (exponent() >= 0)
  11          return *this;
  12
  13 -    uint64_t result = m_data.coefficient();
  14 -    const int numberOfDigits = countDigits(result);
  15 +    uint64_t coefficient = m_data.coefficient();
  16 +    const int numberOfDigits = countDigits(coefficient);
  17      const int numberOfDropDigits = -exponent();
  18      if (numberOfDigits < numberOfDropDigits)
  19          return isPositive() ? Decimal(1) : zero(Positive);
  20
  21 -    result = scaleDown(result, numberOfDropDigits - 1);
  22 -    if (sign() == Positive && result % 10 > 0)
  23 -        result += 10;
  24 -    result /= 10;
  25 +    uint64_t result = scaleDown(coefficient, numberOfDropDigits);
  26 +    uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
  27 +    if (droppedDigits && isPositive())
  28 +        result += 1;
  29      return Decimal(sign(), 0, result);
  30  }
  31
  32  Decimal Decimal::compareTo(const Decimal& rhs) const
  33  {
  34      const Decimal result(*this - rhs);
  35      switch (result.m_data.formatClass()) {
  36      case EncodedData::ClassInfinity:
  37 @@ -660,26 +660,27 @@ Decimal Decimal::compareTo(const Decimal
  38  Decimal Decimal::floor() const
  39  {
  40      if (isSpecial())
  41          return *this;
  42
  43      if (exponent() >= 0)
  44          return *this;
  45
  46 -    uint64_t result = m_data.coefficient();
  47 -    const int numberOfDigits = countDigits(result);
  48 +    uint64_t coefficient = m_data.coefficient();
  49 +    const int numberOfDigits = countDigits(coefficient);
  50      const int numberOfDropDigits = -exponent();
  51      if (numberOfDigits < numberOfDropDigits)
  52          return isPositive() ? zero(Positive) : Decimal(-1);
  53
  54 -    result = scaleDown(result, numberOfDropDigits - 1);
  55 -    if (isNegative() && result % 10 > 0)
  56 -        result += 10;
  57 -    result /= 10;
  58 +    uint64_t result = scaleDown(coefficient, numberOfDropDigits);
  59 +    uint64_t droppedDigits = coefficient - scaleUp(result, numberOfDropDigits);
  60 +    if (droppedDigits && isNegative()) {
  61 +        result += 1;
  62 +    }
  63      return Decimal(sign(), 0, result);
  64  }
  65
  66  Decimal Decimal::fromDouble(double doubleValue)
  67  {
  68      if (std::isfinite(doubleValue))
  69          return fromString(String::numberToStringECMAScript(doubleValue));
  70
  71 @@ -915,16 +916,18 @@ Decimal Decimal::round() const
  72          return *this;
  73
  74      uint64_t result = m_data.coefficient();
  75      const int numberOfDigits = countDigits(result);
  76      const int numberOfDropDigits = -exponent();
  77      if (numberOfDigits < numberOfDropDigits)
  78          return zero(Positive);
  79
  80 +    // We're implementing round-half-away-from-zero, so we only need the one
  81 +    // (the most significant) fractional digit:
  82      result = scaleDown(result, numberOfDropDigits - 1);
  83      if (result % 10 >= 5)
  84          result += 10;
  85      result /= 10;
  86      return Decimal(sign(), 0, result);
  87  }
  88
  89  double Decimal::toDouble() const