decimal.h

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#ifndef POINCARE_DECIMAL_H
#define POINCARE_DECIMAL_H

#include <poincare/static_hierarchy.h>
#include <poincare/integer.h>

namespace Poincare {

/* A decimal as 0.01234 is stored that way:
 *  - m_mantissa = 1234
 *  - m_exponent = -2
 */

class Decimal : public StaticHierarchy<0> {
public:
  static int exponent(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, const char * exponent, int exponentLength, bool exponentNegative);
  static Integer mantissa(const char * integralPart, int integralPartLength, const char * fractionalPart, int fractionalPartLength, bool negative);
  Decimal(Integer mantissa, int exponent);
  Decimal(double f);
  int exponent() const { return m_exponent; }
  Integer mantissa() const { return m_mantissa; }
  // Expression subclassing
  Type type() const override;
  Expression * clone() const override;
  int writeTextInBuffer(char * buffer, int bufferSize, int numberOfSignificantDigits = PrintFloat::k_numberOfStoredSignificantDigits) const override;
  Sign sign() const override { return m_mantissa.isNegative() ? Sign::Negative : Sign::Positive; }
private:
  constexpr static int k_doublePrecision = 15;
  constexpr static double k_biggestMantissaFromDouble = 999999999999999;
  constexpr static int k_maxDoubleExponent = 308;
  int numberOfDigitsInMantissaWithoutSign() const;
  /* Comparison */
  int simplificationOrderSameType(const Expression * e, bool canBeInterrupted) const override;
  /* Layout */
  bool needParenthesisWithParent(const Expression * e) const override;
  ExpressionLayout * privateCreateLayout(PrintFloat::Mode floatDisplayMode, ComplexFormat complexFormat) const override;
  /* Simplification */
  Expression * shallowReduce(Context& context, AngleUnit angleUnit) override;
  Expression * shallowBeautify(Context& context, AngleUnit angleUnit) override;
  /* Evaluation */
  Expression * privateApproximate(SinglePrecision p, Context& context, AngleUnit angleUnit) const override { return templatedApproximate<float>(context, angleUnit); }
  Expression * privateApproximate(DoublePrecision p, Context& context, AngleUnit angleUnit) const override { return templatedApproximate<double>(context, angleUnit); }
  template<typename T> Expression * templatedApproximate(Context& context, Expression::AngleUnit angleUnit) const;

  constexpr static int k_maxLength = 15;
  Integer m_mantissa;
  int m_exponent;
};

}

#endif