double-conversion/cached-powers.h

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#ifndef DOUBLE_CONVERSION_CACHED_POWERS_H_
#define DOUBLE_CONVERSION_CACHED_POWERS_H_

#include "diy-fp.h"

namespace double_conversion {

class PowersOfTenCache {
 public:

  // Not all powers of ten are cached. The decimal exponent of two neighboring
  // cached numbers will differ by kDecimalExponentDistance.
  static const int kDecimalExponentDistance;

  static const int kMinDecimalExponent;
  static const int kMaxDecimalExponent;

  // Returns a cached power-of-ten with a binary exponent in the range
  // [min_exponent; max_exponent] (boundaries included).
  static void GetCachedPowerForBinaryExponentRange(int min_exponent,
                                                   int max_exponent,
                                                   DiyFp* power,
                                                   int* decimal_exponent);

  // Returns a cached power of ten x ~= 10^k such that
  //   k <= decimal_exponent < k + kCachedPowersDecimalDistance.
  // The given decimal_exponent must satisfy
  //   kMinDecimalExponent <= requested_exponent, and
  //   requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance.
  static void GetCachedPowerForDecimalExponent(int requested_exponent,
                                               DiyFp* power,
                                               int* found_exponent);
};

}  // namespace double_conversion

#endif  // DOUBLE_CONVERSION_CACHED_POWERS_H_