mfbt/double-conversion/cached-powers.h

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  27
  28 #ifndef DOUBLE_CONVERSION_CACHED_POWERS_H_
  29 #define DOUBLE_CONVERSION_CACHED_POWERS_H_
  30
  31 #include "diy-fp.h"
  32
  33 namespace double_conversion {
  34
  35 class PowersOfTenCache {
  36  public:
  37
  38   // Not all powers of ten are cached. The decimal exponent of two neighboring
  39   // cached numbers will differ by kDecimalExponentDistance.
  40   static const int kDecimalExponentDistance;
  41
  42   static const int kMinDecimalExponent;
  43   static const int kMaxDecimalExponent;
  44
  45   // Returns a cached power-of-ten with a binary exponent in the range
  46   // [min_exponent; max_exponent] (boundaries included).
  47   static void GetCachedPowerForBinaryExponentRange(int min_exponent,
  48                                                    int max_exponent,
  49                                                    DiyFp* power,
  50                                                    int* decimal_exponent);
  51
  52   // Returns a cached power of ten x ~= 10^k such that
  53   //   k <= decimal_exponent < k + kCachedPowersDecimalDistance.
  54   // The given decimal_exponent must satisfy
  55   //   kMinDecimalExponent <= requested_exponent, and
  56   //   requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance.
  57   static void GetCachedPowerForDecimalExponent(int requested_exponent,
  58                                                DiyFp* power,
  59                                                int* found_exponent);
  60 };
  61
  62 }  // namespace double_conversion
  63
  64 #endif  // DOUBLE_CONVERSION_CACHED_POWERS_H_