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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 WTF {
     34 
     35 namespace double_conversion {
     36 
     37     class PowersOfTenCache {
     38     public:
     39 
     40         // Not all powers of ten are cached. The decimal exponent of two neighboring
     41         // cached numbers will differ by kDecimalExponentDistance.
     42         static int kDecimalExponentDistance;
     43 
     44         static int kMinDecimalExponent;
     45         static int kMaxDecimalExponent;
     46 
     47         // Returns a cached power-of-ten with a binary exponent in the range
     48         // [min_exponent; max_exponent] (boundaries included).
     49         static void GetCachedPowerForBinaryExponentRange(int min_exponent,
     50                                                          int max_exponent,
     51                                                          DiyFp* power,
     52                                                          int* decimal_exponent);
     53 
     54         // Returns a cached power of ten x ~= 10^k such that
     55         //   k <= decimal_exponent < k + kCachedPowersDecimalDistance.
     56         // The given decimal_exponent must satisfy
     57         //   kMinDecimalExponent <= requested_exponent, and
     58         //   requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance.
     59         static void GetCachedPowerForDecimalExponent(int requested_exponent,
     60                                                      DiyFp* power,
     61                                                      int* found_exponent);
     62     };
     63 
     64     // Initializes the table of cached powers used by the dtoa algorithm.
     65     // This needs to be called when JSC is being initialized.
     66     void initialize();
     67 
     68 }  // namespace double_conversion
     69 
     70 } // namespace WTF
     71 
     72 #endif  // DOUBLE_CONVERSION_CACHED_POWERS_H_
     73