double_conversion::PowersOfTenCache Namespace Reference

Classes
struct	CachedPower

Functions
void	GetCachedPowerForBinaryExponentRange (int min_exponent, int max_exponent, DiyFp *power, int *decimal_exponent)
void	GetCachedPowerForDecimalExponent (int requested_exponent, DiyFp *power, int *found_exponent)

Variables
static const CachedPower	kCachedPowers []
static const int	kCachedPowersOffset = 348
static const double	kD_1_LOG2_10 = 0.30102999566398114
static const int	kDecimalExponentDistance = 8
static const int	kMinDecimalExponent = -348
static const int	kMaxDecimalExponent = 340

Function Documentation

GetCachedPowerForBinaryExponentRange()

void double_conversion::PowersOfTenCache::GetCachedPowerForBinaryExponentRange	(	int	min_exponent,
		int	max_exponent,
		DiyFp *	power,
		int *	decimal_exponent
	)

Definition at line 139 of file cached-powers.cc.

                           {
  int kQ = DiyFp::kSignificandSize;
  double k = ceil((min_exponent + kQ - 1) * kD_1_LOG2_10);
  int foo = kCachedPowersOffset;
  int index =
      (foo + static_cast<int>(k) - 1) / kDecimalExponentDistance + 1;
  DOUBLE_CONVERSION_ASSERT(0 <= index && index < static_cast<int>(DOUBLE_CONVERSION_ARRAY_SIZE(kCachedPowers)));
  CachedPower cached_power = kCachedPowers[index];
  DOUBLE_CONVERSION_ASSERT(min_exponent <= cached_power.binary_exponent);
  (void) max_exponent;  // Mark variable as used.
  DOUBLE_CONVERSION_ASSERT(cached_power.binary_exponent <= max_exponent);
  *decimal_exponent = cached_power.decimal_exponent;
  *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
}

GetCachedPowerForDecimalExponent()

void double_conversion::PowersOfTenCache::GetCachedPowerForDecimalExponent	(	int	requested_exponent,
		DiyFp *	power,
		int *	found_exponent
	)

Definition at line 159 of file cached-powers.cc.

                                                           {
  DOUBLE_CONVERSION_ASSERT(kMinDecimalExponent <= requested_exponent);
  DOUBLE_CONVERSION_ASSERT(requested_exponent < kMaxDecimalExponent + kDecimalExponentDistance);
  int index =
      (requested_exponent + kCachedPowersOffset) / kDecimalExponentDistance;
  CachedPower cached_power = kCachedPowers[index];
  *power = DiyFp(cached_power.significand, cached_power.binary_exponent);
  *found_exponent = cached_power.decimal_exponent;
  DOUBLE_CONVERSION_ASSERT(*found_exponent <= requested_exponent);
  DOUBLE_CONVERSION_ASSERT(requested_exponent < *found_exponent + kDecimalExponentDistance);
}

Variable Documentation

kCachedPowers

const CachedPower double_conversion::PowersOfTenCache::kCachedPowers[]

static

Definition at line 46 of file cached-powers.cc.

kCachedPowersOffset

const int double_conversion::PowersOfTenCache::kCachedPowersOffset = 348

static

Definition at line 136 of file cached-powers.cc.

kD_1_LOG2_10

const double double_conversion::PowersOfTenCache::kD_1_LOG2_10 = 0.30102999566398114

static

Definition at line 137 of file cached-powers.cc.

kDecimalExponentDistance

const int double_conversion::PowersOfTenCache::kDecimalExponentDistance = 8

static

Definition at line 39 of file cached-powers.h.

kMaxDecimalExponent

const int double_conversion::PowersOfTenCache::kMaxDecimalExponent = 340

static

Definition at line 42 of file cached-powers.h.

kMinDecimalExponent

const int double_conversion::PowersOfTenCache::kMinDecimalExponent = -348

static

Definition at line 41 of file cached-powers.h.