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This commit is contained in:
Victor Zverovich 2020-09-22 14:36:10 -07:00
parent aae7a1338c
commit e5942ac9dd
1 changed files with 18 additions and 20 deletions
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38
include/fmt/format-inl.h
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@ -1720,10 +1720,9 @@ struct grisu_shortest_handler {
} }
}; };
// Implementation of Dragonbox algorithm // Implementation of Dragonbox algorithm: https://github.com/jk-jeon/dragonbox.
// (https://github.com/jk-jeon/dragonbox)
namespace dragonbox { namespace dragonbox {
// Gets 128-bit result of multiplication of two 64-bit unsigned integers // Computes 128-bit result of multiplication of two 64-bit unsigned integers.
FMT_SAFEBUFFERS inline uint128_wrapper umul128(uint64_t x, FMT_SAFEBUFFERS inline uint128_wrapper umul128(uint64_t x,
uint64_t y) FMT_NOEXCEPT { uint64_t y) FMT_NOEXCEPT {
#if FMT_USE_INT128 #if FMT_USE_INT128
@ -1752,8 +1751,7 @@ FMT_SAFEBUFFERS inline uint128_wrapper umul128(uint64_t x,
#endif #endif
} }
// Gets upper 64-bits of multiplication of a 64-bit unsigned integer and a // Computes upper 64 bits of multiplication of two 64-bit unsigned integers.
// 64-bit unsigned integer
FMT_SAFEBUFFERS inline uint64_t umul128_upper64(uint64_t x, FMT_SAFEBUFFERS inline uint64_t umul128_upper64(uint64_t x,
uint64_t y) FMT_NOEXCEPT { uint64_t y) FMT_NOEXCEPT {
#if FMT_USE_INT128 #if FMT_USE_INT128
@ -1780,8 +1778,8 @@ FMT_SAFEBUFFERS inline uint64_t umul128_upper64(uint64_t x,
#endif #endif
} }
// Gets upper 64-bits of multiplication of a 64-bit unsigned integer and a // Computes upper 64 bits of multiplication of a 64-bit unsigned integer and a
// 128-bit unsigned integer // 128-bit unsigned integer.
FMT_SAFEBUFFERS inline uint64_t umul192_upper64(uint64_t x, uint128_wrapper y) FMT_SAFEBUFFERS inline uint64_t umul192_upper64(uint64_t x, uint128_wrapper y)
FMT_NOEXCEPT { FMT_NOEXCEPT {
uint128_wrapper g0 = umul128(x, y.high()); uint128_wrapper g0 = umul128(x, y.high());
@ -1789,14 +1787,14 @@ FMT_SAFEBUFFERS inline uint64_t umul192_upper64(uint64_t x, uint128_wrapper y)
return g0.high(); return g0.high();
} }
// Gets upper 32-bits of multiplication of a 32-bit unsigned integer and a // Computes upper 32 bits of multiplication of a 32-bit unsigned integer and a
// 64-bit unsigned integer // 64-bit unsigned integer.
inline uint32_t umul96_upper32(uint32_t x, uint64_t y) FMT_NOEXCEPT { inline uint32_t umul96_upper32(uint32_t x, uint64_t y) FMT_NOEXCEPT {
return static_cast<uint32_t>(umul128_upper64(x, y)); return static_cast<uint32_t>(umul128_upper64(x, y));
} }
// Gets middle 64-bits of multiplication of a 64-bit unsigned integer and a // Computes middle 64 bits of multiplication of a 64-bit unsigned integer and a
// 128-bit unsigned integer // 128-bit unsigned integer.
FMT_SAFEBUFFERS inline uint64_t umul192_middle64(uint64_t x, uint128_wrapper y) FMT_SAFEBUFFERS inline uint64_t umul192_middle64(uint64_t x, uint128_wrapper y)
FMT_NOEXCEPT { FMT_NOEXCEPT {
uint64_t g01 = x * y.high(); uint64_t g01 = x * y.high();
@ -1804,13 +1802,13 @@ FMT_SAFEBUFFERS inline uint64_t umul192_middle64(uint64_t x, uint128_wrapper y)
return g01 + g10; return g01 + g10;
} }
// Get middle 32-bits of multiplication of a 32-bit unsigned integer and a // Computes lower 64 bits of multiplication of a 32-bit unsigned integer and a
// 64-bit unsigned integer // 64-bit unsigned integer.
inline uint64_t umul96_lower64(uint32_t x, uint64_t y) FMT_NOEXCEPT { inline uint64_t umul96_lower64(uint32_t x, uint64_t y) FMT_NOEXCEPT {
return x * y; return x * y;
} }
// Various fast log computations // Various fast log computations.
inline int floor_log10_pow2(int e) FMT_NOEXCEPT { inline int floor_log10_pow2(int e) FMT_NOEXCEPT {
FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent"); FMT_ASSERT(e <= 1700 && e >= -1700, "too large exponent");
const uint64_t log10_2_fractional_digits = 0x4d104d427de7fbcc; const uint64_t log10_2_fractional_digits = 0x4d104d427de7fbcc;
@ -1841,7 +1839,7 @@ inline int floor_log10_pow2_minus_log10_4_over_3(int e) FMT_NOEXCEPT {
shift_amount; shift_amount;
} }
// Type-specific information that Dragonbox uses // Type-specific information that Dragonbox uses.
template <class T> struct float_info; template <class T> struct float_info;
template <> struct float_info<float> { template <> struct float_info<float> {
@ -1902,7 +1900,7 @@ template <class T> struct decimal_fp {
int exponent; int exponent;
}; };
// Fast divisibility test for powers of 2 (float) // Fast divisibility test for powers of 2 (float).
inline bool divisible_by_power_of_2(uint32_t x, int exp) FMT_NOEXCEPT { inline bool divisible_by_power_of_2(uint32_t x, int exp) FMT_NOEXCEPT {
FMT_ASSERT(exp >= 1, ""); FMT_ASSERT(exp >= 1, "");
FMT_ASSERT(x != 0, ""); FMT_ASSERT(x != 0, "");
@ -1915,7 +1913,7 @@ inline bool divisible_by_power_of_2(uint32_t x, int exp) FMT_NOEXCEPT {
return x == ((x >> exp) << exp); return x == ((x >> exp) << exp);
#endif #endif
} }
// Fast divisibility test for powers of 2 (double) // Fast divisibility test for powers of 2 (double).
inline bool divisible_by_power_of_2(uint64_t x, int exp) FMT_NOEXCEPT { inline bool divisible_by_power_of_2(uint64_t x, int exp) FMT_NOEXCEPT {
FMT_ASSERT(exp >= 1, ""); FMT_ASSERT(exp >= 1, "");
FMT_ASSERT(x != 0, ""); FMT_ASSERT(x != 0, "");
@ -1929,13 +1927,13 @@ inline bool divisible_by_power_of_2(uint64_t x, int exp) FMT_NOEXCEPT {
#endif #endif
} }
// Fast divisibility test for powers of 5 (float) // Fast divisibility test for powers of 5 (float).
inline bool divisible_by_power_of_5(uint32_t x, int exp) FMT_NOEXCEPT { inline bool divisible_by_power_of_5(uint32_t x, int exp) FMT_NOEXCEPT {
FMT_ASSERT(exp <= 10, "too large exponent"); FMT_ASSERT(exp <= 10, "too large exponent");
return (x * data::divtest_table_for_pow5_32[exp].mod_inv) <= return (x * data::divtest_table_for_pow5_32[exp].mod_inv) <=
data::divtest_table_for_pow5_32[exp].max_quotient; data::divtest_table_for_pow5_32[exp].max_quotient;
} }
// Fast divisibility test for powers of 5 (double) // Fast divisibility test for powers of 5 (double).
inline bool divisible_by_power_of_5(uint64_t x, int exp) FMT_NOEXCEPT { inline bool divisible_by_power_of_5(uint64_t x, int exp) FMT_NOEXCEPT {
FMT_ASSERT(exp <= 23, "too large exponent"); FMT_ASSERT(exp <= 23, "too large exponent");
return (x * data::divtest_table_for_pow5_64[exp].mod_inv) <= return (x * data::divtest_table_for_pow5_64[exp].mod_inv) <=
@ -2167,7 +2165,7 @@ template <> struct cache_accessor<double> {
1) / 1) /
2; 2;
} }
}; // namespace dragonbox };
// Various integer checks // Various integer checks
template <class T> template <class T>