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Implement Dragonbox (first version)

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Junekey Jeon 2020-09-18 11:14:28 -07:00 committed by Victor Zverovich
parent 42699bf408
commit 0c8ffe9b0f
2 changed files with 1747 additions and 37 deletions
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1651
include/fmt/format-inl.h
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133
include/fmt/format.h
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@ -182,6 +182,12 @@ FMT_END_NAMESPACE
#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clzll)) && !FMT_MSC_VER
# define FMT_BUILTIN_CLZLL(n) __builtin_clzll(n)
#endif
#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctz))
# define FMT_BUILTIN_CTZ(n) __builtin_ctz(n)
#endif
#if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_ctzll))
# define FMT_BUILTIN_CTZLL(n) __builtin_ctzll(n)
#endif
// Some compilers masquerade as both MSVC and GCC-likes or otherwise support
// __builtin_clz and __builtin_clzll, so only define FMT_BUILTIN_CLZ using the
@ -236,6 +242,59 @@ inline int clzll(uint64_t x) {
FMT_END_NAMESPACE
#endif
// Same for __builtin_ctz and __builtin_ctzll
#if FMT_MSC_VER && !defined(FMT_BUILTIN_CTZLL) && !defined(_MANAGED)
# include <intrin.h> // _BitScanReverse, _BitScanReverse64
FMT_BEGIN_NAMESPACE
namespace detail {
// Avoid Clang with Microsoft CodeGen's -Wunknown-pragmas warning.
# ifndef __clang__
# pragma intrinsic(_BitScanForward)
# endif
inline int ctz(uint32_t x) {
unsigned long r = 0;
_BitScanForward(&r, x);
FMT_ASSERT(x != 0, "");
// Static analysis complains about using uninitialized data
// "r", but the only way that can happen is if "x" is 0,
// which the callers guarantee to not happen.
FMT_SUPPRESS_MSC_WARNING(6102)
return static_cast<int>(r);
}
# define FMT_BUILTIN_CTZ(n) detail::ctz(n)
# if defined(_WIN64) && !defined(__clang__)
# pragma intrinsic(_BitScanForward64)
# endif
inline int ctzll(uint64_t x) {
unsigned long r = 0;
FMT_ASSERT(x != 0, "");
// Static analysis complains about using uninitialized data
// "r", but the only way that can happen is if "x" is 0,
// which the callers guarantee to not happen.
FMT_SUPPRESS_MSC_WARNING(6102)
# ifdef _WIN64
_BitScanForward64(&r, x);
# else
// Scan the low 32 bits.
if (_BitScanForward(&r, static_cast<uint32_t>(x))) return r;
// Scan the high 32 bits.
_BitScanReverse(&r, static_cast<uint32_t>(x >> 32));
r += 32;
# endif
return static_cast<int>(r);
}
# define FMT_BUILTIN_CTZLL(n) detail::ctzll(n)
} // namespace detail
FMT_END_NAMESPACE
#endif
// Enable the deprecated numeric alignment.
#ifndef FMT_DEPRECATED_NUMERIC_ALIGN
# define FMT_DEPRECATED_NUMERIC_ALIGN 0
@ -555,6 +614,10 @@ template <typename T> constexpr bool use_grisu() {
sizeof(T) <= sizeof(double);
}
#ifndef FMT_USE_FULL_CACHE_DRAGONBOX
# define FMT_USE_FULL_CACHE_DRAGONBOX 0
#endif
template <typename T>
template <typename U>
void buffer<T>::append(const U* begin, const U* end) {
@ -778,13 +841,72 @@ using uint32_or_64_or_128_t =
conditional_t<num_bits<T>() <= 64, uint64_t, uint128_t>>;
#endif
// 128-bit integer type used internally
struct uint128_wrapper {
uint128_wrapper() = default;
#if FMT_USE_INT128
uint128_t internal_;
uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT
: internal_{static_cast<uint128_t>(low) |
(static_cast<uint128_t>(high) << 64)} {}
uint128_wrapper(uint128_t u) : internal_{u} {}
uint64_t high() const FMT_NOEXCEPT { return uint64_t(internal_ >> 64); }
uint64_t low() const FMT_NOEXCEPT { return uint64_t(internal_); }
uint128_wrapper& operator+=(uint64_t n) & FMT_NOEXCEPT {
internal_ += n;
return *this;
}
#else
uint64_t high_;
uint64_t low_;
uint128_wrapper(uint64_t high, uint64_t low) FMT_NOEXCEPT : high_{high},
low_{low} {}
uint64_t high() const FMT_NOEXCEPT { return high_; }
uint64_t low() const FMT_NOEXCEPT { return low_; }
uint128_wrapper& operator+=(uint64_t n) & FMT_NOEXCEPT {
# if defined(_MSC_VER) && defined(_M_X64)
unsigned char carry = _addcarry_u64(0, low_, n, &low_);
_addcarry_u64(carry, high_, 0, &high_);
return *this;
# else
uint64_t sum = low_ + n;
high_ += (sum < low_ ? 1 : 0);
low_ = sum;
return *this;
# endif
}
#endif
};
// Table entry type for divisibility test used internally
template <typename T> struct divtest_table_entry {
T mod_inv;
T max_quotient;
};
// Static data is placed in this class template for the header-only config.
template <typename T = void> struct FMT_EXTERN_TEMPLATE_API basic_data {
static const uint64_t powers_of_10_64[];
static const uint32_t zero_or_powers_of_10_32[];
static const uint64_t zero_or_powers_of_10_64[];
static const uint64_t pow10_significands[];
static const int16_t pow10_exponents[];
static const uint64_t grisu_pow10_significands[];
static const int16_t grisu_pow10_exponents[];
static const divtest_table_entry<uint32_t> divtest_table_for_pow5_32[];
static const divtest_table_entry<uint64_t> divtest_table_for_pow5_64[];
static const uint64_t dragonbox_pow10_significands_64[];
static const uint128_wrapper dragonbox_pow10_significands_128[];
#if !FMT_USE_FULL_CACHE_DRAGONBOX
static const uint64_t powers_of_5_64[];
static const uint32_t dragonbox_pow10_recovery_errors[];
#endif
// GCC generates slightly better code for pairs than chars.
using digit_pair = char[2];
static const digit_pair digits[];
@ -878,6 +1000,13 @@ template <> int count_digits<4>(detail::fallback_uintptr n);
# define FMT_ALWAYS_INLINE inline
#endif
// To suppress unnecessary security cookie checks
#if defined(FMT_MSC_VER) && !defined(__clang__)
# define FMT_SAFEBUFFERS __declspec(safebuffers)
#else
# define FMT_SAFEBUFFERS
#endif
#ifdef FMT_BUILTIN_CLZ
// Optional version of count_digits for better performance on 32-bit platforms.
inline int count_digits(uint32_t n) {