mirror/fmt
1
0
Fork 0
mirror of https://github.com/fmtlib/fmt.git synced 2024-11-07 17:41:11 +00:00
Code Issues Packages Projects Releases Wiki Activity

Ditch decimal_formatter (#1363)

Browse Source
This commit is contained in:
Victor Zverovich 2019-12-05 19:07:45 -08:00
parent 1219b65f21
commit f443bd3baf
1 changed files with 0 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
include/fmt/format.h
View File

@ -802,60 +802,6 @@ template <> int count_digits<4>(internal::fallback_uintptr n);
# define FMT_ALWAYS_INLINE
#endif
// Computes g = floor(log10(n)) and calls h.on<g>(n);
template <typename Handler> FMT_ALWAYS_INLINE char* lg(uint32_t n, Handler h) {
return n < 100 ? n < 10 ? h.template on<0>(n) : h.template on<1>(n)
: n < 1000000
? n < 10000 ? n < 1000 ? h.template on<2>(n)
: h.template on<3>(n)
: n < 100000 ? h.template on<4>(n)
: h.template on<5>(n)
: n < 100000000 ? n < 10000000 ? h.template on<6>(n)
: h.template on<7>(n)
: n < 1000000000 ? h.template on<8>(n)
: h.template on<9>(n);
}
// An lg handler that formats a decimal number.
// Usage: lg(n, decimal_formatter(buffer));
class decimal_formatter {
private:
char* buffer_;
void write_pair(unsigned N, uint32_t index) {
std::memcpy(buffer_ + N, data::digits + index * 2, 2);
}
public:
explicit decimal_formatter(char* buf) : buffer_(buf) {}
template <unsigned N> char* on(uint32_t u) {
if (N == 0) {
*buffer_ = static_cast<char>(u) + '0';
} else if (N == 1) {
write_pair(0, u);
} else {
// The idea of using 4.32 fixed-point numbers is based on
// https://github.com/jeaiii/itoa
unsigned n = N - 1;
unsigned a = n / 5 * n * 53 / 16;
uint64_t t =
((1ULL << (32 + a)) / data::zero_or_powers_of_10_32[n] + 1 - n / 9);
t = ((t * u) >> a) + n / 5 * 4;
write_pair(0, t >> 32);
for (unsigned i = 2; i < N; i += 2) {
t = 100ULL * static_cast<uint32_t>(t);
write_pair(i, t >> 32);
}
if (N % 2 == 0) {
buffer_[N] =
static_cast<char>((10ULL * static_cast<uint32_t>(t)) >> 32) + '0';
}
}
return buffer_ += N + 1;
}
};
#ifdef FMT_BUILTIN_CLZ
// Optional version of count_digits for better performance on 32-bit platforms.
inline int count_digits(uint32_t n) {