mirror/fmt
1
0
Fork 0
mirror of https://github.com/fmtlib/fmt.git synced 2024-11-02 02:29:08 +00:00
Code Issues Packages Projects Releases Wiki Activity

Use grisu for fixed precision

Browse Source
This commit is contained in:
Victor Zverovich 2019-02-23 06:42:45 -10:00
parent 327d4b6e9e
commit a97757736b
4 changed files with 17 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/fmt/format-inl.h
View File

@ -534,8 +534,14 @@ int grisu2_gen_digits(char* buf, fp value, uint64_t error_ulp, int& exp,
struct fixed_stop {
int precision;
int exp10;
bool fixed;
void on_exp(int exp) { precision += exp + exp10; }
void on_exp(int exp) {
if (!fixed) return;
exp += exp10;
if (exp >= 0)
precision += exp;
}
bool operator()(char*, int& size, uint64_t remainder, uint64_t divisor,
uint64_t error, int&, bool integral) {
@ -549,8 +555,9 @@ struct fixed_stop {
size = -1;
return true;
}
} else
} else {
assert(error == 1 && divisor > 2);
}
// Round down if (remainder + error) * 2 <= divisor.
if (remainder < divisor - remainder && error * 2 <= divisor - remainder * 2)
return true;
@ -582,7 +589,7 @@ struct shortest_stop {
template <typename Double>
FMT_FUNC typename std::enable_if<sizeof(Double) == sizeof(uint64_t), bool>::type
grisu2_format(Double value, buffer& buf, int precision, int& exp) {
grisu2_format(Double value, buffer& buf, int precision, bool fixed, int& exp) {
FMT_ASSERT(value >= 0, "value is negative");
if (value <= 0) { // <= instead of == to silence a warning.
if (precision < 0) {
@ -606,7 +613,7 @@ grisu2_format(Double value, buffer& buf, int precision, int& exp) {
min_exp - (fp_value.e + fp::significand_size), cached_exp10);
fp_value = fp_value * cached_pow;
int size = grisu2_gen_digits(buf.data(), fp_value, 1, exp,
fixed_stop{precision, -cached_exp10});
fixed_stop{precision, -cached_exp10, fixed});
if (size < 0) return false;
buf.resize(to_unsigned(size));
} else {

8
include/fmt/format.h
View File

@ -1139,10 +1139,10 @@ namespace internal {
// https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf
template <typename Double>
FMT_API typename std::enable_if<sizeof(Double) == sizeof(uint64_t), bool>::type
grisu2_format(Double value, buffer& buf, int precision, int& exp);
grisu2_format(Double value, buffer& buf, int precision, bool fixed, int& exp);
template <typename Double>
inline typename std::enable_if<sizeof(Double) != sizeof(uint64_t), bool>::type
grisu2_format(Double, buffer&, int, int&) {
grisu2_format(Double, buffer&, int, bool, int&) {
return false;
}
@ -2866,9 +2866,9 @@ void basic_writer<Range>::write_double(T value, const format_specs& spec) {
int exp = 0;
int precision = spec.has_precision() || !spec.type ? spec.precision : 6;
bool use_grisu = fmt::internal::use_grisu<T>() &&
(!spec.type || handler.fixed) && !spec.has_precision() &&
(!spec.type || handler.fixed) &&
internal::grisu2_format(static_cast<double>(value), buffer,
precision, exp);
precision, handler.fixed, exp);
if (!use_grisu) internal::sprintf_format(value, buffer, spec);
align_spec as = spec;
if (spec.align() == ALIGN_NUMERIC) {

2
src/format.cc
View File

@ -11,7 +11,7 @@ FMT_BEGIN_NAMESPACE
template struct internal::basic_data<void>;
// Workaround a bug in MSVC2013 that prevents instantiation of grisu2_format.
bool (*instantiate_grisu2_format)(double, internal::buffer&, int,
bool (*instantiate_grisu2_format)(double, internal::buffer&, int, bool,
int&) = internal::grisu2_format;
#ifndef FMT_STATIC_THOUSANDS_SEPARATOR

2
test/format-impl-test.cc
View File

@ -103,7 +103,7 @@ TEST(FPTest, GetCachedPower) {
TEST(FPTest, Grisu2FormatCompilesWithNonIEEEDouble) {
fmt::memory_buffer buf;
int exp = 0;
grisu2_format(4.2f, buf, -1, exp);
grisu2_format(4.2f, buf, -1, false, exp);
}
template <typename T> struct ValueExtractor : fmt::internal::function<T> {