Add formatters for chrono::time_point<system_clock> (#1837)

Add formatters for chrono::time_point and helper overloads for localtime/gmtime(time_point)
Fixes #1819
This commit is contained in:
Adam Burgess 2020-08-29 00:41:38 +10:00 committed by GitHub
parent 77b627be20
commit f39e6fb617
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2 changed files with 32 additions and 0 deletions

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@ -325,6 +325,11 @@ inline std::tm localtime(std::time_t time) {
return lt.tm_;
}
inline std::tm localtime(
std::chrono::time_point<std::chrono::system_clock> time_point) {
return localtime(std::chrono::system_clock::to_time_t(time_point));
}
// Thread-safe replacement for std::gmtime
inline std::tm gmtime(std::time_t time) {
struct dispatcher {
@ -361,6 +366,11 @@ inline std::tm gmtime(std::time_t time) {
return gt.tm_;
}
inline std::tm gmtime(
std::chrono::time_point<std::chrono::system_clock> time_point) {
return gmtime(std::chrono::system_clock::to_time_t(time_point));
}
namespace detail {
inline size_t strftime(char* str, size_t count, const char* format,
const std::tm* time) {
@ -373,6 +383,17 @@ inline size_t strftime(wchar_t* str, size_t count, const wchar_t* format,
}
} // namespace detail
template <typename Char>
struct formatter<std::chrono::time_point<std::chrono::system_clock>, Char>
: formatter<std::tm, Char> {
template <typename FormatContext>
auto format(std::chrono::time_point<std::chrono::system_clock> val,
FormatContext& ctx) -> decltype(ctx.out()) {
std::tm time = localtime(val);
return formatter<std::tm, Char>::format(time, ctx);
}
};
template <typename Char> struct formatter<std::tm, Char> {
template <typename ParseContext>
auto parse(ParseContext& ctx) -> decltype(ctx.begin()) {

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@ -95,6 +95,17 @@ TEST(TimeTest, GMTime) {
EXPECT_TRUE(EqualTime(tm, fmt::gmtime(t)));
}
TEST(TimeTest, TimePoint) {
std::chrono::system_clock::time_point point = std::chrono::system_clock::now();
std::time_t t = std::chrono::system_clock::to_time_t(point);
std::tm tm = *std::localtime(&t);
char strftime_output[256];
std::strftime(strftime_output, sizeof(strftime_output), "It is %Y-%m-%d %H:%M:%S", &tm);
EXPECT_EQ(strftime_output, fmt::format("It is {:%Y-%m-%d %H:%M:%S}", point));
}
#define EXPECT_TIME(spec, time, duration) \
{ \
std::locale loc("ja_JP.utf8"); \