fmtlegacy/include/fmt/time.h
2018-05-12 11:02:15 -07:00

152 lines
4.0 KiB
C++

// Formatting library for C++ - time formatting
//
// Copyright (c) 2012 - 2016, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
#ifndef FMT_TIME_H_
#define FMT_TIME_H_
#include "format.h"
#include <ctime>
FMT_BEGIN_NAMESPACE
namespace internal{
inline null<> localtime_r(...) { return null<>(); }
inline null<> localtime_s(...) { return null<>(); }
inline null<> gmtime_r(...) { return null<>(); }
inline null<> gmtime_s(...) { return null<>(); }
}
// Thread-safe replacement for std::localtime
inline std::tm localtime(std::time_t time) {
struct LocalTime {
std::time_t time_;
std::tm tm_;
LocalTime(std::time_t t): time_(t) {}
bool run() {
using namespace fmt::internal;
return handle(localtime_r(&time_, &tm_));
}
bool handle(std::tm *tm) { return tm != FMT_NULL; }
bool handle(internal::null<>) {
using namespace fmt::internal;
return fallback(localtime_s(&tm_, &time_));
}
bool fallback(int res) { return res == 0; }
bool fallback(internal::null<>) {
using namespace fmt::internal;
std::tm *tm = std::localtime(&time_);
if (tm) tm_ = *tm;
return tm != FMT_NULL;
}
};
LocalTime lt(time);
if (lt.run())
return lt.tm_;
// Too big time values may be unsupported.
FMT_THROW(format_error("time_t value out of range"));
return std::tm();
}
// Thread-safe replacement for std::gmtime
inline std::tm gmtime(std::time_t time) {
struct GMTime {
std::time_t time_;
std::tm tm_;
GMTime(std::time_t t): time_(t) {}
bool run() {
using namespace fmt::internal;
return handle(gmtime_r(&time_, &tm_));
}
bool handle(std::tm *tm) { return tm != FMT_NULL; }
bool handle(internal::null<>) {
using namespace fmt::internal;
return fallback(gmtime_s(&tm_, &time_));
}
bool fallback(int res) { return res == 0; }
bool fallback(internal::null<>) {
std::tm *tm = std::gmtime(&time_);
if (tm) tm_ = *tm;
return tm != FMT_NULL;
}
};
GMTime gt(time);
if (gt.run())
return gt.tm_;
// Too big time values may be unsupported.
FMT_THROW(format_error("time_t value out of range"));
return std::tm();
}
namespace internal {
inline std::size_t strftime(char *str, std::size_t count, const char *format, const std::tm *time) {
return std::strftime(str, count, format, time);
}
inline std::size_t strftime(wchar_t *str, std::size_t count, const wchar_t *format, const std::tm *time) {
return std::wcsftime(str, count, format, time);
}
}
template <typename Char>
struct formatter<std::tm, Char> {
template <typename ParseContext>
auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
auto it = internal::null_terminating_iterator<Char>(ctx);
if (*it == ':')
++it;
auto end = it;
while (*end && *end != '}')
++end;
tm_format.reserve(end - it + 1);
using internal::pointer_from;
tm_format.append(pointer_from(it), pointer_from(end));
tm_format.push_back('\0');
return pointer_from(end);
}
template <typename FormatContext>
auto format(const std::tm &tm, FormatContext &ctx) -> decltype(ctx.out()) {
internal::basic_buffer<Char> &buf = internal::get_container(ctx.out());
std::size_t start = buf.size();
for (;;) {
std::size_t size = buf.capacity() - start;
std::size_t count = internal::strftime(&buf[start], size, &tm_format[0], &tm);
if (count != 0) {
buf.resize(start + count);
break;
}
if (size >= tm_format.size() * 256) {
// If the buffer is 256 times larger than the format string, assume
// that `strftime` gives an empty result. There doesn't seem to be a
// better way to distinguish the two cases:
// https://github.com/fmtlib/fmt/issues/367
break;
}
const std::size_t MIN_GROWTH = 10;
buf.reserve(buf.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
}
return ctx.out();
}
basic_memory_buffer<Char> tm_format;
};
FMT_END_NAMESPACE
#endif // FMT_TIME_H_