fmtlegacy/include/fmt/time.h
2017-10-21 07:38:49 -07:00

61 lines
1.6 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 "fmt/format.h"
#include <ctime>
namespace fmt {
template <>
struct formatter<std::tm> {
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);
}
void format(buffer &buf, const std::tm &tm, context &ctx) {
std::size_t start = buf.size();
for (;;) {
std::size_t size = buf.capacity() - start;
std::size_t count = std::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));
}
}
memory_buffer tm_format;
};
}
#endif // FMT_TIME_H_