time.h

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/*
 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>

namespace fmt
{
template <typename ArgFormatter>
void format(BasicFormatter<char, ArgFormatter> &f,
            const char *&format_str, const std::tm &tm)
{
    if (*format_str == ':')
        ++format_str;
    const char *end = format_str;
    while (*end && *end != '}')
        ++end;
    if (*end != '}')
        FMT_THROW(FormatError("missing '}' in format string"));
    internal::MemoryBuffer<char, internal::INLINE_BUFFER_SIZE> format;
    format.append(format_str, end + 1);
    format[format.size() - 1] = '\0';
    Buffer<char> &buffer = f.writer().buffer();
    std::size_t start = buffer.size();
    for (;;)
    {
        std::size_t size = buffer.capacity() - start;
        std::size_t count = std::strftime(&buffer[start], size, &format[0], &tm);
        if (count != 0)
        {
            buffer.resize(start + count);
            break;
        }
        if (size >= 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;
        buffer.reserve(buffer.capacity() + (size > MIN_GROWTH ? size : MIN_GROWTH));
    }
    format_str = end + 1;
}
}

#endif  // FMT_TIME_H_