Dep/fmt: Upgrade to 7.1.3 (#26816)

Printing enum values as integers was broken before 7.1.0.
Upgrade the library so we include commits

https://github.com/fmtlib/fmt/commit/20d4f2e83677be035a15693127e404c4a5d68ac9
https://github.com/fmtlib/fmt/commit/86287b8d5625ef390da6ef10fc77a872b8ad41ac

which fix the issue.

dep/PackageList.txt

@@ -22,7 +22,7 @@ efws (Entropia File System Watcher - crossplatform file system watcher)
 
 fmt (a small, safe and fast formatting library)
   https://github.com/fmtlib/fmt
-  Version: 7.0.3 https://github.com/fmtlib/fmt/releases/tag/7.0.3
+  Version: 7.1.3 https://github.com/fmtlib/fmt/releases/tag/7.1.3
 
 G3D (a commercial-grade C++ 3D engine available as Open Source (BSD License)
   http://g3d.sourceforge.net/

dep/fmt/CONTRIBUTING.md

@@ -14,4 +14,7 @@ exceptions:
 * snake_case should be used instead of UpperCamelCase for function and type
   names
 
+All documentation must adhere to the [Google Developer Documentation Style
+Guide](https://developers.google.com/style).
+
 Thanks for contributing!

dep/fmt/ChangeLog.rst

@@ -1,3 +1,428 @@
+7.1.3 - 2020-11-24
+------------------
+
+* Fixed handling of buffer boundaries in ``format_to_n``
+  (`#1996 <https://github.com/fmtlib/fmt/issues/1996>`_,
+  `#2029 <https://github.com/fmtlib/fmt/issues/2029>`_).
+
+* Fixed linkage errors when linking with a shared library
+  (`#2011 <https://github.com/fmtlib/fmt/issues/2011>`_).
+
+* Reintroduced ostream support to range formatters
+  (`#2014 <https://github.com/fmtlib/fmt/issues/2014>`_).
+
+* Worked around an issue with mixing std versions in gcc
+  (`#2017 <https://github.com/fmtlib/fmt/issues/2017>`_).
+
+7.1.2 - 2020-11-04
+------------------
+
+* Fixed floating point formatting with large precision
+  (`#1976 <https://github.com/fmtlib/fmt/issues/1976>`_).
+
+7.1.1 - 2020-11-01
+------------------
+
+* Fixed ABI compatibility with 7.0.x
+  (`#1961 <https://github.com/fmtlib/fmt/issues/1961>`_).
+
+* Added the ``FMT_ARM_ABI_COMPATIBILITY`` macro to work around ABI
+  incompatibility between GCC and Clang on ARM
+  (`#1919 <https://github.com/fmtlib/fmt/issues/1919>`_).
+
+* Worked around a SFINAE bug in GCC 8
+  (`#1957 <https://github.com/fmtlib/fmt/issues/1957>`_).
+
+* Fixed linkage errors when building with GCC's LTO
+  (`#1955 <https://github.com/fmtlib/fmt/issues/1955>`_).
+
+* Fixed a compilation error when building without ``__builtin_clz`` or equivalent
+  (`#1968 <https://github.com/fmtlib/fmt/pull/1968>`_).
+  Thanks `@tohammer (Tobias Hammer) <https://github.com/tohammer>`_.
+
+* Fixed a sign conversion warning
+  (`#1964 <https://github.com/fmtlib/fmt/pull/1964>`_).
+  Thanks `@OptoCloud <https://github.com/OptoCloud>`_.
+
+7.1.0 - 2020-10-25
+------------------
+
+* Switched from `Grisu3
+  <https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf>`_
+  to `Dragonbox <https://github.com/jk-jeon/dragonbox>`_ for the default
+  floating-point formatting which gives the shortest decimal representation
+  with round-trip guarantee and correct rounding
+  (`#1882 <https://github.com/fmtlib/fmt/pull/1882>`_,
+  `#1887 <https://github.com/fmtlib/fmt/pull/1887>`_,
+  `#1894 <https://github.com/fmtlib/fmt/pull/1894>`_). This makes {fmt} up to
+  20-30x faster than common implementations of ``std::ostringstream`` and
+  ``sprintf`` on `dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_
+  and faster than double-conversion and Ryū:
+
+  .. image:: https://user-images.githubusercontent.com/576385/
+             95684665-11719600-0ba8-11eb-8e5b-972ff4e49428.png
+
+  It is possible to get even better performance at the cost of larger binary
+  size by compiling with the ``FMT_USE_FULL_CACHE_DRAGONBOX`` macro set to 1.
+
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Added an experimental unsynchronized file output API which, together with
+  `format string compilation <https://fmt.dev/latest/api.html#compile-api>`_,
+  can give `5-9 times speed up compared to fprintf
+  <https://www.zverovich.net/2020/08/04/optimal-file-buffer-size.html>`_
+  on common platforms (`godbolt <https://godbolt.org/z/nsTcG8>`__):
+
+  .. code:: c++
+
+     #include <fmt/os.h>
+
+     int main() {
+       auto f = fmt::output_file("guide");
+       f.print("The answer is {}.", 42);
+     }
+
+* Added a formatter for ``std::chrono::time_point<system_clock>``
+  (`#1819 <https://github.com/fmtlib/fmt/issues/1819>`_,
+  `#1837 <https://github.com/fmtlib/fmt/pull/1837>`_). For example
+  (`godbolt <https://godbolt.org/z/c4M6fh>`__):
+
+  .. code:: c++
+
+     #include <fmt/chrono.h>
+
+     int main() {
+       auto now = std::chrono::system_clock::now();
+       fmt::print("The time is {:%H:%M:%S}.\n", now);
+     }
+
+  Thanks `@adamburgess (Adam Burgess) <https://github.com/adamburgess>`_.
+
+* Added support for ranges with non-const ``begin``/``end`` to ``fmt::join``
+  (`#1784 <https://github.com/fmtlib/fmt/issues/1784>`_,
+  `#1786 <https://github.com/fmtlib/fmt/pull/1786>`_). For example
+  (`godbolt <https://godbolt.org/z/jP63Tv>`__):
+
+  .. code:: c++
+
+     #include <fmt/ranges.h>
+     #include <range/v3/view/filter.hpp>
+
+     int main() {
+       using std::literals::string_literals::operator""s;
+       auto strs = std::array{"a"s, "bb"s, "ccc"s};
+       auto range = strs | ranges::views::filter(
+         [] (const std::string &x) { return x.size() != 2; }
+       );
+       fmt::print("{}\n", fmt::join(range, ""));
+     }
+
+  prints "accc".
+
+  Thanks `@tonyelewis (Tony E Lewis) <https://github.com/tonyelewis>`_.
+
+* Added a ``memory_buffer::append`` overload that takes a range
+  (`#1806 <https://github.com/fmtlib/fmt/pull/1806>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Improved handling of single code units in ``FMT_COMPILE``. For example:
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     char* f(char* buf) {
+       return fmt::format_to(buf, FMT_COMPILE("x{}"), 42);
+     }
+
+  compiles to just (`godbolt <https://godbolt.org/z/5vncz3>`__):
+
+  .. code:: asm
+
+     _Z1fPc:
+       movb $120, (%rdi)
+       xorl %edx, %edx
+       cmpl $42, _ZN3fmt2v76detail10basic_dataIvE23zero_or_powers_of_10_32E+8(%rip)
+       movl $3, %eax
+       seta %dl
+       subl %edx, %eax
+       movzwl _ZN3fmt2v76detail10basic_dataIvE6digitsE+84(%rip), %edx
+       cltq
+       addq %rdi, %rax
+       movw %dx, -2(%rax)
+       ret
+
+  Here a single ``mov`` instruction writes ``'x'`` (``$120``) to the output
+  buffer.
+
+* Added dynamic width support to format string compilation
+  (`#1809 <https://github.com/fmtlib/fmt/issues/1809>`_).
+
+* Improved error reporting for unformattable types: now you'll get the type name
+  directly in the error message instead of the note:
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     struct how_about_no {};
+
+     int main() {
+       fmt::print("{}", how_about_no());
+     }
+
+  Error (`godbolt <https://godbolt.org/z/GoxM4e>`__):
+
+  ``fmt/core.h:1438:3: error: static_assert failed due to requirement
+  'fmt::v7::formattable<how_about_no>()' "Cannot format an argument.
+  To make type T formattable provide a formatter<T> specialization:
+  https://fmt.dev/latest/api.html#udt"
+  ...``
+
+* Added the `make_args_checked <https://fmt.dev/7.1.0/api.html#argument-lists>`_
+  function template that allows you to write formatting functions with
+  compile-time format string checks and avoid binary code bloat
+  (`godbolt <https://godbolt.org/z/PEf9qr>`__):
+
+  .. code:: c++
+
+     void vlog(const char* file, int line, fmt::string_view format,
+               fmt::format_args args) {
+       fmt::print("{}: {}: ", file, line);
+       fmt::vprint(format, args);
+     }
+
+     template <typename S, typename... Args>
+     void log(const char* file, int line, const S& format, Args&&... args) {
+       vlog(file, line, format,
+           fmt::make_args_checked<Args...>(format, args...));
+     }
+
+     #define MY_LOG(format, ...) \
+       log(__FILE__, __LINE__, FMT_STRING(format), __VA_ARGS__)
+
+     MY_LOG("invalid squishiness: {}", 42);
+
+* Replaced ``snprintf`` fallback with a faster internal IEEE 754 ``float`` and
+  ``double`` formatter for arbitrary precision. For example
+  (`godbolt <https://godbolt.org/z/dPhWvj>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("{:.500}\n", 4.9406564584124654E-324);
+     }
+
+  prints
+
+  ``4.9406564584124654417656879286822137236505980261432476442558568250067550727020875186529983636163599237979656469544571773092665671035593979639877479601078187812630071319031140452784581716784898210368871863605699873072305000638740915356498438731247339727316961514003171538539807412623856559117102665855668676818703956031062493194527159149245532930545654440112748012970999954193198940908041656332452475714786901472678015935523861155013480352649347201937902681071074917033322268447533357208324319360923829e-324``.
+
+* Made ``format_to_n`` and ``formatted_size`` part of the `core API
+  <https://fmt.dev/latest/api.html#core-api>`__
+  (`godbolt <https://godbolt.org/z/sPjY1K>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       char buffer[10];
+       auto result = fmt::format_to_n(buffer, sizeof(buffer), "{}", 42);
+     }
+
+* Added ``fmt::format_to_n`` overload with format string compilation
+  (`#1764 <https://github.com/fmtlib/fmt/issues/1764>`_,
+  `#1767 <https://github.com/fmtlib/fmt/pull/1767>`_,
+  `#1869 <https://github.com/fmtlib/fmt/pull/1869>`_). For example
+  (`godbolt <https://godbolt.org/z/93h86q>`__):
+
+  .. code:: c++
+
+     #include <fmt/compile.h>
+
+     int main() {
+       char buffer[8];
+       fmt::format_to_n(buffer, sizeof(buffer), FMT_COMPILE("{}"), 42);
+     }
+
+  Thanks `@Kurkin (Dmitry Kurkin) <https://github.com/Kurkin>`_,
+  `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added ``fmt::format_to`` overload that take ``text_style``
+  (`#1593 <https://github.com/fmtlib/fmt/issues/1593>`_,
+  `#1842 <https://github.com/fmtlib/fmt/issues/1842>`_,
+  `#1843 <https://github.com/fmtlib/fmt/pull/1843>`_). For example
+  (`godbolt <https://godbolt.org/z/91153r>`__):
+
+  .. code:: c++
+
+     #include <fmt/color.h>
+
+     int main() {
+       std::string out;
+       fmt::format_to(std::back_inserter(out),
+                      fmt::emphasis::bold | fg(fmt::color::red),
+                      "The answer is {}.", 42);
+     }
+
+  Thanks `@Naios (Denis Blank) <https://github.com/Naios>`_.
+
+* Made the ``#`` specifier emit trailing zeros in addition to the decimal point
+  (`#1797 <https://github.com/fmtlib/fmt/issues/1797>`_). For example
+  (`godbolt <https://godbolt.org/z/bhdcW9>`__):
+
+  .. code:: c++
+
+     #include <fmt/core.h>
+
+     int main() {
+       fmt::print("{:#.2g}", 0.5);
+     }
+
+  prints ``0.50``.
+
+* Changed the default floating point format to not include ``.0`` for
+  consistency with ``std::format`` and ``std::to_chars``
+  (`#1893 <https://github.com/fmtlib/fmt/issues/1893>`_,
+  `#1943 <https://github.com/fmtlib/fmt/issues/1943>`_). It is possible to get
+  the decimal point and trailing zero with the ``#`` specifier.
+
+* Fixed an issue with floating-point formatting that could result in addition of
+  a non-significant trailing zero in rare cases e.g. ``1.00e-34`` instead of
+  ``1.0e-34`` (`#1873 <https://github.com/fmtlib/fmt/issues/1873>`_,
+  `#1917 <https://github.com/fmtlib/fmt/issues/1917>`_).
+
+* Made ``fmt::to_string`` fallback on ``ostream`` insertion operator if
+  the ``formatter`` specialization is not provided
+  (`#1815 <https://github.com/fmtlib/fmt/issues/1815>`_,
+  `#1829 <https://github.com/fmtlib/fmt/pull/1829>`_).
+  Thanks `@alexezeder (Alexey Ochapov) <https://github.com/alexezeder>`_.
+
+* Added support for the append mode to the experimental file API and
+  improved ``fcntl.h`` detection.
+  (`#1847 <https://github.com/fmtlib/fmt/pull/1847>`_,
+  `#1848 <https://github.com/fmtlib/fmt/pull/1848>`_).
+  Thanks `@t-wiser <https://github.com/t-wiser>`_.
+
+* Fixed handling of types that have both an implicit conversion operator and
+  an overloaded ``ostream`` insertion operator
+  (`#1766 <https://github.com/fmtlib/fmt/issues/1766>`_).
+
+* Fixed a slicing issue in an internal iterator type
+  (`#1822 <https://github.com/fmtlib/fmt/pull/1822>`_).
+  Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
+
+* Fixed an issue in locale-specific integer formatting
+  (`#1927 <https://github.com/fmtlib/fmt/issues/1927>`_).
+
+* Fixed handling of exotic code unit types
+  (`#1870 <https://github.com/fmtlib/fmt/issues/1870>`_,
+  `#1932 <https://github.com/fmtlib/fmt/issues/1932>`_).
+
+* Improved ``FMT_ALWAYS_INLINE``
+  (`#1878 <https://github.com/fmtlib/fmt/pull/1878>`_).
+  Thanks `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_.
+
+* Removed dependency on ``windows.h``
+  (`#1900 <https://github.com/fmtlib/fmt/pull/1900>`_).
+  Thanks `@bernd5 (Bernd Baumanns) <https://github.com/bernd5>`_.
+
+* Optimized counting of decimal digits on MSVC
+  (`#1890 <https://github.com/fmtlib/fmt/pull/1890>`_).
+  Thanks `@mwinterb <https://github.com/mwinterb>`_.
+
+* Improved documentation
+  (`#1772 <https://github.com/fmtlib/fmt/issues/1772>`_,
+  `#1775 <https://github.com/fmtlib/fmt/pull/1775>`_,
+  `#1792 <https://github.com/fmtlib/fmt/pull/1792>`_,
+  `#1838 <https://github.com/fmtlib/fmt/pull/1838>`_,
+  `#1888 <https://github.com/fmtlib/fmt/pull/1888>`_,
+  `#1918 <https://github.com/fmtlib/fmt/pull/1918>`_,
+  `#1939 <https://github.com/fmtlib/fmt/pull/1939>`_).
+  Thanks `@leolchat (Léonard Gérard) <https://github.com/leolchat>`_,
+  `@pepsiman (Malcolm Parsons) <https://github.com/pepsiman>`_,
+  `@Klaim (Joël Lamotte) <https://github.com/Klaim>`_,
+  `@ravijanjam (Ravi J) <https://github.com/ravijanjam>`_,
+  `@francesco-st <https://github.com/francesco-st>`_,
+  `@udnaan (Adnan) <https://github.com/udnaan>`_.
+
+* Added the ``FMT_REDUCE_INT_INSTANTIATIONS`` CMake option that reduces the
+  binary code size at the cost of some integer formatting performance. This can
+  be useful for extremely memory-constrained embedded systems
+  (`#1778 <https://github.com/fmtlib/fmt/issues/1778>`_,
+  `#1781 <https://github.com/fmtlib/fmt/pull/1781>`_).
+  Thanks `@kammce (Khalil Estell) <https://github.com/kammce>`_.
+
+* Added the ``FMT_USE_INLINE_NAMESPACES`` macro to control usage of inline
+  namespaces (`#1945 <https://github.com/fmtlib/fmt/pull/1945>`_).
+  Thanks `@darklukee <https://github.com/darklukee>`_.
+
+* Improved build configuration
+  (`#1760 <https://github.com/fmtlib/fmt/pull/1760>`_,
+  `#1770 <https://github.com/fmtlib/fmt/pull/1770>`_,
+  `#1779 <https://github.com/fmtlib/fmt/issues/1779>`_,
+  `#1783 <https://github.com/fmtlib/fmt/pull/1783>`_,
+  `#1823 <https://github.com/fmtlib/fmt/pull/1823>`_).
+  Thanks `@dvetutnev (Dmitriy Vetutnev) <https://github.com/dvetutnev>`_,
+  `@xvitaly (Vitaly Zaitsev) <https://github.com/xvitaly>`_,
+  `@tambry (Raul Tambre) <https://github.com/tambry>`_,
+  `@medithe <https://github.com/medithe>`_,
+  `@martinwuehrer (Martin Wührer) <https://github.com/martinwuehrer>`_.
+
+* Fixed various warnings and compilation issues
+  (`#1790 <https://github.com/fmtlib/fmt/pull/1790>`_,
+  `#1802 <https://github.com/fmtlib/fmt/pull/1802>`_,
+  `#1808 <https://github.com/fmtlib/fmt/pull/1808>`_,
+  `#1810 <https://github.com/fmtlib/fmt/issues/1810>`_,
+  `#1811 <https://github.com/fmtlib/fmt/issues/1811>`_,
+  `#1812 <https://github.com/fmtlib/fmt/pull/1812>`_,
+  `#1814 <https://github.com/fmtlib/fmt/pull/1814>`_,
+  `#1816 <https://github.com/fmtlib/fmt/pull/1816>`_,
+  `#1817 <https://github.com/fmtlib/fmt/pull/1817>`_,
+  `#1818 <https://github.com/fmtlib/fmt/pull/1818>`_,
+  `#1825 <https://github.com/fmtlib/fmt/issues/1825>`_,
+  `#1836 <https://github.com/fmtlib/fmt/pull/1836>`_,
+  `#1855 <https://github.com/fmtlib/fmt/pull/1855>`_,
+  `#1856 <https://github.com/fmtlib/fmt/pull/1856>`_,
+  `#1860 <https://github.com/fmtlib/fmt/pull/1860>`_,
+  `#1877 <https://github.com/fmtlib/fmt/pull/1877>`_,
+  `#1879 <https://github.com/fmtlib/fmt/pull/1879>`_,
+  `#1880 <https://github.com/fmtlib/fmt/pull/1880>`_,
+  `#1896 <https://github.com/fmtlib/fmt/issues/1896>`_,
+  `#1897 <https://github.com/fmtlib/fmt/pull/1897>`_,
+  `#1898 <https://github.com/fmtlib/fmt/pull/1898>`_,
+  `#1904 <https://github.com/fmtlib/fmt/issues/1904>`_,
+  `#1908 <https://github.com/fmtlib/fmt/pull/1908>`_,
+  `#1911 <https://github.com/fmtlib/fmt/issues/1911>`_,
+  `#1912 <https://github.com/fmtlib/fmt/issues/1912>`_,
+  `#1928 <https://github.com/fmtlib/fmt/issues/1928>`_,
+  `#1929 <https://github.com/fmtlib/fmt/pull/1929>`_,
+  `#1935 <https://github.com/fmtlib/fmt/issues/1935>`_
+  `#1937 <https://github.com/fmtlib/fmt/pull/1937>`_,
+  `#1942 <https://github.com/fmtlib/fmt/pull/1942>`_,
+  `#1949 <https://github.com/fmtlib/fmt/issues/1949>`_).
+  Thanks `@TheQwertiest <https://github.com/TheQwertiest>`_,
+  `@medithe <https://github.com/medithe>`_,
+  `@martinwuehrer (Martin Wührer) <https://github.com/martinwuehrer>`_,
+  `@n16h7hunt3r <https://github.com/n16h7hunt3r>`_,
+  `@Othereum (Seokjin Lee) <https://github.com/Othereum>`_,
+  `@gsjaardema (Greg Sjaardema) <https://github.com/gsjaardema>`_,
+  `@AlexanderLanin (Alexander Lanin) <https://github.com/AlexanderLanin>`_,
+  `@gcerretani (Giovanni Cerretani) <https://github.com/gcerretani>`_,
+  `@chronoxor (Ivan Shynkarenka) <https://github.com/chronoxor>`_,
+  `@noizefloor (Jan Schwers) <https://github.com/noizefloor>`_,
+  `@akohlmey (Axel Kohlmeyer) <https://github.com/akohlmey>`_,
+  `@jk-jeon (Junekey Jeon) <https://github.com/jk-jeon>`_,
+  `@rimathia <https://github.com/rimathia>`_,
+  `@rglarix (Riccardo Ghetta (larix)) <https://github.com/rglarix>`_,
+  `@moiwi <https://github.com/moiwi>`_,
+  `@heckad (Kazantcev Andrey) <https://github.com/heckad>`_,
+  `@MarcDirven <https://github.com/MarcDirven>`_.
+  `@BartSiwek (Bart Siwek) <https://github.com/BartSiwek>`_,
+  `@darklukee <https://github.com/darklukee>`_.
+
 7.0.3 - 2020-08-06
 ------------------
 
@@ -49,7 +474,7 @@
   <http://www.zverovich.net/2020/05/21/reducing-library-size.html>`_.
 
 * Added a simpler and more efficient `format string compilation API
-  <https://fmt.dev/dev/api.html#compile-api>`_:
+  <https://fmt.dev/7.0.0/api.html#compile-api>`_:
 
   .. code:: c++
 
@@ -188,7 +613,7 @@
 
   Thanks `@BRevzin (Barry Revzin) <https://github.com/BRevzin>`_.
 
-* Added support for named args, ``clear`` and ``reserve`` to
+* Added support for named arguments, ``clear`` and ``reserve`` to
   ``dynamic_format_arg_store``
   (`#1655 <https://github.com/fmtlib/fmt/issues/1655>`_,
   `#1663 <https://github.com/fmtlib/fmt/pull/1663>`_,
@@ -1705,7 +2130,7 @@
 
 * Implemented ``constexpr`` parsing of format strings and `compile-time format
   string checks
-  <https://fmt.dev/dev/api.html#compile-time-format-string-checks>`_. For
+  <https://fmt.dev/latest/api.html#compile-time-format-string-checks>`_. For
   example
 
   .. code:: c++
@@ -1766,7 +2191,7 @@
             throw format_error("invalid specifier");
 
 * Added `iterator support
-  <https://fmt.dev/dev/api.html#output-iterator-support>`_:
+  <https://fmt.dev/latest/api.html#output-iterator-support>`_:
 
   .. code:: c++
 
@@ -1777,7 +2202,7 @@
      fmt::format_to(std::back_inserter(out), "{}", 42);
 
 * Added the `format_to_n
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt11format_to_nE8OutputItNSt6size_tE11string_viewDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt11format_to_nE8OutputItNSt6size_tE11string_viewDpRK4Args>`_
   function that restricts the output to the specified number of characters
   (`#298 <https://github.com/fmtlib/fmt/issues/298>`_):
 
@@ -1788,7 +2213,7 @@
      // out == "1234" (without terminating '\0')
 
 * Added the `formatted_size
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt14formatted_sizeE11string_viewDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt14formatted_sizeE11string_viewDpRK4Args>`_
   function for computing the output size:
 
   .. code:: c++
@@ -1798,7 +2223,7 @@
      auto size = fmt::formatted_size("{}", 12345); // size == 5
 
 * Improved compile times by reducing dependencies on standard headers and
-  providing a lightweight `core API <https://fmt.dev/dev/api.html#core-api>`_:
+  providing a lightweight `core API <https://fmt.dev/latest/api.html#core-api>`_:
 
   .. code:: c++
 
@@ -1810,7 +2235,7 @@
   <https://github.com/fmtlib/fmt#compile-time-and-code-bloat>`_.
 
 * Added the `make_format_args
-  <https://fmt.dev/dev/api.html#_CPPv2N3fmt16make_format_argsEDpRK4Args>`_
+  <https://fmt.dev/latest/api.html#_CPPv2N3fmt16make_format_argsEDpRK4Args>`_
   function for capturing formatting arguments:
 
   .. code:: c++
@@ -1892,7 +2317,7 @@
      fmt::format("{} {two}", 1, fmt::arg("two", 2));
 
 * Removed the write API in favor of the `format API
-  <https://fmt.dev/dev/api.html#format-api>`_ with compile-time handling of
+  <https://fmt.dev/latest/api.html#format-api>`_ with compile-time handling of
   format strings.
 
 * Disallowed formatting of multibyte strings into a wide character target

dep/fmt/README.rst

@@ -7,48 +7,57 @@
 .. image:: https://ci.appveyor.com/api/projects/status/ehjkiefde6gucy1v
    :target: https://ci.appveyor.com/project/vitaut/fmt
 
-.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/libfmt.svg
+.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/fmt.svg
-   :alt: fmt is continuously fuzzed att oss-fuzz
+   :alt: fmt is continuously fuzzed at oss-fuzz
    :target: https://bugs.chromium.org/p/oss-fuzz/issues/list?\
             colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20\
-            Summary&q=proj%3Dlibfmt&can=1
+            Summary&q=proj%3Dfmt&can=1
 
 .. image:: https://img.shields.io/badge/stackoverflow-fmt-blue.svg
    :alt: Ask questions at StackOverflow with the tag fmt
    :target: https://stackoverflow.com/questions/tagged/fmt
 
-**{fmt}** is an open-source formatting library for C++.
+**{fmt}** is an open-source formatting library providing a fast and safe
-It can be used as a safe and fast alternative to (s)printf and iostreams.
+alternative to C stdio and C++ iostreams.
 
-`Documentation <https://fmt.dev/latest/>`__
+If you like this project, please consider donating to BYSOL,
+an initiative to help victims of political repressions in Belarus:
+https://www.facebook.com/donate/759400044849707/108388587646909/.
+
+`Documentation <https://fmt.dev>`__
 
 Q&A: ask questions on `StackOverflow with the tag fmt
 <https://stackoverflow.com/questions/tagged/fmt>`_.
 
+Try {fmt} in `Compiler Explorer <https://godbolt.org/z/Eq5763>`_.
+
 Features
 --------
 
-* Simple `format API <https://fmt.dev/dev/api.html>`_ with positional arguments
+* Simple `format API <https://fmt.dev/latest/api.html>`_ with positional arguments
   for localization
 * Implementation of `C++20 std::format
   <https://en.cppreference.com/w/cpp/utility/format>`__
-* `Format string syntax <https://fmt.dev/dev/syntax.html>`_ similar to the one
+* `Format string syntax <https://fmt.dev/latest/syntax.html>`_ similar to Python's
-  of Python's
   `format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
+* Fast IEEE 754 floating-point formatter with correct rounding, shortness and
+  round-trip guarantees
 * Safe `printf implementation
-  <https://fmt.dev/latest/api.html#printf-formatting>`_ including
+  <https://fmt.dev/latest/api.html#printf-formatting>`_ including the POSIX
-  the POSIX extension for positional arguments
+  extension for positional arguments
-* Extensibility: support for user-defined types
+* Extensibility: `support for user-defined types
+  <https://fmt.dev/latest/api.html#formatting-user-defined-types>`_
 * High performance: faster than common standard library implementations of
-  `printf <https://en.cppreference.com/w/cpp/io/c/fprintf>`_,
+  ``(s)printf``, iostreams, ``to_string`` and ``to_chars``, see `Speed tests`_
-  iostreams, ``to_string`` and ``to_chars``, see `Speed tests`_ and
+  and `Converting a hundred million integers to strings per second
-  `Converting a hundred million integers to strings per second
   <http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_
-* Small code size both in terms of source code (the minimum configuration
+* Small code size both in terms of source code with the minimum configuration
-  consists of just three header files, ``core.h``, ``format.h`` and
+  consisting of just three files, ``core.h``, ``format.h`` and ``format-inl.h``,
-  ``format-inl.h``) and compiled code. See `Compile time and code bloat`_
+  and compiled code; see `Compile time and code bloat`_
-* Reliability: the library has an extensive set of `unit tests
+* Reliability: the library has an extensive set of `tests
-  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is continuously fuzzed
+  <https://github.com/fmtlib/fmt/tree/master/test>`_ and is `continuously fuzzed
+  <https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20
+  Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dfmt&can=1>`_
 * Safety: the library is fully type safe, errors in format strings can be
   reported at compile time, automatic memory management prevents buffer overflow
   errors
@@ -57,18 +66,17 @@ Features
   <https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_
 * `Portability <https://fmt.dev/latest/index.html#portability>`_ with
   consistent output across platforms and support for older compilers
-* Clean warning-free codebase even on high warning levels
+* Clean warning-free codebase even on high warning levels such as
-  (``-Wall -Wextra -pedantic``)
+  ``-Wall -Wextra -pedantic``
 * Locale-independence by default
-* Support for wide strings
 * Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro
 
-See the `documentation <https://fmt.dev/latest/>`_ for more details.
+See the `documentation <https://fmt.dev>`_ for more details.
 
 Examples
 --------
 
-Print ``Hello, world!`` to ``stdout``:
+**Print to stdout** (`run <https://godbolt.org/z/Tevcjh>`_)
 
 .. code:: c++
 
@@ -78,100 +86,95 @@ Print ``Hello, world!`` to ``stdout``:
       fmt::print("Hello, world!\n");
     }
 
-Format a string:
+**Format a string** (`run <https://godbolt.org/z/oK8h33>`_)
 
 .. code:: c++
 
     std::string s = fmt::format("The answer is {}.", 42);
     // s == "The answer is 42."
 
-Format a string using positional arguments:
+**Format a string using positional arguments** (`run <https://godbolt.org/z/Yn7Txe>`_)
 
 .. code:: c++
 
     std::string s = fmt::format("I'd rather be {1} than {0}.", "right", "happy");
     // s == "I'd rather be happy than right."
 
-Print a chrono duration:
+**Print chrono durations** (`run <https://godbolt.org/z/K8s4Mc>`_)
 
 .. code:: c++
 
     #include <fmt/chrono.h>
 
     int main() {
-      using namespace std::chrono_literals;
+      using namespace std::literals::chrono_literals;
-      fmt::print("Elapsed time: {}", 42ms);
+      fmt::print("Default format: {} {}\n", 42s, 100ms);
+      fmt::print("strftime-like format: {:%H:%M:%S}\n", 3h + 15min + 30s);
     }
 
-prints "Elapsed time: 42ms".
+Output::
 
-Check a format string at compile time:
+    Default format: 42s 100ms
+    strftime-like format: 03:15:30
+
+**Print a container** (`run <https://godbolt.org/z/MjsY7c>`_)
 
 .. code:: c++
 
-    // test.cc
+    #include <vector>
-    #include <fmt/format.h>
+    #include <fmt/ranges.h>
-    std::string s = format(FMT_STRING("{:d}"), "hello");
 
-gives a compile-time error because ``d`` is an invalid format specifier for a
+    int main() {
-string.
+      std::vector<int> v = {1, 2, 3};
-
+      fmt::print("{}\n", v);
-Use {fmt} as a safe portable replacement for ``itoa``
-(`godbolt <https://godbolt.org/g/NXmpU4>`_):
-
-.. code:: c++
-
-    fmt::memory_buffer buf;
-    format_to(buf, "{}", 42);    // replaces itoa(42, buffer, 10)
-    format_to(buf, "{:x}", 42);  // replaces itoa(42, buffer, 16)
-    // access the string with to_string(buf) or buf.data()
-
-Format objects of user-defined types via a simple `extension API
-<https://fmt.dev/latest/api.html#formatting-user-defined-types>`_:
-
-.. code:: c++
-
-    #include <fmt/format.h>
-
-    struct date {
-      int year, month, day;
-    };
-
-    template <>
-    struct fmt::formatter<date> {
-      constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
-
-      template <typename FormatContext>
-      auto format(const date& d, FormatContext& ctx) {
-        return format_to(ctx.out(), "{}-{}-{}", d.year, d.month, d.day);
-      }
-    };
-
-    std::string s = fmt::format("The date is {}", date{2012, 12, 9});
-    // s == "The date is 2012-12-9"
-
-Create your own functions similar to `format
-<https://fmt.dev/latest/api.html#format>`_ and
-`print <https://fmt.dev/latest/api.html#print>`_
-which take arbitrary arguments (`godbolt <https://godbolt.org/g/MHjHVf>`_):
-
-.. code:: c++
-
-    // Prints formatted error message.
-    void vreport_error(const char* format, fmt::format_args args) {
-      fmt::print("Error: ");
-      fmt::vprint(format, args);
-    }
-    template <typename... Args>
-    void report_error(const char* format, const Args & ... args) {
-      vreport_error(format, fmt::make_format_args(args...));
     }
 
-    report_error("file not found: {}", path);
+Output::
 
-Note that ``vreport_error`` is not parameterized on argument types which can
+    {1, 2, 3}
-improve compile times and reduce code size compared to a fully parameterized
+
-version.
+**Check a format string at compile time**
+
+.. code:: c++
+
+    std::string s = fmt::format(FMT_STRING("{:d}"), "don't panic");
+
+This gives a compile-time error because ``d`` is an invalid format specifier for
+a string.
+
+**Write a file from a single thread**
+
+.. code:: c++
+
+    #include <fmt/os.h>
+
+    int main() {
+      auto out = fmt::output_file("guide.txt");
+      out.print("Don't {}", "Panic");
+    }
+
+This can be `5 to 9 times faster than fprintf
+<http://www.zverovich.net/2020/08/04/optimal-file-buffer-size.html>`_.
+
+**Print with colors and text styles**
+
+.. code:: c++
+
+    #include <fmt/color.h>
+
+    int main() {
+      fmt::print(fg(fmt::color::crimson) | fmt::emphasis::bold,
+                 "Hello, {}!\n", "world");
+      fmt::print(fg(fmt::color::floral_white) | bg(fmt::color::slate_gray) |
+                 fmt::emphasis::underline, "Hello, {}!\n", "мир");
+      fmt::print(fg(fmt::color::steel_blue) | fmt::emphasis::italic,
+                 "Hello, {}!\n", "世界");
+    }
+
+Output on a modern terminal:
+
+.. image:: https://user-images.githubusercontent.com/
+           576385/88485597-d312f600-cf2b-11ea-9cbe-61f535a86e28.png
 
 Benchmarks
 ----------
@@ -198,12 +201,14 @@ or equivalent is filled 2,000,000 times with output sent to ``/dev/null``; for
 further details refer to the `source
 <https://github.com/fmtlib/format-benchmark/blob/master/tinyformat_test.cpp>`_.
 
-{fmt} is up to 10x faster than ``std::ostringstream`` and ``sprintf`` on
+{fmt} is up to 20-30x faster than ``std::ostringstream`` and ``sprintf`` on
 floating-point formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
-and faster than `double-conversion <https://github.com/google/double-conversion>`_:
+and faster than `double-conversion <https://github.com/google/double-conversion>`_ and
+`ryu <https://github.com/ulfjack/ryu>`_:
 
-.. image:: https://user-images.githubusercontent.com/576385/69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
+.. image:: https://user-images.githubusercontent.com/576385/
-   :target: https://fmt.dev/unknown_mac64_clang10.0.html
+           95684665-11719600-0ba8-11eb-8e5b-972ff4e49428.png
+   :target: https://fmt.dev/unknown_mac64_clang12.0.html
 
 Compile time and code bloat
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -282,30 +287,33 @@ or the bloat test::
 Projects using this library
 ---------------------------
 
-* `0 A.D. <https://play0ad.com/>`_: A free, open-source, cross-platform
+* `0 A.D. <https://play0ad.com/>`_: a free, open-source, cross-platform
   real-time strategy game
 
 * `AMPL/MP <https://github.com/ampl/mp>`_:
-  An open-source library for mathematical programming
+  an open-source library for mathematical programming
 
 * `Aseprite <https://github.com/aseprite/aseprite>`_:
-  Animated sprite editor & pixel art tool 
+  animated sprite editor & pixel art tool 
 
-* `AvioBook <https://www.aviobook.aero/en>`_: A comprehensive aircraft
+* `AvioBook <https://www.aviobook.aero/en>`_: a comprehensive aircraft
   operations suite
   
-* `Celestia <https://celestia.space/>`_: Real-time 3D visualization of space
+* `Blizzard Battle.net <https://battle.net/>`_: an online gaming platform
+  
+* `Celestia <https://celestia.space/>`_: real-time 3D visualization of space
 
-* `Ceph <https://ceph.com/>`_: A scalable distributed storage system
+* `Ceph <https://ceph.com/>`_: a scalable distributed storage system
 
-* `ccache <https://ccache.dev/>`_: A compiler cache
+* `ccache <https://ccache.dev/>`_: a compiler cache
 
-* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database management system
+* `ClickHouse <https://github.com/ClickHouse/ClickHouse>`_: analytical database
+  management system
 
 * `CUAUV <http://cuauv.org/>`_: Cornell University's autonomous underwater
   vehicle
 
-* `Drake <https://drake.mit.edu/>`_: A planning, control, and analysis toolbox
+* `Drake <https://drake.mit.edu/>`_: a planning, control, and analysis toolbox
   for nonlinear dynamical systems (MIT)
 
 * `Envoy <https://lyft.github.io/envoy/>`_: C++ L7 proxy and communication bus
@@ -318,66 +326,70 @@ Projects using this library
 * `HarpyWar/pvpgn <https://github.com/pvpgn/pvpgn-server>`_:
   Player vs Player Gaming Network with tweaks
 
-* `KBEngine <https://kbengine.org/>`_: An open-source MMOG server engine
+* `KBEngine <https://github.com/kbengine/kbengine>`_: an open-source MMOG server
+  engine
 
-* `Keypirinha <https://keypirinha.com/>`_: A semantic launcher for Windows
+* `Keypirinha <https://keypirinha.com/>`_: a semantic launcher for Windows
 
-* `Kodi <https://kodi.tv/>`_ (formerly xbmc): Home theater software
+* `Kodi <https://kodi.tv/>`_ (formerly xbmc): home theater software
 
-* `Knuth <https://kth.cash/>`_: High-performance Bitcoin full-node
+* `Knuth <https://kth.cash/>`_: high-performance Bitcoin full-node
 
 * `Microsoft Verona <https://github.com/microsoft/verona>`_:
-  Research programming language for concurrent ownership
+  research programming language for concurrent ownership
 
-* `MongoDB <https://mongodb.com/>`_: Distributed document database
+* `MongoDB <https://mongodb.com/>`_: distributed document database
 
-* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: A small tool to
+* `MongoDB Smasher <https://github.com/duckie/mongo_smasher>`_: a small tool to
   generate randomized datasets
 
-* `OpenSpace <https://openspaceproject.com/>`_: An open-source
+* `OpenSpace <https://openspaceproject.com/>`_: an open-source
   astrovisualization framework
 
 * `PenUltima Online (POL) <https://www.polserver.com/>`_:
-  An MMO server, compatible with most Ultima Online clients
+  an MMO server, compatible with most Ultima Online clients
 
-* `PyTorch <https://github.com/pytorch/pytorch>`_: An open-source machine
+* `PyTorch <https://github.com/pytorch/pytorch>`_: an open-source machine
   learning library
 
-* `quasardb <https://www.quasardb.net/>`_: A distributed, high-performance,
+* `quasardb <https://www.quasardb.net/>`_: a distributed, high-performance,
   associative database
+  
+* `Quill <https://github.com/odygrd/quill>`_: asynchronous low-latency logging library
 
-* `readpe <https://bitbucket.org/sys_dev/readpe>`_: Read Portable Executable
+* `QKW <https://github.com/ravijanjam/qkw>`_: generalizing aliasing to simplify
+  navigation, and executing complex multi-line terminal command sequences
 
-* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: A Redis cluster
+* `redis-cerberus <https://github.com/HunanTV/redis-cerberus>`_: a Redis cluster
   proxy
 
-* `redpanda <https://vectorized.io/redpanda>`_: A 10x faster Kafka® replacement
+* `redpanda <https://vectorized.io/redpanda>`_: a 10x faster Kafka® replacement
   for mission critical systems written in C++
 
-* `rpclib <http://rpclib.net/>`_: A modern C++ msgpack-RPC server and client
+* `rpclib <http://rpclib.net/>`_: a modern C++ msgpack-RPC server and client
   library
 
 * `Salesforce Analytics Cloud
   <https://www.salesforce.com/analytics-cloud/overview/>`_:
-  Business intelligence software
+  business intelligence software
 
-* `Scylla <https://www.scylladb.com/>`_: A Cassandra-compatible NoSQL data store
+* `Scylla <https://www.scylladb.com/>`_: a Cassandra-compatible NoSQL data store
   that can handle 1 million transactions per second on a single server
 
-* `Seastar <http://www.seastar-project.org/>`_: An advanced, open-source C++
+* `Seastar <http://www.seastar-project.org/>`_: an advanced, open-source C++
   framework for high-performance server applications on modern hardware
 
-* `spdlog <https://github.com/gabime/spdlog>`_: Super fast C++ logging library
+* `spdlog <https://github.com/gabime/spdlog>`_: super fast C++ logging library
 
-* `Stellar <https://www.stellar.org/>`_: Financial platform
+* `Stellar <https://www.stellar.org/>`_: financial platform
 
-* `Touch Surgery <https://www.touchsurgery.com/>`_: Surgery simulator
+* `Touch Surgery <https://www.touchsurgery.com/>`_: surgery simulator
 
-* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: Open-source
+* `TrinityCore <https://github.com/TrinityCore/TrinityCore>`_: open-source
   MMORPG framework
 
-* `Windows Terminal <https://github.com/microsoft/terminal>`_: The new Windows
+* `Windows Terminal <https://github.com/microsoft/terminal>`_: the new Windows
-  Terminal
+  terminal
 
 `More... <https://github.com/search?q=fmtlib&type=Code>`_
 
@@ -435,7 +447,7 @@ Boost Format
 
 This is a very powerful library which supports both ``printf``-like format
 strings and positional arguments. Its main drawback is performance. According to
-various benchmarks it is much slower than other methods considered here. Boost
+various, benchmarks it is much slower than other methods considered here. Boost
 Format also has excessive build times and severe code bloat issues (see
 `Benchmarks`_).
 

dep/fmt/include/fmt/chrono.h

@@ -72,43 +72,27 @@ FMT_CONSTEXPR To lossless_integral_conversion(const From from, int& ec) {
   static_assert(F::is_integer, "From must be integral");
   static_assert(T::is_integer, "To must be integral");
 
-  if (F::is_signed && !T::is_signed) {
+  if (detail::const_check(F::is_signed && !T::is_signed)) {
     // From may be negative, not allowed!
     if (fmt::detail::is_negative(from)) {
       ec = 1;
       return {};
     }
-
     // From is positive. Can it always fit in To?
-    if (F::digits <= T::digits) {
+    if (F::digits > T::digits &&
-      // yes, From always fits in To.
+        from > static_cast<From>(detail::max_value<To>())) {
-    } else {
+      ec = 1;
-      // from may not fit in To, we have to do a dynamic check
+      return {};
-      if (from > static_cast<From>((T::max)())) {
-        ec = 1;
-        return {};
-      }
     }
   }
 
-  if (!F::is_signed && T::is_signed) {
+  if (!F::is_signed && T::is_signed && F::digits >= T::digits &&
-    // can from be held in To?
+      from > static_cast<From>(detail::max_value<To>())) {
-    if (F::digits < T::digits) {
+    ec = 1;
-      // yes, From always fits in To.
+    return {};
-    } else {
-      // from may not fit in To, we have to do a dynamic check
-      if (from > static_cast<From>((T::max)())) {
-        // outside range.
-        ec = 1;
-        return {};
-      }
-    }
   }
-
+  return static_cast<To>(from);  // Lossless conversion.
-  // reaching here means all is ok for lossless conversion.
+}
-  return static_cast<To>(from);
-
-}  // function
 
 template <typename To, typename From,
           FMT_ENABLE_IF(std::is_same<From, To>::value)>
@@ -190,11 +174,9 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
   // safe conversion to IntermediateRep
   IntermediateRep count =
       lossless_integral_conversion<IntermediateRep>(from.count(), ec);
-  if (ec) {
+  if (ec) return {};
-    return {};
-  }
   // multiply with Factor::num without overflow or underflow
-  if (Factor::num != 1) {
+  if (detail::const_check(Factor::num != 1)) {
     const auto max1 = detail::max_value<IntermediateRep>() / Factor::num;
     if (count > max1) {
       ec = 1;
@@ -209,17 +191,9 @@ To safe_duration_cast(std::chrono::duration<FromRep, FromPeriod> from,
     count *= Factor::num;
   }
 
-  // this can't go wrong, right? den>0 is checked earlier.
+  if (detail::const_check(Factor::den != 1)) count /= Factor::den;
-  if (Factor::den != 1) {
+  auto tocount = lossless_integral_conversion<typename To::rep>(count, ec);
-    count /= Factor::den;
+  return ec ? To() : To(tocount);
-  }
-  // convert to the to type, safely
-  using ToRep = typename To::rep;
-  const ToRep tocount = lossless_integral_conversion<ToRep>(count, ec);
-  if (ec) {
-    return {};
-  }
-  return To{tocount};
 }
 
 /**
@@ -351,6 +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 {
@@ -387,6 +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) {
@@ -399,6 +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()) {

dep/fmt/include/fmt/color.h

@@ -463,16 +463,16 @@ template <> inline void reset_color<wchar_t>(FILE* stream) FMT_NOEXCEPT {
 }
 
 template <typename Char>
-inline void reset_color(basic_memory_buffer<Char>& buffer) FMT_NOEXCEPT {
+inline void reset_color(buffer<Char>& buffer) FMT_NOEXCEPT {
   const char* begin = data::reset_color;
   const char* end = begin + sizeof(data::reset_color) - 1;
   buffer.append(begin, end);
 }
 
 template <typename Char>
-void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
+void vformat_to(buffer<Char>& buf, const text_style& ts,
                 basic_string_view<Char> format_str,
-                basic_format_args<buffer_context<Char>> args) {
+                basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   bool has_style = false;
   if (ts.has_emphasis()) {
     has_style = true;
@@ -496,7 +496,7 @@ void vformat_to(basic_memory_buffer<Char>& buf, const text_style& ts,
 
 template <typename S, typename Char = char_t<S>>
 void vprint(std::FILE* f, const text_style& ts, const S& format,
-            basic_format_args<buffer_context<Char>> args) {
+            basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buf;
   detail::vformat_to(buf, ts, to_string_view(format), args);
   buf.push_back(Char(0));
@@ -504,20 +504,22 @@ void vprint(std::FILE* f, const text_style& ts, const S& format,
 }
 
 /**
+  \rst
   Formats a string and prints it to the specified file stream using ANSI
   escape sequences to specify text formatting.
-  Example:
+
+  **Example**::
+
     fmt::print(fmt::emphasis::bold | fg(fmt::color::red),
                "Elapsed time: {0:.2f} seconds", 1.23);
+  \endrst
  */
 template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_string<S>::value)>
 void print(std::FILE* f, const text_style& ts, const S& format_str,
            const Args&... args) {
-  detail::check_format_string<Args...>(format_str);
+  vprint(f, ts, format_str,
-  using context = buffer_context<char_t<S>>;
+         fmt::make_args_checked<Args...>(format_str, args...));
-  format_arg_store<context, Args...> as{args...};
-  vprint(f, ts, format_str, basic_format_args<context>(as));
 }
 
 /**
@@ -558,7 +560,42 @@ template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const text_style& ts, const S& format_str,
                                       const Args&... args) {
   return vformat(ts, to_string_view(format_str),
-                 detail::make_args_checked<Args...>(format_str, args...));
+                 fmt::make_args_checked<Args...>(format_str, args...));
+}
+
+/**
+  Formats a string with the given text_style and writes the output to ``out``.
+ */
+template <typename OutputIt, typename Char,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+OutputIt vformat_to(
+    OutputIt out, const text_style& ts, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
+  detail::vformat_to(buf, ts, format_str, args);
+  return detail::get_iterator(buf);
+}
+
+/**
+  \rst
+  Formats arguments with the given text_style, writes the result to the output
+  iterator ``out`` and returns the iterator past the end of the output range.
+
+  **Example**::
+
+    std::vector<char> out;
+    fmt::format_to(std::back_inserter(out),
+                   fmt::emphasis::bold | fg(fmt::color::red), "{}", 42);
+  \endrst
+*/
+template <typename OutputIt, typename S, typename... Args,
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value&&
+              detail::is_string<S>::value>
+inline auto format_to(OutputIt out, const text_style& ts, const S& format_str,
+                      Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  return vformat_to(out, ts, to_string_view(format_str),
+                    fmt::make_args_checked<Args...>(format_str, args...));
 }
 
 FMT_END_NAMESPACE

dep/fmt/include/fmt/compile.h

@@ -368,7 +368,8 @@ template <typename... Args> struct type_list {};
 
 // Returns a reference to the argument at index N from [first, rest...].
 template <int N, typename T, typename... Args>
-constexpr const auto& get(const T& first, const Args&... rest) {
+constexpr const auto& get([[maybe_unused]] const T& first,
+                          [[maybe_unused]] const Args&... rest) {
   static_assert(N < 1 + sizeof...(Args), "index is out of bounds");
   if constexpr (N == 0)
     return first;
@@ -406,6 +407,19 @@ constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos,
   return {{&s[pos], size}};
 }
 
+template <typename Char> struct code_unit {
+  Char value;
+  using char_type = Char;
+
+  template <typename OutputIt, typename... Args>
+  OutputIt format(OutputIt out, const Args&...) const {
+    return write<Char>(out, value);
+  }
+};
+
+template <typename Char>
+struct is_compiled_format<code_unit<Char>> : std::true_type {};
+
 // A replacement field that refers to argument N.
 template <typename Char, typename T, int N> struct field {
   using char_type = Char;
@@ -430,7 +444,9 @@ template <typename Char, typename T, int N> struct spec_field {
   OutputIt format(OutputIt out, const Args&... args) const {
     // This ensures that the argument type is convertile to `const T&`.
     const T& arg = get<N>(args...);
-    basic_format_context<OutputIt, Char> ctx(out, {});
+    const auto& vargs =
+        make_format_args<basic_format_context<OutputIt, Char>>(args...);
+    basic_format_context<OutputIt, Char> ctx(out, vargs);
     return fmt.format(arg, ctx);
   }
 };
@@ -489,16 +505,17 @@ constexpr auto parse_tail(T head, S format_str) {
 template <typename T, typename Char> struct parse_specs_result {
   formatter<T, Char> fmt;
   size_t end;
+  int next_arg_id;
 };
 
 template <typename T, typename Char>
 constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
-                                                  size_t pos) {
+                                                  size_t pos, int arg_id) {
   str.remove_prefix(pos);
-  auto ctx = basic_format_parse_context<Char>(str);
+  auto ctx = basic_format_parse_context<Char>(str, {}, arg_id + 1);
   auto f = formatter<T, Char>();
   auto end = f.parse(ctx);
-  return {f, pos + (end - str.data()) + 1};
+  return {f, pos + (end - str.data()) + 1, ctx.next_arg_id()};
 }
 
 // Compiles a non-empty format string and returns the compiled representation
@@ -518,8 +535,8 @@ constexpr auto compile_format_string(S format_str) {
                                                format_str);
     } else if constexpr (str[POS + 1] == ':') {
       using type = get_type<ID, Args>;
-      constexpr auto result = parse_specs<type>(str, POS + 2);
+      constexpr auto result = parse_specs<type>(str, POS + 2, ID);
-      return parse_tail<Args, result.end, ID + 1>(
+      return parse_tail<Args, result.end, result.next_arg_id>(
           spec_field<char_type, type, ID>{result.fmt}, format_str);
     } else {
       return unknown_format();
@@ -530,8 +547,13 @@ constexpr auto compile_format_string(S format_str) {
     return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str);
   } else {
     constexpr auto end = parse_text(str, POS + 1);
-    return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
+    if constexpr (end - POS > 1) {
-                                     format_str);
+      return parse_tail<Args, end, ID>(make_text(str, POS, end - POS),
+                                       format_str);
+    } else {
+      return parse_tail<Args, end, ID>(code_unit<char_type>{str[POS]},
+                                       format_str);
+    }
   }
 }
 
@@ -587,8 +609,7 @@ template <typename CompiledFormat, typename... Args,
 FMT_INLINE std::basic_string<Char> format(const CompiledFormat& cf,
                                           const Args&... args) {
   basic_memory_buffer<Char> buffer;
-  detail::buffer<Char>& base = buffer;
+  cf.format(detail::buffer_appender<Char>(buffer), args...);
-  cf.format(std::back_inserter(base), args...);
   return to_string(buffer);
 }
 
@@ -608,8 +629,7 @@ template <typename CompiledFormat, typename... Args,
 std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
   basic_memory_buffer<Char> buffer;
   using context = buffer_context<Char>;
-  detail::buffer<Char>& base = buffer;
+  detail::cf::vformat_to<context>(detail::buffer_appender<Char>(buffer), cf,
-  detail::cf::vformat_to<context>(std::back_inserter(base), cf,
                                   make_format_args<context>(args...));
   return to_string(buffer);
 }
@@ -618,9 +638,13 @@ template <typename S, typename... Args,
           FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
 FMT_INLINE std::basic_string<typename S::char_type> format(const S&,
                                                            Args&&... args) {
-  constexpr basic_string_view<typename S::char_type> str = S();
+#ifdef __cpp_if_constexpr
-  if (str.size() == 2 && str[0] == '{' && str[1] == '}')
+  if constexpr (std::is_same<typename S::char_type, char>::value) {
-    return fmt::to_string(detail::first(args...));
+    constexpr basic_string_view<typename S::char_type> str = S();
+    if (str.size() == 2 && str[0] == '{' && str[1] == '}')
+      return fmt::to_string(detail::first(args...));
+  }
+#endif
   constexpr auto compiled = detail::compile<Args...>(S());
   return format(compiled, std::forward<Args>(args)...);
 }
@@ -643,18 +667,30 @@ OutputIt format_to(OutputIt out, const S&, const Args&... args) {
   return format_to(out, compiled, args...);
 }
 
-template <
+template <typename OutputIt, typename CompiledFormat, typename... Args>
-    typename OutputIt, typename CompiledFormat, typename... Args,
+auto format_to_n(OutputIt out, size_t n, const CompiledFormat& cf,
-    FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&& std::is_base_of<
+                 const Args&... args) ->
-                  detail::basic_compiled_format, CompiledFormat>::value)>
+    typename std::enable_if<
-format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n,
+        detail::is_output_iterator<OutputIt,
-                                         const CompiledFormat& cf,
+                                   typename CompiledFormat::char_type>::value &&
-                                         const Args&... args) {
+            std::is_base_of<detail::basic_compiled_format,
+                            CompiledFormat>::value,
+        format_to_n_result<OutputIt>>::type {
   auto it =
       format_to(detail::truncating_iterator<OutputIt>(out, n), cf, args...);
   return {it.base(), it.count()};
 }
 
+template <typename OutputIt, typename S, typename... Args,
+          FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
+format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n, const S&,
+                                         const Args&... args) {
+  constexpr auto compiled = detail::compile<Args...>(S());
+  auto it = format_to(detail::truncating_iterator<OutputIt>(out, n), compiled,
+                      args...);
+  return {it.base(), it.count()};
+}
+
 template <typename CompiledFormat, typename... Args>
 size_t formatted_size(const CompiledFormat& cf, const Args&... args) {
   return format_to(detail::counting_iterator(), cf, args...).count();

dep/fmt/include/fmt/core.h

@@ -18,7 +18,7 @@
 #include <vector>
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 70003
+#define FMT_VERSION 70103
 
 #ifdef __clang__
 #  define FMT_CLANG_VERSION (__clang_major__ * 100 + __clang_minor__)
@@ -57,6 +57,7 @@
 #  define FMT_MSC_VER 0
 #  define FMT_SUPPRESS_MSC_WARNING(n)
 #endif
+
 #ifdef __has_feature
 #  define FMT_HAS_FEATURE(x) __has_feature(x)
 #else
@@ -64,7 +65,7 @@
 #endif
 
 #if defined(__has_include) && !defined(__INTELLISENSE__) && \
-    !(FMT_ICC_VERSION && FMT_ICC_VERSION < 1600)
+    (!FMT_ICC_VERSION || FMT_ICC_VERSION >= 1600)
 #  define FMT_HAS_INCLUDE(x) __has_include(x)
 #else
 #  define FMT_HAS_INCLUDE(x) 0
@@ -99,7 +100,7 @@
 #endif
 
 #ifndef FMT_OVERRIDE
-#  if FMT_HAS_FEATURE(cxx_override) || \
+#  if FMT_HAS_FEATURE(cxx_override_control) || \
       (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || FMT_MSC_VER >= 1900
 #    define FMT_OVERRIDE override
 #  else
@@ -152,7 +153,7 @@
 #  if FMT_HAS_CPP14_ATTRIBUTE(deprecated) || FMT_MSC_VER >= 1900
 #    define FMT_DEPRECATED [[deprecated]]
 #  else
-#    if defined(__GNUC__) || defined(__clang__)
+#    if (defined(__GNUC__) && !defined(__LCC__)) || defined(__clang__)
 #      define FMT_DEPRECATED __attribute__((deprecated))
 #    elif FMT_MSC_VER
 #      define FMT_DEPRECATED __declspec(deprecated)
@@ -177,9 +178,17 @@
 #  endif
 #endif
 
-#ifndef FMT_BEGIN_NAMESPACE
+#ifndef FMT_USE_INLINE_NAMESPACES
 #  if FMT_HAS_FEATURE(cxx_inline_namespaces) || FMT_GCC_VERSION >= 404 || \
-      FMT_MSC_VER >= 1900
+      (FMT_MSC_VER >= 1900 && !_MANAGED)
+#    define FMT_USE_INLINE_NAMESPACES 1
+#  else
+#    define FMT_USE_INLINE_NAMESPACES 0
+#  endif
+#endif
+
+#ifndef FMT_BEGIN_NAMESPACE
+#  if FMT_USE_INLINE_NAMESPACES
 #    define FMT_INLINE_NAMESPACE inline namespace
 #    define FMT_END_NAMESPACE \
       }                       \
@@ -269,8 +278,7 @@ struct monostate {};
 
 namespace detail {
 
-// A helper function to suppress bogus "conditional expression is constant"
+// A helper function to suppress "conditional expression is constant" warnings.
-// warnings.
 template <typename T> constexpr T const_check(T value) { return value; }
 
 FMT_NORETURN FMT_API void assert_fail(const char* file, int line,
@@ -299,7 +307,8 @@ template <typename T> struct std_string_view {};
 
 #ifdef FMT_USE_INT128
 // Do nothing.
-#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && !(FMT_CLANG_VERSION && FMT_MSC_VER)
+#elif defined(__SIZEOF_INT128__) && !FMT_NVCC && \
+    !(FMT_CLANG_VERSION && FMT_MSC_VER)
 #  define FMT_USE_INT128 1
 using int128_t = __int128_t;
 using uint128_t = __uint128_t;
@@ -506,6 +515,18 @@ template <typename S> struct char_t_impl<S, enable_if_t<is_string<S>::value>> {
   using type = typename result::value_type;
 };
 
+// Reports a compile-time error if S is not a valid format string.
+template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
+FMT_INLINE void check_format_string(const S&) {
+#ifdef FMT_ENFORCE_COMPILE_STRING
+  static_assert(is_compile_string<S>::value,
+                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
+                "FMT_STRING.");
+#endif
+}
+template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
+void check_format_string(S);
+
 struct error_handler {
   constexpr error_handler() = default;
   constexpr error_handler(const error_handler&) = default;
@@ -545,8 +566,9 @@ class basic_format_parse_context : private ErrorHandler {
   using iterator = typename basic_string_view<Char>::iterator;
 
   explicit constexpr basic_format_parse_context(
-      basic_string_view<Char> format_str, ErrorHandler eh = {})
+      basic_string_view<Char> format_str, ErrorHandler eh = {},
-      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(0) {}
+      int next_arg_id = 0)
+      : ErrorHandler(eh), format_str_(format_str), next_arg_id_(next_arg_id) {}
 
   /**
     Returns an iterator to the beginning of the format string range being
@@ -616,8 +638,24 @@ template <typename T, typename Context>
 using has_formatter =
     std::is_constructible<typename Context::template formatter_type<T>>;
 
+// Checks whether T is a container with contiguous storage.
+template <typename T> struct is_contiguous : std::false_type {};
+template <typename Char>
+struct is_contiguous<std::basic_string<Char>> : std::true_type {};
+
 namespace detail {
 
+// Extracts a reference to the container from back_insert_iterator.
+template <typename Container>
+inline Container& get_container(std::back_insert_iterator<Container> it) {
+  using bi_iterator = std::back_insert_iterator<Container>;
+  struct accessor : bi_iterator {
+    accessor(bi_iterator iter) : bi_iterator(iter) {}
+    using bi_iterator::container;
+  };
+  return *accessor(it).container;
+}
+
 /**
   \rst
   A contiguous memory buffer with an optional growing ability. It is an internal
@@ -640,6 +678,8 @@ template <typename T> class buffer {
         size_(sz),
         capacity_(cap) {}
 
+  ~buffer() = default;
+
   /** Sets the buffer data and capacity. */
   void set(T* buf_data, size_t buf_capacity) FMT_NOEXCEPT {
     ptr_ = buf_data;
@@ -655,7 +695,6 @@ template <typename T> class buffer {
 
   buffer(const buffer&) = delete;
   void operator=(const buffer&) = delete;
-  virtual ~buffer() = default;
 
   T* begin() FMT_NOEXCEPT { return ptr_; }
   T* end() FMT_NOEXCEPT { return ptr_ + size_; }
@@ -675,24 +714,26 @@ template <typename T> class buffer {
   /** Returns a pointer to the buffer data. */
   const T* data() const FMT_NOEXCEPT { return ptr_; }
 
-  /**
-    Resizes the buffer. If T is a POD type new elements may not be initialized.
-   */
-  void resize(size_t new_size) {
-    reserve(new_size);
-    size_ = new_size;
-  }
-
   /** Clears this buffer. */
   void clear() { size_ = 0; }
 
-  /** Reserves space to store at least *capacity* elements. */
+  // Tries resizing the buffer to contain *count* elements. If T is a POD type
-  void reserve(size_t new_capacity) {
+  // the new elements may not be initialized.
+  void try_resize(size_t count) {
+    try_reserve(count);
+    size_ = count <= capacity_ ? count : capacity_;
+  }
+
+  // Tries increasing the buffer capacity to *new_capacity*. It can increase the
+  // capacity by a smaller amount than requested but guarantees there is space
+  // for at least one additional element either by increasing the capacity or by
+  // flushing the buffer if it is full.
+  void try_reserve(size_t new_capacity) {
     if (new_capacity > capacity_) grow(new_capacity);
   }
 
   void push_back(const T& value) {
-    reserve(size_ + 1);
+    try_reserve(size_ + 1);
     ptr_[size_++] = value;
   }
 
@@ -705,32 +746,150 @@ template <typename T> class buffer {
   }
 };
 
-// A container-backed buffer.
+struct buffer_traits {
+  explicit buffer_traits(size_t) {}
+  size_t count() const { return 0; }
+  size_t limit(size_t size) { return size; }
+};
+
+class fixed_buffer_traits {
+ private:
+  size_t count_ = 0;
+  size_t limit_;
+
+ public:
+  explicit fixed_buffer_traits(size_t limit) : limit_(limit) {}
+  size_t count() const { return count_; }
+  size_t limit(size_t size) {
+    size_t n = limit_ > count_ ? limit_ - count_ : 0;
+    count_ += size;
+    return size < n ? size : n;
+  }
+};
+
+// A buffer that writes to an output iterator when flushed.
+template <typename OutputIt, typename T, typename Traits = buffer_traits>
+class iterator_buffer final : public Traits, public buffer<T> {
+ private:
+  OutputIt out_;
+  enum { buffer_size = 256 };
+  T data_[buffer_size];
+
+ protected:
+  void grow(size_t) final FMT_OVERRIDE {
+    if (this->size() == buffer_size) flush();
+  }
+  void flush();
+
+ public:
+  explicit iterator_buffer(OutputIt out, size_t n = buffer_size)
+      : Traits(n),
+        buffer<T>(data_, 0, buffer_size),
+        out_(out) {}
+  ~iterator_buffer() { flush(); }
+
+  OutputIt out() {
+    flush();
+    return out_;
+  }
+  size_t count() const { return Traits::count() + this->size(); }
+};
+
+template <typename T> class iterator_buffer<T*, T> final : public buffer<T> {
+ protected:
+  void grow(size_t) final FMT_OVERRIDE {}
+
+ public:
+  explicit iterator_buffer(T* out, size_t = 0) : buffer<T>(out, 0, ~size_t()) {}
+
+  T* out() { return &*this->end(); }
+};
+
+// A buffer that writes to a container with the contiguous storage.
 template <typename Container>
-class container_buffer : public buffer<typename Container::value_type> {
+class iterator_buffer<std::back_insert_iterator<Container>,
+                      enable_if_t<is_contiguous<Container>::value,
+                                  typename Container::value_type>>
+    final : public buffer<typename Container::value_type> {
  private:
   Container& container_;
 
  protected:
-  void grow(size_t capacity) FMT_OVERRIDE {
+  void grow(size_t capacity) final FMT_OVERRIDE {
     container_.resize(capacity);
     this->set(&container_[0], capacity);
   }
 
  public:
-  explicit container_buffer(Container& c)
+  explicit iterator_buffer(Container& c)
       : buffer<typename Container::value_type>(c.size()), container_(c) {}
+  explicit iterator_buffer(std::back_insert_iterator<Container> out, size_t = 0)
+      : iterator_buffer(get_container(out)) {}
+  std::back_insert_iterator<Container> out() {
+    return std::back_inserter(container_);
+  }
 };
 
-// Extracts a reference to the container from back_insert_iterator.
+// A buffer that counts the number of code units written discarding the output.
-template <typename Container>
+template <typename T = char> class counting_buffer final : public buffer<T> {
-inline Container& get_container(std::back_insert_iterator<Container> it) {
+ private:
-  using bi_iterator = std::back_insert_iterator<Container>;
+  enum { buffer_size = 256 };
-  struct accessor : bi_iterator {
+  T data_[buffer_size];
-    accessor(bi_iterator iter) : bi_iterator(iter) {}
+  size_t count_ = 0;
-    using bi_iterator::container;
+
-  };
+ protected:
-  return *accessor(it).container;
+  void grow(size_t) final FMT_OVERRIDE {
+    if (this->size() != buffer_size) return;
+    count_ += this->size();
+    this->clear();
+  }
+
+ public:
+  counting_buffer() : buffer<T>(data_, 0, buffer_size) {}
+
+  size_t count() { return count_ + this->size(); }
+};
+
+// An output iterator that appends to the buffer.
+// It is used to reduce symbol sizes for the common case.
+template <typename T>
+class buffer_appender : public std::back_insert_iterator<buffer<T>> {
+  using base = std::back_insert_iterator<buffer<T>>;
+
+ public:
+  explicit buffer_appender(buffer<T>& buf) : base(buf) {}
+  buffer_appender(base it) : base(it) {}
+
+  buffer_appender& operator++() {
+    base::operator++();
+    return *this;
+  }
+
+  buffer_appender operator++(int) {
+    buffer_appender tmp = *this;
+    ++*this;
+    return tmp;
+  }
+};
+
+// Maps an output iterator into a buffer.
+template <typename T, typename OutputIt>
+iterator_buffer<OutputIt, T> get_buffer(OutputIt);
+template <typename T> buffer<T>& get_buffer(buffer_appender<T>);
+
+template <typename OutputIt> OutputIt get_buffer_init(OutputIt out) {
+  return out;
+}
+template <typename T> buffer<T>& get_buffer_init(buffer_appender<T> out) {
+  return get_container(out);
+}
+
+template <typename Buffer>
+auto get_iterator(Buffer& buf) -> decltype(buf.out()) {
+  return buf.out();
+}
+template <typename T> buffer_appender<T> get_iterator(buffer<T>& buf) {
+  return buffer_appender<T>(buf);
 }
 
 template <typename T, typename Char = char, typename Enable = void>
@@ -759,7 +918,8 @@ template <typename Char> struct named_arg_info {
 template <typename T, typename Char, size_t NUM_ARGS, size_t NUM_NAMED_ARGS>
 struct arg_data {
   // args_[0].named_args points to named_args_ to avoid bloating format_args.
-  T args_[1 + (NUM_ARGS != 0 ? NUM_ARGS : 1)];
+  // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
+  T args_[1 + (NUM_ARGS != 0 ? NUM_ARGS : +1)];
   named_arg_info<Char> named_args_[NUM_NAMED_ARGS];
 
   template <typename... U>
@@ -771,7 +931,8 @@ struct arg_data {
 
 template <typename T, typename Char, size_t NUM_ARGS>
 struct arg_data<T, Char, NUM_ARGS, 0> {
-  T args_[NUM_ARGS != 0 ? NUM_ARGS : 1];
+  // +1 to workaround a bug in gcc 7.5 that causes duplicated-branches warning.
+  T args_[NUM_ARGS != 0 ? NUM_ARGS : +1];
 
   template <typename... U>
   FMT_INLINE arg_data(const U&... init) : args_{init...} {}
@@ -959,6 +1120,8 @@ enum { long_short = sizeof(long) == sizeof(int) };
 using long_type = conditional_t<long_short, int, long long>;
 using ulong_type = conditional_t<long_short, unsigned, unsigned long long>;
 
+struct unformattable {};
+
 // Maps formatting arguments to core types.
 template <typename Context> struct arg_mapper {
   using char_type = typename Context::char_type;
@@ -1067,15 +1230,7 @@ template <typename Context> struct arg_mapper {
     return map(val.value);
   }
 
-  int map(...) {
+  unformattable map(...) { return {}; }
-    constexpr bool formattable = sizeof(Context) == 0;
-    static_assert(
-        formattable,
-        "Cannot format argument. To make type T formattable provide a "
-        "formatter<T> specialization: "
-        "https://fmt.dev/latest/api.html#formatting-user-defined-types");
-    return 0;
-  }
 };
 
 // A type constant after applying arg_mapper<Context>.
@@ -1199,15 +1354,25 @@ FMT_CONSTEXPR_DECL FMT_INLINE auto visit_format_arg(
   return vis(monostate());
 }
 
-// Checks whether T is a container with contiguous storage.
+template <typename T> struct formattable : std::false_type {};
-template <typename T> struct is_contiguous : std::false_type {};
-template <typename Char>
-struct is_contiguous<std::basic_string<Char>> : std::true_type {};
-template <typename Char>
-struct is_contiguous<detail::buffer<Char>> : std::true_type {};
 
 namespace detail {
 
+// A workaround for gcc 4.8 to make void_t work in a SFINAE context.
+template <typename... Ts> struct void_t_impl { using type = void; };
+template <typename... Ts>
+using void_t = typename detail::void_t_impl<Ts...>::type;
+
+template <typename It, typename T, typename Enable = void>
+struct is_output_iterator : std::false_type {};
+
+template <typename It, typename T>
+struct is_output_iterator<
+    It, T,
+    void_t<typename std::iterator_traits<It>::iterator_category,
+           decltype(*std::declval<It>() = std::declval<T>())>>
+    : std::true_type {};
+
 template <typename OutputIt>
 struct is_back_insert_iterator : std::false_type {};
 template <typename Container>
@@ -1219,6 +1384,9 @@ struct is_contiguous_back_insert_iterator : std::false_type {};
 template <typename Container>
 struct is_contiguous_back_insert_iterator<std::back_insert_iterator<Container>>
     : is_contiguous<Container> {};
+template <typename Char>
+struct is_contiguous_back_insert_iterator<buffer_appender<Char>>
+    : std::true_type {};
 
 // A type-erased reference to an std::locale to avoid heavy <locale> include.
 class locale_ref {
@@ -1250,13 +1418,24 @@ FMT_CONSTEXPR basic_format_arg<Context> make_arg(const T& value) {
   return arg;
 }
 
+template <typename T> int check(unformattable) {
+  static_assert(
+      formattable<T>(),
+      "Cannot format an argument. To make type T formattable provide a "
+      "formatter<T> specialization: https://fmt.dev/latest/api.html#udt");
+  return 0;
+}
+template <typename T, typename U> inline const U& check(const U& val) {
+  return val;
+}
+
 // The type template parameter is there to avoid an ODR violation when using
 // a fallback formatter in one translation unit and an implicit conversion in
 // another (not recommended).
 template <bool IS_PACKED, typename Context, type, typename T,
           FMT_ENABLE_IF(IS_PACKED)>
 inline value<Context> make_arg(const T& val) {
-  return arg_mapper<Context>().map(val);
+  return check<T>(arg_mapper<Context>().map(val));
 }
 
 template <bool IS_PACKED, typename Context, type, typename T,
@@ -1356,13 +1535,13 @@ template <typename OutputIt, typename Char> class basic_format_context {
 
 template <typename Char>
 using buffer_context =
-    basic_format_context<std::back_insert_iterator<detail::buffer<Char>>, Char>;
+    basic_format_context<detail::buffer_appender<Char>, Char>;
 using format_context = buffer_context<char>;
 using wformat_context = buffer_context<wchar_t>;
 
-// Workaround a bug in gcc: https://stackoverflow.com/q/62767544/471164.
+// Workaround an alias issue: https://stackoverflow.com/q/62767544/471164.
 #define FMT_BUFFER_CONTEXT(Char) \
-  basic_format_context<std::back_insert_iterator<detail::buffer<Char>>, Char>
+  basic_format_context<detail::buffer_appender<Char>, Char>
 
 /**
   \rst
@@ -1414,7 +1593,7 @@ class format_arg_store
 
 /**
   \rst
-  Constructs an `~fmt::format_arg_store` object that contains references to
+  Constructs a `~fmt::format_arg_store` object that contains references to
   arguments and can be implicitly converted to `~fmt::format_args`. `Context`
   can be omitted in which case it defaults to `~fmt::context`.
   See `~fmt::arg` for lifetime considerations.
@@ -1426,6 +1605,27 @@ inline format_arg_store<Context, Args...> make_format_args(
   return {args...};
 }
 
+/**
+  \rst
+  Constructs a `~fmt::format_arg_store` object that contains references
+  to arguments and can be implicitly converted to `~fmt::format_args`.
+  If ``format_str`` is a compile-time string then `make_args_checked` checks
+  its validity at compile time.
+  \endrst
+ */
+template <typename... Args, typename S, typename Char = char_t<S>>
+inline auto make_args_checked(const S& format_str,
+                              const remove_reference_t<Args>&... args)
+    -> format_arg_store<buffer_context<Char>, remove_reference_t<Args>...> {
+  static_assert(
+      detail::count<(
+              std::is_base_of<detail::view, remove_reference_t<Args>>::value &&
+              std::is_reference<Args>::value)...>() == 0,
+      "passing views as lvalues is disallowed");
+  detail::check_format_string<Args...>(format_str);
+  return {args...};
+}
+
 /**
   \rst
   Returns a named argument to be used in a formatting function. It should only
@@ -1729,7 +1929,14 @@ template <typename Context> class basic_format_args {
   }
 };
 
-/** An alias to ``basic_format_args<context>``. */
+#ifdef FMT_ARM_ABI_COMPATIBILITY
+/** An alias to ``basic_format_args<format_context>``. */
+// Separate types would result in shorter symbols but break ABI compatibility
+// between clang and gcc on ARM (#1919).
+using format_args = basic_format_args<format_context>;
+using wformat_args = basic_format_args<wformat_context>;
+#else
+// DEPRECATED! These are kept for ABI compatibility.
 // It is a separate type rather than an alias to make symbols readable.
 struct format_args : basic_format_args<format_context> {
   template <typename... Args>
@@ -1738,32 +1945,10 @@ struct format_args : basic_format_args<format_context> {
 struct wformat_args : basic_format_args<wformat_context> {
   using basic_format_args::basic_format_args;
 };
+#endif
 
 namespace detail {
 
-// Reports a compile-time error if S is not a valid format string.
-template <typename..., typename S, FMT_ENABLE_IF(!is_compile_string<S>::value)>
-FMT_INLINE void check_format_string(const S&) {
-#ifdef FMT_ENFORCE_COMPILE_STRING
-  static_assert(is_compile_string<S>::value,
-                "FMT_ENFORCE_COMPILE_STRING requires all format strings to use "
-                "FMT_STRING.");
-#endif
-}
-template <typename..., typename S, FMT_ENABLE_IF(is_compile_string<S>::value)>
-void check_format_string(S);
-
-template <typename... Args, typename S, typename Char = char_t<S>>
-inline format_arg_store<buffer_context<Char>, remove_reference_t<Args>...>
-make_args_checked(const S& format_str,
-                  const remove_reference_t<Args>&... args) {
-  static_assert(count<(std::is_base_of<view, remove_reference_t<Args>>::value &&
-                       std::is_reference<Args>::value)...>() == 0,
-                "passing views as lvalues is disallowed");
-  check_format_string<Args...>(format_str);
-  return {args...};
-}
-
 template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
 std::basic_string<Char> vformat(
     basic_string_view<Char> format_str,
@@ -1772,9 +1957,10 @@ std::basic_string<Char> vformat(
 FMT_API std::string vformat(string_view format_str, format_args args);
 
 template <typename Char>
-typename FMT_BUFFER_CONTEXT(Char)::iterator vformat_to(
+void vformat_to(
     buffer<Char>& buf, basic_string_view<Char> format_str,
-    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args);
+    basic_format_args<FMT_BUFFER_CONTEXT(type_identity_t<Char>)> args,
+    detail::locale_ref loc = {});
 
 template <typename Char, typename Args,
           FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
@@ -1789,26 +1975,80 @@ inline void vprint_mojibake(std::FILE*, string_view, format_args) {}
 /** Formats a string and writes the output to ``out``. */
 // GCC 8 and earlier cannot handle std::back_insert_iterator<Container> with
 // vformat_to<ArgFormatter>(...) overload, so SFINAE on iterator type instead.
-template <
+template <typename OutputIt, typename S, typename Char = char_t<S>,
-    typename OutputIt, typename S, typename Char = char_t<S>,
+          bool enable = detail::is_output_iterator<OutputIt, Char>::value>
-    FMT_ENABLE_IF(detail::is_contiguous_back_insert_iterator<OutputIt>::value)>
+auto vformat_to(OutputIt out, const S& format_str,
-OutputIt vformat_to(
+                basic_format_args<buffer_context<type_identity_t<Char>>> args)
-    OutputIt out, const S& format_str,
+    -> typename std::enable_if<enable, OutputIt>::type {
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
-  auto& c = detail::get_container(out);
-  detail::container_buffer<remove_reference_t<decltype(c)>> buf(c);
   detail::vformat_to(buf, to_string_view(format_str), args);
-  return out;
+  return detail::get_iterator(buf);
 }
 
-template <typename Container, typename S, typename... Args,
+/**
-          FMT_ENABLE_IF(
+ \rst
-              is_contiguous<Container>::value&& detail::is_string<S>::value)>
+ Formats arguments, writes the result to the output iterator ``out`` and returns
-inline std::back_insert_iterator<Container> format_to(
+ the iterator past the end of the output range.
-    std::back_insert_iterator<Container> out, const S& format_str,
+
-    Args&&... args) {
+ **Example**::
-  return vformat_to(out, to_string_view(format_str),
+
-                    detail::make_args_checked<Args...>(format_str, args...));
+   std::vector<char> out;
+   fmt::format_to(std::back_inserter(out), "{}", 42);
+ \endrst
+ */
+// We cannot use FMT_ENABLE_IF because of a bug in gcc 8.3.
+template <typename OutputIt, typename S, typename... Args,
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
+inline auto format_to(OutputIt out, const S& format_str, Args&&... args) ->
+    typename std::enable_if<enable, OutputIt>::type {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return vformat_to(out, to_string_view(format_str), vargs);
+}
+
+template <typename OutputIt> struct format_to_n_result {
+  /** Iterator past the end of the output range. */
+  OutputIt out;
+  /** Total (not truncated) output size. */
+  size_t size;
+};
+
+template <typename OutputIt, typename Char, typename... Args,
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
+inline format_to_n_result<OutputIt> vformat_to_n(
+    OutputIt out, size_t n, basic_string_view<Char> format_str,
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
+  detail::iterator_buffer<OutputIt, Char, detail::fixed_buffer_traits> buf(out,
+                                                                           n);
+  detail::vformat_to(buf, format_str, args);
+  return {buf.out(), buf.count()};
+}
+
+/**
+ \rst
+ Formats arguments, writes up to ``n`` characters of the result to the output
+ iterator ``out`` and returns the total output size and the iterator past the
+ end of the output range.
+ \endrst
+ */
+template <typename OutputIt, typename S, typename... Args,
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
+inline auto format_to_n(OutputIt out, size_t n, const S& format_str,
+                        const Args&... args) ->
+    typename std::enable_if<enable, format_to_n_result<OutputIt>>::type {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  return vformat_to_n(out, n, to_string_view(format_str), vargs);
+}
+
+/**
+  Returns the number of characters in the output of
+  ``format(format_str, args...)``.
+ */
+template <typename... Args>
+inline size_t formatted_size(string_view format_str, Args&&... args) {
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
+  detail::counting_buffer<> buf;
+  detail::vformat_to(buf, format_str, vargs);
+  return buf.count();
 }
 
 template <typename S, typename Char = char_t<S>>
@@ -1832,7 +2072,7 @@ FMT_INLINE std::basic_string<Char> vformat(
 // std::basic_string<char_t<S>> to reduce the symbol size.
 template <typename S, typename... Args, typename Char = char_t<S>>
 FMT_INLINE std::basic_string<Char> format(const S& format_str, Args&&... args) {
-  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
   return detail::vformat(to_string_view(format_str), vargs);
 }
 
@@ -1852,7 +2092,7 @@ FMT_API void vprint(std::FILE*, string_view, format_args);
  */
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline void print(std::FILE* f, const S& format_str, Args&&... args) {
-  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
   return detail::is_unicode<Char>()
              ? vprint(f, to_string_view(format_str), vargs)
              : detail::vprint_mojibake(f, to_string_view(format_str), vargs);
@@ -1871,7 +2111,7 @@ inline void print(std::FILE* f, const S& format_str, Args&&... args) {
  */
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline void print(const S& format_str, Args&&... args) {
-  const auto& vargs = detail::make_args_checked<Args...>(format_str, args...);
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
   return detail::is_unicode<Char>()
              ? vprint(to_string_view(format_str), vargs)
              : detail::vprint_mojibake(stdout, to_string_view(format_str),

dep/fmt/include/fmt/locale.h

@@ -15,22 +15,12 @@
 FMT_BEGIN_NAMESPACE
 
 namespace detail {
-template <typename Char>
-typename buffer_context<Char>::iterator vformat_to(
-    const std::locale& loc, buffer<Char>& buf,
-    basic_string_view<Char> format_str,
-    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  using af = arg_formatter<typename buffer_context<Char>::iterator, Char>;
-  return vformat_to<af>(std::back_inserter(buf), to_string_view(format_str),
-                        args, detail::locale_ref(loc));
-}
-
 template <typename Char>
 std::basic_string<Char> vformat(
     const std::locale& loc, basic_string_view<Char> format_str,
     basic_format_args<buffer_context<type_identity_t<Char>>> args) {
   basic_memory_buffer<Char> buffer;
-  detail::vformat_to(loc, buffer, format_str, args);
+  detail::vformat_to(buffer, format_str, args, detail::locale_ref(loc));
   return fmt::to_string(buffer);
 }
 }  // namespace detail
@@ -45,32 +35,28 @@ inline std::basic_string<Char> vformat(
 template <typename S, typename... Args, typename Char = char_t<S>>
 inline std::basic_string<Char> format(const std::locale& loc,
                                       const S& format_str, Args&&... args) {
-  return detail::vformat(
+  return detail::vformat(loc, to_string_view(format_str),
-      loc, to_string_view(format_str),
+                         fmt::make_args_checked<Args...>(format_str, args...));
-      detail::make_args_checked<Args...>(format_str, args...));
 }
 
 template <typename S, typename OutputIt, typename... Args,
-          typename Char = enable_if_t<
+          typename Char = char_t<S>,
-              detail::is_output_iterator<OutputIt>::value, char_t<S>>>
+          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value)>
 inline OutputIt vformat_to(
     OutputIt out, const std::locale& loc, const S& format_str,
-    format_args_t<type_identity_t<OutputIt>, Char> args) {
+    basic_format_args<buffer_context<type_identity_t<Char>>> args) {
-  using af = detail::arg_formatter<OutputIt, Char>;
+  decltype(detail::get_buffer<Char>(out)) buf(detail::get_buffer_init(out));
-  return vformat_to<af>(out, to_string_view(format_str), args,
+  vformat_to(buf, to_string_view(format_str), args, detail::locale_ref(loc));
-                        detail::locale_ref(loc));
+  return detail::get_iterator(buf);
 }
 
 template <typename OutputIt, typename S, typename... Args,
-          FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&&
+          bool enable = detail::is_output_iterator<OutputIt, char_t<S>>::value>
-                            detail::is_string<S>::value)>
+inline auto format_to(OutputIt out, const std::locale& loc,
-inline OutputIt format_to(OutputIt out, const std::locale& loc,
+                      const S& format_str, Args&&... args) ->
-                          const S& format_str, Args&&... args) {
+    typename std::enable_if<enable, OutputIt>::type {
-  detail::check_format_string<Args...>(format_str);
+  const auto& vargs = fmt::make_args_checked<Args...>(format_str, args...);
-  using context = format_context_t<OutputIt, char_t<S>>;
+  return vformat_to(out, loc, to_string_view(format_str), vargs);
-  format_arg_store<context, Args...> as{args...};
-  return vformat_to(out, loc, to_string_view(format_str),
-                    basic_format_args<context>(as));
 }
 
 FMT_END_NAMESPACE

dep/fmt/include/fmt/os.h

@@ -29,7 +29,8 @@
 #if FMT_HAS_INCLUDE("winapifamily.h")
 #  include <winapifamily.h>
 #endif
-#if FMT_HAS_INCLUDE("fcntl.h") && \
+#if (FMT_HAS_INCLUDE(<fcntl.h>) || defined(__APPLE__) || \
+     defined(__linux__)) &&                              \
     (!defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP))
 #  include <fcntl.h>  // for O_RDONLY
 #  define FMT_USE_FCNTL 1
@@ -278,7 +279,8 @@ class file {
     RDONLY = FMT_POSIX(O_RDONLY),  // Open for reading only.
     WRONLY = FMT_POSIX(O_WRONLY),  // Open for writing only.
     RDWR = FMT_POSIX(O_RDWR),      // Open for reading and writing.
-    CREATE = FMT_POSIX(O_CREAT)    // Create if the file doesn't exist.
+    CREATE = FMT_POSIX(O_CREAT),   // Create if the file doesn't exist.
+    APPEND = FMT_POSIX(O_APPEND)   // Open in append mode.
   };
 
   // Constructs a file object which doesn't represent any file.
@@ -343,36 +345,69 @@ class file {
 // Returns the memory page size.
 long getpagesize();
 
-class direct_buffered_file;
+namespace detail {
 
-template <typename S, typename... Args>
+struct buffer_size {
-void print(direct_buffered_file& f, const S& format_str,
+  size_t value = 0;
-           const Args&... args);
+  buffer_size operator=(size_t val) const {
+    auto bs = buffer_size();
+    bs.value = val;
+    return bs;
+  }
+};
 
-// A buffered file with a direct buffer access and no synchronization.
+struct ostream_params {
-class direct_buffered_file {
+  int oflag = file::WRONLY | file::CREATE;
+  size_t buffer_size = BUFSIZ > 32768 ? BUFSIZ : 32768;
+
+  ostream_params() {}
+
+  template <typename... T>
+  ostream_params(T... params, int oflag) : ostream_params(params...) {
+    this->oflag = oflag;
+  }
+
+  template <typename... T>
+  ostream_params(T... params, detail::buffer_size bs)
+      : ostream_params(params...) {
+    this->buffer_size = bs.value;
+  }
+};
+}  // namespace detail
+
+static constexpr detail::buffer_size buffer_size;
+
+// A fast output stream which is not thread-safe.
+class ostream final : private detail::buffer<char> {
  private:
   file file_;
 
-  enum { buffer_size = 4096 };
-  char buffer_[buffer_size];
-  int pos_;
-
   void flush() {
-    if (pos_ == 0) return;
+    if (size() == 0) return;
-    file_.write(buffer_, pos_);
+    file_.write(data(), size());
-    pos_ = 0;
+    clear();
   }
 
-  int free_capacity() const { return buffer_size - pos_; }
+  FMT_API void grow(size_t) override final;
+
+  ostream(cstring_view path, const detail::ostream_params& params)
+      : file_(path, params.oflag) {
+    set(new char[params.buffer_size], params.buffer_size);
+  }
 
  public:
-  direct_buffered_file(cstring_view path, int oflag)
+  ostream(ostream&& other)
-    : file_(path, oflag), pos_(0) {}
+      : detail::buffer<char>(other.data(), other.size(), other.capacity()),
-
+        file_(std::move(other.file_)) {
-  ~direct_buffered_file() {
+    other.set(nullptr, 0);
-    flush();
   }
+  ~ostream() {
+    flush();
+    delete[] data();
+  }
+
+  template <typename... T>
+  friend ostream output_file(cstring_view path, T... params);
 
   void close() {
     flush();
@@ -380,25 +415,20 @@ class direct_buffered_file {
   }
 
   template <typename S, typename... Args>
-  friend void print(direct_buffered_file& f, const S& format_str,
+  void print(const S& format_str, const Args&... args) {
-                    const Args&... args) {
+    format_to(detail::buffer_appender<char>(*this), format_str, args...);
-    // We could avoid double buffering.
-    auto buf = fmt::memory_buffer();
-    fmt::format_to(std::back_inserter(buf), format_str, args...);
-    auto remaining_pos = 0;
-    auto remaining_size = buf.size();
-    while (remaining_size > detail::to_unsigned(f.free_capacity())) {
-      auto size = f.free_capacity();
-      memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, size);
-      f.pos_ += size;
-      f.flush();
-      remaining_pos += size;
-      remaining_size -= size;
-    }
-    memcpy(f.buffer_ + f.pos_, buf.data() + remaining_pos, remaining_size);
-    f.pos_ += static_cast<int>(remaining_size);
   }
 };
+
+/**
+  Opens a file for writing. Supported parameters passed in `params`:
+  * ``<integer>``: Output flags (``file::WRONLY | file::CREATE`` by default)
+  * ``buffer_size=<integer>``: Output buffer size
+ */
+template <typename... T>
+inline ostream output_file(cstring_view path, T... params) {
+  return {path, detail::ostream_params(params...)};
+}
 #endif  // FMT_USE_FCNTL
 
 #ifdef FMT_LOCALE

dep/fmt/include/fmt/ostream.h

@@ -49,17 +49,27 @@ template <class Char> class formatbuf : public std::basic_streambuf<Char> {
   }
 };
 
+struct converter {
+  template <typename T, FMT_ENABLE_IF(is_integral<T>::value)> converter(T);
+};
+
 template <typename Char> struct test_stream : std::basic_ostream<Char> {
  private:
-  // Hide all operator<< from std::basic_ostream<Char>.
+  void_t<> operator<<(converter);
-  void_t<> operator<<(null<>);
-  void_t<> operator<<(const Char*);
-
-  template <typename T, FMT_ENABLE_IF(std::is_convertible<T, int>::value &&
-                                      !std::is_enum<T>::value)>
-  void_t<> operator<<(T);
 };
 
+// Hide insertion operators for built-in types.
+template <typename Char, typename Traits>
+void_t<> operator<<(std::basic_ostream<Char, Traits>&, Char);
+template <typename Char, typename Traits>
+void_t<> operator<<(std::basic_ostream<Char, Traits>&, char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, signed char);
+template <typename Traits>
+void_t<> operator<<(std::basic_ostream<char, Traits>&, unsigned char);
+
 // Checks if T has a user-defined operator<< (e.g. not a member of
 // std::ostream).
 template <typename T, typename Char> class is_streamable {
@@ -103,7 +113,7 @@ void format_value(buffer<Char>& buf, const T& value,
 #endif
   output << value;
   output.exceptions(std::ios_base::failbit | std::ios_base::badbit);
-  buf.resize(buf.size());
+  buf.try_resize(buf.size());
 }
 
 // Formats an object of type T that has an overloaded ostream operator<<.
@@ -160,7 +170,7 @@ template <typename S, typename... Args,
           typename Char = enable_if_t<detail::is_string<S>::value, char_t<S>>>
 void print(std::basic_ostream<Char>& os, const S& format_str, Args&&... args) {
   vprint(os, to_string_view(format_str),
-         detail::make_args_checked<Args...>(format_str, args...));
+         fmt::make_args_checked<Args...>(format_str, args...));
 }
 FMT_END_NAMESPACE
 

dep/fmt/include/fmt/printf.h

@@ -181,7 +181,7 @@ template <typename Char> class printf_width_handler {
 template <typename Char, typename Context>
 void vprintf(buffer<Char>& buf, basic_string_view<Char> format,
              basic_format_args<Context> args) {
-  Context(std::back_inserter(buf), format, args).format();
+  Context(buffer_appender<Char>(buf), format, args).format();
 }
 }  // namespace detail
 
@@ -598,7 +598,7 @@ OutputIt basic_printf_context<OutputIt, Char>::format() {
 
 template <typename Char>
 using basic_printf_context_t =
-    basic_printf_context<std::back_insert_iterator<detail::buffer<Char>>, Char>;
+    basic_printf_context<detail::buffer_appender<Char>, Char>;
 
 using printf_context = basic_printf_context_t<char>;
 using wprintf_context = basic_printf_context_t<wchar_t>;

dep/fmt/include/fmt/ranges.h

@@ -157,6 +157,9 @@ template <class Tuple, class F> void for_each(Tuple&& tup, F&& f) {
   for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
 }
 
+template <typename Range>
+using value_type = remove_cvref_t<decltype(*std::declval<Range>().begin())>;
+
 template <typename Arg, FMT_ENABLE_IF(!is_like_std_string<
                                       typename std::decay<Arg>::type>::value)>
 FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&) {
@@ -182,7 +185,6 @@ FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
 FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
   return add_space ? L" '{}'" : L"'{}'";
 }
-
 }  // namespace detail
 
 template <typename T> struct is_tuple_like {
@@ -246,9 +248,18 @@ template <typename T, typename Char> struct is_range {
       !std::is_constructible<detail::std_string_view<Char>, T>::value;
 };
 
-template <typename RangeT, typename Char>
+template <typename T, typename Char>
-struct formatter<RangeT, Char,
+struct formatter<
-                 enable_if_t<fmt::is_range<RangeT, Char>::value>> {
+    T, Char,
+    enable_if_t<fmt::is_range<T, Char>::value
+// Workaround a bug in MSVC 2017 and earlier.
+#if !FMT_MSC_VER || FMT_MSC_VER >= 1927
+                &&
+                (has_formatter<detail::value_type<T>, format_context>::value ||
+                 detail::has_fallback_formatter<detail::value_type<T>,
+                                                format_context>::value)
+#endif
+                >> {
   formatting_range<Char> formatting;
 
   template <typename ParseContext>
@@ -257,8 +268,7 @@ struct formatter<RangeT, Char,
   }
 
   template <typename FormatContext>
-  typename FormatContext::iterator format(const RangeT& values,
+  typename FormatContext::iterator format(const T& values, FormatContext& ctx) {
-                                          FormatContext& ctx) {
     auto out = detail::copy(formatting.prefix, ctx.out());
     size_t i = 0;
     auto it = values.begin();

dep/fmt/src/format.cc

@@ -23,6 +23,36 @@ int format_float(char* buf, std::size_t size, const char* format, int precision,
   return precision < 0 ? snprintf_ptr(buf, size, format, value)
                        : snprintf_ptr(buf, size, format, precision, value);
 }
+
+template FMT_API dragonbox::decimal_fp<float> dragonbox::to_decimal(float x)
+    FMT_NOEXCEPT;
+template FMT_API dragonbox::decimal_fp<double> dragonbox::to_decimal(double x)
+    FMT_NOEXCEPT;
+
+// DEPRECATED! This function exists for ABI compatibility.
+template <typename Char>
+typename basic_format_context<std::back_insert_iterator<buffer<Char>>,
+                              Char>::iterator
+vformat_to(buffer<Char>& buf, basic_string_view<Char> format_str,
+           basic_format_args<basic_format_context<
+               std::back_insert_iterator<buffer<type_identity_t<Char>>>,
+               type_identity_t<Char>>>
+               args) {
+  using iterator = std::back_insert_iterator<buffer<char>>;
+  using context = basic_format_context<
+      std::back_insert_iterator<buffer<type_identity_t<Char>>>,
+      type_identity_t<Char>>;
+  auto out = iterator(buf);
+  format_handler<iterator, Char, context> h(out, format_str, args, {});
+  parse_format_string<false>(format_str, h);
+  return out;
+}
+template basic_format_context<std::back_insert_iterator<buffer<char>>,
+                              char>::iterator
+vformat_to(buffer<char>&, string_view,
+           basic_format_args<basic_format_context<
+               std::back_insert_iterator<buffer<type_identity_t<char>>>,
+               type_identity_t<char>>>);
 }  // namespace detail
 
 template struct FMT_INSTANTIATION_DEF_API detail::basic_data<void>;
@@ -44,9 +74,9 @@ template FMT_API char detail::decimal_point_impl(locale_ref);
 
 template FMT_API void detail::buffer<char>::append(const char*, const char*);
 
-template FMT_API FMT_BUFFER_CONTEXT(char)::iterator detail::vformat_to(
+template FMT_API void detail::vformat_to(
     detail::buffer<char>&, string_view,
-    basic_format_args<FMT_BUFFER_CONTEXT(char)>);
+    basic_format_args<FMT_BUFFER_CONTEXT(char)>, detail::locale_ref);
 
 template FMT_API int detail::snprintf_float(double, int, detail::float_specs,
                                             detail::buffer<char>&);

dep/fmt/src/os.cc

@@ -62,7 +62,7 @@ using RWResult = int;
 inline unsigned convert_rwcount(std::size_t count) {
   return count <= UINT_MAX ? static_cast<unsigned>(count) : UINT_MAX;
 }
-#else
+#elif FMT_USE_FCNTL
 // Return type of read and write functions.
 using RWResult = ssize_t;
 
@@ -124,7 +124,8 @@ void detail::format_windows_error(detail::buffer<char>& out, int error_code,
       if (result != 0) {
         utf16_to_utf8 utf8_message;
         if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
-          format_to(std::back_inserter(out), "{}: {}", message, utf8_message);
+          format_to(buffer_appender<char>(out), "{}: {}", message,
+                    utf8_message);
           return;
         }
         break;
@@ -288,12 +289,12 @@ void file::pipe(file& read_end, file& write_end) {
 }
 
 buffered_file file::fdopen(const char* mode) {
-  // Don't retry as fdopen doesn't return EINTR.
+// Don't retry as fdopen doesn't return EINTR.
-  #if defined(__MINGW32__) && defined(_POSIX_)
+#  if defined(__MINGW32__) && defined(_POSIX_)
   FILE* f = ::fdopen(fd_, mode);
-  #else
+#  else
   FILE* f = FMT_POSIX_CALL(fdopen(fd_, mode));
-  #endif
+#  endif
   if (!f)
     FMT_THROW(
         system_error(errno, "cannot associate stream with file descriptor"));
@@ -313,5 +314,9 @@ long getpagesize() {
   return size;
 #  endif
 }
+
+FMT_API void ostream::grow(size_t) {
+  if (this->size() == this->capacity()) flush();
+}
 #endif  // FMT_USE_FCNTL
 FMT_END_NAMESPACE