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Update changelog and readme

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Victor Zverovich
2020-07-04 08:20:10 -07:00
parent 01309a34ab
commit c56cf3d074
2 changed files with 102 additions and 118 deletions
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README.rst
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@@ -9,7 +9,8 @@
.. image:: https://oss-fuzz-build-logs.storage.googleapis.com/badges/libfmt.svg
:alt: fmt is continuously fuzzed att oss-fuzz
:target: https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type%20Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dlibfmt&can=1
:target: https://bugs.chromium.org/p/oss-fuzz/issues/list?colspec=ID%20Type\
%20Component%20Status%20Proj%20Reported%20Owner%20Summary&q=proj%3Dlibfmt&can=1
.. image:: https://img.shields.io/badge/stackoverflow-fmt-blue.svg
:alt: Ask questions at StackOverflow with the tag fmt
@@ -20,25 +21,28 @@ It can be used as a safe and fast alternative to (s)printf and iostreams.
`Documentation <https://fmt.dev/latest/>`__
Q&A: ask questions on `StackOverflow with the tag fmt <https://stackoverflow.com/questions/tagged/fmt>`_.
Q&A: ask questions on `StackOverflow with the tag fmt
<https://stackoverflow.com/questions/tagged/fmt>`_.
Features
--------
* Replacement-based `format API <https://fmt.dev/dev/api.html>`_ with
positional arguments for localization.
* Simple `format API <https://fmt.dev/dev/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
of `str.format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
in Python.
of Python's
`format <https://docs.python.org/3/library/stdtypes.html#str.format>`_
* Safe `printf implementation
<https://fmt.dev/latest/api.html#printf-formatting>`_ including
the POSIX extension for positional arguments.
* Implementation of `C++20 std::format <https://en.cppreference.com/w/cpp/utility/format>`__.
* Support for user-defined types.
the POSIX extension for positional arguments
* Extensibility: supports user-defined types
* High performance: faster than common standard library implementations of
`printf <https://en.cppreference.com/w/cpp/io/c/fprintf>`_,
iostreams and `to_string`. See `Speed tests`_ and `Fast integer to string conversion in C++
<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
iostreams, ``to_string`` and ``to_chars``. See `Speed tests`_ and
`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
consists of just three header files, ``core.h``, ``format.h`` and
``format-inl.h``) and compiled code. See `Compile time and code bloat`_.
@@ -46,16 +50,17 @@ Features
<https://github.com/fmtlib/fmt/tree/master/test>`_ and is continuously fuzzed.
* Safety: the library is fully type safe, errors in format strings can be
reported at compile time, automatic memory management prevents buffer overflow
errors.
errors
* Ease of use: small self-contained code base, no external dependencies,
permissive MIT `license
<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.
consistent output across platforms and support for older compilers
* Clean warning-free codebase even on high warning levels
(``-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.
* Optional header-only configuration enabled with the ``FMT_HEADER_ONLY`` macro
See the `documentation <https://fmt.dev/latest/>`_ for more details.
@@ -177,14 +182,14 @@ Folly Format folly::format 2.23
{fmt} is the fastest of the benchmarked methods, ~35% faster than ``printf``.
The above results were generated by building ``tinyformat_test.cpp`` on macOS
10.14.6 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the best of
three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
10.14.6 with ``clang++ -O3 -DNDEBUG -DSPEED_TEST -DHAVE_FORMAT``, and taking the
best of three runs. In the test, the format string ``"%0.10f:%04d:%+g:%s:%p:%c:%%\n"``
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 10x faster than ``std::ostringstream`` and ``sprintf`` on floating-point
formatting (`dtoa-benchmark <https://github.com/fmtlib/dtoa-benchmark>`_)
{fmt} is up to 10x 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>`_:
.. image:: https://user-images.githubusercontent.com/576385/69767160-cdaca400-112f-11ea-9fc5-347c9f83caad.png
@@ -425,8 +430,8 @@ Format also has excessive build times and severe code bloat issues (see
FastFormat
~~~~~~~~~~
This is an interesting library which is fast, safe and has positional
arguments. However it has significant limitations, citing its author:
This is an interesting library which is fast, safe and has positional arguments.
However, it has significant limitations, citing its author:
Three features that have no hope of being accommodated within the
current design are:
@@ -435,8 +440,8 @@ arguments. However it has significant limitations, citing its author:
* Octal/hexadecimal encoding
* Runtime width/alignment specification
It is also quite big and has a heavy dependency, STLSoft, which might be
too restrictive for using it in some projects.
It is also quite big and has a heavy dependency, STLSoft, which might be too
restrictive for using it in some projects.
Boost Spirit.Karma
~~~~~~~~~~~~~~~~~~
@@ -444,32 +449,9 @@ Boost Spirit.Karma
This is not really a formatting library but I decided to include it here for
completeness. As iostreams, it suffers from the problem of mixing verbatim text
with arguments. The library is pretty fast, but slower on integer formatting
than ``fmt::format_int`` on Karma's own benchmark,
see `Fast integer to string conversion in C++
<http://zverovich.net/2013/09/07/integer-to-string-conversion-in-cplusplus.html>`_.
FAQ
---
Q: how can I capture formatting arguments and format them later?
A: use ``std::tuple``:
.. code:: c++
template <typename... Args>
auto capture(const Args&... args) {
return std::make_tuple(args...);
}
auto print_message = [](const auto&... args) {
fmt::print(args...);
};
// Capture and store arguments:
auto args = capture("{} {}", 42, "foo");
// Do formatting:
std::apply(print_message, args);
than ``fmt::format_to`` with format string compilation on Karma's own benchmark,
see `Converting a hundred million integers to strings per second
<http://www.zverovich.net/2020/06/13/fast-int-to-string-revisited.html>`_.
License
-------
@@ -477,18 +459,19 @@ License
{fmt} is distributed under the MIT `license
<https://github.com/fmtlib/fmt/blob/master/LICENSE.rst>`_.
The `Format String Syntax
<https://fmt.dev/latest/syntax.html>`_
section in the documentation is based on the one from Python `string module
documentation <https://docs.python.org/3/library/string.html#module-string>`_
adapted for the current library. For this reason the documentation is
distributed under the Python Software Foundation license available in
`doc/python-license.txt
<https://raw.github.com/fmtlib/fmt/master/doc/python-license.txt>`_.
It only applies if you distribute the documentation of fmt.
Documentation License
---------------------
Acknowledgments
---------------
The `Format String Syntax <https://fmt.dev/latest/syntax.html>`_
section in the documentation is based on the one from Python `string module
documentation <https://docs.python.org/3/library/string.html#module-string>`_.
For this reason the documentation is distributed under the Python Software
Foundation license available in `doc/python-license.txt
<https://raw.github.com/fmtlib/fmt/master/doc/python-license.txt>`_.
It only applies if you distribute the documentation of {fmt}.
Maintainers
-----------
The {fmt} library is maintained by Victor Zverovich (`vitaut
<https://github.com/vitaut>`_) and Jonathan Müller (`foonathan
@@ -497,23 +480,3 @@ See `Contributors <https://github.com/fmtlib/fmt/graphs/contributors>`_ and
`Releases <https://github.com/fmtlib/fmt/releases>`_ for some of the names.
Let us know if your contribution is not listed or mentioned incorrectly and
we'll make it right.
The benchmark section of this readme file and the performance tests are taken
from the excellent `tinyformat <https://github.com/c42f/tinyformat>`_ library
written by Chris Foster. Boost Format library is acknowledged transitively
since it had some influence on tinyformat.
Some ideas used in the implementation are borrowed from `Loki
<http://loki-lib.sourceforge.net/>`_ SafeFormat and `Diagnostic API
<https://clang.llvm.org/doxygen/classclang_1_1Diagnostic.html>`_ in
`Clang <https://clang.llvm.org/>`_.
Format string syntax and the documentation are based on Python's `str.format
<https://docs.python.org/3/library/stdtypes.html#str.format>`_.
Thanks `Doug Turnbull <https://github.com/softwaredoug>`_ for his valuable
comments and contribution to the design of the type-safe API and
`Gregory Czajkowski <https://github.com/gcflymoto>`_ for implementing binary
formatting. Thanks `Ruslan Baratov <https://github.com/ruslo>`_ for comprehensive
`comparison of integer formatting algorithms <https://github.com/ruslo/int-dec-format-tests>`_
and useful comments regarding performance, `Boris Kaul <https://github.com/localvoid>`_ for
`C++ counting digits benchmark <https://github.com/localvoid/cxx-benchmark-count-digits>`_.
Thanks to `CarterLi <https://github.com/CarterLi>`_ for contributing various
improvements to the code.