Add support for ranges, containers and tuple-like types in fmt/ranges.h
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Remotion
committed by
Victor Zverovich
Victor Zverovich
parent
984232db15
commit
e3f7f3a2e9
231
include/fmt/ranges.h
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231
include/fmt/ranges.h
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// Formatting library for C++ - the core API
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//
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// Copyright (c) 2012 - present, Victor Zverovich
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// All rights reserved.
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//
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// For the license information refer to format.h.
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//
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// Copyright (c) 2018 - present, Remotion (Igor Schulz)
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// All Rights Reserved
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// {fmt} support for ranges, containers and types tuple interface.
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#ifndef FMT_RANGES_H_
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#define FMT_RANGES_H_
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#include "format.h"
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#include <type_traits>
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// output only up to N items from the range.
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#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
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# define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
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#endif
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FMT_BEGIN_NAMESPACE
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template <typename Char>
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struct formatting_base {
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
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return ctx.begin();
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}
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};
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template <typename Char, typename Enable = void>
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struct formatting_range : formatting_base<Char> {
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static FMT_CONSTEXPR_DECL const std::size_t range_length_limit =
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FMT_RANGE_OUTPUT_LENGTH_LIMIT; // output only up to N items from the range.
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Char prefix = '{';
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Char delimiter = ',';
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Char postfix = '}';
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static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
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static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
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};
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template <typename Char, typename Enable = void>
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struct formatting_tuple : formatting_base<Char> {
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Char prefix = '(';
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Char delimiter = ',';
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Char postfix = ')';
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static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
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static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
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};
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namespace internal {
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template <typename RangeT, typename OutputIterator>
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void copy(const RangeT &range, OutputIterator out) {
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for (const auto &it : range) {
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*out++ = it;
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}
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}
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template <typename OutputIterator>
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void copy(const char *str, OutputIterator out) {
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const char *p_curr = str;
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while (*p_curr) {
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*out++ = *p_curr++;
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}
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}
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template <typename OutputIterator>
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void copy(char ch, OutputIterator out) {
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*out++ = ch;
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}
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/// Return true value if T has std::string interface, like std::string_view.
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template <typename T>
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class is_like_std_string {
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template <typename U>
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static auto check(U *p) ->
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decltype(p->find('a'), p->length(), p->data(), int());
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template <typename>
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static void check(...);
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public:
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static FMT_CONSTEXPR_DECL const bool value =
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!std::is_void<decltype(check<T>(nullptr))>::value;
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};
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template <typename... Ts>
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struct conditional_helper {};
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template <typename T, typename _ = void>
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struct is_range_ : std::false_type {};
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template <typename T>
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struct is_range_<T,typename std::conditional<
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false,
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conditional_helper<decltype(std::declval<T>().begin()),
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decltype(std::declval<T>().end())>,
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void>::type> : std::true_type {};
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template <typename T>
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struct is_range {
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static FMT_CONSTEXPR_DECL const bool value =
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is_range_<T>::value && !is_like_std_string<T>::value;
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};
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/// tuple_size and tuple_element check.
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template <typename T>
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class is_tuple_like_ {
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template <typename U>
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static auto check(U *p) ->
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decltype(std::tuple_size<U>::value,
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std::declval<typename std::tuple_element<0, U>::type>(), int());
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template <typename>
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static void check(...);
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public:
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static FMT_CONSTEXPR_DECL const bool value =
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!std::is_void<decltype(check<T>(nullptr))>::value;
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};
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template <typename T>
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struct is_tuple_like {
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static FMT_CONSTEXPR_DECL const bool value =
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is_tuple_like_<T>::value && !is_range_<T>::value;
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};
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template <size_t... Is, class Tuple, class F>
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void for_each(std::index_sequence<Is...>, Tuple &&tup, F &&f) noexcept {
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using std::get;
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// using free function get<I>(T) now.
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const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
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(void)_; // blocks warnings
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}
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template <class T>
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FMT_CONSTEXPR std::make_index_sequence<std::tuple_size<T>::value>
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get_indexes(T const &) { return {}; }
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template <class Tuple, class F>
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void for_each(Tuple &&tup, F &&f) {
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const auto indexes = get_indexes(tup);
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for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
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}
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} // namespace internal
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template <typename TupleT, typename Char>
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struct formatter<TupleT, Char,
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typename std::enable_if<fmt::internal::is_tuple_like<TupleT>::value>::type> {
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fmt::formatting_tuple<Char> formatting;
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
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return formatting.parse(ctx);
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}
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template <typename FormatContext = format_context>
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auto format(const TupleT &values, FormatContext &ctx) -> decltype(ctx.out()) {
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auto out = ctx.out();
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std::size_t i = 0;
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internal::copy(formatting.prefix, out);
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internal::for_each(values, [&](const auto &v) {
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if (i > 0) {
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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internal::copy(formatting.delimiter, out);
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}
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if (formatting.add_delimiter_spaces && i > 0) {
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format_to(out, " {}", v);
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} else {
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format_to(out, "{}", v);
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}
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++i;
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});
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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internal::copy(formatting.postfix, out);
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return ctx.out();
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}
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};
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template <typename RangeT, typename Char>
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struct formatter< RangeT, Char,
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typename std::enable_if<fmt::internal::is_range<RangeT>::value>::type> {
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fmt::formatting_range<Char> formatting;
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template <typename ParseContext>
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FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
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return formatting.parse(ctx);
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}
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template <typename FormatContext>
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auto format(const RangeT &values, FormatContext &ctx) -> decltype(ctx.out()) {
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auto out = ctx.out();
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internal::copy(formatting.prefix, out);
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std::size_t i = 0;
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for (const auto &it : values) {
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if (i > 0) {
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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internal::copy(formatting.delimiter, out);
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}
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if (formatting.add_delimiter_spaces && i > 0) {
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format_to(out, " {}", it);
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} else {
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format_to(out, "{}", it);
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}
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if (++i > formatting.range_length_limit) {
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format_to(out, " ... <other elements>");
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break;
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}
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}
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if (formatting.add_prepostfix_space) {
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*out++ = ' ';
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}
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internal::copy(formatting.postfix, out);
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return ctx.out();
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}
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};
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FMT_END_NAMESPACE
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#endif // FMT_RANGES_H_
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