fmt/include/fmt/ranges.h
2018-06-08 19:48:41 +02:00

304 lines
8.7 KiB
C++

// Formatting library for C++ - the core API
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
//
// Copyright (c) 2018 - present, Remotion (Igor Schulz)
// All Rights Reserved
// {fmt} support for ranges, containers and types tuple interface.
#ifndef FMT_RANGES_H_
#define FMT_RANGES_H_
#include "format.h"
#include <type_traits>
// output only up to N items from the range.
#ifndef FMT_RANGE_OUTPUT_LENGTH_LIMIT
# define FMT_RANGE_OUTPUT_LENGTH_LIMIT 256
#endif
FMT_BEGIN_NAMESPACE
template <typename Char>
struct formatting_base {
template <typename ParseContext>
FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
return ctx.begin();
}
};
template <typename Char, typename Enable = void>
struct formatting_range : formatting_base<Char> {
static FMT_CONSTEXPR_DECL const std::size_t range_length_limit =
FMT_RANGE_OUTPUT_LENGTH_LIMIT; // output only up to N items from the range.
Char prefix;
Char delimiter;
Char postfix;
formatting_range() : prefix('{'), delimiter(','), postfix('}') {}
static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
};
template <typename Char, typename Enable = void>
struct formatting_tuple : formatting_base<Char> {
Char prefix;
Char delimiter;
Char postfix;
formatting_tuple() : prefix('('), delimiter(','), postfix(')') {}
static FMT_CONSTEXPR_DECL const bool add_delimiter_spaces = true;
static FMT_CONSTEXPR_DECL const bool add_prepostfix_space = false;
};
namespace internal {
template <typename RangeT, typename OutputIterator>
void copy(const RangeT &range, OutputIterator out) {
for (auto it = range.begin(), end = range.end(); it != end; ++it)
*out++ = *it;
}
template <typename OutputIterator>
void copy(const char *str, OutputIterator out) {
const char *p_curr = str;
while (*p_curr) {
*out++ = *p_curr++;
}
}
template <typename OutputIterator>
void copy(char ch, OutputIterator out) {
*out++ = ch;
}
/// Return true value if T has std::string interface, like std::string_view.
template <typename T>
class is_like_std_string {
template <typename U>
static auto check(U *p) ->
decltype(p->find('a'), p->length(), p->data(), int());
template <typename>
static void check(...);
public:
static FMT_CONSTEXPR_DECL const bool value =
!std::is_void<decltype(check<T>(FMT_NULL))>::value;
};
template <typename... Ts>
struct conditional_helper {};
template <typename T, typename _ = void>
struct is_range_ : std::false_type {};
template <typename T>
struct is_range_<T,typename std::conditional<
false,
conditional_helper<decltype(internal::declval<T>().begin()),
decltype(internal::declval<T>().end())>,
void>::type> : std::true_type {};
/// tuple_size and tuple_element check.
template <typename T>
class is_tuple_like_ {
template <typename U>
static auto check(U *p) ->
decltype(std::tuple_size<U>::value,
internal::declval<typename std::tuple_element<0, U>::type>(), int());
template <typename>
static void check(...);
public:
static FMT_CONSTEXPR_DECL const bool value =
!std::is_void<decltype(check<T>(FMT_NULL))>::value;
};
// Check for integer_sequence
#if defined(__cpp_lib_integer_sequence) || FMT_MSC_VER >= 1900
template <typename T, T... N>
using integer_sequence = std::integer_sequence<T, N...>;
template <std::size_t... N>
using index_sequence = std::index_sequence<N...>;
template <std::size_t N>
using make_index_sequence = std::make_index_sequence<N>;
#else
template <typename T, T... N>
struct integer_sequence {
typedef T value_type;
static FMT_CONSTEXPR std::size_t size() {
return sizeof...(N);
}
};
template <std::size_t... N>
using index_sequence = integer_sequence<std::size_t, N...>;
template <typename T, std::size_t N, T... Ns>
struct make_integer_sequence : make_integer_sequence<T, N - 1, N - 1, Ns...> {};
template <typename T, T... Ns>
struct make_integer_sequence<T, 0, Ns...> : integer_sequence<T, Ns...> {};
template <std::size_t N>
using make_index_sequence = make_integer_sequence<std::size_t, N>;
#endif
template <class Tuple, class F, size_t... Is>
void for_each(index_sequence<Is...>, Tuple &&tup, F &&f) noexcept {
using std::get;
// using free function get<I>(T) now.
const int _[] = {0, ((void)f(get<Is>(tup)), 0)...};
(void)_; // blocks warnings
}
template <class T>
FMT_CONSTEXPR make_index_sequence<std::tuple_size<T>::value>
get_indexes(T const &) { return {}; }
template <class Tuple, class F>
void for_each(Tuple &&tup, F &&f) {
const auto indexes = get_indexes(tup);
for_each(indexes, std::forward<Tuple>(tup), std::forward<F>(f));
}
template<typename Arg>
FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&,
typename std::enable_if<
!is_like_std_string<typename std::decay<Arg>::type>::value>::type* = nullptr) {
return add_space ? " {}" : "{}";
}
template<typename Arg>
FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const Arg&,
typename std::enable_if<
is_like_std_string<typename std::decay<Arg>::type>::value>::type* = nullptr) {
return add_space ? " \"{}\"" : "\"{}\"";
}
FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char*) {
return add_space ? " \"{}\"" : "\"{}\"";
}
FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t*) {
return add_space ? L" \"{}\"" : L"\"{}\"";
}
FMT_CONSTEXPR const char* format_str_quoted(bool add_space, const char) {
return add_space ? " '{}'" : "'{}'";
}
FMT_CONSTEXPR const wchar_t* format_str_quoted(bool add_space, const wchar_t) {
return add_space ? L" '{}'" : L"'{}'";
}
} // namespace internal
template <typename T>
struct is_tuple_like {
static FMT_CONSTEXPR_DECL const bool value =
internal::is_tuple_like_<T>::value && !internal::is_range_<T>::value;
};
template <typename TupleT, typename Char>
struct formatter<TupleT, Char,
typename std::enable_if<fmt::is_tuple_like<TupleT>::value>::type> {
private:
// C++11 generic lambda for format()
template <typename FormatContext>
struct format_each {
template <typename T>
void operator()(const T& v) {
if (i > 0) {
if (formatting.add_prepostfix_space) {
*out++ = ' ';
}
internal::copy(formatting.delimiter, out);
}
format_to(out,
internal::format_str_quoted(
(formatting.add_delimiter_spaces && i > 0), v),
v);
++i;
}
formatting_tuple<Char>& formatting;
std::size_t& i;
typename std::add_lvalue_reference<decltype(std::declval<FormatContext>().out())>::type out;
};
public:
formatting_tuple<Char> formatting;
template <typename ParseContext>
FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
return formatting.parse(ctx);
}
template <typename FormatContext = format_context>
auto format(const TupleT &values, FormatContext &ctx) -> decltype(ctx.out()) {
auto out = ctx.out();
std::size_t i = 0;
internal::copy(formatting.prefix, out);
internal::for_each(values, format_each<FormatContext>{formatting, i, out});
if (formatting.add_prepostfix_space) {
*out++ = ' ';
}
internal::copy(formatting.postfix, out);
return ctx.out();
}
};
template <typename T>
struct is_range {
static FMT_CONSTEXPR_DECL const bool value =
internal::is_range_<T>::value && !internal::is_like_std_string<T>::value;
};
template <typename RangeT, typename Char>
struct formatter<RangeT, Char,
typename std::enable_if<fmt::is_range<RangeT>::value>::type> {
formatting_range<Char> formatting;
template <typename ParseContext>
FMT_CONSTEXPR auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
return formatting.parse(ctx);
}
template <typename FormatContext>
typename FormatContext::iterator format(
const RangeT &values, FormatContext &ctx) {
auto out = ctx.out();
internal::copy(formatting.prefix, out);
std::size_t i = 0;
for (auto it = values.begin(), end = values.end(); it != end; ++it) {
if (i > 0) {
if (formatting.add_prepostfix_space) {
*out++ = ' ';
}
internal::copy(formatting.delimiter, out);
}
format_to(out,
internal::format_str_quoted(
(formatting.add_delimiter_spaces && i > 0), *it),
*it);
if (++i > formatting.range_length_limit) {
format_to(out, " ... <other elements>");
break;
}
}
if (formatting.add_prepostfix_space) {
*out++ = ' ';
}
internal::copy(formatting.postfix, out);
return ctx.out();
}
};
FMT_END_NAMESPACE
#endif // FMT_RANGES_H_