diff options
Diffstat (limited to 'src/fmt/include/fmt/compile.h')
| -rw-r--r-- | src/fmt/include/fmt/compile.h | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/src/fmt/include/fmt/compile.h b/src/fmt/include/fmt/compile.h new file mode 100644 index 000000000..35fe63f86 --- /dev/null +++ b/src/fmt/include/fmt/compile.h @@ -0,0 +1,595 @@ +// Formatting library for C++ - experimental format string compilation +// +// Copyright (c) 2012 - present, Victor Zverovich and fmt contributors +// All rights reserved. +// +// For the license information refer to format.h. + +#ifndef FMT_COMPILE_H_ +#define FMT_COMPILE_H_ + +#include <vector> + +#include "format.h" + +FMT_BEGIN_NAMESPACE +namespace detail { + +// Part of a compiled format string. It can be either literal text or a +// replacement field. +template <typename Char> struct format_part { + enum class kind { arg_index, arg_name, text, replacement }; + + struct replacement { + arg_ref<Char> arg_id; + dynamic_format_specs<Char> specs; + }; + + kind part_kind; + union value { + int arg_index; + basic_string_view<Char> str; + replacement repl; + + FMT_CONSTEXPR value(int index = 0) : arg_index(index) {} + FMT_CONSTEXPR value(basic_string_view<Char> s) : str(s) {} + FMT_CONSTEXPR value(replacement r) : repl(r) {} + } val; + // Position past the end of the argument id. + const Char* arg_id_end = nullptr; + + FMT_CONSTEXPR format_part(kind k = kind::arg_index, value v = {}) + : part_kind(k), val(v) {} + + static FMT_CONSTEXPR format_part make_arg_index(int index) { + return format_part(kind::arg_index, index); + } + static FMT_CONSTEXPR format_part make_arg_name(basic_string_view<Char> name) { + return format_part(kind::arg_name, name); + } + static FMT_CONSTEXPR format_part make_text(basic_string_view<Char> text) { + return format_part(kind::text, text); + } + static FMT_CONSTEXPR format_part make_replacement(replacement repl) { + return format_part(kind::replacement, repl); + } +}; + +template <typename Char> struct part_counter { + unsigned num_parts = 0; + + FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) { + if (begin != end) ++num_parts; + } + + FMT_CONSTEXPR void on_arg_id() { ++num_parts; } + FMT_CONSTEXPR void on_arg_id(int) { ++num_parts; } + FMT_CONSTEXPR void on_arg_id(basic_string_view<Char>) { ++num_parts; } + + FMT_CONSTEXPR void on_replacement_field(const Char*) {} + + FMT_CONSTEXPR const Char* on_format_specs(const Char* begin, + const Char* end) { + // Find the matching brace. + unsigned brace_counter = 0; + for (; begin != end; ++begin) { + if (*begin == '{') { + ++brace_counter; + } else if (*begin == '}') { + if (brace_counter == 0u) break; + --brace_counter; + } + } + return begin; + } + + FMT_CONSTEXPR void on_error(const char*) {} +}; + +// Counts the number of parts in a format string. +template <typename Char> +FMT_CONSTEXPR unsigned count_parts(basic_string_view<Char> format_str) { + part_counter<Char> counter; + parse_format_string<true>(format_str, counter); + return counter.num_parts; +} + +template <typename Char, typename PartHandler> +class format_string_compiler : public error_handler { + private: + using part = format_part<Char>; + + PartHandler handler_; + part part_; + basic_string_view<Char> format_str_; + basic_format_parse_context<Char> parse_context_; + + public: + FMT_CONSTEXPR format_string_compiler(basic_string_view<Char> format_str, + PartHandler handler) + : handler_(handler), + format_str_(format_str), + parse_context_(format_str) {} + + FMT_CONSTEXPR void on_text(const Char* begin, const Char* end) { + if (begin != end) + handler_(part::make_text({begin, to_unsigned(end - begin)})); + } + + FMT_CONSTEXPR void on_arg_id() { + part_ = part::make_arg_index(parse_context_.next_arg_id()); + } + + FMT_CONSTEXPR void on_arg_id(int id) { + parse_context_.check_arg_id(id); + part_ = part::make_arg_index(id); + } + + FMT_CONSTEXPR void on_arg_id(basic_string_view<Char> id) { + part_ = part::make_arg_name(id); + } + + FMT_CONSTEXPR void on_replacement_field(const Char* ptr) { + part_.arg_id_end = ptr; + handler_(part_); + } + + FMT_CONSTEXPR const Char* on_format_specs(const Char* begin, + const Char* end) { + auto repl = typename part::replacement(); + dynamic_specs_handler<basic_format_parse_context<Char>> handler( + repl.specs, parse_context_); + auto it = parse_format_specs(begin, end, handler); + if (*it != '}') on_error("missing '}' in format string"); + repl.arg_id = part_.part_kind == part::kind::arg_index + ? arg_ref<Char>(part_.val.arg_index) + : arg_ref<Char>(part_.val.str); + auto part = part::make_replacement(repl); + part.arg_id_end = begin; + handler_(part); + return it; + } +}; + +// Compiles a format string and invokes handler(part) for each parsed part. +template <bool IS_CONSTEXPR, typename Char, typename PartHandler> +FMT_CONSTEXPR void compile_format_string(basic_string_view<Char> format_str, + PartHandler handler) { + parse_format_string<IS_CONSTEXPR>( + format_str, + format_string_compiler<Char, PartHandler>(format_str, handler)); +} + +template <typename Range, typename Context, typename Id> +void format_arg( + basic_format_parse_context<typename Range::value_type>& parse_ctx, + Context& ctx, Id arg_id) { + ctx.advance_to( + visit_format_arg(arg_formatter<Range>(ctx, &parse_ctx), ctx.arg(arg_id))); +} + +// vformat_to is defined in a subnamespace to prevent ADL. +namespace cf { +template <typename Context, typename Range, typename CompiledFormat> +auto vformat_to(Range out, CompiledFormat& cf, basic_format_args<Context> args) + -> typename Context::iterator { + using char_type = typename Context::char_type; + basic_format_parse_context<char_type> parse_ctx( + to_string_view(cf.format_str_)); + Context ctx(out.begin(), args); + + const auto& parts = cf.parts(); + for (auto part_it = std::begin(parts); part_it != std::end(parts); + ++part_it) { + const auto& part = *part_it; + const auto& value = part.val; + + using format_part_t = format_part<char_type>; + switch (part.part_kind) { + case format_part_t::kind::text: { + const auto text = value.str; + auto output = ctx.out(); + auto&& it = reserve(output, text.size()); + it = std::copy_n(text.begin(), text.size(), it); + ctx.advance_to(output); + break; + } + + case format_part_t::kind::arg_index: + advance_to(parse_ctx, part.arg_id_end); + detail::format_arg<Range>(parse_ctx, ctx, value.arg_index); + break; + + case format_part_t::kind::arg_name: + advance_to(parse_ctx, part.arg_id_end); + detail::format_arg<Range>(parse_ctx, ctx, value.str); + break; + + case format_part_t::kind::replacement: { + const auto& arg_id_value = value.repl.arg_id.val; + const auto arg = value.repl.arg_id.kind == arg_id_kind::index + ? ctx.arg(arg_id_value.index) + : ctx.arg(arg_id_value.name); + + auto specs = value.repl.specs; + + handle_dynamic_spec<width_checker>(specs.width, specs.width_ref, ctx); + handle_dynamic_spec<precision_checker>(specs.precision, + specs.precision_ref, ctx); + + error_handler h; + numeric_specs_checker<error_handler> checker(h, arg.type()); + if (specs.align == align::numeric) checker.require_numeric_argument(); + if (specs.sign != sign::none) checker.check_sign(); + if (specs.alt) checker.require_numeric_argument(); + if (specs.precision >= 0) checker.check_precision(); + + advance_to(parse_ctx, part.arg_id_end); + ctx.advance_to( + visit_format_arg(arg_formatter<Range>(ctx, nullptr, &specs), arg)); + break; + } + } + } + return ctx.out(); +} +} // namespace cf + +struct basic_compiled_format {}; + +template <typename S, typename = void> +struct compiled_format_base : basic_compiled_format { + using char_type = char_t<S>; + using parts_container = std::vector<detail::format_part<char_type>>; + + parts_container compiled_parts; + + explicit compiled_format_base(basic_string_view<char_type> format_str) { + compile_format_string<false>(format_str, + [this](const format_part<char_type>& part) { + compiled_parts.push_back(part); + }); + } + + const parts_container& parts() const { return compiled_parts; } +}; + +template <typename Char, unsigned N> struct format_part_array { + format_part<Char> data[N] = {}; + FMT_CONSTEXPR format_part_array() = default; +}; + +template <typename Char, unsigned N> +FMT_CONSTEXPR format_part_array<Char, N> compile_to_parts( + basic_string_view<Char> format_str) { + format_part_array<Char, N> parts; + unsigned counter = 0; + // This is not a lambda for compatibility with older compilers. + struct { + format_part<Char>* parts; + unsigned* counter; + FMT_CONSTEXPR void operator()(const format_part<Char>& part) { + parts[(*counter)++] = part; + } + } collector{parts.data, &counter}; + compile_format_string<true>(format_str, collector); + if (counter < N) { + parts.data[counter] = + format_part<Char>::make_text(basic_string_view<Char>()); + } + return parts; +} + +template <typename T> constexpr const T& constexpr_max(const T& a, const T& b) { + return (a < b) ? b : a; +} + +template <typename S> +struct compiled_format_base<S, enable_if_t<is_compile_string<S>::value>> + : basic_compiled_format { + using char_type = char_t<S>; + + FMT_CONSTEXPR explicit compiled_format_base(basic_string_view<char_type>) {} + +// Workaround for old compilers. Format string compilation will not be +// performed there anyway. +#if FMT_USE_CONSTEXPR + static FMT_CONSTEXPR_DECL const unsigned num_format_parts = + constexpr_max(count_parts(to_string_view(S())), 1u); +#else + static const unsigned num_format_parts = 1; +#endif + + using parts_container = format_part<char_type>[num_format_parts]; + + const parts_container& parts() const { + static FMT_CONSTEXPR_DECL const auto compiled_parts = + compile_to_parts<char_type, num_format_parts>( + detail::to_string_view(S())); + return compiled_parts.data; + } +}; + +template <typename S, typename... Args> +class compiled_format : private compiled_format_base<S> { + public: + using typename compiled_format_base<S>::char_type; + + private: + basic_string_view<char_type> format_str_; + + template <typename Context, typename Range, typename CompiledFormat> + friend auto cf::vformat_to(Range out, CompiledFormat& cf, + basic_format_args<Context> args) -> + typename Context::iterator; + + public: + compiled_format() = delete; + explicit constexpr compiled_format(basic_string_view<char_type> format_str) + : compiled_format_base<S>(format_str), format_str_(format_str) {} +}; + +#ifdef __cpp_if_constexpr +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) { + static_assert(N < 1 + sizeof...(Args), "index is out of bounds"); + if constexpr (N == 0) + return first; + else + return get<N - 1>(rest...); +} + +template <int N, typename> struct get_type_impl; + +template <int N, typename... Args> struct get_type_impl<N, type_list<Args...>> { + using type = remove_cvref_t<decltype(get<N>(std::declval<Args>()...))>; +}; + +template <int N, typename T> +using get_type = typename get_type_impl<N, T>::type; + +template <typename T> struct is_compiled_format : std::false_type {}; + +template <typename Char> struct text { + basic_string_view<Char> data; + using char_type = Char; + + template <typename OutputIt, typename... Args> + OutputIt format(OutputIt out, const Args&...) const { + // TODO: reserve + return copy_str<Char>(data.begin(), data.end(), out); + } +}; + +template <typename Char> +struct is_compiled_format<text<Char>> : std::true_type {}; + +template <typename Char> +constexpr text<Char> make_text(basic_string_view<Char> s, size_t pos, + size_t size) { + return {{&s[pos], size}}; +} + +template <typename Char, typename OutputIt, typename T, + std::enable_if_t<std::is_integral_v<T>, int> = 0> +OutputIt format_default(OutputIt out, T value) { + // TODO: reserve + format_int fi(value); + return std::copy(fi.data(), fi.data() + fi.size(), out); +} + +template <typename Char, typename OutputIt> +OutputIt format_default(OutputIt out, double value) { + return detail::write(out, value); +} + +template <typename Char, typename OutputIt> +OutputIt format_default(OutputIt out, Char value) { + *out++ = value; + return out; +} + +template <typename Char, typename OutputIt> +OutputIt format_default(OutputIt out, const Char* value) { + auto length = std::char_traits<Char>::length(value); + return copy_str<Char>(value, value + length, out); +} + +// A replacement field that refers to argument N. +template <typename Char, typename T, int N> struct field { + using char_type = Char; + + template <typename OutputIt, typename... Args> + 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...); + return format_default<Char>(out, arg); + } +}; + +template <typename Char, typename T, int N> +struct is_compiled_format<field<Char, T, N>> : std::true_type {}; + +template <typename L, typename R> struct concat { + L lhs; + R rhs; + using char_type = typename L::char_type; + + template <typename OutputIt, typename... Args> + OutputIt format(OutputIt out, const Args&... args) const { + out = lhs.format(out, args...); + return rhs.format(out, args...); + } +}; + +template <typename L, typename R> +struct is_compiled_format<concat<L, R>> : std::true_type {}; + +template <typename L, typename R> +constexpr concat<L, R> make_concat(L lhs, R rhs) { + return {lhs, rhs}; +} + +struct unknown_format {}; + +template <typename Char> +constexpr size_t parse_text(basic_string_view<Char> str, size_t pos) { + for (size_t size = str.size(); pos != size; ++pos) { + if (str[pos] == '{' || str[pos] == '}') break; + } + return pos; +} + +template <typename Args, size_t POS, int ID, typename S> +constexpr auto compile_format_string(S format_str); + +template <typename Args, size_t POS, int ID, typename T, typename S> +constexpr auto parse_tail(T head, S format_str) { + if constexpr (POS != to_string_view(format_str).size()) { + constexpr auto tail = compile_format_string<Args, POS, ID>(format_str); + if constexpr (std::is_same<remove_cvref_t<decltype(tail)>, + unknown_format>()) + return tail; + else + return make_concat(head, tail); + } else { + return head; + } +} + +// Compiles a non-empty format string and returns the compiled representation +// or unknown_format() on unrecognized input. +template <typename Args, size_t POS, int ID, typename S> +constexpr auto compile_format_string(S format_str) { + using char_type = typename S::char_type; + constexpr basic_string_view<char_type> str = format_str; + if constexpr (str[POS] == '{') { + if (POS + 1 == str.size()) + throw format_error("unmatched '{' in format string"); + if constexpr (str[POS + 1] == '{') { + return parse_tail<Args, POS + 2, ID>(make_text(str, POS, 1), format_str); + } else if constexpr (str[POS + 1] == '}') { + using type = get_type<ID, Args>; + if constexpr (std::is_same<type, int>::value) { + return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(), + format_str); + } else { + return unknown_format(); + } + } else { + return unknown_format(); + } + } else if constexpr (str[POS] == '}') { + if (POS + 1 == str.size()) + throw format_error("unmatched '}' in format string"); + 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), + format_str); + } +} +#endif // __cpp_if_constexpr +} // namespace detail + +#if FMT_USE_CONSTEXPR +# ifdef __cpp_if_constexpr +template <typename... Args, typename S, + FMT_ENABLE_IF(is_compile_string<S>::value)> +constexpr auto compile(S format_str) { + constexpr basic_string_view<typename S::char_type> str = format_str; + if constexpr (str.size() == 0) { + return detail::make_text(str, 0, 0); + } else { + constexpr auto result = + detail::compile_format_string<detail::type_list<Args...>, 0, 0>( + format_str); + if constexpr (std::is_same<remove_cvref_t<decltype(result)>, + detail::unknown_format>()) { + return detail::compiled_format<S, Args...>(to_string_view(format_str)); + } else { + return result; + } + } +} + +template <typename CompiledFormat, typename... Args, + typename Char = typename CompiledFormat::char_type, + FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)> +std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) { + basic_memory_buffer<Char> buffer; + cf.format(std::back_inserter(buffer), args...); + return to_string(buffer); +} + +template <typename OutputIt, typename CompiledFormat, typename... Args, + FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)> +OutputIt format_to(OutputIt out, const CompiledFormat& cf, + const Args&... args) { + return cf.format(out, args...); +} +# else +template <typename... Args, typename S, + FMT_ENABLE_IF(is_compile_string<S>::value)> +constexpr auto compile(S format_str) -> detail::compiled_format<S, Args...> { + return detail::compiled_format<S, Args...>(to_string_view(format_str)); +} +# endif // __cpp_if_constexpr +#endif // FMT_USE_CONSTEXPR + +// Compiles the format string which must be a string literal. +template <typename... Args, typename Char, size_t N> +auto compile(const Char (&format_str)[N]) + -> detail::compiled_format<const Char*, Args...> { + return detail::compiled_format<const Char*, Args...>( + basic_string_view<Char>(format_str, N - 1)); +} + +template <typename CompiledFormat, typename... Args, + typename Char = typename CompiledFormat::char_type, + FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format, + CompiledFormat>::value)> +std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) { + basic_memory_buffer<Char> buffer; + using range = buffer_range<Char>; + using context = buffer_context<Char>; + detail::cf::vformat_to<context>(range(buffer), cf, + make_format_args<context>(args...)); + return to_string(buffer); +} + +template <typename OutputIt, typename CompiledFormat, typename... Args, + FMT_ENABLE_IF(std::is_base_of<detail::basic_compiled_format, + CompiledFormat>::value)> +OutputIt format_to(OutputIt out, const CompiledFormat& cf, + const Args&... args) { + using char_type = typename CompiledFormat::char_type; + using range = detail::output_range<OutputIt, char_type>; + using context = format_context_t<OutputIt, char_type>; + return detail::cf::vformat_to<context>(range(out), cf, + make_format_args<context>(args...)); +} + +template < + typename OutputIt, typename CompiledFormat, typename... Args, + FMT_ENABLE_IF(detail::is_output_iterator<OutputIt>::value&& std::is_base_of< + detail::basic_compiled_format, CompiledFormat>::value)> +format_to_n_result<OutputIt> format_to_n(OutputIt out, size_t n, + const CompiledFormat& cf, + const Args&... args) { + auto it = + format_to(detail::truncating_iterator<OutputIt>(out, n), cf, 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(); +} + +FMT_END_NAMESPACE + +#endif // FMT_COMPILE_H_ |