ResInsight/ThirdParty/fmtlib/include/fmt/compile.h
2021-09-13 10:00:45 +02:00

666 lines
22 KiB
C++

// 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 {
// A compile-time string which is compiled into fast formatting code.
class compiled_string {};
template <typename S>
struct is_compiled_string : std::is_base_of<compiled_string, S> {};
/**
\rst
Converts a string literal *s* into a format string that will be parsed at
compile time and converted into efficient formatting code. Requires C++17
``constexpr if`` compiler support.
**Example**::
// Converts 42 into std::string using the most efficient method and no
// runtime format string processing.
std::string s = fmt::format(FMT_COMPILE("{}"), 42);
\endrst
*/
#define FMT_COMPILE(s) FMT_STRING_IMPL(s, fmt::detail::compiled_string)
template <typename T, typename... Tail>
const T& first(const T& value, const Tail&...) {
return value;
}
// 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 int on_arg_id() { return ++num_parts, 0; }
FMT_CONSTEXPR int on_arg_id(int) { return ++num_parts, 0; }
FMT_CONSTEXPR int on_arg_id(basic_string_view<Char>) {
return ++num_parts, 0;
}
FMT_CONSTEXPR void on_replacement_field(int, const Char*) {}
FMT_CONSTEXPR const Char* on_format_specs(int, 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 int on_arg_id() {
part_ = part::make_arg_index(parse_context_.next_arg_id());
return 0;
}
FMT_CONSTEXPR int on_arg_id(int id) {
parse_context_.check_arg_id(id);
part_ = part::make_arg_index(id);
return 0;
}
FMT_CONSTEXPR int on_arg_id(basic_string_view<Char> id) {
part_ = part::make_arg_name(id);
return 0;
}
FMT_CONSTEXPR void on_replacement_field(int, const Char* ptr) {
part_.arg_id_end = ptr;
handler_(part_);
}
FMT_CONSTEXPR const Char* on_format_specs(int, 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 OutputIt, typename Context, typename Id>
void format_arg(
basic_format_parse_context<typename Context::char_type>& parse_ctx,
Context& ctx, Id arg_id) {
ctx.advance_to(visit_format_arg(
arg_formatter<OutputIt, typename Context::char_type>(ctx, &parse_ctx),
ctx.arg(arg_id)));
}
// vformat_to is defined in a subnamespace to prevent ADL.
namespace cf {
template <typename Context, typename OutputIt, typename CompiledFormat>
auto vformat_to(OutputIt 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, 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<OutputIt>(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<OutputIt>(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<OutputIt, typename Context::char_type>(
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 OutputIt, typename CompiledFormat>
friend auto cf::vformat_to(OutputIt 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 {
return write<Char>(out, data);
}
};
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}};
}
// 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 write<Char>(out, arg);
}
};
template <typename Char, typename T, int N>
struct is_compiled_format<field<Char, T, N>> : std::true_type {};
// A replacement field that refers to argument N and has format specifiers.
template <typename Char, typename T, int N> struct spec_field {
using char_type = Char;
mutable formatter<T, Char> fmt;
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...);
basic_format_context<OutputIt, Char> ctx(out, {});
return fmt.format(arg, ctx);
}
};
template <typename Char, typename T, int N>
struct is_compiled_format<spec_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 !=
basic_string_view<typename S::char_type>(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;
}
}
template <typename T, typename Char> struct parse_specs_result {
formatter<T, Char> fmt;
size_t end;
};
template <typename T, typename Char>
constexpr parse_specs_result<T, Char> parse_specs(basic_string_view<Char> str,
size_t pos) {
str.remove_prefix(pos);
auto ctx = basic_format_parse_context<Char>(str);
auto f = formatter<T, Char>();
auto end = f.parse(ctx);
return {f, pos + (end - str.data()) + 1};
}
// 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>;
return parse_tail<Args, POS + 2, ID + 1>(field<char_type, type, ID>(),
format_str);
} else if constexpr (str[POS + 1] == ':') {
using type = get_type<ID, Args>;
constexpr auto result = parse_specs<type>(str, POS + 2);
return parse_tail<Args, result.end, ID + 1>(
spec_field<char_type, type, ID>{result.fmt}, format_str);
} 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);
}
}
template <typename... Args, typename S,
FMT_ENABLE_IF(is_compile_string<S>::value ||
detail::is_compiled_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;
}
}
}
#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
// 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));
}
} // namespace detail
// DEPRECATED! use FMT_COMPILE instead.
template <typename... Args>
FMT_DEPRECATED auto compile(const Args&... args)
-> decltype(detail::compile(args...)) {
return detail::compile(args...);
}
#if FMT_USE_CONSTEXPR
# ifdef __cpp_if_constexpr
template <typename CompiledFormat, typename... Args,
typename Char = typename CompiledFormat::char_type,
FMT_ENABLE_IF(detail::is_compiled_format<CompiledFormat>::value)>
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(std::back_inserter(base), 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...);
}
# endif // __cpp_if_constexpr
#endif // FMT_USE_CONSTEXPR
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 context = buffer_context<Char>;
detail::buffer<Char>& base = buffer;
detail::cf::vformat_to<context>(std::back_inserter(base), cf,
make_format_args<context>(args...));
return to_string(buffer);
}
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();
if (str.size() == 2 && str[0] == '{' && str[1] == '}')
return fmt::to_string(detail::first(args...));
constexpr auto compiled = detail::compile<Args...>(S());
return format(compiled, std::forward<Args>(args)...);
}
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 context = format_context_t<OutputIt, char_type>;
return detail::cf::vformat_to<context>(out, cf,
make_format_args<context>(args...));
}
template <typename OutputIt, typename S, typename... Args,
FMT_ENABLE_IF(detail::is_compiled_string<S>::value)>
OutputIt format_to(OutputIt out, const S&, const Args&... args) {
constexpr auto compiled = detail::compile<Args...>(S());
return format_to(out, compiled, 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_