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