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Improve parsing

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This commit is contained in:
Victor Zverovich 2024-07-21 09:38:00 -07:00
parent bdc45eef76
commit 524ca1c715
2 changed files with 53 additions and 49 deletions
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96
include/fmt/base.h
View File

@ -2282,8 +2282,8 @@ template <typename Char> constexpr auto is_name_start(Char c) -> bool {
}
template <typename Char, typename Handler>
FMT_CONSTEXPR auto do_parse_arg_id(const Char* begin, const Char* end,
Handler&& handler) -> const Char* {
FMT_CONSTEXPR auto parse_arg_id(const Char* begin, const Char* end,
Handler&& handler) -> const Char* {
Char c = *begin;
if (c >= '0' && c <= '9') {
int index = 0;
@ -2309,25 +2309,10 @@ FMT_CONSTEXPR auto do_parse_arg_id(const Char* begin, const Char* end,
return it;
}
template <typename Char, typename Handler>
FMT_CONSTEXPR auto parse_arg_id(const Char* begin, const Char* end,
Handler&& handler) -> const Char* {
FMT_ASSERT(begin != end, "");
Char c = *begin;
if (c != '}' && c != ':') return do_parse_arg_id(begin, end, handler);
handler.on_auto();
return begin;
}
template <typename Char> struct dynamic_spec_id_handler {
basic_format_parse_context<Char>& ctx;
arg_ref<Char>& ref;
FMT_CONSTEXPR void on_auto() {
int id = ctx.next_arg_id();
ref = arg_ref<Char>(id);
ctx.check_dynamic_spec(id);
}
FMT_CONSTEXPR void on_index(int id) {
ref = arg_ref<Char>(id);
ctx.check_arg_id(id);
@ -2354,8 +2339,17 @@ FMT_CONSTEXPR auto parse_dynamic_spec(const Char* begin, const Char* end,
report_error("number is too big");
} else if (*begin == '{') {
++begin;
auto handler = dynamic_spec_id_handler<Char>{ctx, ref};
if (begin != end) begin = parse_arg_id(begin, end, handler);
if (begin != end) {
Char c = *begin;
if (c == '}' || c == ':') {
int id = ctx.next_arg_id();
ref = arg_ref<Char>(id);
ctx.check_dynamic_spec(id);
} else {
begin =
parse_arg_id(begin, end, dynamic_spec_id_handler<Char>{ctx, ref});
}
}
if (begin != end && *begin == '}') return ++begin;
report_error("invalid format string");
}
@ -2563,39 +2557,53 @@ FMT_CONSTEXPR auto parse_format_specs(const Char* begin, const Char* end,
}
template <typename Char, typename Handler>
FMT_CONSTEXPR auto parse_replacement_field(const Char* begin, const Char* end,
Handler&& handler) -> const Char* {
struct id_adapter {
Handler& handler;
int arg_id;
FMT_CONSTEXPR void on_auto() { arg_id = handler.on_arg_id(); }
FMT_CONSTEXPR void on_index(int id) { arg_id = handler.on_arg_id(id); }
FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
arg_id = handler.on_arg_id(id);
}
};
FMT_CONSTEXPR FMT_INLINE auto parse_replacement_field(const Char* begin,
const Char* end,
Handler&& handler)
-> const Char* {
++begin;
if (begin == end) return handler.on_error("invalid format string"), end;
if (*begin == '}') {
if (begin == end) {
handler.on_error("invalid format string");
return end;
}
int arg_id = 0;
switch (*begin) {
case '}':
handler.on_replacement_field(handler.on_arg_id(), begin);
} else if (*begin == '{') {
return begin + 1;
case '{':
handler.on_text(begin, begin + 1);
} else {
auto adapter = id_adapter{handler, 0};
return begin + 1;
case ':':
arg_id = handler.on_arg_id();
break;
default: {
struct id_adapter {
Handler& handler;
int arg_id;
FMT_CONSTEXPR void on_index(int id) { arg_id = handler.on_arg_id(id); }
FMT_CONSTEXPR void on_name(basic_string_view<Char> id) {
arg_id = handler.on_arg_id(id);
}
} adapter = {handler, 0};
begin = parse_arg_id(begin, end, adapter);
arg_id = adapter.arg_id;
Char c = begin != end ? *begin : Char();
if (c == '}') {
handler.on_replacement_field(adapter.arg_id, begin);
} else if (c == ':') {
begin = handler.on_format_specs(adapter.arg_id, begin + 1, end);
if (begin == end || *begin != '}')
return handler.on_error("unknown format specifier"), end;
} else {
return handler.on_error("missing '}' in format string"), end;
handler.on_replacement_field(arg_id, begin);
return begin + 1;
}
if (c != ':') {
handler.on_error("missing '}' in format string");
return end;
}
break;
}
}
begin = handler.on_format_specs(arg_id, begin + 1, end);
if (begin == end || *begin != '}')
return handler.on_error("unknown format specifier"), end;
return begin + 1;
}

6
test/base-test.cc
View File

@ -481,14 +481,12 @@ TEST(arg_test, visit_invalid_arg) {
#if FMT_USE_CONSTEXPR
enum class arg_id_result { none, empty, index, name };
enum class arg_id_result { none, index, name };
struct test_arg_id_handler {
arg_id_result res = arg_id_result::none;
int index = 0;
string_view name;
constexpr void on_auto() { res = arg_id_result::empty; }
constexpr void on_index(int i) {
res = arg_id_result::index;
index = i;
@ -508,8 +506,6 @@ constexpr test_arg_id_handler parse_arg_id(const char (&s)[N]) {
}
TEST(base_test, constexpr_parse_arg_id) {
static_assert(parse_arg_id(":").res == arg_id_result::empty, "");
static_assert(parse_arg_id("}").res == arg_id_result::empty, "");
static_assert(parse_arg_id("42:").res == arg_id_result::index, "");
static_assert(parse_arg_id("42:").index == 42, "");
static_assert(parse_arg_id("foo:").res == arg_id_result::name, "");