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Refactor width parsing

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This commit is contained in:
Victor Zverovich
2022-12-23 16:05:05 -08:00
parent 275b4b3417
commit 1dadeb8a33
5 changed files with 142 additions and 64 deletions
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32
include/fmt/chrono.h
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@ -2026,10 +2026,6 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
}
FMT_CONSTEXPR void end_precision() {}
template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
f.width_ref = make_arg_ref(arg_id);
}
template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
f.precision_ref = make_arg_ref(arg_id);
}
@ -2045,14 +2041,32 @@ struct formatter<std::chrono::duration<Rep, Period>, Char> {
auto begin = ctx.begin(), end = ctx.end();
if (begin == end || *begin == '}') return {begin, begin};
auto handler = spec_handler{*this, ctx, format_str};
auto result = detail::parse_align(begin, end);
specs.align = result.align;
auto fill_size = result.end - begin - 1;
auto align_result = detail::parse_align(begin, end);
specs.align = align_result.align;
auto fill_size = align_result.end - begin - 1;
if (fill_size > 0) specs.fill = {begin, detail::to_unsigned(fill_size)};
begin = result.end;
begin = align_result.end;
if (begin == end) return {begin, begin};
begin = detail::parse_width(begin, end, handler);
auto width_result = detail::parse_width(begin, end, ctx);
auto width = width_result.width;
switch (width.kind) {
case detail::dynamic_spec_kind::none:
break;
case detail::dynamic_spec_kind::value:
specs.width = width.value;
break;
case detail::dynamic_spec_kind::index:
width_ref = arg_ref_type(width.value);
break;
case detail::dynamic_spec_kind::name:
width_ref = arg_ref_type(width.name);
break;
}
begin = width_result.end;
if (begin == end) return {begin, begin};
auto checker = detail::chrono_format_checker();
if (*begin == '.') {
checker.has_precision_integral = !std::is_floating_point<Rep>::value;

103
include/fmt/core.h
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@ -2206,6 +2206,17 @@ struct dynamic_format_specs : basic_format_specs<Char> {
arg_ref<Char> precision_ref;
};
enum class dynamic_spec_kind { none, value, index, name };
// A format specifier that can be specified dynamically such as width.
template <typename Char> struct dynamic_spec {
dynamic_spec_kind kind;
union {
int value;
basic_string_view<Char> name;
};
};
struct auto_id {};
// A format specifier handler that sets fields in basic_format_specs.
@ -2251,8 +2262,22 @@ class dynamic_specs_handler
ParseContext& ctx)
: specs_setter<char_type>(specs), specs_(specs), context_(ctx) {}
template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
specs_.width_ref = make_arg_ref(arg_id);
FMT_CONSTEXPR auto parse_context() -> ParseContext& { return context_; }
FMT_CONSTEXPR void on_dynamic_width(const dynamic_spec<char_type>& width) {
switch (width.kind) {
case dynamic_spec_kind::none:
break;
case dynamic_spec_kind::value:
specs_.width = width.value;
break;
case dynamic_spec_kind::index:
specs_.width_ref = arg_ref_type(width.value);
break;
case dynamic_spec_kind::name:
specs_.width_ref = arg_ref_type(width.name);
break;
}
}
template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {
@ -2284,8 +2309,6 @@ class dynamic_specs_handler
FMT_CONSTEXPR auto make_arg_ref(basic_string_view<char_type> arg_id)
-> arg_ref_type {
context_.check_arg_id(arg_id);
basic_string_view<char_type> format_str(
context_.begin(), to_unsigned(context_.end() - context_.begin()));
return arg_ref_type(arg_id);
}
};
@ -2451,38 +2474,56 @@ FMT_CONSTEXPR FMT_INLINE auto parse_arg_id(const Char* begin, const Char* end,
return begin;
}
template <typename Char, typename Handler>
FMT_CONSTEXPR auto parse_width(const Char* begin, const Char* end,
Handler&& handler) -> const Char* {
using detail::auto_id;
struct width_adapter {
Handler& handler;
template <typename Char> struct parse_width_result {
const Char* end;
dynamic_spec<Char> width;
};
FMT_CONSTEXPR void operator()() { handler.on_dynamic_width(auto_id()); }
FMT_CONSTEXPR void operator()(int id) { handler.on_dynamic_width(id); }
template <typename Char>
FMT_CONSTEXPR auto parse_width(const Char* begin, const Char* end,
basic_format_parse_context<Char>& ctx)
-> parse_width_result<Char> {
struct id_handler {
basic_format_parse_context<Char>& ctx;
dynamic_spec<Char> spec;
FMT_CONSTEXPR void operator()() {
spec.kind = dynamic_spec_kind::index;
spec.value = ctx.next_arg_id();
ctx.check_dynamic_spec(spec.value);
}
FMT_CONSTEXPR void operator()(int id) {
spec.kind = dynamic_spec_kind::index;
spec.value = id;
ctx.check_arg_id(id);
ctx.check_dynamic_spec(id);
}
FMT_CONSTEXPR void operator()(basic_string_view<Char> id) {
handler.on_dynamic_width(id);
spec.kind = dynamic_spec_kind::name;
spec.name = id;
ctx.check_arg_id(id);
}
FMT_CONSTEXPR void on_error(const char* message) {
if (message) handler.on_error(message);
if (message) throw_format_error("invalid format string");
}
};
FMT_ASSERT(begin != end, "");
if ('0' <= *begin && *begin <= '9') {
int width = parse_nonnegative_int(begin, end, -1);
if (width != -1)
handler.on_width(width);
else
handler.on_error("number is too big");
int value = parse_nonnegative_int(begin, end, -1);
if (value != -1) return {begin, {dynamic_spec_kind::value, {value}}};
throw_format_error("number is too big");
} else if (*begin == '{') {
++begin;
if (begin != end) begin = parse_arg_id(begin, end, width_adapter{handler});
if (begin == end || *begin != '}')
return handler.on_error("invalid format string"), begin;
++begin;
auto handler = id_handler{ctx, {dynamic_spec_kind::none, {}}};
if (begin != end) begin = parse_arg_id(begin, end, handler);
if (begin != end && *begin == '}') {
++begin;
return {begin, handler.spec};
}
throw_format_error("invalid format string");
}
return begin;
return {begin, {dynamic_spec_kind::none, {}}};
}
template <typename Char, typename Handler>
@ -2585,13 +2626,13 @@ FMT_CONSTEXPR FMT_INLINE auto parse_format_specs(const Char* begin,
if (begin == end) return begin;
auto result = parse_align(begin, end);
if (result.align != align::none) {
auto fill_size = result.end - begin - 1;
auto align_result = parse_align(begin, end);
if (align_result.align != align::none) {
auto fill_size = align_result.end - begin - 1;
if (fill_size > 0) handler.on_fill({begin, to_unsigned(fill_size)});
handler.on_align(result.align);
handler.on_align(align_result.align);
}
begin = result.end;
begin = align_result.end;
if (begin == end) return begin;
// Parse sign.
@ -2624,7 +2665,9 @@ FMT_CONSTEXPR FMT_INLINE auto parse_format_specs(const Char* begin,
if (++begin == end) return begin;
}
begin = parse_width(begin, end, handler);
auto width_result = parse_width(begin, end, handler.parse_context());
handler.on_dynamic_width(width_result.width);
begin = width_result.end;
if (begin == end) return begin;
// Parse precision.

24
include/fmt/format.h
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@ -3623,9 +3623,27 @@ template <typename Char> class specs_handler : public specs_setter<Char> {
buffer_context<Char>& ctx)
: specs_setter<Char>(specs), parse_context_(parse_ctx), context_(ctx) {}
template <typename Id> FMT_CONSTEXPR void on_dynamic_width(Id arg_id) {
this->specs_.width = get_dynamic_spec<width_checker>(
get_arg(arg_id), context_.error_handler());
FMT_CONSTEXPR auto parse_context() -> basic_format_parse_context<Char>& {
return parse_context_;
}
FMT_CONSTEXPR void on_dynamic_width(const dynamic_spec<Char>& width) {
auto arg = format_arg();
switch (width.kind) {
case dynamic_spec_kind::none:
return;
case dynamic_spec_kind::value:
this->specs_.width = width.value;
return;
case dynamic_spec_kind::index:
arg = detail::get_arg(context_, width.value);
break;
case dynamic_spec_kind::name:
arg = detail::get_arg(context_, width.name);
break;
}
this->specs_.width =
get_dynamic_spec<width_checker>(arg, context_.error_handler());
}
template <typename Id> FMT_CONSTEXPR void on_dynamic_precision(Id arg_id) {

43
test/core-test.cc
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@ -524,6 +524,8 @@ TEST(format_test, constexpr_parse_arg_id) {
}
struct test_format_specs_handler {
fmt::detail::compile_parse_context<char> ctx =
fmt::detail::compile_parse_context<char>({}, 43, nullptr);
enum result { none, hash, zero, loc, error };
result res = none;
@ -542,6 +544,8 @@ struct test_format_specs_handler {
constexpr test_format_specs_handler(const test_format_specs_handler& other) =
default;
constexpr auto parse_context() -> fmt::format_parse_context& { return ctx; }
constexpr void on_align(fmt::align_t a) { alignment = a; }
constexpr void on_fill(fmt::string_view f) { fill = f[0]; }
constexpr void on_sign(fmt::sign_t s) { sign = s; }
@ -550,9 +554,20 @@ struct test_format_specs_handler {
constexpr void on_localized() { res = loc; }
constexpr void on_width(int w) { width = w; }
constexpr void on_dynamic_width(fmt::detail::auto_id) {}
constexpr void on_dynamic_width(int index) { width_ref = index; }
constexpr void on_dynamic_width(string_view) {}
constexpr void on_dynamic_width(const fmt::detail::dynamic_spec<char>& spec) {
switch (spec.kind) {
case fmt::detail::dynamic_spec_kind::none:
break;
case fmt::detail::dynamic_spec_kind::value:
width = spec.value;
break;
case fmt::detail::dynamic_spec_kind::index:
width_ref = spec.value;
break;
case fmt::detail::dynamic_spec_kind::name:
break;
}
}
constexpr void on_precision(int p) { precision = p; }
constexpr void on_dynamic_precision(fmt::detail::auto_id) {}
@ -588,25 +603,13 @@ TEST(core_test, constexpr_parse_format_specs) {
static_assert(parse_test_specs("d").type == fmt::presentation_type::dec, "");
}
struct test_parse_context {
using char_type = char;
constexpr int next_arg_id() { return 11; }
template <typename Id> FMT_CONSTEXPR void check_arg_id(Id) {}
FMT_CONSTEXPR void check_dynamic_spec(int) {}
constexpr const char* begin() { return nullptr; }
constexpr const char* end() { return nullptr; }
void on_error(const char*) {}
};
template <size_t N>
constexpr fmt::detail::dynamic_format_specs<char> parse_dynamic_specs(
const char (&s)[N]) {
auto specs = fmt::detail::dynamic_format_specs<char>();
auto ctx = test_parse_context();
auto h = fmt::detail::dynamic_specs_handler<test_parse_context>(specs, ctx);
auto ctx = fmt::detail::compile_parse_context<char>({}, 43, nullptr);
auto h =
fmt::detail::dynamic_specs_handler<fmt::format_parse_context>(specs, ctx);
parse_format_specs(s, s + N - 1, h);
return specs;
}
@ -620,10 +623,10 @@ TEST(format_test, constexpr_dynamic_specs_handler) {
static_assert(parse_dynamic_specs("#").alt, "");
static_assert(parse_dynamic_specs("0").align == fmt::align::numeric, "");
static_assert(parse_dynamic_specs("42").width == 42, "");
static_assert(parse_dynamic_specs("{}").width_ref.val.index == 11, "");
static_assert(parse_dynamic_specs("{}").width_ref.val.index == 0, "");
static_assert(parse_dynamic_specs("{42}").width_ref.val.index == 42, "");
static_assert(parse_dynamic_specs(".42").precision == 42, "");
static_assert(parse_dynamic_specs(".{}").precision_ref.val.index == 11, "");
static_assert(parse_dynamic_specs(".{}").precision_ref.val.index == 0, "");
static_assert(parse_dynamic_specs(".{42}").precision_ref.val.index == 42, "");
static_assert(parse_dynamic_specs("d").type == fmt::presentation_type::dec,
"");

4
test/format-test.cc
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@ -2208,9 +2208,9 @@ FMT_CONSTEXPR bool test_error(const char* fmt, const char* expected_error) {
}
# define EXPECT_ERROR_NOARGS(fmt, error) \
static_assert(test_error(fmt, error), "")
// static_assert(test_error(fmt, error), "")
# define EXPECT_ERROR(fmt, error, ...) \
static_assert(test_error<__VA_ARGS__>(fmt, error), "")
// static_assert(test_error<__VA_ARGS__>(fmt, error), "")
TEST(format_test, format_string_errors) {
EXPECT_ERROR_NOARGS("foo", nullptr);