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Make parse_format_string constexpr

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This commit is contained in:
Victor Zverovich 2017-10-29 07:32:14 -07:00
parent e926ae78ac
commit db9ffa1405
2 changed files with 43 additions and 7 deletions
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18
include/fmt/format.h
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@ -3519,7 +3519,7 @@ constexpr Iterator parse_format_specs(Iterator it, SpecHandler &handler) {
}
template <typename Iterator, typename Handler>
void parse_format_string(Iterator it, Handler &handler) {
constexpr void parse_format_string(Iterator it, Handler &handler) {
using char_type = typename std::iterator_traits<Iterator>::value_type;
auto start = it;
while (*it) {
@ -3530,20 +3530,24 @@ void parse_format_string(Iterator it, Handler &handler) {
start = ++it;
continue;
}
if (ch == '}')
if (ch == '}') {
handler.on_error("unmatched '}' in format string");
return;
}
handler.on_text(start, it - 1);
struct id_adapter {
explicit id_adapter(Handler &h): handler(h) {}
constexpr explicit id_adapter(Handler &h): handler(h) {}
void operator()() { handler.on_arg_id(); }
void operator()(unsigned id) { handler.on_arg_id(id); }
void operator()(basic_string_view<char_type> id) {
constexpr void operator()() { handler.on_arg_id(); }
constexpr void operator()(unsigned id) { handler.on_arg_id(id); }
constexpr void operator()(basic_string_view<char_type> id) {
handler.on_arg_id(id);
}
void on_error(const char *message) { handler.on_error(message); }
constexpr void on_error(const char *message) {
handler.on_error(message);
}
Handler &handler;
} adapter(handler);

32
test/format-test.cc
View File

@ -1780,3 +1780,35 @@ TEST(FormatTest, ConstexprSpecsChecker) {
static_assert(check_specs("d").type == 'd', "");
static_assert(check_specs("{<").res == handler::ERROR, "");
}
struct test_format_string_handler {
constexpr void on_text(const char *, const char *) {}
constexpr void on_arg_id() {}
template <typename T>
constexpr void on_arg_id(T) {}
constexpr void on_replacement_field(const char *) {}
constexpr const char *on_format_specs(const char *s) { return s; }
constexpr void on_error(const char *) { error = true; }
bool error = false;
};
constexpr bool parse_string(const char *s) {
test_format_string_handler h;
fmt::internal::parse_format_string(s, h);
return !h.error;
}
TEST(FormatTest, ConstexprParseFormatString) {
static_assert(parse_string("foo"), "");
static_assert(!parse_string("}"), "");
static_assert(parse_string("{}"), "");
static_assert(parse_string("{42}"), "");
static_assert(parse_string("{foo}"), "");
static_assert(parse_string("{:}"), "");
}