Add detection of wostream operator<< (#650)

This commit is contained in:
Victor Zverovich 2018-02-17 09:03:43 +00:00
parent 1efc15c177
commit 91721caa42
4 changed files with 17 additions and 16 deletions

View File

@ -413,7 +413,7 @@ FMT_CONSTEXPR bool is_arithmetic(type t) {
return t > internal::none_type && t <= internal::last_numeric_type;
}
template <typename T, bool ENABLE = true>
template <typename T, typename Char, bool ENABLE = true>
struct convert_to_int {
enum {
value = !std::is_arithmetic<T>::value && std::is_convertible<T, int>::value
@ -421,8 +421,8 @@ struct convert_to_int {
};
#define FMT_DISABLE_CONVERSION_TO_INT(Type) \
template <> \
struct convert_to_int<Type> { enum { value = 0 }; }
template <typename Char> \
struct convert_to_int<Type, Char> { enum { value = 0 }; }
// Silence warnings about convering float to int.
FMT_DISABLE_CONVERSION_TO_INT(float);
@ -589,13 +589,13 @@ void make_value(const T *p) {
template <typename C, typename T>
inline typename std::enable_if<
convert_to_int<T>::value && std::is_enum<T>::value,
convert_to_int<T, typename C::char_type>::value && std::is_enum<T>::value,
typed_value<C, int_type>>::type
make_value(const T &val) { return static_cast<int>(val); }
template <typename C, typename T>
inline typename std::enable_if<
!convert_to_int<T>::value, typed_value<C, custom_type>>::type
inline typename std::enable_if<!convert_to_int<
T, typename C::char_type>::value, typed_value<C, custom_type>>::type
make_value(const T &val) { return val; }
template <typename C, typename T>

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@ -46,21 +46,22 @@ class FormatBuf : public std::basic_streambuf<Char> {
}
};
struct test_stream : std::ostream {
template <typename Char>
struct test_stream : std::basic_ostream<Char> {
private:
struct null;
// Hide all operator<< from std::ostream.
// Hide all operator<< from std::basic_ostream<Char>.
void operator<<(null);
};
// Disable conversion to int if T has an overloaded operator<< which is a free
// function (not a member of std::ostream).
template <typename T>
class convert_to_int<T, true> {
template <typename T, typename Char>
class convert_to_int<T, Char, true> {
private:
template <typename U>
static decltype(
std::declval<test_stream&>() << std::declval<U>(), std::true_type())
std::declval<test_stream<Char>&>() << std::declval<U>(), std::true_type())
test(int);
template <typename>

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@ -53,7 +53,7 @@ std::ostream &operator<<(std::ostream &os, TestEnum) {
enum TestEnum2 {A};
TEST(OStreamTest, Enum) {
EXPECT_FALSE(fmt::internal::convert_to_int<TestEnum>::value);
EXPECT_FALSE((fmt::internal::convert_to_int<TestEnum, char>::value));
EXPECT_EQ("TestEnum", fmt::format("{}", TestEnum()));
EXPECT_EQ("0", fmt::format("{}", A));
}

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@ -843,15 +843,15 @@ TEST(UtilTest, ReportWindowsError) {
enum TestEnum2 {};
TEST(UtilTest, ConvertToInt) {
EXPECT_FALSE(fmt::internal::convert_to_int<char>::value);
EXPECT_FALSE(fmt::internal::convert_to_int<const char *>::value);
EXPECT_TRUE(fmt::internal::convert_to_int<TestEnum2>::value);
EXPECT_FALSE((fmt::internal::convert_to_int<char, char>::value));
EXPECT_FALSE((fmt::internal::convert_to_int<const char *, char>::value));
EXPECT_TRUE((fmt::internal::convert_to_int<TestEnum2, char>::value));
}
#if FMT_USE_ENUM_BASE
enum TestEnum : char {TestValue};
TEST(UtilTest, IsEnumConvertibleToInt) {
EXPECT_TRUE(fmt::internal::convert_to_int<TestEnum>::value);
EXPECT_TRUE((fmt::internal::convert_to_int<TestEnum, char>::value));
}
#endif