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ircd: Add template for constexpr literal overloads.

This commit is contained in:
Jason Volk 2020-08-04 17:06:27 -07:00
parent 7b335a8285
commit 541997ab9d

View file

@ -16,7 +16,10 @@ namespace ircd
struct string_view;
constexpr size_t _constexpr_strlen(const char *) noexcept;
template<size_t N> constexpr size_t _constexpr_strlen(const char (&)[N]) noexcept;
constexpr bool _constexpr_equal(const char *a, const char *b) noexcept;
template<size_t N0, size_t N1> constexpr bool _constexpr_equal(const char (&)[N0], const char (&)[N1]) noexcept;
constexpr const char *data(const string_view &) noexcept;
constexpr size_t size(const string_view &) noexcept;
@ -270,17 +273,44 @@ noexcept
return str.data();
}
/// Compile-time comparison of string literals
///
template<size_t N0,
size_t N1>
constexpr bool
ircd::_constexpr_equal(const char *a,
const char *b)
ircd::_constexpr_equal(const char (&a)[N0],
const char (&b)[N1])
noexcept
{
if constexpr(_constexpr_strlen(a) != _constexpr_strlen(b))
return false;
for(size_t i(0); i < _constexpr_strlen(a); ++i)
if constexpr(a[i] != b[i])
return false;
return true;
}
constexpr bool
ircd::_constexpr_equal(const char *const a,
const char *const b)
noexcept
{
return *a == *b && (*a == '\0' || _constexpr_equal(a + 1, b + 1));
}
[[gnu::pure]]
template<size_t N>
constexpr size_t
ircd::_constexpr_strlen(const char (&a)[N])
noexcept
{
size_t i(0);
while(i < N)
if constexpr(a[i] == '\0')
return i;
return N;
}
constexpr size_t
ircd::_constexpr_strlen(const char *const s)
noexcept