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hashed_string: non-recursive helper (close #400)

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This commit is contained in:
Michele Caini
2020-01-27 22:46:24 +01:00
parent f32f3ab895
commit f36d838df1
1 changed files with 12 additions and 6 deletions
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18
src/entt/core/hashed_string.hpp
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@@ -68,8 +68,14 @@ class basic_hashed_string {
};
// Fowler–Noll–Vo hash function v. 1a - the good
static constexpr ENTT_ID_TYPE helper(ENTT_ID_TYPE partial, const Char *curr) ENTT_NOEXCEPT {
return curr[0] == 0 ? partial : helper((partial^curr[0])*traits_type::prime, curr+1);
static constexpr ENTT_ID_TYPE helper(const Char *curr) ENTT_NOEXCEPT {
auto value = traits_type::offset;
while(*curr != 0) {
value = (value ^ (*(curr++))) * traits_type::prime;
}
return value;
}
public:
@@ -95,7 +101,7 @@ public:
*/
template<std::size_t N>
static constexpr hash_type value(const value_type (&str)[N]) ENTT_NOEXCEPT {
return helper(traits_type::offset, str);
return helper(str);
}
/**
@@ -104,7 +110,7 @@ public:
* @return The numeric representation of the string.
*/
static hash_type value(const_wrapper wrapper) ENTT_NOEXCEPT {
return helper(traits_type::offset, wrapper.str);
return helper(wrapper.str);
}
/**
@@ -140,7 +146,7 @@ public:
*/
template<std::size_t N>
constexpr basic_hashed_string(const value_type (&curr)[N]) ENTT_NOEXCEPT
: str{curr}, hash{helper(traits_type::offset, curr)}
: str{curr}, hash{helper(curr)}
{}
/**
@@ -149,7 +155,7 @@ public:
* @param wrapper Helps achieving the purpose by relying on overloading.
*/
explicit constexpr basic_hashed_string(const_wrapper wrapper) ENTT_NOEXCEPT
: str{wrapper.str}, hash{helper(traits_type::offset, wrapper.str)}
: str{wrapper.str}, hash{helper(wrapper.str)}
{}
/**