common/hash: Remove unused HashableStruct
This is unused, so it can be removed. There's better ways of ensuring zeroed out padding bits, like using zero-initialization, anyhow.
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@ -35,41 +35,6 @@ static inline u64 ComputeStructHash64(const T& data) {
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return ComputeHash64(&data, sizeof(data));
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}
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/// A helper template that ensures the padding in a struct is initialized by memsetting to 0.
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template <typename T>
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struct HashableStruct {
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// In addition to being trivially copyable, T must also have a trivial default constructor,
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// because any member initialization would be overridden by memset
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static_assert(std::is_trivial_v<T>, "Type passed to HashableStruct must be trivial");
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/*
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* We use a union because "implicitly-defined copy/move constructor for a union X copies the
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* object representation of X." and "implicitly-defined copy assignment operator for a union X
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* copies the object representation (3.9) of X." = Bytewise copy instead of memberwise copy.
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* This is important because the padding bytes are included in the hash and comparison between
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* objects.
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*/
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union {
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T state;
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};
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HashableStruct() {
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// Memset structure to zero padding bits, so that they will be deterministic when hashing
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std::memset(&state, 0, sizeof(T));
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}
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bool operator==(const HashableStruct<T>& o) const {
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return std::memcmp(&state, &o.state, sizeof(T)) == 0;
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};
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bool operator!=(const HashableStruct<T>& o) const {
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return !(*this == o);
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};
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std::size_t Hash() const {
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return Common::ComputeStructHash64(state);
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}
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};
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struct PairHash {
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template <class T1, class T2>
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std::size_t operator()(const std::pair<T1, T2>& pair) const noexcept {
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