hashmap_base.h | Explore in Territory

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#ifndef SRC_TINT_UTILS_CONTAINERS_HASHMAP_BASE_H_
#define SRC_TINT_UTILS_CONTAINERS_HASHMAP_BASE_H_

#include <algorithm>
#include <functional>
#include <optional>
#include <tuple>
#include <utility>

#include "src/tint/utils/containers/vector.h"
#include "src/tint/utils/ice/ice.h"
#include "src/tint/utils/math/hash.h"
#include "src/tint/utils/math/math.h"
#include "src/tint/utils/memory/aligned_storage.h"
#include "src/tint/utils/traits/traits.h"

namespace tint {

/// HashmapKey wraps the comparator type for a Hashmap and Hashset.
/// HashmapKey acts like a read-only `T`, but can be reassigned so long as the value is equivalent.
/// @tparam T the key comparator type.
/// @tparam HASH the hash function for the key type.
/// @tparam EQUAL the equality function for the key type.
template <typename T, typename HASH = Hasher<T>, typename EQUAL = std::equal_to<T>>
class HashmapKey {
    T value_;

  public:
    /// Key is an alias to this templated class.
    using Key = HashmapKey<T, HASH, EQUAL>;
    /// Hash is an alias to the hash function for the key type.
    using Hash = HASH;
    /// Equal is an alias to the equality function for the key type.
    using Equal = EQUAL;

    /// KeyOf() returns @p key, so a HashmapKey can be used as the entry type for a Hashset.
    /// @param key the HashmapKey
    /// @return @p key
    static const Key& KeyOf(const Key& key) { … }

    /// Constructor using copied value.
    /// @param value the key value.
    HashmapKey(const T& value) : … { … }  // NOLINT

    /// Constructor using moved value.
    /// @param value the key value.
    HashmapKey(T&& value) : … { … }  // NOLINT

    /// Constructor using pre-computed hash and copied value.
    /// @param hash_ the precomputed hash of @p value
    /// @param value the key value
    HashmapKey(HashCode hash_, const T& value) : … { … }

    /// Constructor using pre-computed hash and moved value.
    /// @param hash_ the precomputed hash of @p value
    /// @param value the key value
    HashmapKey(HashCode hash_, T&& value) : … { … }

    /// Copy constructor
    HashmapKey(const HashmapKey&) = default;

    /// Move constructor
    HashmapKey(HashmapKey&&) = default;

    /// Destructor
    ~HashmapKey() = default;

    /// Copy-assignment operator.
    /// @note As a hashmap uses the HashmapKey for indexing, the new value *must* have the same hash
    /// value and be equal to this key.
    /// @param other the key to copy to this key.
    /// @return this HashmapKey.
    HashmapKey& operator=(const HashmapKey& other) { … }

    /// Move-assignment operator.
    /// @note As a hashmap uses the HashmapKey for indexing, the new value *must* have the same hash
    /// value and be equal to this key.
    /// @param other the key to move to this key.
    /// @return this HashmapKey.
    HashmapKey& operator=(HashmapKey&& other) { … }

    /// Equality operator
    /// @param other the other key.
    /// @return true if the hash and value of @p other are equal to this key.
    bool operator==(const HashmapKey& other) const { … }

    /// Equality operator
    /// @param other the other key.
    /// @return true if the hash of other and value of @p other are equal to this key.
    template <typename RHS>
    bool operator==(const RHS& other) const { … }

    /// @returns the value of the key
    const T& Value() const { … }

    /// @returns the value of the key
    operator const T&() const { return value_; }

    /// @returns the pointer to the value, or the value itself if T is a pointer.
    auto operator->() const { … }

    /// The hash of value
    const HashCode hash;
};

/// Writes the HashmapKey to the stream.
/// @param out the stream to write to
/// @param key the HashmapKey to write
/// @returns out so calls can be chained
template <typename STREAM, typename T, typename = traits::EnableIfIsOStream<STREAM>>
auto& operator<<(STREAM& out, const HashmapKey<T>& key) { … }

/// HashmapBase is the base class for Hashmap and Hashset.
/// @tparam ENTRY is the single record in the map. The entry type must alias 'Key' to the HashmapKey
/// type, and implement the method `static HashmapKey<...> KeyOf(ENTRY)` to return the key for the
/// entry.
template <typename ENTRY, size_t N>
class HashmapBase { … };

}  // namespace tint

#endif  // SRC_TINT_UTILS_CONTAINERS_HASHMAP_BASE_H_
chromium/third_party/dawn/src/tint/utils/containers/hashmap_base.h
