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Diffstat (limited to 'include/EASTL/hash_map.h')
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diff --git a/include/EASTL/hash_map.h b/include/EASTL/hash_map.h new file mode 100644 index 0000000..c363597 --- /dev/null +++ b/include/EASTL/hash_map.h @@ -0,0 +1,580 @@ +/////////////////////////////////////////////////////////////////////////////// +// Copyright (c) Electronic Arts Inc. All rights reserved. +/////////////////////////////////////////////////////////////////////////////// + +/////////////////////////////////////////////////////////////////////////////// +// This file is based on the TR1 (technical report 1) reference implementation +// of the unordered_set/unordered_map C++ classes as of about 4/2005. Most likely +// many or all C++ library vendors' implementations of this classes will be +// based off of the reference version and so will look pretty similar to this +// file as well as other vendors' versions. +/////////////////////////////////////////////////////////////////////////////// + + +#ifndef EASTL_HASH_MAP_H +#define EASTL_HASH_MAP_H + + +#include <EASTL/internal/config.h> +#include <EASTL/internal/hashtable.h> +#include <EASTL/functional.h> +#include <EASTL/utility.h> + +#if defined(EA_PRAGMA_ONCE_SUPPORTED) + #pragma once // Some compilers (e.g. VC++) benefit significantly from using this. We've measured 3-4% build speed improvements in apps as a result. +#endif + + + +namespace eastl +{ + + /// EASTL_HASH_MAP_DEFAULT_NAME + /// + /// Defines a default container name in the absence of a user-provided name. + /// + #ifndef EASTL_HASH_MAP_DEFAULT_NAME + #define EASTL_HASH_MAP_DEFAULT_NAME EASTL_DEFAULT_NAME_PREFIX " hash_map" // Unless the user overrides something, this is "EASTL hash_map". + #endif + + + /// EASTL_HASH_MULTIMAP_DEFAULT_NAME + /// + /// Defines a default container name in the absence of a user-provided name. + /// + #ifndef EASTL_HASH_MULTIMAP_DEFAULT_NAME + #define EASTL_HASH_MULTIMAP_DEFAULT_NAME EASTL_DEFAULT_NAME_PREFIX " hash_multimap" // Unless the user overrides something, this is "EASTL hash_multimap". + #endif + + + /// EASTL_HASH_MAP_DEFAULT_ALLOCATOR + /// + #ifndef EASTL_HASH_MAP_DEFAULT_ALLOCATOR + #define EASTL_HASH_MAP_DEFAULT_ALLOCATOR allocator_type(EASTL_HASH_MAP_DEFAULT_NAME) + #endif + + /// EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR + /// + #ifndef EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR + #define EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR allocator_type(EASTL_HASH_MULTIMAP_DEFAULT_NAME) + #endif + + + + /// hash_map + /// + /// Implements a hash_map, which is a hashed associative container. + /// Lookups are O(1) (that is, they are fast) but the container is + /// not sorted. Note that lookups are only O(1) if the hash table + /// is well-distributed (non-colliding). The lookup approaches + /// O(n) behavior as the table becomes increasingly poorly distributed. + /// + /// set_max_load_factor + /// If you want to make a hashtable never increase its bucket usage, + /// call set_max_load_factor with a very high value such as 100000.f. + /// + /// bCacheHashCode + /// We provide the boolean bCacheHashCode template parameter in order + /// to allow the storing of the hash code of the key within the map. + /// When this option is disabled, the rehashing of the table will + /// call the hash function on the key. Setting bCacheHashCode to true + /// is useful for cases whereby the calculation of the hash value for + /// a contained object is very expensive. + /// + /// find_as + /// In order to support the ability to have a hashtable of strings but + /// be able to do efficiently lookups via char pointers (i.e. so they + /// aren't converted to string objects), we provide the find_as + /// function. This function allows you to do a find with a key of a + /// type other than the hashtable key type. + /// + /// Example find_as usage: + /// hash_map<string, int> hashMap; + /// i = hashMap.find_as("hello"); // Use default hash and compare. + /// + /// Example find_as usage (namespaces omitted for brevity): + /// hash_map<string, int> hashMap; + /// i = hashMap.find_as("hello", hash<char*>(), equal_to_2<string, char*>()); + /// + template <typename Key, typename T, typename Hash = eastl::hash<Key>, typename Predicate = eastl::equal_to<Key>, + typename Allocator = EASTLAllocatorType, bool bCacheHashCode = false> + class hash_map + : public hashtable<Key, eastl::pair<const Key, T>, Allocator, eastl::use_first<eastl::pair<const Key, T> >, Predicate, + Hash, mod_range_hashing, default_ranged_hash, prime_rehash_policy, bCacheHashCode, true, true> + { + public: + typedef hashtable<Key, eastl::pair<const Key, T>, Allocator, + eastl::use_first<eastl::pair<const Key, T> >, + Predicate, Hash, mod_range_hashing, default_ranged_hash, + prime_rehash_policy, bCacheHashCode, true, true> base_type; + typedef hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode> this_type; + typedef typename base_type::size_type size_type; + typedef typename base_type::key_type key_type; + typedef T mapped_type; + typedef typename base_type::value_type value_type; // NOTE: 'value_type = pair<const key_type, mapped_type>'. + typedef typename base_type::allocator_type allocator_type; + typedef typename base_type::node_type node_type; + typedef typename base_type::insert_return_type insert_return_type; + typedef typename base_type::iterator iterator; + typedef typename base_type::const_iterator const_iterator; + + using base_type::insert; + + public: + /// hash_map + /// + /// Default constructor. + /// + explicit hash_map(const allocator_type& allocator = EASTL_HASH_MAP_DEFAULT_ALLOCATOR) + : base_type(0, Hash(), mod_range_hashing(), default_ranged_hash(), + Predicate(), eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + /// hash_map + /// + /// Constructor which creates an empty container, but start with nBucketCount buckets. + /// We default to a small nBucketCount value, though the user really should manually + /// specify an appropriate value in order to prevent memory from being reallocated. + /// + explicit hash_map(size_type nBucketCount, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MAP_DEFAULT_ALLOCATOR) + : base_type(nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + hash_map(const this_type& x) + : base_type(x) + { + } + + + hash_map(this_type&& x) + : base_type(eastl::move(x)) + { + } + + + hash_map(this_type&& x, const allocator_type& allocator) + : base_type(eastl::move(x), allocator) + { + } + + + /// hash_map + /// + /// initializer_list-based constructor. + /// Allows for initializing with brace values (e.g. hash_map<int, char*> hm = { {3,"c"}, {4,"d"}, {5,"e"} }; ) + /// + hash_map(std::initializer_list<value_type> ilist, size_type nBucketCount = 0, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MAP_DEFAULT_ALLOCATOR) + : base_type(ilist.begin(), ilist.end(), nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + /// hash_map + /// + /// An input bucket count of <= 1 causes the bucket count to be equal to the number of + /// elements in the input range. + /// + template <typename ForwardIterator> + hash_map(ForwardIterator first, ForwardIterator last, size_type nBucketCount = 0, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MAP_DEFAULT_ALLOCATOR) + : base_type(first, last, nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + this_type& operator=(const this_type& x) + { + return static_cast<this_type&>(base_type::operator=(x)); + } + + + this_type& operator=(std::initializer_list<value_type> ilist) + { + return static_cast<this_type&>(base_type::operator=(ilist)); + } + + + this_type& operator=(this_type&& x) + { + return static_cast<this_type&>(base_type::operator=(eastl::move(x))); + } + + + /// insert + /// + /// This is an extension to the C++ standard. We insert a default-constructed + /// element with the given key. The reason for this is that we can avoid the + /// potentially expensive operation of creating and/or copying a mapped_type + /// object on the stack. + insert_return_type insert(const key_type& key) + { + return base_type::DoInsertKey(true_type(), key); + } + + T& at(const key_type& k) + { + iterator it = base_type::find(k); + + if (it == base_type::end()) + { + #if EASTL_EXCEPTIONS_ENABLED + // throw exeption if exceptions enabled + throw std::out_of_range("invalid hash_map<K, T> key"); + #else + // assert false if asserts enabled + EASTL_ASSERT_MSG(false, "invalid hash_map<K, T> key"); + #endif + } + // undefined behaviour if exceptions and asserts are disabled and it == end() + return it->second; + } + + + const T& at(const key_type& k) const + { + const_iterator it = base_type::find(k); + + if (it == base_type::end()) + { + #if EASTL_EXCEPTIONS_ENABLED + // throw exeption if exceptions enabled + throw std::out_of_range("invalid hash_map<K, T> key"); + #else + // assert false if asserts enabled + EASTL_ASSERT_MSG(false, "invalid hash_map<K, T> key"); + #endif + } + // undefined behaviour if exceptions and asserts are disabled and it == end() + return it->second; + } + + + insert_return_type insert(key_type&& key) + { + return base_type::DoInsertKey(true_type(), eastl::move(key)); + } + + + mapped_type& operator[](const key_type& key) + { + return (*base_type::DoInsertKey(true_type(), key).first).second; + + // Slower reference version: + //const typename base_type::iterator it = base_type::find(key); + //if(it != base_type::end()) + // return (*it).second; + //return (*base_type::insert(value_type(key, mapped_type())).first).second; + } + + mapped_type& operator[](key_type&& key) + { + // The Standard states that this function "inserts the value value_type(std::move(key), mapped_type())" + return (*base_type::DoInsertKey(true_type(), eastl::move(key)).first).second; + } + + + }; // hash_map + + /// hash_map erase_if + /// + /// https://en.cppreference.com/w/cpp/container/unordered_map/erase_if + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode, typename UserPredicate> + void erase_if(eastl::hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& c, UserPredicate predicate) + { + // Erases all elements that satisfy the predicate from the container. + for (auto i = c.begin(), last = c.end(); i != last;) + { + if (predicate(*i)) + { + i = c.erase(i); + } + else + { + ++i; + } + } + } + + + /// hash_multimap + /// + /// Implements a hash_multimap, which is the same thing as a hash_map + /// except that contained elements need not be unique. See the + /// documentation for hash_set for details. + /// + template <typename Key, typename T, typename Hash = eastl::hash<Key>, typename Predicate = eastl::equal_to<Key>, + typename Allocator = EASTLAllocatorType, bool bCacheHashCode = false> + class hash_multimap + : public hashtable<Key, eastl::pair<const Key, T>, Allocator, eastl::use_first<eastl::pair<const Key, T> >, Predicate, + Hash, mod_range_hashing, default_ranged_hash, prime_rehash_policy, bCacheHashCode, true, false> + { + public: + typedef hashtable<Key, eastl::pair<const Key, T>, Allocator, + eastl::use_first<eastl::pair<const Key, T> >, + Predicate, Hash, mod_range_hashing, default_ranged_hash, + prime_rehash_policy, bCacheHashCode, true, false> base_type; + typedef hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode> this_type; + typedef typename base_type::size_type size_type; + typedef typename base_type::key_type key_type; + typedef T mapped_type; + typedef typename base_type::value_type value_type; // Note that this is pair<const key_type, mapped_type>. + typedef typename base_type::allocator_type allocator_type; + typedef typename base_type::node_type node_type; + typedef typename base_type::insert_return_type insert_return_type; + typedef typename base_type::iterator iterator; + + using base_type::insert; + + private: + using base_type::try_emplace; + using base_type::insert_or_assign; + + public: + /// hash_multimap + /// + /// Default constructor. + /// + explicit hash_multimap(const allocator_type& allocator = EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR) + : base_type(0, Hash(), mod_range_hashing(), default_ranged_hash(), + Predicate(), eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + /// hash_multimap + /// + /// Constructor which creates an empty container, but start with nBucketCount buckets. + /// We default to a small nBucketCount value, though the user really should manually + /// specify an appropriate value in order to prevent memory from being reallocated. + /// + explicit hash_multimap(size_type nBucketCount, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR) + : base_type(nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + hash_multimap(const this_type& x) + : base_type(x) + { + } + + + hash_multimap(this_type&& x) + : base_type(eastl::move(x)) + { + } + + + hash_multimap(this_type&& x, const allocator_type& allocator) + : base_type(eastl::move(x), allocator) + { + } + + + /// hash_multimap + /// + /// initializer_list-based constructor. + /// Allows for initializing with brace values (e.g. hash_multimap<int, char*> hm = { {3,"c"}, {3,"C"}, {4,"d"} }; ) + /// + hash_multimap(std::initializer_list<value_type> ilist, size_type nBucketCount = 0, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR) + : base_type(ilist.begin(), ilist.end(), nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + /// hash_multimap + /// + /// An input bucket count of <= 1 causes the bucket count to be equal to the number of + /// elements in the input range. + /// + template <typename ForwardIterator> + hash_multimap(ForwardIterator first, ForwardIterator last, size_type nBucketCount = 0, const Hash& hashFunction = Hash(), + const Predicate& predicate = Predicate(), const allocator_type& allocator = EASTL_HASH_MULTIMAP_DEFAULT_ALLOCATOR) + : base_type(first, last, nBucketCount, hashFunction, mod_range_hashing(), default_ranged_hash(), + predicate, eastl::use_first<eastl::pair<const Key, T> >(), allocator) + { + // Empty + } + + + this_type& operator=(const this_type& x) + { + return static_cast<this_type&>(base_type::operator=(x)); + } + + + this_type& operator=(std::initializer_list<value_type> ilist) + { + return static_cast<this_type&>(base_type::operator=(ilist)); + } + + + this_type& operator=(this_type&& x) + { + return static_cast<this_type&>(base_type::operator=(eastl::move(x))); + } + + + /// insert + /// + /// This is an extension to the C++ standard. We insert a default-constructed + /// element with the given key. The reason for this is that we can avoid the + /// potentially expensive operation of creating and/or copying a mapped_type + /// object on the stack. + insert_return_type insert(const key_type& key) + { + return base_type::DoInsertKey(false_type(), key); + } + + + insert_return_type insert(key_type&& key) + { + return base_type::DoInsertKey(false_type(), eastl::move(key)); + } + + }; // hash_multimap + + /// hash_multimap erase_if + /// + /// https://en.cppreference.com/w/cpp/container/unordered_multimap/erase_if + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode, typename UserPredicate> + void erase_if(eastl::hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& c, UserPredicate predicate) + { + // Erases all elements that satisfy the predicate from the container. + for (auto i = c.begin(), last = c.end(); i != last;) + { + if (predicate(*i)) + { + i = c.erase(i); + } + else + { + ++i; + } + } + } + + + + /////////////////////////////////////////////////////////////////////// + // global operators + /////////////////////////////////////////////////////////////////////// + + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode> + inline bool operator==(const hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& a, + const hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& b) + { + typedef typename hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>::const_iterator const_iterator; + + // We implement branching with the assumption that the return value is usually false. + if(a.size() != b.size()) + return false; + + // For map (with its unique keys), we need only test that each element in a can be found in b, + // as there can be only one such pairing per element. multimap needs to do a something more elaborate. + for(const_iterator ai = a.begin(), aiEnd = a.end(), biEnd = b.end(); ai != aiEnd; ++ai) + { + const_iterator bi = b.find(ai->first); + + if((bi == biEnd) || !(*ai == *bi)) // We have to compare the values, because lookups are done by keys alone but the full value_type of a map is a key/value pair. + return false; // It's possible that two elements in the two containers have identical keys but different values. + } + + return true; + } + + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode> + inline bool operator!=(const hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& a, + const hash_map<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& b) + { + return !(a == b); + } + + + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode> + inline bool operator==(const hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& a, + const hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& b) + { + typedef typename hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>::const_iterator const_iterator; + typedef typename eastl::iterator_traits<const_iterator>::difference_type difference_type; + + // We implement branching with the assumption that the return value is usually false. + if(a.size() != b.size()) + return false; + + // We can't simply search for each element of a in b, as it may be that the bucket for + // two elements in a has those same two elements in b but in different order (which should + // still result in equality). Also it's possible that one bucket in a has two elements which + // both match a solitary element in the equivalent bucket in b (which shouldn't result in equality). + eastl::pair<const_iterator, const_iterator> aRange; + eastl::pair<const_iterator, const_iterator> bRange; + + for(const_iterator ai = a.begin(), aiEnd = a.end(); ai != aiEnd; ai = aRange.second) // For each element in a... + { + aRange = a.equal_range(ai->first); // Get the range of elements in a that are equal to ai. + bRange = b.equal_range(ai->first); // Get the range of elements in b that are equal to ai. + + // We need to verify that aRange == bRange. First make sure the range sizes are equivalent... + const difference_type aDistance = eastl::distance(aRange.first, aRange.second); + const difference_type bDistance = eastl::distance(bRange.first, bRange.second); + + if(aDistance != bDistance) + return false; + + // At this point, aDistance > 0 and aDistance == bDistance. + // Implement a fast pathway for the case that there's just a single element. + if(aDistance == 1) + { + if(!(*aRange.first == *bRange.first)) // We have to compare the values, because lookups are done by keys alone but the full value_type of a map is a key/value pair. + return false; // It's possible that two elements in the two containers have identical keys but different values. Ditto for the permutation case below. + } + else + { + // Check to see if these aRange and bRange are any permutation of each other. + // This check gets slower as there are more elements in the range. + if(!eastl::is_permutation(aRange.first, aRange.second, bRange.first)) + return false; + } + } + + return true; + } + + template <typename Key, typename T, typename Hash, typename Predicate, typename Allocator, bool bCacheHashCode> + inline bool operator!=(const hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& a, + const hash_multimap<Key, T, Hash, Predicate, Allocator, bCacheHashCode>& b) + { + return !(a == b); + } + + +} // namespace eastl + + +#endif // Header include guard + + + + + + |