Initial commit

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/.clang-format

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+DisableFormat: true
+SortIncludes: false

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/robin_growth_policy.h

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+/**
+ * MIT License
+ * 
+ * Copyright (c) 2017 Tessil
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_ROBIN_GROWTH_POLICY_H
+#define TSL_ROBIN_GROWTH_POLICY_H 
+
+
+#include <algorithm>
+#include <array>
+#include <climits>
+#include <cmath>
+#include <cstddef>
+#include <iterator>
+#include <limits>
+#include <ratio>
+#include <stdexcept>
+
+
+#ifndef tsl_assert
+#    ifdef TSL_DEBUG
+#        define tsl_assert(expr) assert(expr)
+#    else
+#        define tsl_assert(expr) (static_cast<void>(0))
+#    endif
+#endif
+
+
+/**
+ * If exceptions are enabled, throw the exception passed in parameter, otherwise call std::terminate.
+ */
+#ifndef TSL_THROW_OR_TERMINATE
+#    if (defined(__cpp_exceptions) || defined(__EXCEPTIONS) || (defined (_MSC_VER) && defined (_CPPUNWIND))) && !defined(TSL_NO_EXCEPTIONS)
+#        define TSL_THROW_OR_TERMINATE(ex, msg) throw ex(msg)
+#    else
+#        ifdef NDEBUG
+#            define TSL_THROW_OR_TERMINATE(ex, msg) std::terminate()
+#        else
+#            include <cstdio>
+#            define TSL_THROW_OR_TERMINATE(ex, msg) do { std::fprintf(stderr, msg); std::terminate(); } while(0)
+#        endif
+#    endif
+#endif
+
+
+#ifndef TSL_LIKELY
+#   if defined(__GNUC__) || defined(__clang__)
+#       define TSL_LIKELY(exp) (__builtin_expect(!!(exp), true))
+#   else
+#       define TSL_LIKELY(exp) (exp)
+#   endif
+#endif
+
+
+namespace tsl {
+namespace rh {
+    
+/**
+ * Grow the hash table by a factor of GrowthFactor keeping the bucket count to a power of two. It allows
+ * the table to use a mask operation instead of a modulo operation to map a hash to a bucket.
+ * 
+ * GrowthFactor must be a power of two >= 2.
+ */
+template<std::size_t GrowthFactor>
+class power_of_two_growth_policy {
+public:
+    /**
+     * Called on the hash table creation and on rehash. The number of buckets for the table is passed in parameter.
+     * This number is a minimum, the policy may update this value with a higher value if needed (but not lower).
+     *
+     * If 0 is given, min_bucket_count_in_out must still be 0 after the policy creation and
+     * bucket_for_hash must always return 0 in this case.
+     */
+    explicit power_of_two_growth_policy(std::size_t& min_bucket_count_in_out) {
+        if(min_bucket_count_in_out > max_bucket_count()) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        if(min_bucket_count_in_out > 0) {
+            min_bucket_count_in_out = round_up_to_power_of_two(min_bucket_count_in_out);
+            m_mask = min_bucket_count_in_out - 1;
+        }
+        else {
+            m_mask = 0;
+        }
+    }
+    
+    /**
+     * Return the bucket [0, bucket_count()) to which the hash belongs. 
+     * If bucket_count() is 0, it must always return 0.
+     */
+    std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+        return hash & m_mask;
+    }
+    
+    /**
+     * Return the number of buckets that should be used on next growth.
+     */
+    std::size_t next_bucket_count() const {
+        if((m_mask + 1) > max_bucket_count() / GrowthFactor) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        return (m_mask + 1) * GrowthFactor;
+    }
+    
+    /**
+     * Return the maximum number of buckets supported by the policy.
+     */
+    std::size_t max_bucket_count() const {
+        // Largest power of two.
+        return ((std::numeric_limits<std::size_t>::max)() / 2) + 1;
+    }
+    
+    /**
+     * Reset the growth policy as if it was created with a bucket count of 0.
+     * After a clear, the policy must always return 0 when bucket_for_hash is called.
+     */
+    void clear() noexcept {
+        m_mask = 0;
+    }
+    
+private:
+    static std::size_t round_up_to_power_of_two(std::size_t value) {
+        if(is_power_of_two(value)) {
+            return value;
+        }
+        
+        if(value == 0) {
+            return 1;
+        }
+            
+        --value;
+        for(std::size_t i = 1; i < sizeof(std::size_t) * CHAR_BIT; i *= 2) {
+            value |= value >> i;
+        }
+        
+        return value + 1;
+    }
+    
+    static constexpr bool is_power_of_two(std::size_t value) {
+        return value != 0 && (value & (value - 1)) == 0;
+    }
+    
+protected:
+    static_assert(is_power_of_two(GrowthFactor) && GrowthFactor >= 2, "GrowthFactor must be a power of two >= 2.");
+    
+    std::size_t m_mask;
+};
+
+
+/**
+ * Grow the hash table by GrowthFactor::num / GrowthFactor::den and use a modulo to map a hash
+ * to a bucket. Slower but it can be useful if you want a slower growth.
+ */
+template<class GrowthFactor = std::ratio<3, 2>>
+class mod_growth_policy {
+public:
+    explicit mod_growth_policy(std::size_t& min_bucket_count_in_out) {
+        if(min_bucket_count_in_out > max_bucket_count()) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        if(min_bucket_count_in_out > 0) {
+            m_mod = min_bucket_count_in_out;
+        }
+        else {
+            m_mod = 1;
+        }
+    }
+    
+    std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+        return hash % m_mod;
+    }
+    
+    std::size_t next_bucket_count() const {
+        if(m_mod == max_bucket_count()) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        const double next_bucket_count = std::ceil(double(m_mod) * REHASH_SIZE_MULTIPLICATION_FACTOR);
+        if(!std::isnormal(next_bucket_count)) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        if(next_bucket_count > double(max_bucket_count())) {
+            return max_bucket_count();
+        }
+        else {
+            return std::size_t(next_bucket_count);
+        }
+    }
+    
+    std::size_t max_bucket_count() const {
+        return MAX_BUCKET_COUNT;
+    }
+    
+    void clear() noexcept {
+        m_mod = 1;
+    }
+    
+private:
+    static constexpr double REHASH_SIZE_MULTIPLICATION_FACTOR = 1.0 * GrowthFactor::num / GrowthFactor::den;
+    static const std::size_t MAX_BUCKET_COUNT = 
+            std::size_t(double(
+                    (std::numeric_limits<std::size_t>::max)() / REHASH_SIZE_MULTIPLICATION_FACTOR
+            ));
+            
+    static_assert(REHASH_SIZE_MULTIPLICATION_FACTOR >= 1.1, "Growth factor should be >= 1.1.");
+    
+    std::size_t m_mod;
+};
+
+
+
+namespace detail {
+
+static constexpr const std::array<std::size_t, 40> PRIMES = {{
+    1ul, 5ul, 17ul, 29ul, 37ul, 53ul, 67ul, 79ul, 97ul, 131ul, 193ul, 257ul, 389ul, 521ul, 769ul, 1031ul, 
+    1543ul, 2053ul, 3079ul, 6151ul, 12289ul, 24593ul, 49157ul, 98317ul, 196613ul, 393241ul, 786433ul, 
+    1572869ul, 3145739ul, 6291469ul, 12582917ul, 25165843ul, 50331653ul, 100663319ul, 201326611ul, 
+    402653189ul, 805306457ul, 1610612741ul, 3221225473ul, 4294967291ul
+}};
+
+template<unsigned int IPrime>
+static constexpr std::size_t mod(std::size_t hash) { return hash % PRIMES[IPrime]; }
+
+// MOD_PRIME[iprime](hash) returns hash % PRIMES[iprime]. This table allows for faster modulo as the
+// compiler can optimize the modulo code better with a constant known at the compilation.
+static constexpr const std::array<std::size_t(*)(std::size_t), 40> MOD_PRIME = {{ 
+    &mod<0>, &mod<1>, &mod<2>, &mod<3>, &mod<4>, &mod<5>, &mod<6>, &mod<7>, &mod<8>, &mod<9>, &mod<10>, 
+    &mod<11>, &mod<12>, &mod<13>, &mod<14>, &mod<15>, &mod<16>, &mod<17>, &mod<18>, &mod<19>, &mod<20>, 
+    &mod<21>, &mod<22>, &mod<23>, &mod<24>, &mod<25>, &mod<26>, &mod<27>, &mod<28>, &mod<29>, &mod<30>, 
+    &mod<31>, &mod<32>, &mod<33>, &mod<34>, &mod<35>, &mod<36>, &mod<37> , &mod<38>, &mod<39>
+}};
+
+}
+
+/**
+ * Grow the hash table by using prime numbers as bucket count. Slower than tsl::rh::power_of_two_growth_policy in  
+ * general but will probably distribute the values around better in the buckets with a poor hash function.
+ * 
+ * To allow the compiler to optimize the modulo operation, a lookup table is used with constant primes numbers.
+ * 
+ * With a switch the code would look like:
+ * \code
+ * switch(iprime) { // iprime is the current prime of the hash table
+ *     case 0: hash % 5ul;
+ *             break;
+ *     case 1: hash % 17ul;
+ *             break;
+ *     case 2: hash % 29ul;
+ *             break;
+ *     ...
+ * }    
+ * \endcode
+ * 
+ * Due to the constant variable in the modulo the compiler is able to optimize the operation
+ * by a series of multiplications, substractions and shifts. 
+ * 
+ * The 'hash % 5' could become something like 'hash - (hash * 0xCCCCCCCD) >> 34) * 5' in a 64 bits environement.
+ */
+class prime_growth_policy {
+public:
+    explicit prime_growth_policy(std::size_t& min_bucket_count_in_out) {
+        auto it_prime = std::lower_bound(detail::PRIMES.begin(), 
+                                         detail::PRIMES.end(), min_bucket_count_in_out);
+        if(it_prime == detail::PRIMES.end()) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        m_iprime = static_cast<unsigned int>(std::distance(detail::PRIMES.begin(), it_prime));
+        if(min_bucket_count_in_out > 0) {
+            min_bucket_count_in_out = *it_prime;
+        }
+        else {
+            min_bucket_count_in_out = 0;
+        }
+    }
+    
+    std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+        return detail::MOD_PRIME[m_iprime](hash);
+    }
+    
+    std::size_t next_bucket_count() const {
+        if(m_iprime + 1 >= detail::PRIMES.size()) {
+            TSL_THROW_OR_TERMINATE(std::length_error, "The hash table exceeds its maxmimum size.");
+        }
+        
+        return detail::PRIMES[m_iprime + 1];
+    }   
+    
+    std::size_t max_bucket_count() const {
+        return detail::PRIMES.back();
+    }
+    
+    void clear() noexcept {
+        m_iprime = 0;
+    }
+    
+private:
+    unsigned int m_iprime;
+    
+    static_assert((std::numeric_limits<decltype(m_iprime)>::max)() >= detail::PRIMES.size(), 
+                  "The type of m_iprime is not big enough.");
+}; 
+
+}
+}
+
+#endif

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/robin_map.h

@@ -0,0 +1,668 @@
+/**
+ * MIT License
+ * 
+ * Copyright (c) 2017 Tessil
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_ROBIN_MAP_H
+#define TSL_ROBIN_MAP_H 
+
+
+#include <cstddef>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include "robin_hash.h"
+
+
+namespace tsl {
+
+    
+/**
+ * Implementation of a hash map using open-adressing and the robin hood hashing algorithm with backward shift deletion.
+ * 
+ * For operations modifying the hash map (insert, erase, rehash, ...), the strong exception guarantee 
+ * is only guaranteed when the expression `std::is_nothrow_swappable<std::pair<Key, T>>::value &&
+ * std::is_nothrow_move_constructible<std::pair<Key, T>>::value` is true, otherwise if an exception
+ * is thrown during the swap or the move, the hash map may end up in a undefined state. Per the standard
+ * a `Key` or `T` with a noexcept copy constructor and no move constructor also satisfies the 
+ * `std::is_nothrow_move_constructible<std::pair<Key, T>>::value` criterion (and will thus guarantee the 
+ * strong exception for the map).
+ * 
+ * When `StoreHash` is true, 32 bits of the hash are stored alongside the values. It can improve 
+ * the performance during lookups if the `KeyEqual` function takes time (if it engenders a cache-miss for example) 
+ * as we then compare the stored hashes before comparing the keys. When `tsl::rh::power_of_two_growth_policy` is used
+ * as `GrowthPolicy`, it may also speed-up the rehash process as we can avoid to recalculate the hash. 
+ * When it is detected that storing the hash will not incur any memory penality due to alignement (i.e. 
+ * `sizeof(tsl::detail_robin_hash::bucket_entry<ValueType, true>) == 
+ * sizeof(tsl::detail_robin_hash::bucket_entry<ValueType, false>)`) and `tsl::rh::power_of_two_growth_policy` is
+ * used, the hash will be stored even if `StoreHash` is false so that we can speed-up the rehash (but it will
+ * not be used on lookups unless `StoreHash` is true).
+ * 
+ * `GrowthPolicy` defines how the map grows and consequently how a hash value is mapped to a bucket. 
+ * By default the map uses `tsl::rh::power_of_two_growth_policy`. This policy keeps the number of buckets 
+ * to a power of two and uses a mask to map the hash to a bucket instead of the slow modulo.
+ * Other growth policies are available and you may define your own growth policy, 
+ * check `tsl::rh::power_of_two_growth_policy` for the interface.
+ * 
+ * If the destructor of `Key` or `T` throws an exception, the behaviour of the class is undefined.
+ * 
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators.
+ *  - insert, emplace, emplace_hint, operator[]: if there is an effective insert, invalidate the iterators.
+ *  - erase: always invalidate the iterators.
+ */
+template<class Key, 
+         class T, 
+         class Hash = std::hash<Key>,
+         class KeyEqual = std::equal_to<Key>,
+         class Allocator = std::allocator<std::pair<Key, T>>,
+         bool StoreHash = false,
+         class GrowthPolicy = tsl::rh::power_of_two_growth_policy<2>>
+class robin_map {
+private:
+    template<typename U>
+    using has_is_transparent = tsl::detail_robin_hash::has_is_transparent<U>;
+    
+    class KeySelect {
+    public:
+        using key_type = Key;
+        
+        const key_type& operator()(const std::pair<Key, T>& key_value) const noexcept {
+            return key_value.first;
+        }
+        
+        key_type& operator()(std::pair<Key, T>& key_value) noexcept {
+            return key_value.first;
+        }
+    };  
+    
+    class ValueSelect {
+    public:
+        using value_type = T;
+        
+        const value_type& operator()(const std::pair<Key, T>& key_value) const noexcept {
+            return key_value.second;
+        }
+        
+        value_type& operator()(std::pair<Key, T>& key_value) noexcept {
+            return key_value.second;
+        }
+    };
+    
+    using ht = detail_robin_hash::robin_hash<std::pair<Key, T>, KeySelect, ValueSelect,
+                                             Hash, KeyEqual, Allocator, StoreHash, GrowthPolicy>;  
+                                             
+public:
+    using key_type = typename ht::key_type;
+    using mapped_type = T;
+    using value_type = typename ht::value_type;
+    using size_type = typename ht::size_type;
+    using difference_type = typename ht::difference_type;
+    using hasher = typename ht::hasher;
+    using key_equal = typename ht::key_equal;
+    using allocator_type = typename ht::allocator_type;
+    using reference = typename ht::reference;
+    using const_reference = typename ht::const_reference;
+    using pointer = typename ht::pointer;
+    using const_pointer = typename ht::const_pointer;
+    using iterator = typename ht::iterator;
+    using const_iterator = typename ht::const_iterator;
+    
+    
+public:
+    /*
+     * Constructors
+     */
+    robin_map(): robin_map(ht::DEFAULT_INIT_BUCKETS_SIZE) {
+    }
+    
+    explicit robin_map(size_type bucket_count, 
+                       const Hash& hash = Hash(),
+                       const KeyEqual& equal = KeyEqual(),
+                       const Allocator& alloc = Allocator()): 
+                m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR)
+    {
+    }
+    
+    robin_map(size_type bucket_count,
+              const Allocator& alloc): robin_map(bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+    
+    robin_map(size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): robin_map(bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+    
+    explicit robin_map(const Allocator& alloc): robin_map(ht::DEFAULT_INIT_BUCKETS_SIZE, alloc) {
+    }
+    
+    template<class InputIt>
+    robin_map(InputIt first, InputIt last,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(),
+              const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator()): robin_map(bucket_count, hash, equal, alloc)
+    {
+        insert(first, last);
+    }
+    
+    template<class InputIt>
+    robin_map(InputIt first, InputIt last,
+              size_type bucket_count,
+              const Allocator& alloc): robin_map(first, last, bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+    
+    template<class InputIt>
+    robin_map(InputIt first, InputIt last,
+              size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): robin_map(first, last, bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+
+    robin_map(std::initializer_list<value_type> init,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(),
+              const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator()): 
+          robin_map(init.begin(), init.end(), bucket_count, hash, equal, alloc)
+    {
+    }
+
+    robin_map(std::initializer_list<value_type> init,
+              size_type bucket_count,
+              const Allocator& alloc): 
+          robin_map(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+
+    robin_map(std::initializer_list<value_type> init,
+              size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): 
+          robin_map(init.begin(), init.end(), bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+    
+    robin_map& operator=(std::initializer_list<value_type> ilist) {
+        m_ht.clear();
+        
+        m_ht.reserve(ilist.size());
+        m_ht.insert(ilist.begin(), ilist.end());
+        
+        return *this;
+    }
+    
+    allocator_type get_allocator() const { return m_ht.get_allocator(); }
+    
+    
+    /*
+     * Iterators
+     */
+    iterator begin() noexcept { return m_ht.begin(); }
+    const_iterator begin() const noexcept { return m_ht.begin(); }
+    const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+    
+    iterator end() noexcept { return m_ht.end(); }
+    const_iterator end() const noexcept { return m_ht.end(); }
+    const_iterator cend() const noexcept { return m_ht.cend(); }
+    
+    
+    /*
+     * Capacity
+     */
+    bool empty() const noexcept { return m_ht.empty(); }
+    size_type size() const noexcept { return m_ht.size(); }
+    size_type max_size() const noexcept { return m_ht.max_size(); }
+    
+    /*
+     * Modifiers
+     */
+    void clear() noexcept { m_ht.clear(); }
+    
+    
+    
+    std::pair<iterator, bool> insert(const value_type& value) { 
+        return m_ht.insert(value); 
+    }
+        
+    template<class P, typename std::enable_if<std::is_constructible<value_type, P&&>::value>::type* = nullptr>
+    std::pair<iterator, bool> insert(P&& value) { 
+        return m_ht.emplace(std::forward<P>(value)); 
+    }
+    
+    std::pair<iterator, bool> insert(value_type&& value) { 
+        return m_ht.insert(std::move(value)); 
+    }
+    
+    
+    iterator insert(const_iterator hint, const value_type& value) { 
+        return m_ht.insert(hint, value); 
+    }
+        
+    template<class P, typename std::enable_if<std::is_constructible<value_type, P&&>::value>::type* = nullptr>
+    iterator insert(const_iterator hint, P&& value) { 
+        return m_ht.emplace_hint(hint, std::forward<P>(value));
+    }
+    
+    iterator insert(const_iterator hint, value_type&& value) { 
+        return m_ht.insert(hint, std::move(value)); 
+    }
+    
+    
+    template<class InputIt>
+    void insert(InputIt first, InputIt last) { 
+        m_ht.insert(first, last); 
+    }
+    
+    void insert(std::initializer_list<value_type> ilist) { 
+        m_ht.insert(ilist.begin(), ilist.end()); 
+    }
+
+    
+    
+    
+    template<class M>
+    std::pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj) { 
+        return m_ht.insert_or_assign(k, std::forward<M>(obj)); 
+    }
+
+    template<class M>
+    std::pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj) { 
+        return m_ht.insert_or_assign(std::move(k), std::forward<M>(obj)); 
+    }
+    
+    template<class M>
+    iterator insert_or_assign(const_iterator hint, const key_type& k, M&& obj) {
+        return m_ht.insert_or_assign(hint, k, std::forward<M>(obj));
+    }
+    
+    template<class M>
+    iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj) {
+        return m_ht.insert_or_assign(hint, std::move(k), std::forward<M>(obj));
+    }
+    
+    
+    
+    /**
+     * Due to the way elements are stored, emplace will need to move or copy the key-value once.
+     * The method is equivalent to insert(value_type(std::forward<Args>(args)...));
+     * 
+     * Mainly here for compatibility with the std::unordered_map interface.
+     */
+    template<class... Args>
+    std::pair<iterator, bool> emplace(Args&&... args) { 
+        return m_ht.emplace(std::forward<Args>(args)...); 
+    }
+    
+    
+    
+    /**
+     * Due to the way elements are stored, emplace_hint will need to move or copy the key-value once.
+     * The method is equivalent to insert(hint, value_type(std::forward<Args>(args)...));
+     * 
+     * Mainly here for compatibility with the std::unordered_map interface.
+     */
+    template<class... Args>
+    iterator emplace_hint(const_iterator hint, Args&&... args) {
+        return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+    }
+    
+    
+    
+    
+    template<class... Args>
+    std::pair<iterator, bool> try_emplace(const key_type& k, Args&&... args) { 
+        return m_ht.try_emplace(k, std::forward<Args>(args)...);
+    }
+    
+    template<class... Args>
+    std::pair<iterator, bool> try_emplace(key_type&& k, Args&&... args) {
+        return m_ht.try_emplace(std::move(k), std::forward<Args>(args)...);
+    }
+    
+    template<class... Args>
+    iterator try_emplace(const_iterator hint, const key_type& k, Args&&... args) {
+        return m_ht.try_emplace(hint, k, std::forward<Args>(args)...);
+    }
+    
+    template<class... Args>
+    iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args) {
+        return m_ht.try_emplace(hint, std::move(k), std::forward<Args>(args)...);
+    }
+    
+    
+
+    
+    iterator erase(iterator pos) { return m_ht.erase(pos); }
+    iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+    iterator erase(const_iterator first, const_iterator last) { return m_ht.erase(first, last); }
+    size_type erase(const key_type& key) { return m_ht.erase(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup to the value if you already have the hash.
+     */    
+    size_type erase(const key_type& key, std::size_t precalculated_hash) { 
+        return m_ht.erase(key, precalculated_hash); 
+    }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type erase(const K& key) { return m_ht.erase(key); }
+    
+    /**
+     * @copydoc erase(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup to the value if you already have the hash.
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type erase(const K& key, std::size_t precalculated_hash) { 
+        return m_ht.erase(key, precalculated_hash); 
+    }
+    
+    
+    
+    void swap(robin_map& other) { other.m_ht.swap(m_ht); }
+    
+    
+    
+    /*
+     * Lookup
+     */
+    T& at(const Key& key) { return m_ht.at(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    T& at(const Key& key, std::size_t precalculated_hash) { return m_ht.at(key, precalculated_hash); }
+    
+    
+    const T& at(const Key& key) const { return m_ht.at(key); }
+    
+    /**
+     * @copydoc at(const Key& key, std::size_t precalculated_hash)
+     */
+    const T& at(const Key& key, std::size_t precalculated_hash) const { return m_ht.at(key, precalculated_hash); }
+    
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    T& at(const K& key) { return m_ht.at(key); }
+
+    /**
+     * @copydoc at(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    T& at(const K& key, std::size_t precalculated_hash) { return m_ht.at(key, precalculated_hash); }
+    
+    
+    /**
+     * @copydoc at(const K& key)
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const T& at(const K& key) const { return m_ht.at(key); }
+    
+    /**
+     * @copydoc at(const K& key, std::size_t precalculated_hash)
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const T& at(const K& key, std::size_t precalculated_hash) const { return m_ht.at(key, precalculated_hash); }
+    
+    
+    
+    
+    T& operator[](const Key& key) { return m_ht[key]; }    
+    T& operator[](Key&& key) { return m_ht[std::move(key)]; }
+    
+    
+    
+    
+    size_type count(const Key& key) const { return m_ht.count(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    size_type count(const Key& key, std::size_t precalculated_hash) const { 
+        return m_ht.count(key, precalculated_hash); 
+    }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type count(const K& key) const { return m_ht.count(key); }
+    
+    /**
+     * @copydoc count(const K& key) const
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */     
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type count(const K& key, std::size_t precalculated_hash) const { return m_ht.count(key, precalculated_hash); }
+    
+    
+    
+    
+    iterator find(const Key& key) { return m_ht.find(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    iterator find(const Key& key, std::size_t precalculated_hash) { return m_ht.find(key, precalculated_hash); }
+    
+    const_iterator find(const Key& key) const { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const Key& key, std::size_t precalculated_hash)
+     */
+    const_iterator find(const Key& key, std::size_t precalculated_hash) const { 
+        return m_ht.find(key, precalculated_hash); 
+    }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    iterator find(const K& key) { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    iterator find(const K& key, std::size_t precalculated_hash) { return m_ht.find(key, precalculated_hash); }
+    
+    /**
+     * @copydoc find(const K& key)
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const_iterator find(const K& key) const { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const_iterator find(const K& key, std::size_t precalculated_hash) const { 
+        return m_ht.find(key, precalculated_hash); 
+    }
+    
+    
+    
+    
+    std::pair<iterator, iterator> equal_range(const Key& key) { return m_ht.equal_range(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    std::pair<iterator, iterator> equal_range(const Key& key, std::size_t precalculated_hash) { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    std::pair<const_iterator, const_iterator> equal_range(const Key& key) const { return m_ht.equal_range(key); }
+    
+    /**
+     * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+     */
+    std::pair<const_iterator, const_iterator> equal_range(const Key& key, std::size_t precalculated_hash) const { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<iterator, iterator> equal_range(const K& key) { return m_ht.equal_range(key); }
+    
+    
+    /**
+     * @copydoc equal_range(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<iterator, iterator> equal_range(const K& key, std::size_t precalculated_hash) { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    /**
+     * @copydoc equal_range(const K& key)
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<const_iterator, const_iterator> equal_range(const K& key) const { return m_ht.equal_range(key); }
+    
+    /**
+     * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<const_iterator, const_iterator> equal_range(const K& key, std::size_t precalculated_hash) const { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    
+    
+    
+    /*
+     * Bucket interface 
+     */
+    size_type bucket_count() const { return m_ht.bucket_count(); }
+    size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+    
+    
+    /*
+     *  Hash policy 
+     */
+    float load_factor() const { return m_ht.load_factor(); }
+    float max_load_factor() const { return m_ht.max_load_factor(); }
+    void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+    
+    void rehash(size_type count) { m_ht.rehash(count); }
+    void reserve(size_type count) { m_ht.reserve(count); }
+    
+    
+    /*
+     * Observers
+     */
+    hasher hash_function() const { return m_ht.hash_function(); }
+    key_equal key_eq() const { return m_ht.key_eq(); }
+    
+    /*
+     * Other
+     */
+    
+    /**
+     * Convert a const_iterator to an iterator.
+     */
+    iterator mutable_iterator(const_iterator pos) {
+        return m_ht.mutable_iterator(pos);
+    }
+    
+    friend bool operator==(const robin_map& lhs, const robin_map& rhs) {
+        if(lhs.size() != rhs.size()) {
+            return false;
+        }
+        
+        for(const auto& element_lhs: lhs) {
+            const auto it_element_rhs = rhs.find(element_lhs.first);
+            if(it_element_rhs == rhs.cend() || element_lhs.second != it_element_rhs->second) {
+                return false;
+            }
+        }
+        
+        return true;
+    }
+
+    friend bool operator!=(const robin_map& lhs, const robin_map& rhs) {
+        return !operator==(lhs, rhs);
+    }
+
+    friend void swap(robin_map& lhs, robin_map& rhs) {
+        lhs.swap(rhs);
+    }
+    
+private:
+    ht m_ht;
+};
+
+
+/**
+ * Same as `tsl::robin_map<Key, T, Hash, KeyEqual, Allocator, StoreHash, tsl::rh::prime_growth_policy>`.
+ */
+template<class Key, 
+         class T, 
+         class Hash = std::hash<Key>,
+         class KeyEqual = std::equal_to<Key>,
+         class Allocator = std::allocator<std::pair<Key, T>>,
+         bool StoreHash = false>
+using robin_pg_map = robin_map<Key, T, Hash, KeyEqual, Allocator, StoreHash, tsl::rh::prime_growth_policy>;
+
+} // end namespace tsl
+
+#endif

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/robin_set.h

@@ -0,0 +1,535 @@
+/**
+ * MIT License
+ * 
+ * Copyright (c) 2017 Tessil
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_ROBIN_SET_H
+#define TSL_ROBIN_SET_H
+
+
+#include <cstddef>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include "robin_hash.h"
+
+
+namespace tsl {
+
+    
+/**
+ * Implementation of a hash set using open-adressing and the robin hood hashing algorithm with backward shift deletion.
+ * 
+ * For operations modifying the hash set (insert, erase, rehash, ...), the strong exception guarantee 
+ * is only guaranteed when the expression `std::is_nothrow_swappable<Key>::value &&
+ * std::is_nothrow_move_constructible<Key>::value` is true, otherwise if an exception
+ * is thrown during the swap or the move, the hash set may end up in a undefined state. Per the standard
+ * a `Key` with a noexcept copy constructor and no move constructor also satisfies the 
+ * `std::is_nothrow_move_constructible<Key>::value` criterion (and will thus guarantee the 
+ * strong exception for the set).
+ * 
+ * When `StoreHash` is true, 32 bits of the hash are stored alongside the values. It can improve 
+ * the performance during lookups if the `KeyEqual` function takes time (or engenders a cache-miss for example) 
+ * as we then compare the stored hashes before comparing the keys. When `tsl::rh::power_of_two_growth_policy` is used
+ * as `GrowthPolicy`, it may also speed-up the rehash process as we can avoid to recalculate the hash. 
+ * When it is detected that storing the hash will not incur any memory penality due to alignement (i.e. 
+ * `sizeof(tsl::detail_robin_hash::bucket_entry<ValueType, true>) == 
+ * sizeof(tsl::detail_robin_hash::bucket_entry<ValueType, false>)`) and `tsl::rh::power_of_two_growth_policy` is
+ * used, the hash will be stored even if `StoreHash` is false so that we can speed-up the rehash (but it will
+ * not be used on lookups unless `StoreHash` is true).
+ * 
+ * `GrowthPolicy` defines how the set grows and consequently how a hash value is mapped to a bucket. 
+ * By default the set uses `tsl::rh::power_of_two_growth_policy`. This policy keeps the number of buckets 
+ * to a power of two and uses a mask to set the hash to a bucket instead of the slow modulo.
+ * Other growth policies are available and you may define your own growth policy, 
+ * check `tsl::rh::power_of_two_growth_policy` for the interface.
+ * 
+ * If the destructor of `Key` throws an exception, the behaviour of the class is undefined.
+ * 
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators.
+ *  - insert, emplace, emplace_hint, operator[]: if there is an effective insert, invalidate the iterators.
+ *  - erase: always invalidate the iterators.
+ */
+template<class Key, 
+         class Hash = std::hash<Key>,
+         class KeyEqual = std::equal_to<Key>,
+         class Allocator = std::allocator<Key>,
+         bool StoreHash = false,
+         class GrowthPolicy = tsl::rh::power_of_two_growth_policy<2>>
+class robin_set {
+private:
+    template<typename U>
+    using has_is_transparent = tsl::detail_robin_hash::has_is_transparent<U>;
+    
+    class KeySelect {
+    public:
+        using key_type = Key;
+        
+        const key_type& operator()(const Key& key) const noexcept {
+            return key;
+        }
+        
+        key_type& operator()(Key& key) noexcept {
+            return key;
+        }
+    };
+    
+    using ht = detail_robin_hash::robin_hash<Key, KeySelect, void,
+                                             Hash, KeyEqual, Allocator, StoreHash, GrowthPolicy>;
+            
+public:
+    using key_type = typename ht::key_type;
+    using value_type = typename ht::value_type;
+    using size_type = typename ht::size_type;
+    using difference_type = typename ht::difference_type;
+    using hasher = typename ht::hasher;
+    using key_equal = typename ht::key_equal;
+    using allocator_type = typename ht::allocator_type;
+    using reference = typename ht::reference;
+    using const_reference = typename ht::const_reference;
+    using pointer = typename ht::pointer;
+    using const_pointer = typename ht::const_pointer;
+    using iterator = typename ht::iterator;
+    using const_iterator = typename ht::const_iterator;
+
+    
+    /*
+     * Constructors
+     */
+    robin_set(): robin_set(ht::DEFAULT_INIT_BUCKETS_SIZE) {
+    }
+    
+    explicit robin_set(size_type bucket_count, 
+                       const Hash& hash = Hash(),
+                       const KeyEqual& equal = KeyEqual(),
+                       const Allocator& alloc = Allocator()): 
+                    m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR)
+    {
+    }
+    
+    robin_set(size_type bucket_count,
+              const Allocator& alloc): robin_set(bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+    
+    robin_set(size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): robin_set(bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+    
+    explicit robin_set(const Allocator& alloc): robin_set(ht::DEFAULT_INIT_BUCKETS_SIZE, alloc) {
+    }
+    
+    template<class InputIt>
+    robin_set(InputIt first, InputIt last,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(),
+              const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator()): robin_set(bucket_count, hash, equal, alloc)
+    {
+        insert(first, last);
+    }
+    
+    template<class InputIt>
+    robin_set(InputIt first, InputIt last,
+              size_type bucket_count,
+              const Allocator& alloc): robin_set(first, last, bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+    
+    template<class InputIt>
+    robin_set(InputIt first, InputIt last,
+              size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): robin_set(first, last, bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+
+    robin_set(std::initializer_list<value_type> init,
+              size_type bucket_count = ht::DEFAULT_INIT_BUCKETS_SIZE,
+              const Hash& hash = Hash(),
+              const KeyEqual& equal = KeyEqual(),
+              const Allocator& alloc = Allocator()): 
+          robin_set(init.begin(), init.end(), bucket_count, hash, equal, alloc)
+    {
+    }
+
+    robin_set(std::initializer_list<value_type> init,
+              size_type bucket_count,
+              const Allocator& alloc): 
+          robin_set(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(), alloc)
+    {
+    }
+
+    robin_set(std::initializer_list<value_type> init,
+              size_type bucket_count,
+              const Hash& hash,
+              const Allocator& alloc): 
+          robin_set(init.begin(), init.end(), bucket_count, hash, KeyEqual(), alloc)
+    {
+    }
+
+    
+    robin_set& operator=(std::initializer_list<value_type> ilist) {
+        m_ht.clear();
+        
+        m_ht.reserve(ilist.size());
+        m_ht.insert(ilist.begin(), ilist.end());
+        
+        return *this;
+    }
+    
+    allocator_type get_allocator() const { return m_ht.get_allocator(); }
+    
+    
+    /*
+     * Iterators
+     */
+    iterator begin() noexcept { return m_ht.begin(); }
+    const_iterator begin() const noexcept { return m_ht.begin(); }
+    const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+    
+    iterator end() noexcept { return m_ht.end(); }
+    const_iterator end() const noexcept { return m_ht.end(); }
+    const_iterator cend() const noexcept { return m_ht.cend(); }
+    
+    
+    /*
+     * Capacity
+     */
+    bool empty() const noexcept { return m_ht.empty(); }
+    size_type size() const noexcept { return m_ht.size(); }
+    size_type max_size() const noexcept { return m_ht.max_size(); }
+    
+    /*
+     * Modifiers
+     */
+    void clear() noexcept { m_ht.clear(); }
+    
+    
+    
+    
+    std::pair<iterator, bool> insert(const value_type& value) { 
+        return m_ht.insert(value); 
+    }
+    
+    std::pair<iterator, bool> insert(value_type&& value) { 
+        return m_ht.insert(std::move(value)); 
+    }
+    
+    iterator insert(const_iterator hint, const value_type& value) { 
+        return m_ht.insert(hint, value); 
+    }
+    
+    iterator insert(const_iterator hint, value_type&& value) { 
+        return m_ht.insert(hint, std::move(value)); 
+    }
+    
+    template<class InputIt>
+    void insert(InputIt first, InputIt last) { 
+        m_ht.insert(first, last);
+    }
+    
+    void insert(std::initializer_list<value_type> ilist) { 
+        m_ht.insert(ilist.begin(), ilist.end()); 
+    }
+
+    
+    
+    
+    /**
+     * Due to the way elements are stored, emplace will need to move or copy the key-value once.
+     * The method is equivalent to insert(value_type(std::forward<Args>(args)...));
+     * 
+     * Mainly here for compatibility with the std::unordered_map interface.
+     */
+    template<class... Args>
+    std::pair<iterator, bool> emplace(Args&&... args) { 
+        return m_ht.emplace(std::forward<Args>(args)...); 
+    }
+    
+    
+    
+    /**
+     * Due to the way elements are stored, emplace_hint will need to move or copy the key-value once.
+     * The method is equivalent to insert(hint, value_type(std::forward<Args>(args)...));
+     * 
+     * Mainly here for compatibility with the std::unordered_map interface.
+     */
+    template<class... Args>
+    iterator emplace_hint(const_iterator hint, Args&&... args) {
+        return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+    }
+    
+    
+    
+    iterator erase(iterator pos) { return m_ht.erase(pos); }
+    iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+    iterator erase(const_iterator first, const_iterator last) { return m_ht.erase(first, last); }
+    size_type erase(const key_type& key) { return m_ht.erase(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup to the value if you already have the hash.
+     */    
+    size_type erase(const key_type& key, std::size_t precalculated_hash) { 
+        return m_ht.erase(key, precalculated_hash); 
+    }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type erase(const K& key) { return m_ht.erase(key); }
+    
+    /**
+     * @copydoc erase(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup to the value if you already have the hash.
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type erase(const K& key, std::size_t precalculated_hash) { 
+        return m_ht.erase(key, precalculated_hash); 
+    }
+    
+    
+    
+    void swap(robin_set& other) { other.m_ht.swap(m_ht); }
+    
+    
+    
+    /*
+     * Lookup
+     */
+    size_type count(const Key& key) const { return m_ht.count(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    size_type count(const Key& key, std::size_t precalculated_hash) const { return m_ht.count(key, precalculated_hash); }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type count(const K& key) const { return m_ht.count(key); }
+    
+    /**
+     * @copydoc count(const K& key) const
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    size_type count(const K& key, std::size_t precalculated_hash) const { return m_ht.count(key, precalculated_hash); }
+    
+    
+    
+    
+    iterator find(const Key& key) { return m_ht.find(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    iterator find(const Key& key, std::size_t precalculated_hash) { return m_ht.find(key, precalculated_hash); }
+    
+    const_iterator find(const Key& key) const { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const Key& key, std::size_t precalculated_hash)
+     */
+    const_iterator find(const Key& key, std::size_t precalculated_hash) const { return m_ht.find(key, precalculated_hash); }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    iterator find(const K& key) { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    iterator find(const K& key, std::size_t precalculated_hash) { return m_ht.find(key, precalculated_hash); }
+    
+    /**
+     * @copydoc find(const K& key)
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const_iterator find(const K& key) const { return m_ht.find(key); }
+    
+    /**
+     * @copydoc find(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    const_iterator find(const K& key, std::size_t precalculated_hash) const { return m_ht.find(key, precalculated_hash); }
+    
+    
+    
+    
+    std::pair<iterator, iterator> equal_range(const Key& key) { return m_ht.equal_range(key); }
+    
+    /**
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */
+    std::pair<iterator, iterator> equal_range(const Key& key, std::size_t precalculated_hash) { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    std::pair<const_iterator, const_iterator> equal_range(const Key& key) const { return m_ht.equal_range(key); }
+    
+    /**
+     * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+     */
+    std::pair<const_iterator, const_iterator> equal_range(const Key& key, std::size_t precalculated_hash) const { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    /**
+     * This overload only participates in the overload resolution if the typedef KeyEqual::is_transparent exists. 
+     * If so, K must be hashable and comparable to Key.
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<iterator, iterator> equal_range(const K& key) { return m_ht.equal_range(key); }
+    
+    /**
+     * @copydoc equal_range(const K& key)
+     * 
+     * Use the hash value 'precalculated_hash' instead of hashing the key. The hash value should be the same
+     * as hash_function()(key). Usefull to speed-up the lookup if you already have the hash.
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<iterator, iterator> equal_range(const K& key, std::size_t precalculated_hash) { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    /**
+     * @copydoc equal_range(const K& key)
+     */
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<const_iterator, const_iterator> equal_range(const K& key) const { return m_ht.equal_range(key); }
+
+    /**
+     * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+     */    
+    template<class K, class KE = KeyEqual, typename std::enable_if<has_is_transparent<KE>::value>::type* = nullptr> 
+    std::pair<const_iterator, const_iterator> equal_range(const K& key, std::size_t precalculated_hash) const { 
+        return m_ht.equal_range(key, precalculated_hash); 
+    }
+    
+    
+    
+
+    /*
+     * Bucket interface 
+     */
+    size_type bucket_count() const { return m_ht.bucket_count(); }
+    size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+    
+    
+    /*
+     *  Hash policy 
+     */
+    float load_factor() const { return m_ht.load_factor(); }
+    float max_load_factor() const { return m_ht.max_load_factor(); }
+    void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+    
+    void rehash(size_type count) { m_ht.rehash(count); }
+    void reserve(size_type count) { m_ht.reserve(count); }
+    
+    
+    /*
+     * Observers
+     */
+    hasher hash_function() const { return m_ht.hash_function(); }
+    key_equal key_eq() const { return m_ht.key_eq(); }
+    
+    
+    /*
+     * Other
+     */
+    
+    /**
+     * Convert a const_iterator to an iterator.
+     */
+    iterator mutable_iterator(const_iterator pos) {
+        return m_ht.mutable_iterator(pos);
+    }
+    
+    friend bool operator==(const robin_set& lhs, const robin_set& rhs) {
+        if(lhs.size() != rhs.size()) {
+            return false;
+        }
+        
+        for(const auto& element_lhs: lhs) {
+            const auto it_element_rhs = rhs.find(element_lhs);
+            if(it_element_rhs == rhs.cend()) {
+                return false;
+            }
+        }
+        
+        return true;
+    }
+
+    friend bool operator!=(const robin_set& lhs, const robin_set& rhs) {
+        return !operator==(lhs, rhs);
+    }
+
+    friend void swap(robin_set& lhs, robin_set& rhs) {
+        lhs.swap(rhs);
+    }
+    
+private:
+    ht m_ht;    
+};
+
+
+/**
+ * Same as `tsl::robin_set<Key, Hash, KeyEqual, Allocator, StoreHash, tsl::rh::prime_growth_policy>`.
+ */
+template<class Key, 
+         class Hash = std::hash<Key>,
+         class KeyEqual = std::equal_to<Key>,
+         class Allocator = std::allocator<Key>,
+         bool StoreHash = false>
+using robin_pg_set = robin_set<Key, Hash, KeyEqual, Allocator, StoreHash, tsl::rh::prime_growth_policy>;
+
+} // end namespace tsl
+
+#endif
+ 

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/sparse_growth_policy.h

@@ -0,0 +1,301 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017 Thibaut Goetghebuer-Planchon <tessil@gmx.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_SPARSE_GROWTH_POLICY_H
+#define TSL_SPARSE_GROWTH_POLICY_H
+
+#include <algorithm>
+#include <array>
+#include <climits>
+#include <cmath>
+#include <cstddef>
+#include <iterator>
+#include <limits>
+#include <ratio>
+#include <stdexcept>
+
+namespace tsl {
+namespace sh {
+
+/**
+ * Grow the hash table by a factor of GrowthFactor keeping the bucket count to a
+ * power of two. It allows the table to use a mask operation instead of a modulo
+ * operation to map a hash to a bucket.
+ *
+ * GrowthFactor must be a power of two >= 2.
+ */
+template <std::size_t GrowthFactor>
+class power_of_two_growth_policy {
+ public:
+  /**
+   * Called on the hash table creation and on rehash. The number of buckets for
+   * the table is passed in parameter. This number is a minimum, the policy may
+   * update this value with a higher value if needed (but not lower).
+   *
+   * If 0 is given, min_bucket_count_in_out must still be 0 after the policy
+   * creation and bucket_for_hash must always return 0 in this case.
+   */
+  explicit power_of_two_growth_policy(std::size_t &min_bucket_count_in_out) {
+    if (min_bucket_count_in_out > max_bucket_count()) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    if (min_bucket_count_in_out > 0) {
+      min_bucket_count_in_out =
+          round_up_to_power_of_two(min_bucket_count_in_out);
+      m_mask = min_bucket_count_in_out - 1;
+    } else {
+      m_mask = 0;
+    }
+  }
+
+  /**
+   * Return the bucket [0, bucket_count()) to which the hash belongs.
+   * If bucket_count() is 0, it must always return 0.
+   */
+  std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+    return hash & m_mask;
+  }
+
+  /**
+   * Return the number of buckets that should be used on next growth.
+   */
+  std::size_t next_bucket_count() const {
+    if ((m_mask + 1) > max_bucket_count() / GrowthFactor) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    return (m_mask + 1) * GrowthFactor;
+  }
+
+  /**
+   * Return the maximum number of buckets supported by the policy.
+   */
+  std::size_t max_bucket_count() const {
+    // Largest power of two.
+    return (std::numeric_limits<std::size_t>::max() / 2) + 1;
+  }
+
+  /**
+   * Reset the growth policy as if it was created with a bucket count of 0.
+   * After a clear, the policy must always return 0 when bucket_for_hash is
+   * called.
+   */
+  void clear() noexcept { m_mask = 0; }
+
+ private:
+  static std::size_t round_up_to_power_of_two(std::size_t value) {
+    if (is_power_of_two(value)) {
+      return value;
+    }
+
+    if (value == 0) {
+      return 1;
+    }
+
+    --value;
+    for (std::size_t i = 1; i < sizeof(std::size_t) * CHAR_BIT; i *= 2) {
+      value |= value >> i;
+    }
+
+    return value + 1;
+  }
+
+  static constexpr bool is_power_of_two(std::size_t value) {
+    return value != 0 && (value & (value - 1)) == 0;
+  }
+
+ protected:
+  static_assert(is_power_of_two(GrowthFactor) && GrowthFactor >= 2,
+                "GrowthFactor must be a power of two >= 2.");
+
+  std::size_t m_mask;
+};
+
+/**
+ * Grow the hash table by GrowthFactor::num / GrowthFactor::den and use a modulo
+ * to map a hash to a bucket. Slower but it can be useful if you want a slower
+ * growth.
+ */
+template <class GrowthFactor = std::ratio<3, 2>>
+class mod_growth_policy {
+ public:
+  explicit mod_growth_policy(std::size_t &min_bucket_count_in_out) {
+    if (min_bucket_count_in_out > max_bucket_count()) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    if (min_bucket_count_in_out > 0) {
+      m_mod = min_bucket_count_in_out;
+    } else {
+      m_mod = 1;
+    }
+  }
+
+  std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+    return hash % m_mod;
+  }
+
+  std::size_t next_bucket_count() const {
+    if (m_mod == max_bucket_count()) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    const double next_bucket_count =
+        std::ceil(double(m_mod) * REHASH_SIZE_MULTIPLICATION_FACTOR);
+    if (!std::isnormal(next_bucket_count)) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    if (next_bucket_count > double(max_bucket_count())) {
+      return max_bucket_count();
+    } else {
+      return std::size_t(next_bucket_count);
+    }
+  }
+
+  std::size_t max_bucket_count() const { return MAX_BUCKET_COUNT; }
+
+  void clear() noexcept { m_mod = 1; }
+
+ private:
+  static constexpr double REHASH_SIZE_MULTIPLICATION_FACTOR =
+      1.0 * GrowthFactor::num / GrowthFactor::den;
+  static const std::size_t MAX_BUCKET_COUNT =
+      std::size_t(double(std::numeric_limits<std::size_t>::max() /
+                         REHASH_SIZE_MULTIPLICATION_FACTOR));
+
+  static_assert(REHASH_SIZE_MULTIPLICATION_FACTOR >= 1.1,
+                "Growth factor should be >= 1.1.");
+
+  std::size_t m_mod;
+};
+
+/**
+ * Grow the hash table by using prime numbers as bucket count. Slower than
+ * tsl::sh::power_of_two_growth_policy in general but will probably distribute
+ * the values around better in the buckets with a poor hash function.
+ *
+ * To allow the compiler to optimize the modulo operation, a lookup table is
+ * used with constant primes numbers.
+ *
+ * With a switch the code would look like:
+ * \code
+ * switch(iprime) { // iprime is the current prime of the hash table
+ *     case 0: hash % 5ul;
+ *             break;
+ *     case 1: hash % 17ul;
+ *             break;
+ *     case 2: hash % 29ul;
+ *             break;
+ *     ...
+ * }
+ * \endcode
+ *
+ * Due to the constant variable in the modulo the compiler is able to optimize
+ * the operation by a series of multiplications, substractions and shifts.
+ *
+ * The 'hash % 5' could become something like 'hash - (hash * 0xCCCCCCCD) >> 34)
+ * * 5' in a 64 bits environment.
+ */
+class prime_growth_policy {
+ public:
+  explicit prime_growth_policy(std::size_t &min_bucket_count_in_out) {
+    auto it_prime = std::lower_bound(primes().begin(), primes().end(),
+                                     min_bucket_count_in_out);
+    if (it_prime == primes().end()) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    m_iprime =
+        static_cast<unsigned int>(std::distance(primes().begin(), it_prime));
+    if (min_bucket_count_in_out > 0) {
+      min_bucket_count_in_out = *it_prime;
+    } else {
+      min_bucket_count_in_out = 0;
+    }
+  }
+
+  std::size_t bucket_for_hash(std::size_t hash) const noexcept {
+    return mod_prime()[m_iprime](hash);
+  }
+
+  std::size_t next_bucket_count() const {
+    if (m_iprime + 1 >= primes().size()) {
+      throw std::length_error("The hash table exceeds its maximum size.");
+    }
+
+    return primes()[m_iprime + 1];
+  }
+
+  std::size_t max_bucket_count() const { return primes().back(); }
+
+  void clear() noexcept { m_iprime = 0; }
+
+ private:
+  static const std::array<std::size_t, 40> &primes() {
+    static const std::array<std::size_t, 40> PRIMES = {
+        {1ul,         5ul,         17ul,         29ul,         37ul,
+         53ul,        67ul,        79ul,         97ul,         131ul,
+         193ul,       257ul,       389ul,        521ul,        769ul,
+         1031ul,      1543ul,      2053ul,       3079ul,       6151ul,
+         12289ul,     24593ul,     49157ul,      98317ul,      196613ul,
+         393241ul,    786433ul,    1572869ul,    3145739ul,    6291469ul,
+         12582917ul,  25165843ul,  50331653ul,   100663319ul,  201326611ul,
+         402653189ul, 805306457ul, 1610612741ul, 3221225473ul, 4294967291ul}};
+
+    static_assert(
+        std::numeric_limits<decltype(m_iprime)>::max() >= PRIMES.size(),
+        "The type of m_iprime is not big enough.");
+
+    return PRIMES;
+  }
+
+  static const std::array<std::size_t (*)(std::size_t), 40> &mod_prime() {
+    // MOD_PRIME[iprime](hash) returns hash % PRIMES[iprime]. This table allows
+    // for faster modulo as the compiler can optimize the modulo code better
+    // with a constant known at the compilation.
+    static const std::array<std::size_t (*)(std::size_t), 40> MOD_PRIME = {
+        {&mod<0>,  &mod<1>,  &mod<2>,  &mod<3>,  &mod<4>,  &mod<5>,  &mod<6>,
+         &mod<7>,  &mod<8>,  &mod<9>,  &mod<10>, &mod<11>, &mod<12>, &mod<13>,
+         &mod<14>, &mod<15>, &mod<16>, &mod<17>, &mod<18>, &mod<19>, &mod<20>,
+         &mod<21>, &mod<22>, &mod<23>, &mod<24>, &mod<25>, &mod<26>, &mod<27>,
+         &mod<28>, &mod<29>, &mod<30>, &mod<31>, &mod<32>, &mod<33>, &mod<34>,
+         &mod<35>, &mod<36>, &mod<37>, &mod<38>, &mod<39>}};
+
+    return MOD_PRIME;
+  }
+
+  template <unsigned int IPrime>
+  static std::size_t mod(std::size_t hash) {
+    return hash % primes()[IPrime];
+  }
+
+ private:
+  unsigned int m_iprime;
+};
+
+}  // namespace sh
+}  // namespace tsl
+
+#endif

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/sparse_map.h

@@ -0,0 +1,800 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017 Thibaut Goetghebuer-Planchon <tessil@gmx.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_SPARSE_MAP_H
+#define TSL_SPARSE_MAP_H
+
+#include <cstddef>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "sparse_hash.h"
+
+namespace tsl {
+
+/**
+ * Implementation of a sparse hash map using open-addressing with quadratic
+ * probing. The goal on the hash map is to be the most memory efficient
+ * possible, even at low load factor, while keeping reasonable performances.
+ *
+ * `GrowthPolicy` defines how the map grows and consequently how a hash value is
+ * mapped to a bucket. By default the map uses
+ * `tsl::sh::power_of_two_growth_policy`. This policy keeps the number of
+ * buckets to a power of two and uses a mask to map the hash to a bucket instead
+ * of the slow modulo. Other growth policies are available and you may define
+ * your own growth policy, check `tsl::sh::power_of_two_growth_policy` for the
+ * interface.
+ *
+ * `ExceptionSafety` defines the exception guarantee provided by the class. By
+ * default only the basic exception safety is guaranteed which mean that all
+ * resources used by the hash map will be freed (no memory leaks) but the hash
+ * map may end-up in an undefined state if an exception is thrown (undefined
+ * here means that some elements may be missing). This can ONLY happen on rehash
+ * (either on insert or if `rehash` is called explicitly) and will occur if the
+ * Allocator can't allocate memory (`std::bad_alloc`) or if the copy constructor
+ * (when a nothrow move constructor is not available) throws an exception. This
+ * can be avoided by calling `reserve` beforehand. This basic guarantee is
+ * similar to the one of `google::sparse_hash_map` and `spp::sparse_hash_map`.
+ * It is possible to ask for the strong exception guarantee with
+ * `tsl::sh::exception_safety::strong`, the drawback is that the map will be
+ * slower on rehashes and will also need more memory on rehashes.
+ *
+ * `Sparsity` defines how much the hash set will compromise between insertion
+ * speed and memory usage. A high sparsity means less memory usage but longer
+ * insertion times, and vice-versa for low sparsity. The default
+ * `tsl::sh::sparsity::medium` sparsity offers a good compromise. It doesn't
+ * change the lookup speed.
+ *
+ * `Key` and `T` must be nothrow move constructible and/or copy constructible.
+ *
+ * If the destructor of `Key` or `T` throws an exception, the behaviour of the
+ * class is undefined.
+ *
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators.
+ *  - insert, emplace, emplace_hint, operator[]: if there is an effective
+ * insert, invalidate the iterators.
+ *  - erase: always invalidate the iterators.
+ */
+template <class Key, class T, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<std::pair<Key, T>>,
+          class GrowthPolicy = tsl::sh::power_of_two_growth_policy<2>,
+          tsl::sh::exception_safety ExceptionSafety =
+              tsl::sh::exception_safety::basic,
+          tsl::sh::sparsity Sparsity = tsl::sh::sparsity::medium>
+class sparse_map {
+ private:
+  template <typename U>
+  using has_is_transparent = tsl::detail_sparse_hash::has_is_transparent<U>;
+
+  class KeySelect {
+   public:
+    using key_type = Key;
+
+    const key_type &operator()(
+        const std::pair<Key, T> &key_value) const noexcept {
+      return key_value.first;
+    }
+
+    key_type &operator()(std::pair<Key, T> &key_value) noexcept {
+      return key_value.first;
+    }
+  };
+
+  class ValueSelect {
+   public:
+    using value_type = T;
+
+    const value_type &operator()(
+        const std::pair<Key, T> &key_value) const noexcept {
+      return key_value.second;
+    }
+
+    value_type &operator()(std::pair<Key, T> &key_value) noexcept {
+      return key_value.second;
+    }
+  };
+
+  using ht = detail_sparse_hash::sparse_hash<
+      std::pair<Key, T>, KeySelect, ValueSelect, Hash, KeyEqual, Allocator,
+      GrowthPolicy, ExceptionSafety, Sparsity, tsl::sh::probing::quadratic>;
+
+ public:
+  using key_type = typename ht::key_type;
+  using mapped_type = T;
+  using value_type = typename ht::value_type;
+  using size_type = typename ht::size_type;
+  using difference_type = typename ht::difference_type;
+  using hasher = typename ht::hasher;
+  using key_equal = typename ht::key_equal;
+  using allocator_type = typename ht::allocator_type;
+  using reference = typename ht::reference;
+  using const_reference = typename ht::const_reference;
+  using pointer = typename ht::pointer;
+  using const_pointer = typename ht::const_pointer;
+  using iterator = typename ht::iterator;
+  using const_iterator = typename ht::const_iterator;
+
+ public:
+  /*
+   * Constructors
+   */
+  sparse_map() : sparse_map(ht::DEFAULT_INIT_BUCKET_COUNT) {}
+
+  explicit sparse_map(size_type bucket_count, const Hash &hash = Hash(),
+                      const KeyEqual &equal = KeyEqual(),
+                      const Allocator &alloc = Allocator())
+      : m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR) {}
+
+  sparse_map(size_type bucket_count, const Allocator &alloc)
+      : sparse_map(bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  sparse_map(size_type bucket_count, const Hash &hash, const Allocator &alloc)
+      : sparse_map(bucket_count, hash, KeyEqual(), alloc) {}
+
+  explicit sparse_map(const Allocator &alloc)
+      : sparse_map(ht::DEFAULT_INIT_BUCKET_COUNT, alloc) {}
+
+  template <class InputIt>
+  sparse_map(InputIt first, InputIt last,
+             size_type bucket_count = ht::DEFAULT_INIT_BUCKET_COUNT,
+             const Hash &hash = Hash(), const KeyEqual &equal = KeyEqual(),
+             const Allocator &alloc = Allocator())
+      : sparse_map(bucket_count, hash, equal, alloc) {
+    insert(first, last);
+  }
+
+  template <class InputIt>
+  sparse_map(InputIt first, InputIt last, size_type bucket_count,
+             const Allocator &alloc)
+      : sparse_map(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  template <class InputIt>
+  sparse_map(InputIt first, InputIt last, size_type bucket_count,
+             const Hash &hash, const Allocator &alloc)
+      : sparse_map(first, last, bucket_count, hash, KeyEqual(), alloc) {}
+
+  sparse_map(std::initializer_list<value_type> init,
+             size_type bucket_count = ht::DEFAULT_INIT_BUCKET_COUNT,
+             const Hash &hash = Hash(), const KeyEqual &equal = KeyEqual(),
+             const Allocator &alloc = Allocator())
+      : sparse_map(init.begin(), init.end(), bucket_count, hash, equal, alloc) {
+  }
+
+  sparse_map(std::initializer_list<value_type> init, size_type bucket_count,
+             const Allocator &alloc)
+      : sparse_map(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(),
+                   alloc) {}
+
+  sparse_map(std::initializer_list<value_type> init, size_type bucket_count,
+             const Hash &hash, const Allocator &alloc)
+      : sparse_map(init.begin(), init.end(), bucket_count, hash, KeyEqual(),
+                   alloc) {}
+
+  sparse_map &operator=(std::initializer_list<value_type> ilist) {
+    m_ht.clear();
+
+    m_ht.reserve(ilist.size());
+    m_ht.insert(ilist.begin(), ilist.end());
+
+    return *this;
+  }
+
+  allocator_type get_allocator() const { return m_ht.get_allocator(); }
+
+  /*
+   * Iterators
+   */
+  iterator begin() noexcept { return m_ht.begin(); }
+  const_iterator begin() const noexcept { return m_ht.begin(); }
+  const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+
+  iterator end() noexcept { return m_ht.end(); }
+  const_iterator end() const noexcept { return m_ht.end(); }
+  const_iterator cend() const noexcept { return m_ht.cend(); }
+
+  /*
+   * Capacity
+   */
+  bool empty() const noexcept { return m_ht.empty(); }
+  size_type size() const noexcept { return m_ht.size(); }
+  size_type max_size() const noexcept { return m_ht.max_size(); }
+
+  /*
+   * Modifiers
+   */
+  void clear() noexcept { m_ht.clear(); }
+
+  std::pair<iterator, bool> insert(const value_type &value) {
+    return m_ht.insert(value);
+  }
+
+  template <class P, typename std::enable_if<std::is_constructible<
+                         value_type, P &&>::value>::type * = nullptr>
+  std::pair<iterator, bool> insert(P &&value) {
+    return m_ht.emplace(std::forward<P>(value));
+  }
+
+  std::pair<iterator, bool> insert(value_type &&value) {
+    return m_ht.insert(std::move(value));
+  }
+
+  iterator insert(const_iterator hint, const value_type &value) {
+    return m_ht.insert_hint(hint, value);
+  }
+
+  template <class P, typename std::enable_if<std::is_constructible<
+                         value_type, P &&>::value>::type * = nullptr>
+  iterator insert(const_iterator hint, P &&value) {
+    return m_ht.emplace_hint(hint, std::forward<P>(value));
+  }
+
+  iterator insert(const_iterator hint, value_type &&value) {
+    return m_ht.insert_hint(hint, std::move(value));
+  }
+
+  template <class InputIt>
+  void insert(InputIt first, InputIt last) {
+    m_ht.insert(first, last);
+  }
+
+  void insert(std::initializer_list<value_type> ilist) {
+    m_ht.insert(ilist.begin(), ilist.end());
+  }
+
+  template <class M>
+  std::pair<iterator, bool> insert_or_assign(const key_type &k, M &&obj) {
+    return m_ht.insert_or_assign(k, std::forward<M>(obj));
+  }
+
+  template <class M>
+  std::pair<iterator, bool> insert_or_assign(key_type &&k, M &&obj) {
+    return m_ht.insert_or_assign(std::move(k), std::forward<M>(obj));
+  }
+
+  template <class M>
+  iterator insert_or_assign(const_iterator hint, const key_type &k, M &&obj) {
+    return m_ht.insert_or_assign(hint, k, std::forward<M>(obj));
+  }
+
+  template <class M>
+  iterator insert_or_assign(const_iterator hint, key_type &&k, M &&obj) {
+    return m_ht.insert_or_assign(hint, std::move(k), std::forward<M>(obj));
+  }
+
+  /**
+   * Due to the way elements are stored, emplace will need to move or copy the
+   * key-value once. The method is equivalent to
+   * `insert(value_type(std::forward<Args>(args)...));`.
+   *
+   * Mainly here for compatibility with the `std::unordered_map` interface.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace(Args &&...args) {
+    return m_ht.emplace(std::forward<Args>(args)...);
+  }
+
+  /**
+   * Due to the way elements are stored, emplace_hint will need to move or copy
+   * the key-value once. The method is equivalent to `insert(hint,
+   * value_type(std::forward<Args>(args)...));`.
+   *
+   * Mainly here for compatibility with the `std::unordered_map` interface.
+   */
+  template <class... Args>
+  iterator emplace_hint(const_iterator hint, Args &&...args) {
+    return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace(const key_type &k, Args &&...args) {
+    return m_ht.try_emplace(k, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  std::pair<iterator, bool> try_emplace(key_type &&k, Args &&...args) {
+    return m_ht.try_emplace(std::move(k), std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  iterator try_emplace(const_iterator hint, const key_type &k, Args &&...args) {
+    return m_ht.try_emplace_hint(hint, k, std::forward<Args>(args)...);
+  }
+
+  template <class... Args>
+  iterator try_emplace(const_iterator hint, key_type &&k, Args &&...args) {
+    return m_ht.try_emplace_hint(hint, std::move(k),
+                                 std::forward<Args>(args)...);
+  }
+
+  iterator erase(iterator pos) { return m_ht.erase(pos); }
+  iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+  iterator erase(const_iterator first, const_iterator last) {
+    return m_ht.erase(first, last);
+  }
+  size_type erase(const key_type &key) { return m_ht.erase(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  size_type erase(const key_type &key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type erase(const K &key) {
+    return m_ht.erase(key);
+  }
+
+  /**
+   * @copydoc erase(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type erase(const K &key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  void swap(sparse_map &other) { other.m_ht.swap(m_ht); }
+
+  /*
+   * Lookup
+   */
+  T &at(const Key &key) { return m_ht.at(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  T &at(const Key &key, std::size_t precalculated_hash) {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  const T &at(const Key &key) const { return m_ht.at(key); }
+
+  /**
+   * @copydoc at(const Key& key, std::size_t precalculated_hash)
+   */
+  const T &at(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  T &at(const K &key) {
+    return m_ht.at(key);
+  }
+
+  /**
+   * @copydoc at(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  T &at(const K &key, std::size_t precalculated_hash) {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc at(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const T &at(const K &key) const {
+    return m_ht.at(key);
+  }
+
+  /**
+   * @copydoc at(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const T &at(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.at(key, precalculated_hash);
+  }
+
+  T &operator[](const Key &key) { return m_ht[key]; }
+  T &operator[](Key &&key) { return m_ht[std::move(key)]; }
+
+  size_type count(const Key &key) const { return m_ht.count(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  size_type count(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type count(const K &key) const {
+    return m_ht.count(key);
+  }
+
+  /**
+   * @copydoc count(const K& key) const
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type count(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  iterator find(const Key &key) { return m_ht.find(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  iterator find(const Key &key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  const_iterator find(const Key &key) const { return m_ht.find(key); }
+
+  /**
+   * @copydoc find(const Key& key, std::size_t precalculated_hash)
+   */
+  const_iterator find(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  iterator find(const K &key) {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  iterator find(const K &key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const_iterator find(const K &key) const {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const_iterator find(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  bool contains(const Key &key) const { return m_ht.contains(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  bool contains(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  bool contains(const K &key) const {
+    return m_ht.contains(key);
+  }
+
+  /**
+   * @copydoc contains(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  bool contains(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  std::pair<iterator, iterator> equal_range(const Key &key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  std::pair<iterator, iterator> equal_range(const Key &key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  std::pair<const_iterator, const_iterator> equal_range(const Key &key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+   */
+  std::pair<const_iterator, const_iterator> equal_range(
+      const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<iterator, iterator> equal_range(const K &key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<iterator, iterator> equal_range(const K &key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(const K &key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(
+      const K &key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /*
+   * Bucket interface
+   */
+  size_type bucket_count() const { return m_ht.bucket_count(); }
+  size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+
+  /*
+   *  Hash policy
+   */
+  float load_factor() const { return m_ht.load_factor(); }
+  float max_load_factor() const { return m_ht.max_load_factor(); }
+  void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+
+  void rehash(size_type count) { m_ht.rehash(count); }
+  void reserve(size_type count) { m_ht.reserve(count); }
+
+  /*
+   * Observers
+   */
+  hasher hash_function() const { return m_ht.hash_function(); }
+  key_equal key_eq() const { return m_ht.key_eq(); }
+
+  /*
+   * Other
+   */
+
+  /**
+   * Convert a `const_iterator` to an `iterator`.
+   */
+  iterator mutable_iterator(const_iterator pos) {
+    return m_ht.mutable_iterator(pos);
+  }
+
+  /**
+   * Serialize the map through the `serializer` parameter.
+   *
+   * The `serializer` parameter must be a function object that supports the
+   * following call:
+   *  - `template<typename U> void operator()(const U& value);` where the types
+   * `std::uint64_t`, `float` and `std::pair<Key, T>` must be supported for U.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, ...) of the types it serializes in the hands of the `Serializer`
+   * function object if compatibility is required.
+   */
+  template <class Serializer>
+  void serialize(Serializer &serializer) const {
+    m_ht.serialize(serializer);
+  }
+
+  /**
+   * Deserialize a previously serialized map through the `deserializer`
+   * parameter.
+   *
+   * The `deserializer` parameter must be a function object that supports the
+   * following calls:
+   *  - `template<typename U> U operator()();` where the types `std::uint64_t`,
+   * `float` and `std::pair<Key, T>` must be supported for U.
+   *
+   * If the deserialized hash map type is hash compatible with the serialized
+   * map, the deserialization process can be sped up by setting
+   * `hash_compatible` to true. To be hash compatible, the Hash, KeyEqual and
+   * GrowthPolicy must behave the same way than the ones used on the serialized
+   * map. The `std::size_t` must also be of the same size as the one on the
+   * platform used to serialize the map. If these criteria are not met, the
+   * behaviour is undefined with `hash_compatible` sets to true.
+   *
+   * The behaviour is undefined if the type `Key` and `T` of the `sparse_map`
+   * are not the same as the types used during serialization.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, size of int, ...) of the types it deserializes in the hands of the
+   * `Deserializer` function object if compatibility is required.
+   */
+  template <class Deserializer>
+  static sparse_map deserialize(Deserializer &deserializer,
+                                bool hash_compatible = false) {
+    sparse_map map(0);
+    map.m_ht.deserialize(deserializer, hash_compatible);
+
+    return map;
+  }
+
+  friend bool operator==(const sparse_map &lhs, const sparse_map &rhs) {
+    if (lhs.size() != rhs.size()) {
+      return false;
+    }
+
+    for (const auto &element_lhs : lhs) {
+      const auto it_element_rhs = rhs.find(element_lhs.first);
+      if (it_element_rhs == rhs.cend() ||
+          element_lhs.second != it_element_rhs->second) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  friend bool operator!=(const sparse_map &lhs, const sparse_map &rhs) {
+    return !operator==(lhs, rhs);
+  }
+
+  friend void swap(sparse_map &lhs, sparse_map &rhs) { lhs.swap(rhs); }
+
+ private:
+  ht m_ht;
+};
+
+/**
+ * Same as `tsl::sparse_map<Key, T, Hash, KeyEqual, Allocator,
+ * tsl::sh::prime_growth_policy>`.
+ */
+template <class Key, class T, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<std::pair<Key, T>>>
+using sparse_pg_map =
+    sparse_map<Key, T, Hash, KeyEqual, Allocator, tsl::sh::prime_growth_policy>;
+
+}  // end namespace tsl
+
+#endif

packages/leann-backend-diskann/third_party/DiskANN/include/tsl/sparse_set.h

@@ -0,0 +1,655 @@
+/**
+ * MIT License
+ *
+ * Copyright (c) 2017 Thibaut Goetghebuer-Planchon <tessil@gmx.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#ifndef TSL_SPARSE_SET_H
+#define TSL_SPARSE_SET_H
+
+#include <cstddef>
+#include <functional>
+#include <initializer_list>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#include "sparse_hash.h"
+
+namespace tsl {
+
+/**
+ * Implementation of a sparse hash set using open-addressing with quadratic
+ * probing. The goal on the hash set is to be the most memory efficient
+ * possible, even at low load factor, while keeping reasonable performances.
+ *
+ * `GrowthPolicy` defines how the set grows and consequently how a hash value is
+ * mapped to a bucket. By default the set uses
+ * `tsl::sh::power_of_two_growth_policy`. This policy keeps the number of
+ * buckets to a power of two and uses a mask to map the hash to a bucket instead
+ * of the slow modulo. Other growth policies are available and you may define
+ * your own growth policy, check `tsl::sh::power_of_two_growth_policy` for the
+ * interface.
+ *
+ * `ExceptionSafety` defines the exception guarantee provided by the class. By
+ * default only the basic exception safety is guaranteed which mean that all
+ * resources used by the hash set will be freed (no memory leaks) but the hash
+ * set may end-up in an undefined state if an exception is thrown (undefined
+ * here means that some elements may be missing). This can ONLY happen on rehash
+ * (either on insert or if `rehash` is called explicitly) and will occur if the
+ * Allocator can't allocate memory (`std::bad_alloc`) or if the copy constructor
+ * (when a nothrow move constructor is not available) throws an exception. This
+ * can be avoided by calling `reserve` beforehand. This basic guarantee is
+ * similar to the one of `google::sparse_hash_map` and `spp::sparse_hash_map`.
+ * It is possible to ask for the strong exception guarantee with
+ * `tsl::sh::exception_safety::strong`, the drawback is that the set will be
+ * slower on rehashes and will also need more memory on rehashes.
+ *
+ * `Sparsity` defines how much the hash set will compromise between insertion
+ * speed and memory usage. A high sparsity means less memory usage but longer
+ * insertion times, and vice-versa for low sparsity. The default
+ * `tsl::sh::sparsity::medium` sparsity offers a good compromise. It doesn't
+ * change the lookup speed.
+ *
+ * `Key` must be nothrow move constructible and/or copy constructible.
+ *
+ * If the destructor of `Key` throws an exception, the behaviour of the class is
+ * undefined.
+ *
+ * Iterators invalidation:
+ *  - clear, operator=, reserve, rehash: always invalidate the iterators.
+ *  - insert, emplace, emplace_hint: if there is an effective insert, invalidate
+ * the iterators.
+ *  - erase: always invalidate the iterators.
+ */
+template <class Key, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<Key>,
+          class GrowthPolicy = tsl::sh::power_of_two_growth_policy<2>,
+          tsl::sh::exception_safety ExceptionSafety =
+              tsl::sh::exception_safety::basic,
+          tsl::sh::sparsity Sparsity = tsl::sh::sparsity::medium>
+class sparse_set {
+ private:
+  template <typename U>
+  using has_is_transparent = tsl::detail_sparse_hash::has_is_transparent<U>;
+
+  class KeySelect {
+   public:
+    using key_type = Key;
+
+    const key_type &operator()(const Key &key) const noexcept { return key; }
+
+    key_type &operator()(Key &key) noexcept { return key; }
+  };
+
+  using ht =
+      detail_sparse_hash::sparse_hash<Key, KeySelect, void, Hash, KeyEqual,
+                                      Allocator, GrowthPolicy, ExceptionSafety,
+                                      Sparsity, tsl::sh::probing::quadratic>;
+
+ public:
+  using key_type = typename ht::key_type;
+  using value_type = typename ht::value_type;
+  using size_type = typename ht::size_type;
+  using difference_type = typename ht::difference_type;
+  using hasher = typename ht::hasher;
+  using key_equal = typename ht::key_equal;
+  using allocator_type = typename ht::allocator_type;
+  using reference = typename ht::reference;
+  using const_reference = typename ht::const_reference;
+  using pointer = typename ht::pointer;
+  using const_pointer = typename ht::const_pointer;
+  using iterator = typename ht::iterator;
+  using const_iterator = typename ht::const_iterator;
+
+  /*
+   * Constructors
+   */
+  sparse_set() : sparse_set(ht::DEFAULT_INIT_BUCKET_COUNT) {}
+
+  explicit sparse_set(size_type bucket_count, const Hash &hash = Hash(),
+                      const KeyEqual &equal = KeyEqual(),
+                      const Allocator &alloc = Allocator())
+      : m_ht(bucket_count, hash, equal, alloc, ht::DEFAULT_MAX_LOAD_FACTOR) {}
+
+  sparse_set(size_type bucket_count, const Allocator &alloc)
+      : sparse_set(bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  sparse_set(size_type bucket_count, const Hash &hash, const Allocator &alloc)
+      : sparse_set(bucket_count, hash, KeyEqual(), alloc) {}
+
+  explicit sparse_set(const Allocator &alloc)
+      : sparse_set(ht::DEFAULT_INIT_BUCKET_COUNT, alloc) {}
+
+  template <class InputIt>
+  sparse_set(InputIt first, InputIt last,
+             size_type bucket_count = ht::DEFAULT_INIT_BUCKET_COUNT,
+             const Hash &hash = Hash(), const KeyEqual &equal = KeyEqual(),
+             const Allocator &alloc = Allocator())
+      : sparse_set(bucket_count, hash, equal, alloc) {
+    insert(first, last);
+  }
+
+  template <class InputIt>
+  sparse_set(InputIt first, InputIt last, size_type bucket_count,
+             const Allocator &alloc)
+      : sparse_set(first, last, bucket_count, Hash(), KeyEqual(), alloc) {}
+
+  template <class InputIt>
+  sparse_set(InputIt first, InputIt last, size_type bucket_count,
+             const Hash &hash, const Allocator &alloc)
+      : sparse_set(first, last, bucket_count, hash, KeyEqual(), alloc) {}
+
+  sparse_set(std::initializer_list<value_type> init,
+             size_type bucket_count = ht::DEFAULT_INIT_BUCKET_COUNT,
+             const Hash &hash = Hash(), const KeyEqual &equal = KeyEqual(),
+             const Allocator &alloc = Allocator())
+      : sparse_set(init.begin(), init.end(), bucket_count, hash, equal, alloc) {
+  }
+
+  sparse_set(std::initializer_list<value_type> init, size_type bucket_count,
+             const Allocator &alloc)
+      : sparse_set(init.begin(), init.end(), bucket_count, Hash(), KeyEqual(),
+                   alloc) {}
+
+  sparse_set(std::initializer_list<value_type> init, size_type bucket_count,
+             const Hash &hash, const Allocator &alloc)
+      : sparse_set(init.begin(), init.end(), bucket_count, hash, KeyEqual(),
+                   alloc) {}
+
+  sparse_set &operator=(std::initializer_list<value_type> ilist) {
+    m_ht.clear();
+
+    m_ht.reserve(ilist.size());
+    m_ht.insert(ilist.begin(), ilist.end());
+
+    return *this;
+  }
+
+  allocator_type get_allocator() const { return m_ht.get_allocator(); }
+
+  /*
+   * Iterators
+   */
+  iterator begin() noexcept { return m_ht.begin(); }
+  const_iterator begin() const noexcept { return m_ht.begin(); }
+  const_iterator cbegin() const noexcept { return m_ht.cbegin(); }
+
+  iterator end() noexcept { return m_ht.end(); }
+  const_iterator end() const noexcept { return m_ht.end(); }
+  const_iterator cend() const noexcept { return m_ht.cend(); }
+
+  /*
+   * Capacity
+   */
+  bool empty() const noexcept { return m_ht.empty(); }
+  size_type size() const noexcept { return m_ht.size(); }
+  size_type max_size() const noexcept { return m_ht.max_size(); }
+
+  /*
+   * Modifiers
+   */
+  void clear() noexcept { m_ht.clear(); }
+
+  std::pair<iterator, bool> insert(const value_type &value) {
+    return m_ht.insert(value);
+  }
+
+  std::pair<iterator, bool> insert(value_type &&value) {
+    return m_ht.insert(std::move(value));
+  }
+
+  iterator insert(const_iterator hint, const value_type &value) {
+    return m_ht.insert_hint(hint, value);
+  }
+
+  iterator insert(const_iterator hint, value_type &&value) {
+    return m_ht.insert_hint(hint, std::move(value));
+  }
+
+  template <class InputIt>
+  void insert(InputIt first, InputIt last) {
+    m_ht.insert(first, last);
+  }
+
+  void insert(std::initializer_list<value_type> ilist) {
+    m_ht.insert(ilist.begin(), ilist.end());
+  }
+
+  /**
+   * Due to the way elements are stored, emplace will need to move or copy the
+   * key-value once. The method is equivalent to
+   * `insert(value_type(std::forward<Args>(args)...));`.
+   *
+   * Mainly here for compatibility with the `std::unordered_map` interface.
+   */
+  template <class... Args>
+  std::pair<iterator, bool> emplace(Args &&...args) {
+    return m_ht.emplace(std::forward<Args>(args)...);
+  }
+
+  /**
+   * Due to the way elements are stored, emplace_hint will need to move or copy
+   * the key-value once. The method is equivalent to `insert(hint,
+   * value_type(std::forward<Args>(args)...));`.
+   *
+   * Mainly here for compatibility with the `std::unordered_map` interface.
+   */
+  template <class... Args>
+  iterator emplace_hint(const_iterator hint, Args &&...args) {
+    return m_ht.emplace_hint(hint, std::forward<Args>(args)...);
+  }
+
+  iterator erase(iterator pos) { return m_ht.erase(pos); }
+  iterator erase(const_iterator pos) { return m_ht.erase(pos); }
+  iterator erase(const_iterator first, const_iterator last) {
+    return m_ht.erase(first, last);
+  }
+  size_type erase(const key_type &key) { return m_ht.erase(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  size_type erase(const key_type &key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type erase(const K &key) {
+    return m_ht.erase(key);
+  }
+
+  /**
+   * @copydoc erase(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type erase(const K &key, std::size_t precalculated_hash) {
+    return m_ht.erase(key, precalculated_hash);
+  }
+
+  void swap(sparse_set &other) { other.m_ht.swap(m_ht); }
+
+  /*
+   * Lookup
+   */
+  size_type count(const Key &key) const { return m_ht.count(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  size_type count(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type count(const K &key) const {
+    return m_ht.count(key);
+  }
+
+  /**
+   * @copydoc count(const K& key) const
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  size_type count(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.count(key, precalculated_hash);
+  }
+
+  iterator find(const Key &key) { return m_ht.find(key); }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  iterator find(const Key &key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  const_iterator find(const Key &key) const { return m_ht.find(key); }
+
+  /**
+   * @copydoc find(const Key& key, std::size_t precalculated_hash)
+   */
+  const_iterator find(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  iterator find(const K &key) {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  iterator find(const K &key, std::size_t precalculated_hash) {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const_iterator find(const K &key) const {
+    return m_ht.find(key);
+  }
+
+  /**
+   * @copydoc find(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  const_iterator find(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.find(key, precalculated_hash);
+  }
+
+  bool contains(const Key &key) const { return m_ht.contains(key); }
+
+  /**
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  bool contains(const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * KeyEqual::is_transparent exists. If so, K must be hashable and comparable
+   * to Key.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  bool contains(const K &key) const {
+    return m_ht.contains(key);
+  }
+
+  /**
+   * @copydoc contains(const K& key) const
+   *
+   * Use the hash value 'precalculated_hash' instead of hashing the key. The
+   * hash value should be the same as hash_function()(key). Useful to speed-up
+   * the lookup if you already have the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  bool contains(const K &key, std::size_t precalculated_hash) const {
+    return m_ht.contains(key, precalculated_hash);
+  }
+
+  std::pair<iterator, iterator> equal_range(const Key &key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  std::pair<iterator, iterator> equal_range(const Key &key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  std::pair<const_iterator, const_iterator> equal_range(const Key &key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const Key& key, std::size_t precalculated_hash)
+   */
+  std::pair<const_iterator, const_iterator> equal_range(
+      const Key &key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * This overload only participates in the overload resolution if the typedef
+   * `KeyEqual::is_transparent` exists. If so, `K` must be hashable and
+   * comparable to `Key`.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<iterator, iterator> equal_range(const K &key) {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   *
+   * Use the hash value `precalculated_hash` instead of hashing the key. The
+   * hash value should be the same as `hash_function()(key)`, otherwise the
+   * behaviour is undefined. Useful to speed-up the lookup if you already have
+   * the hash.
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<iterator, iterator> equal_range(const K &key,
+                                            std::size_t precalculated_hash) {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(const K &key) const {
+    return m_ht.equal_range(key);
+  }
+
+  /**
+   * @copydoc equal_range(const K& key, std::size_t precalculated_hash)
+   */
+  template <
+      class K, class KE = KeyEqual,
+      typename std::enable_if<has_is_transparent<KE>::value>::type * = nullptr>
+  std::pair<const_iterator, const_iterator> equal_range(
+      const K &key, std::size_t precalculated_hash) const {
+    return m_ht.equal_range(key, precalculated_hash);
+  }
+
+  /*
+   * Bucket interface
+   */
+  size_type bucket_count() const { return m_ht.bucket_count(); }
+  size_type max_bucket_count() const { return m_ht.max_bucket_count(); }
+
+  /*
+   *  Hash policy
+   */
+  float load_factor() const { return m_ht.load_factor(); }
+  float max_load_factor() const { return m_ht.max_load_factor(); }
+  void max_load_factor(float ml) { m_ht.max_load_factor(ml); }
+
+  void rehash(size_type count) { m_ht.rehash(count); }
+  void reserve(size_type count) { m_ht.reserve(count); }
+
+  /*
+   * Observers
+   */
+  hasher hash_function() const { return m_ht.hash_function(); }
+  key_equal key_eq() const { return m_ht.key_eq(); }
+
+  /*
+   * Other
+   */
+
+  /**
+   * Convert a `const_iterator` to an `iterator`.
+   */
+  iterator mutable_iterator(const_iterator pos) {
+    return m_ht.mutable_iterator(pos);
+  }
+
+  /**
+   * Serialize the set through the `serializer` parameter.
+   *
+   * The `serializer` parameter must be a function object that supports the
+   * following call:
+   *  - `void operator()(const U& value);` where the types `std::uint64_t`,
+   * `float` and `Key` must be supported for U.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, ...) of the types it serializes in the hands of the `Serializer`
+   * function object if compatibility is required.
+   */
+  template <class Serializer>
+  void serialize(Serializer &serializer) const {
+    m_ht.serialize(serializer);
+  }
+
+  /**
+   * Deserialize a previously serialized set through the `deserializer`
+   * parameter.
+   *
+   * The `deserializer` parameter must be a function object that supports the
+   * following calls:
+   *  - `template<typename U> U operator()();` where the types `std::uint64_t`,
+   * `float` and `Key` must be supported for U.
+   *
+   * If the deserialized hash set type is hash compatible with the serialized
+   * set, the deserialization process can be sped up by setting
+   * `hash_compatible` to true. To be hash compatible, the Hash, KeyEqual and
+   * GrowthPolicy must behave the same way than the ones used on the serialized
+   * set. The `std::size_t` must also be of the same size as the one on the
+   * platform used to serialize the set. If these criteria are not met, the
+   * behaviour is undefined with `hash_compatible` sets to true.
+   *
+   * The behaviour is undefined if the type `Key` of the `sparse_set` is not the
+   * same as the type used during serialization.
+   *
+   * The implementation leaves binary compatibility (endianness, IEEE 754 for
+   * floats, size of int, ...) of the types it deserializes in the hands of the
+   * `Deserializer` function object if compatibility is required.
+   */
+  template <class Deserializer>
+  static sparse_set deserialize(Deserializer &deserializer,
+                                bool hash_compatible = false) {
+    sparse_set set(0);
+    set.m_ht.deserialize(deserializer, hash_compatible);
+
+    return set;
+  }
+
+  friend bool operator==(const sparse_set &lhs, const sparse_set &rhs) {
+    if (lhs.size() != rhs.size()) {
+      return false;
+    }
+
+    for (const auto &element_lhs : lhs) {
+      const auto it_element_rhs = rhs.find(element_lhs);
+      if (it_element_rhs == rhs.cend()) {
+        return false;
+      }
+    }
+
+    return true;
+  }
+
+  friend bool operator!=(const sparse_set &lhs, const sparse_set &rhs) {
+    return !operator==(lhs, rhs);
+  }
+
+  friend void swap(sparse_set &lhs, sparse_set &rhs) { lhs.swap(rhs); }
+
+ private:
+  ht m_ht;
+};
+
+/**
+ * Same as `tsl::sparse_set<Key, Hash, KeyEqual, Allocator,
+ * tsl::sh::prime_growth_policy>`.
+ */
+template <class Key, class Hash = std::hash<Key>,
+          class KeyEqual = std::equal_to<Key>,
+          class Allocator = std::allocator<Key>>
+using sparse_pg_set =
+    sparse_set<Key, Hash, KeyEqual, Allocator, tsl::sh::prime_growth_policy>;
+
+}  // end namespace tsl
+
+#endif