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[ox/std] Add expand to HashMap

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This commit is contained in:
Gary Talent 2019-02-03 01:13:35 -06:00
parent 87e6b8d19f
commit 9ca27361dc
2 changed files with 42 additions and 17 deletions
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58
deps/ox/src/ox/std/hashmap.hpp vendored
View File

@ -39,10 +39,17 @@ class HashMap {
std::size_t size() const noexcept;
private:
void expand() noexcept;
/**
* K is assumed to be a null terminated string.
*/
static std::uint64_t hash(K, int len = 0xFFFF);
static std::uint64_t hash(K, int len = 0xFFFF) noexcept;
/**
* K is assumed to be a null terminated string.
*/
Pair *&access(Vector<Pair*> &pairs, K key) noexcept;
};
@ -72,30 +79,35 @@ HashMap<K, T> &HashMap<K, T>::operator=(HashMap<K, T> &other) noexcept {
template<typename K, typename T>
T &HashMap<K, T>::operator[](K k) noexcept {
auto h = hash(k) % m_pairs.size();
auto hashStr = reinterpret_cast<char*>(&h);
while (1) {
auto &p = m_pairs[h];
if (p == nullptr) {
p = new Pair;
p->key = k;
m_keys.push_back(k);
return p->value;
} else if (ox_strcmp(p->key, k) == 0) {
return p->value;
} else {
h = hash(hashStr, 8) % m_pairs.size();
auto &p = access(m_pairs, k);
if (p == nullptr) {
if (m_pairs.size() * 0.7 < m_keys.size()) {
expand();
}
p = new Pair;
p->key = k;
m_keys.push_back(k);
}
return p->value;
}
template<typename K, typename T>
std::size_t HashMap<K, T>::size() const noexcept {
return m_keys.size();
};
}
template<typename K, typename T>
std::uint64_t HashMap<K, T>::hash(K k, int len) {
void HashMap<K, T>::expand() noexcept {
Vector<Pair*> r;
for (std::size_t i = 0; i < m_keys.size(); i++) {
auto k = m_keys[i];
access(r, k) = access(m_pairs, k);
}
m_pairs = r;
}
template<typename K, typename T>
std::uint64_t HashMap<K, T>::hash(K k, int len) noexcept {
std::uint64_t sum = 1;
for (int i = 0; i < len && k[i]; i++) {
sum += ((sum + k[i]) * 7) * sum;
@ -103,4 +115,18 @@ std::uint64_t HashMap<K, T>::hash(K k, int len) {
return sum;
}
template<typename K, typename T>
typename HashMap<K, T>::Pair *&HashMap<K, T>::access(Vector<Pair*> &pairs, K k) noexcept {
auto h = hash(k) % pairs.size();
auto hashStr = reinterpret_cast<char*>(&h);
while (1) {
auto &p = pairs[h];
if (p == nullptr || ox_strcmp(p->key, k) == 0) {
return p;
} else {
h = hash(hashStr, 8) % pairs.size();
}
}
}
}

1
deps/ox/src/ox/std/test/tests.cpp vendored
View File

@ -59,7 +59,6 @@ map<string, function<int()>> tests = {
ox::HashMap<const char*, int> v;
v["asdf"] = 42;
v["aoeu"] = 100;
std::cout << v["asdf"];
oxAssert(v["asdf"] == 42, "asdf != 42");
oxAssert(v["aoeu"] == 100, "aoeu != 100");
return 0;