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Flow 2.0.0
Flow project: Public API.
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An object of this class is a map that combines the lookup speed of an unordered_set<> and ordering and iterator stability capabilities of a list<>.
More...
#include <linked_hash_set.hpp>
Public Types | |
| using | Key = Key_t |
| Convenience alias for template arg. | |
| using | Hash = Hash_t |
| Convenience alias for template arg. | |
| using | Pred = Pred_t |
| Convenience alias for template arg. | |
| using | Value = Key |
| Short-hand for values, which in this case are simply the keys. | |
| using | size_type = std::size_t |
| Expresses sizes/lengths of relevant things. | |
| using | difference_type = std::ptrdiff_t |
Type for difference of size_types. | |
| using | Const_iterator = typename Value_list::const_iterator |
| Type for iterator pointing into an immutable structure of this type. | |
| using | Iterator = Const_iterator |
| Type for iterator pointing into a mutable structure of this type but actually that is not possible; so alias to Const_iterator. More... | |
| using | Const_reverse_iterator = typename Value_list::const_reverse_iterator |
| Type for reverse iterator pointing into an immutable structure of this type. | |
| using | Reverse_iterator = Const_reverse_iterator |
| Type for reverse iterator pointing into a mutable structure of this type but actually that is not possible; so alias to Const_reverse_iterator. More... | |
| using | key_type = Key |
| For container compliance (hence the irregular capitalization): Key type. | |
| using | value_type = Value |
| For container compliance (hence the irregular capitalization): Value type. | |
| using | hasher = Hash |
| For container compliance (hence the irregular capitalization): Hash type. | |
| using | key_equal = Pred |
| For container compliance (hence the irregular capitalization): Pred type. | |
| using | pointer = Value * |
| For container compliance (hence the irregular capitalization): pointer to Key type. | |
| using | const_pointer = const Value * |
For container compliance (hence the irregular capitalization): pointer to const Key type. | |
| using | reference = Value & |
| For container compliance (hence the irregular capitalization): reference to Key type. | |
| using | const_reference = const Value & |
For container compliance (hence the irregular capitalization): reference to const Key type. | |
| using | iterator = Iterator |
For container compliance (hence the irregular capitalization): Iterator type. | |
| using | const_iterator = Const_iterator |
For container compliance (hence the irregular capitalization): Const_iterator type. | |
Public Member Functions | |
| Linked_hash_set (size_type n_buckets=size_type(-1), const Hash &hasher_obj=Hash{}, const Pred &pred=Pred{}) | |
| Constructs empty structure with some basic parameters. More... | |
| Linked_hash_set (std::initializer_list< Value > values, size_type n_buckets=size_type(-1), const Hash &hasher_obj=Hash{}, const Pred &pred=Pred{}) | |
| Constructs structure with some basic parameters, and values initialized from initializer list. More... | |
| Linked_hash_set (const Linked_hash_set &src) | |
| Constructs object that is a copy of the given source. More... | |
| Linked_hash_set (Linked_hash_set &&src) | |
| Constructs object by making it equal to the given source, while the given source becomes as-if default-cted. More... | |
| Linked_hash_set & | operator= (const Linked_hash_set &src) |
| Overwrites this object with a copy of the given source. More... | |
| Linked_hash_set & | operator= (Linked_hash_set &&src) |
| Overwrites this object making it identical to the given source, while the given source becomes as-if default-cted. More... | |
| void | swap (Linked_hash_set &other) |
Swaps the contents of this structure and other. More... | |
| std::pair< Iterator, bool > | insert (const Key &key) |
Attempts to insert (copying it) the given keyinto the map; if key already in *this makes no change. More... | |
| std::pair< Iterator, bool > | insert (Key &&key) |
Identical to the other overload, except that (if key not already present in *this) the key is moved, not copied, into *this. More... | |
| Const_iterator | find (const Key &key) const |
| Attempts to find value at the given key in the map. More... | |
| size_type | count (const Key &key) const |
| Returns the number of times a key equal to the given one is present (as-if via find()) in the map: either 1 or 0. More... | |
| void | touch (const Const_iterator &it) |
| Given a valid iterator into the structure, makes the pointed-to element "newest" by moving it from wherever it is to be first in the iteration order. More... | |
| bool | touch (const Key &key) |
| Given a key into the structure, makes the corresponding element "newest" by moving it from wherever it is to be first in the iteration order; or does nothing if no such key. More... | |
| Const_iterator | erase (const Const_iterator &it) |
| Erases the element pointed to by the given valid iterator. More... | |
| Const_iterator | erase (const Const_iterator &it_newest, const Const_iterator &it_past_oldest) |
Erases all elements in the range [it_newest, it_past_oldest). More... | |
| size_type | erase (const Key &key) |
| Erases the element with the given key, if it exists. More... | |
| void | clear () |
Makes it so that size() == 0. | |
| Iterator | begin () const |
| Synonym of newest(). More... | |
| Iterator | newest () const |
| Returns first, a/k/a "newest," element's iterator (to immutable element, due to nature of this type). More... | |
| Iterator | end () const |
| Synonym of past_oldest(). More... | |
| Iterator | past_oldest () const |
| Returns one past last, a/k/a "oldest," element's iterator (to immutable element, due to nature of this type). More... | |
| Const_iterator | cbegin () const |
| Synonym of const_newest(). More... | |
| Const_iterator | const_newest () const |
| Returns first, a/k/a "newest," element's iterator (to immutable element). More... | |
| Const_iterator | cend () const |
| Synonym of const_past_oldest(). More... | |
| Const_iterator | const_past_oldest () const |
| Returns one past last, a/k/a "oldest," element's iterator (to immutable element). More... | |
| Reverse_iterator | rbegin () const |
| Synonym of oldest(). More... | |
| Reverse_iterator | oldest () const |
| Returns first, a/k/a "oldest," element's reverse iterator (to immutable element, due to nature of this type). More... | |
| Reverse_iterator | rend () const |
| Synonym of past_newest(). More... | |
| Reverse_iterator | past_newest () const |
| Returns one past last, a/k/a "newest," element's reverse iterator (to immutable element, due to nature of this type). More... | |
| Const_reverse_iterator | crbegin () const |
| Synonym of const_oldest(). More... | |
| Const_reverse_iterator | const_oldest () const |
| Returns first, a/k/a "oldest," element's reverse iterator (to immutable element). More... | |
| Const_reverse_iterator | crend () const |
| Synonym of const_past_newest(). More... | |
| Const_reverse_iterator | const_past_newest () const |
| Returns one past last, a/k/a "newest," element's reverse iterator (to immutable element). More... | |
| bool | empty () const |
| Returns true if and only if container is empty. More... | |
| size_type | size () const |
| Returns number of elements stored. More... | |
| size_type | max_size () const |
| Returns max number of elements that can be stored. More... | |
Related Functions | |
(Note that these are not member functions.) | |
| template<typename Key_t , typename Hash_t , typename Pred_t > | |
| void | swap (Linked_hash_set< Key_t, Hash_t, Pred_t > &val1, Linked_hash_set< Key_t, Hash_t, Pred_t > &val2) |
Equivalent to val1.swap(val2). More... | |
An object of this class is a map that combines the lookup speed of an unordered_set<> and ordering and iterator stability capabilities of a list<>.
This is just like Linked_hash_map, except it only stores keys – no mapped values. All comments, except for self-explanatory differences, from Linked_hash_map apply here. Thus I will only speak of differences below to avoid duplication of this header. Incidentally the most visible API difference (aside from having no Mappeds to speak of, only Keys) is that Linked_hash_set lacks (*this)[] operator; so one always uses insert() to insert.
Move semantics for keys are supported (let x be a *this):
x.insert(std::move(a_key));x.insert(Key{...}).The iterators are, really, list<Key> const-iterators; and as such are not invalidated except due to direct erasure of a given pointee.
| Key_t | Key type. Same as for Linked_hash_map. |
| Hash_t | Hasher type. Same as for Linked_hash_map. |
| Pred_t | Equality functor type. Same as for Linked_hash_map. |
| using flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator = Const_iterator |
Type for iterator pointing into a mutable structure of this type but actually that is not possible; so alias to Const_iterator.
Note these are standard semantics (see std::set, etc.).
| using flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::Reverse_iterator = Const_reverse_iterator |
Type for reverse iterator pointing into a mutable structure of this type but actually that is not possible; so alias to Const_reverse_iterator.
Note these are standard semantics (see std::set, etc.).
| flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::Linked_hash_set | ( | size_type | n_buckets = size_type(-1), |
| const Hash & | hasher_obj = Hash{}, |
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| const Pred & | pred = Pred{} |
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| ) |
Constructs empty structure with some basic parameters.
| n_buckets | Number of buckets for the unordered (hash) table. Special value -1 (default) will cause us to use whatever unordered_set<> would use by default. |
| hasher_obj | Instance of the hash function type (hasher_obj(k) -> size_t should be hash of Key k). |
| pred | Instance of the equality function type (pred(k1, k2) should return true if and only if the Keys are equal by value). |
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explicit |
Constructs structure with some basic parameters, and values initialized from initializer list.
The values are inserted as if insert(v) was called for each element v in values in reverse order. Since the canonical ordering places the newest (last inserted/touch()ed) element at the front of the ordering, that means that forward iteration through the set (right after this constructor runs) will yield values in the same order as in initializer list values.
| values | Values with which to fill the structure after initializing it. Typically you'd provide a series of keys like this: { key1, key2, ... }. They will appear in iterated sequence in the same order as they appear in this list. |
| n_buckets | See other constructor. |
| hasher_obj | See other constructor. |
| pred | See other constructor. |
| flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::Linked_hash_set | ( | const Linked_hash_set< Key_t, Hash_t, Pred_t > & | src | ) |
Constructs object that is a copy of the given source.
Equivalent to default-ction followed by operator=(src).
| src | Source object. |
| flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::Linked_hash_set | ( | Linked_hash_set< Key_t, Hash_t, Pred_t > && | src | ) |
Constructs object by making it equal to the given source, while the given source becomes as-if default-cted.
Equivalent to default-ction followed by operator=(std::move(src)).
This is a constant-time operation.
| src | Source object which is emptied. |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::begin |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::cbegin |
Synonym of const_newest().
Exists as standard container method (hence the odd formatting).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::cend |
Synonym of const_past_oldest().
Exists as standard container method (hence the odd formatting).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::const_newest |
Returns first, a/k/a "newest," element's iterator (to immutable element).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::const_oldest |
Returns first, a/k/a "oldest," element's reverse iterator (to immutable element).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::const_past_newest |
Returns one past last, a/k/a "newest," element's reverse iterator (to immutable element).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::const_past_oldest |
Returns one past last, a/k/a "oldest," element's iterator (to immutable element).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::size_type flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::count | ( | const Key & | key | ) | const |
Returns the number of times a key equal to the given one is present (as-if via find()) in the map: either 1 or 0.
| key | Key whose equal to find. |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::crbegin |
Synonym of const_oldest().
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::crend |
Synonym of const_past_newest().
Exists as standard container method.
| bool flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::empty |
Returns true if and only if container is empty.
Same performance as of unordered_set<>.
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::end |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::erase | ( | const Const_iterator & | it | ) |
Erases the element pointed to by the given valid iterator.
Behavior undefined if it is not valid. it becomes invalid.
| it | Iterator of element to erase. |
it, before *it was removed. | Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::erase | ( | const Const_iterator & | it_newest, |
| const Const_iterator & | it_past_oldest | ||
| ) |
Erases all elements in the range [it_newest, it_past_oldest).
Behavior undefined if a given iterator is invalid, or if the range is invalid. Corner case: an empty range is allowed; then this no-ops. Unless no-op, it_newest becomes invalid.
| it_newest | Iterator of first ("newest") element to erase. |
| it_past_oldest | Iterator of one past last ("oldest") element to erase. |
it_past_oldest copy. | Linked_hash_set< Key_t, Hash_t, Pred_t >::size_type flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::erase | ( | const Key & | key | ) |
Erases the element with the given key, if it exists.
find(key) equivalent is performed first. Return value indicates whether it existed.
| key | Key such that its equal's (if found) element will be erased. |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Const_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::find | ( | const Key & | key | ) | const |
Attempts to find value at the given key in the map.
Key presence is determined identically to how it would be done in an unordered_set<Key_t, Hash_t, Pred_t>, with the particular Hash and Pred instances given to ctor (typically their default-cted instances, typically occupying no memory).
The returned iterator (if valid) cannot be used to mutate the key inside the map.
| key | Key whose equal to find. |
this->end(). | std::pair< typename Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator, bool > flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::insert | ( | const Key & | key | ) |
Attempts to insert (copying it) the given keyinto the map; if key already in *this makes no change.
See also the overload which can avoid a copy and destructively move the key instead.
Return value indicates various info of interest about what occurred or did not occur. If inserted, the new element is considered "newest," as if by touch(). If not inserted, the existing element location is not affected (use touch() upon consulting the return value, if this is desirable).
| key | The key to attempt to insert. A copy of this value is placed in *this. |
key. | std::pair< typename Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator, bool > flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::insert | ( | Key && | key | ) |
Identical to the other overload, except that (if key not already present in *this) the key is moved, not copied, into *this.
| key | The key to attempt to insert (it is moved-from, if insertion occurs). |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::size_type flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::max_size |
Returns max number of elements that can be stored.
Same performance as of unordered_set<> + list<>.
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::newest |
Returns first, a/k/a "newest," element's iterator (to immutable element, due to nature of this type).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::oldest |
Returns first, a/k/a "oldest," element's reverse iterator (to immutable element, due to nature of this type).
| Linked_hash_set< Key_t, Hash_t, Pred_t > & flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::operator= | ( | const Linked_hash_set< Key_t, Hash_t, Pred_t > & | src | ) |
Overwrites this object with a copy of the given source.
We become equal to src but independent of it to a common-sense extent. In addition, the hasher instance and equality predicate are copied from src. Finally, a reasonable attempt is made to also make the internal structure of the hash map to be similar to that of `src.
| src | Source object. No-op if this == &src. |
*this. | Linked_hash_set< Key_t, Hash_t, Pred_t > & flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::operator= | ( | Linked_hash_set< Key_t, Hash_t, Pred_t > && | src | ) |
Overwrites this object making it identical to the given source, while the given source becomes as-if default-cted.
This is a constant-time operation, plus whatever is the cost of this->clear() (linear in pre-op .size()).
| src | Source object which is emptied; except no-op if this == &src. |
*this. | Linked_hash_set< Key_t, Hash_t, Pred_t >::Reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::past_newest |
Returns one past last, a/k/a "newest," element's reverse iterator (to immutable element, due to nature of this type).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::past_oldest |
Returns one past last, a/k/a "oldest," element's iterator (to immutable element, due to nature of this type).
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::rbegin |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::Reverse_iterator flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::rend |
| Linked_hash_set< Key_t, Hash_t, Pred_t >::size_type flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::size |
Returns number of elements stored.
Same performance as of unordered_set<>.
| void flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::swap | ( | Linked_hash_set< Key_t, Hash_t, Pred_t > & | other | ) |
Swaps the contents of this structure and other.
This is a constant-time operation, as internal representations are swapped instead of any copy-assignment.
swap() free function. It is generally best (equivalent but covers more generic cases) to use the ADL-enabled swap(a, b) pattern instead of this member function. That is: using std::swap; ...; swap(a, b);. (Details are outside our scope here; but in short ADL will cause the right thing to happen.)| other | The other structure. |
| void flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::touch | ( | const Const_iterator & | it | ) |
Given a valid iterator into the structure, makes the pointed-to element "newest" by moving it from wherever it is to be first in the iteration order.
Behavior undefined if iterator invalid.
The iterator continues to be valid.
| it | Iterator to an element of the structure. |
| bool flow::util::Linked_hash_set< Key_t, Hash_t, Pred_t >::touch | ( | const Key & | key | ) |
Given a key into the structure, makes the corresponding element "newest" by moving it from wherever it is to be first in the iteration order; or does nothing if no such key.
find(key) equivalent is performed first. Return value indicates whether it was found.
| key | Key whose equal to find. |
true if the key was found (even if it was already "newest"); false if not found.
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related |
Equivalent to val1.swap(val2).
| val1 | Object. |
| val2 | Object. |