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Mar 15, 2019
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P0920R2 Precalculated hash values in lookup #2718

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154 changes: 149 additions & 5 deletions source/containers.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -2298,8 +2298,9 @@
\end{itemize}
where \tcode{r1} and \tcode{r2} are keys of elements in \tcode{a_tran},
\item \tcode{n} denotes a value of type \tcode{size_type},
\item \tcode{z} denotes a value of type \tcode{float}, and
\item \tcode{nh} denotes a non-const rvalue of type \tcode{X::node_type}.
\item \tcode{z} denotes a value of type \tcode{float},
\item \tcode{nh} denotes a non-const rvalue of type \tcode{X::node_type}, and
\item \tcode{hk} and \tcode{hke} denote values of type \tcode{size_t}.
\end{itemize}

% Local command to index names as members of all unordered containers.
Expand Down Expand Up @@ -2753,12 +2754,29 @@
& Average case \bigoh{1}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{b.find(k, hk)}
& \tcode{iterator}; \br \tcode{const_iterator} for const \tcode{b}.
& \expects \tcode{b.hash_function()(k)} equals \tcode{hk}.\br
\returns an iterator pointing to an element with key equivalent to
\tcode{k}, or \tcode{b.end()} if no such element exists.
& Average case \bigoh{1}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{a_tran.find(ke)}
& \tcode{iterator}; \br \tcode{const_iterator} for const \tcode{a_tran}.
& \returns An iterator pointing to an element with key equivalent to
\tcode{ke}, or \tcode{a_tran.end()} if no such element exists.
& Average case \bigoh{1},
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid wverfull
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\tcode{a_tran.find(ke, hke)}
& \tcode{iterator}; \br \tcode{const_iterator} for const \tcode{a_tran}.
& \expects \tcode{a_tran.hash_function()(ke)} equals \tcode{hke}.\br
\returns an iterator pointing to an element with key equivalent to
\tcode{ke}, or \tcode{a_tran.end()} if no such element exists.%
& Average case \bigoh{1},
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\indexunordmem{count}%
Expand All @@ -2768,6 +2786,13 @@
& Average case \bigoh{\tcode{b.count(k)}}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{b.count(k, hk)}
& \tcode{size_type}
& \expects \tcode{b.hash_function()(k)} equals \tcode{hk}.\br
\returns the number of elements with key equivalent to \tcode{k}.%
& Average case \bigoh{\tcode{b.count(k)}}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{a_tran.count(ke)}
& \tcode{size_type}
& \returns The number of elements with key equivalent to \tcode{ke}.%
Expand All @@ -2776,16 +2801,40 @@
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\tcode{a_tran.count(ke, hke)}
& \tcode{size_type}
& \expects \tcode{b.hash_function()(ke)} equals \tcode{hke}.\br
\returns the number of elements with key equivalent to \tcode{ke}.%
& Average case
\bigoh{\tcode{a_tran.}\br{}\tcode{count(ke)}}, % avoid overfull
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\indexunordmem{contains}%
\tcode{b.contains(k)}
& \tcode{bool}
& Equivalent to \tcode{b.find(k) != b.end()}%
& \effects Equivalent to \tcode{b.find(k) != b.end()}%
& Average case \bigoh{1}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{b.contains(k, hk)}
& \tcode{bool}
& \expects \tcode{b.hash_function()(ke)} equals \tcode{hke}.\br
\effects Equivalent to \tcode{b.find(k) != b.end()}%
& Average case \bigoh{1}, worst case \bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{a_tran.contains(ke)}
& \tcode{bool}
& Equivalent to \tcode{a_tran.find(ke) != a_tran.end()}%
& \effects Equivalent to \tcode{a_tran.find(ke) != a_tran.end()}%
& Average case \bigoh{1},
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\tcode{a_tran.contains(ke, hke)}
& \tcode{bool}
& \expects \tcode{a_tran.hash_function()(ke)} equals \tcode{hke}.\br
\effects Equivalent to \tcode{a_tran.find(ke, hke) != a_tran.end()}%
& Average case \bigoh{1},
worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
Expand All @@ -2801,6 +2850,17 @@
\bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{b.equal_range(k, hk)}
& \tcode{pair<iterator, iterator>}; \br
\tcode{pair<const_iterator, const_iterator>} for const \tcode{b}.
& \expects \tcode{b.hash_function()(k)} equals \tcode{hk}.\br
\returns a range containing all elements with keys equivalent to
\tcode{k}. Returns \tcode{make_pair(b.end(), b.end())} if
no such elements exist.%
& Average case \bigoh{\tcode{b.count(k)}}. Worst case
\bigoh{\tcode{b.size()}}.
\\ \rowsep
%
\tcode{a_tran.equal_range(ke)}
& \tcode{pair<iterator, iterator>}; \br
\tcode{pair<const_iterator, const_iterator>} for const \tcode{a_tran}.
Expand All @@ -2811,6 +2871,18 @@
\bigoh{\tcode{a_tran.}\br{}\tcode{count(ke)}}. % avoid overfull
Worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
%
\tcode{a_tran.equal_range(ke, hke)}
& \tcode{pair<iterator, iterator>}; \br
\tcode{pair<const_iterator, const_iterator>} for const \tcode{a_tran}.
& \expects \tcode{a_tran.hash_function()(ke)} equals \tcode{hke}.\br
\returns a range containing all elements with keys equivalent to
\tcode{ke}. Returns \tcode{make_pair(a_tran.end(), a_tran.end())} if
no such elements exist.%
& Average case
\bigoh{\tcode{a_tran.}\br{}\tcode{count(ke)}}. % avoid overfull
Worst case \bigoh{\tcode{a_tran.}\br{}\tcode{size()}}. % avoid overfull
\\ \rowsep
\indexunordmem{bucket_count}%
\tcode{b.bucket_count()}
& \tcode{size_type}
Expand Down Expand Up @@ -7964,22 +8036,40 @@
// map operations
iterator find(const key_type& k);
const_iterator find(const key_type& k) const;
iterator find(const key_type& k, size_t hash);
const_iterator find(const key_type& k, size_t hash) const;
template <class K>
iterator find(const K& k);
template <class K>
const_iterator find(const K& k) const;
template <class K>
iterator find(const K& k, size_t hash);
template <class K>
const_iterator find(const K& k, size_t hash) const;
size_type count(const key_type& k) const;
size_type count(const key_type& k, size_t hash) const;
template <class K>
size_type count(const K& k) const;
template <class K>
size_type count(const K& k, size_t hash) const;
bool contains(const key_type& k) const;
bool contains(const key_type& k, size_t hash) const;
template <class K>
bool contains(const K& k) const;
template <class K>
bool contains(const K& k, size_t hash) const;
pair<iterator, iterator> equal_range(const key_type& k);
pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
pair<iterator, iterator> equal_range(const key_type& k, size_t hash);
pair<const_iterator, const_iterator> equal_range(const key_type& k, size_t hash) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k, size_t hash);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k, size_t hash) const;

// \ref{unord.map.elem}, element access
mapped_type& operator[](const key_type& k);
Expand Down Expand Up @@ -8534,22 +8624,40 @@
// map operations
iterator find(const key_type& k);
const_iterator find(const key_type& k) const;
iterator find(const key_type& k, size_t hash);
const_iterator find(const key_type& k, size_t hash) const;
template <class K>
iterator find(const K& k);
template <class K>
const_iterator find(const K& k) const;
template <class K>
iterator find(const K& k, size_t hash);
template <class K>
const_iterator find(const K& k, size_t hash) const;
size_type count(const key_type& k) const;
size_type count(const key_type& k, size_t hash) const;
template <class K>
size_type count(const K& k) const;
template <class K>
size_type count(const K& k, size_t hash) const;
bool contains(const key_type& k) const;
bool contains(const key_type& k, size_t hash) const;
template <class K>
bool contains(const K& k) const;
template <class K>
bool contains(const K& k, size_t hash) const;
pair<iterator, iterator> equal_range(const key_type& k);
pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
pair<iterator, iterator> equal_range(const key_type& k, size_t hash);
pair<const_iterator, const_iterator> equal_range(const key_type& k, size_t hash) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k, size_t hash);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k, size_t hash) const;

// bucket interface
size_type bucket_count() const noexcept;
Expand Down Expand Up @@ -8896,22 +9004,40 @@
// set operations
iterator find(const key_type& k);
const_iterator find(const key_type& k) const;
iterator find(const key_type& k, size_t hash);
const_iterator find(const key_type& k, size_t hash) const;
template <class K>
iterator find(const K& k);
template <class K>
const_iterator find(const K& k) const;
template <class K>
iterator find(const K& k, size_t hash);
template <class K>
const_iterator find(const K& k, size_t hash) const;
size_type count(const key_type& k) const;
size_type count(const key_type& k, size_t hash) const;
template <class K>
size_type count(const K& k) const;
template <class K>
size_type count(const K& k, size_t hash) const;
bool contains(const key_type& k) const;
bool contains(const key_type& k, size_t hash) const;
template <class K>
bool contains(const K& k) const;
template <class K>
bool contains(const K& k, size_t hash) const;
pair<iterator, iterator> equal_range(const key_type& k);
pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
pair<iterator, iterator> equal_range(const key_type& k, size_t hash);
pair<const_iterator, const_iterator> equal_range(const key_type& k, size_t hash) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k, size_t hash);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k, size_t hash) const;

// bucket interface
size_type bucket_count() const noexcept;
Expand Down Expand Up @@ -9220,22 +9346,40 @@
// set operations
iterator find(const key_type& k);
const_iterator find(const key_type& k) const;
iterator find(const key_type& k, size_t hash);
const_iterator find(const key_type& k, size_t hash) const;
template <class K>
iterator find(const K& k);
template <class K>
const_iterator find(const K& k) const;
template <class K>
iterator find(const K& k, size_t hash);
template <class K>
const_iterator find(const K& k, size_t hash) const;
size_type count(const key_type& k) const;
size_type count(const key_type& k, size_t hash) const;
template <class K>
size_type count(const K& k) const;
template <class K>
size_type count(const K& k, size_t hash) const;
bool contains(const key_type& k) const;
bool contains(const key_type& k, size_t hash) const;
template <class K>
bool contains(const K& k) const;
template <class K>
bool contains(const K& k, size_t hash) const;
pair<iterator, iterator> equal_range(const key_type& k);
pair<const_iterator, const_iterator> equal_range(const key_type& k) const;
pair<iterator, iterator> equal_range(const key_type& k, size_t hash);
pair<const_iterator, const_iterator> equal_range(const key_type& k, size_t hash) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k) const;
template <class K>
pair<iterator, iterator> equal_range(const K& k, size_t hash);
template <class K>
pair<const_iterator, const_iterator> equal_range(const K& k, size_t hash) const;

// bucket interface
size_type bucket_count() const noexcept;
Expand Down
2 changes: 2 additions & 0 deletions source/support.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -598,6 +598,8 @@
\tcode{<map>} \tcode{<set>} \\ \rowsep
\defnlibxname{cpp_lib_generic_unordered_lookup} & \tcode{201811L} &
\tcode{<unordered_map>} \tcode{<unordered_set>} \\ \rowsep
\defnlibxname{cpp_lib_generic_unordered_hash_lookup} & \tcode{201902L} &
\tcode{<unordered_map>} \tcode{<unordered_set>} \\ \rowsep
\defnlibxname{cpp_lib_hardware_interference_size} & \tcode{201703L} &
\tcode{<new>} \\ \rowsep
\defnlibxname{cpp_lib_has_unique_object_representations} & \tcode{201606L} &
Expand Down