Files
openfoam/src/OpenFOAM/containers/HashTables/HashTable/HashTableIO.C
Mark Olesen 89d3687278 ENH: HashTable sizing improvements
- earlier deletion of unpopulated HashTable on resizing:

  If the table is already clear (ie, has no entries),
  can immediately remove the old internal table before reallocating
  the newly sized table, which may avoid a needless memory spike.

- reserve() method:

  Naming and general behaviour as per std::unordered_map.
  It behaves similarly to the resize() method but is supplied the
  number of elements instead of the capacity, which can be a more
  natural way of specifying the storage requirements.
  Additionally, reserve() will only increase the table capacity for
  behaviour similar to DynamicList and std::vector, std::string etc.

  Old:
     labelHashSet set;
     set.resize(2*nElems);

  Now:
     labelHashSet set;
     set.reserve(nElems);

- remove unused HashTable(Istream&, label) constructor

STYLE: static_cast of (nullptr) and std::fill_n for filling table
2023-10-11 18:11:37 +00:00

284 lines
6.8 KiB
C

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | www.openfoam.com
\\/ M anipulation |
-------------------------------------------------------------------------------
Copyright (C) 2011-2016 OpenFOAM Foundation
Copyright (C) 2017-2023 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
\*---------------------------------------------------------------------------*/
#include "HashTable.H"
#include "Istream.H"
#include "Ostream.H"
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
template<class T, class Key, class Hash>
Foam::HashTable<T, Key, Hash>::HashTable(Istream& is)
:
HashTable<T, Key, Hash>()
{
operator>>(is, *this);
}
// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
template<class T, class Key, class Hash>
Foam::Ostream& Foam::HashTable<T, Key, Hash>::printInfo(Ostream& os) const
{
label used = 0;
label maxChain = 0;
unsigned avgChain = 0;
for (label i=0; i < capacity_; ++i)
{
label count = 0;
for (node_type* ep = table_[i]; ep; ep = ep->next_)
{
++count;
}
if (count)
{
++used;
avgChain += count;
if (maxChain < count)
{
maxChain = count;
}
}
}
os << "HashTable<T,Key,Hash>"
<< " elements:" << size() << " slots:" << used << "/" << capacity_
<< " chaining(avg/max):" << (used ? (float(avgChain)/used) : 0)
<< "/" << maxChain << endl;
return os;
}
template<class T, class Key, class Hash>
Foam::Ostream& Foam::HashTable<T, Key, Hash>::writeKeys
(
Ostream& os,
const label shortLen
) const
{
// Similar to UList::writeList version except the following:
// - the keys can never be uniform
// - never write in binary
label i = this->size();
if
(
(i <= 1 || !shortLen)
|| (i <= shortLen)
)
{
// Write size and start delimiter
os << i << token::BEGIN_LIST;
i = 0;
for (const_iterator iter = this->cbegin(); iter != this->cend(); ++iter)
{
if (i++) os << token::SPACE;
os << iter.key();
}
os << token::END_LIST; // End delimiter
}
else
{
// Write size and start delimiter
os << nl << i << nl << token::BEGIN_LIST << nl;
for (const_iterator iter = this->cbegin(); iter != this->cend(); ++iter)
{
os << iter.key() << nl;
}
os << token::END_LIST << nl; // End delimiter
}
os.check(FUNCTION_NAME);
return os;
}
template<class T, class Key, class Hash>
Foam::Istream& Foam::HashTable<T, Key, Hash>::readTable
(
Istream& is
)
{
HashTable<T, Key, Hash>& tbl = *this;
// Anull existing table
tbl.clear();
is.fatalCheck(FUNCTION_NAME);
token tok(is);
is.fatalCheck
(
"operator>>(Istream&, HashTable&) : "
"reading first token"
);
if (tok.isLabel())
{
const label len = tok.labelToken();
// Read beginning of contents
const char delimiter = is.readBeginList("HashTable");
if (len)
{
if (delimiter != token::BEGIN_LIST)
{
FatalIOErrorInFunction(is)
<< "incorrect first token, '(', found "
<< tok.info() << nl
<< exit(FatalIOError);
}
tbl.reserve(tbl.size() + len);
for (label i=0; i<len; ++i)
{
Key key;
is >> key; // Read the key
T& val = tbl(key); // Insert nameless T() into table
is >> val; // Read directly into the table value
is.fatalCheck
(
"operator>>(Istream&, HashTable&) : "
"reading entry"
);
}
}
// Read end of contents
is.readEndList("HashTable");
}
else if (tok.isPunctuation(token::BEGIN_LIST))
{
is >> tok;
while (!tok.isPunctuation(token::END_LIST))
{
is.putBack(tok);
Key key;
is >> key; // Read the key
T& val = tbl(key); // Insert nameless T() into table
is >> val; // Read directly into the table value
is.fatalCheck
(
"operator>>(Istream&, HashTable&) : "
"reading entry"
);
is >> tok;
}
}
else
{
FatalIOErrorInFunction(is)
<< "incorrect first token, expected <int> or '(', found "
<< tok.info() << nl
<< exit(FatalIOError);
}
is.fatalCheck(FUNCTION_NAME);
return is;
}
template<class T, class Key, class Hash>
Foam::Ostream& Foam::HashTable<T, Key, Hash>::writeTable
(
Ostream& os
) const
{
const HashTable<T, Key, Hash>& tbl = *this;
const label len = tbl.size();
if (len)
{
// Size and start list delimiter
os << nl << len << nl << token::BEGIN_LIST << nl;
// Contents
for (auto iter = tbl.cbegin(); iter != tbl.cend(); ++iter)
{
iter.print(os) << nl;
}
os << token::END_LIST; // End list delimiter
}
else
{
// Empty hash table
os << len << token::BEGIN_LIST << token::END_LIST;
}
os.check(FUNCTION_NAME);
return os;
}
// * * * * * * * * * * * * * * * IOstream Operators * * * * * * * * * * * * //
template<class T, class Key, class Hash>
Foam::Istream& Foam::operator>>
(
Istream& is,
HashTable<T, Key, Hash>& tbl
)
{
return tbl.readTable(is);
}
template<class T, class Key, class Hash>
Foam::Ostream& Foam::operator<<
(
Ostream& os,
const HashTable<T, Key, Hash>& tbl
)
{
return tbl.writeTable(os);
}
// ************************************************************************* //