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/******************************************************************************
* Top contributors (to current version):
* MikolasJanota
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
* in the top-level source directory and their institutional affiliations.
* All rights reserved. See the file COPYING in the top-level source
* directory for licensing information.
* ****************************************************************************
*
* Implementation of a trie that store subsets of tuples of term indices
* that are not yielding useful instantiations. of quantifier instantiation.
* This is used in the term_tuple_enumerator.
*/
#include "theory/quantifiers/index_trie.h"
namespace cvc5 {
namespace theory {
namespace quantifiers {
void IndexTrie::add(const std::vector<bool>& mask,
const std::vector<size_t>& values)
{
const size_t cardinality = std::count(mask.begin(), mask.end(), true);
if (d_ignoreFullySpecified && cardinality == mask.size())
{
return;
}
d_root = addRec(d_root, 0, cardinality, mask, values);
}
void IndexTrie::freeRec(IndexTrieNode* n)
{
if (!n)
{
return;
}
for (auto c : n->d_children)
{
freeRec(c.second);
}
freeRec(n->d_blank);
delete n;
}
bool IndexTrie::findRec(const IndexTrieNode* n,
size_t index,
const std::vector<size_t>& members,
size_t& nonBlankLength) const
{
if (!n || index >= members.size())
{
return true; // all elements of members matched
}
if (n->d_blank && findRec(n->d_blank, index + 1, members, nonBlankLength))
{
return true; // found in the blank branch
}
nonBlankLength = index + 1;
for (const auto& c : n->d_children)
{
if (c.first == members[index]
&& findRec(c.second, index + 1, members, nonBlankLength))
{
return true; // found in the matching subtree
}
}
return false;
}
IndexTrieNode* IndexTrie::addRec(IndexTrieNode* n,
size_t index,
size_t cardinality,
const std::vector<bool>& mask,
const std::vector<size_t>& values)
{
if (!n)
{
return nullptr; // this tree matches everything, no point to add
}
if (cardinality == 0) // all blanks, all strings match
{
freeRec(n);
return nullptr;
}
Assert(index < mask.size());
if (!mask[index]) // blank position in the added vector
{
auto blank = n->d_blank ? n->d_blank : new IndexTrieNode();
n->d_blank = addRec(blank, index + 1, cardinality, mask, values);
return n;
}
Assert(cardinality);
for (auto& edge : n->d_children)
{
if (edge.first == values[index])
{
// value already amongst the children
edge.second =
addRec(edge.second, index + 1, cardinality - 1, mask, values);
return n;
}
}
// new child needs to be added
auto child =
addRec(new IndexTrieNode(), index + 1, cardinality - 1, mask, values);
n->d_children.push_back(std::make_pair(values[index], child));
return n;
}
} // namespace quantifiers
} // namespace theory
} // namespace cvc5
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