mirror of
https://github.com/JakubMelka/PDF4QT.git
synced 2024-12-29 09:40:26 +01:00
261 lines
8.8 KiB
C++
261 lines
8.8 KiB
C++
// Copyright (C) 2021 Jakub Melka
|
|
//
|
|
// This file is part of PDF4QT.
|
|
//
|
|
// PDF4QT is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Lesser General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// with the written consent of the copyright owner, any later version.
|
|
//
|
|
// PDF4QT 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 Lesser General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Lesser General Public License
|
|
// along with PDF4QT. If not, see <https://www.gnu.org/licenses/>.
|
|
|
|
#ifndef PDFALGORITHMLCS_H
|
|
#define PDFALGORITHMLCS_H
|
|
|
|
#include "pdfglobal.h"
|
|
|
|
namespace pdf
|
|
{
|
|
|
|
class PDFAlgorithmLongestCommonSubsequenceBase
|
|
{
|
|
public:
|
|
|
|
enum SequenceItemFlag
|
|
{
|
|
None = 0x0000,
|
|
MovedLeft = 0x0001, ///< Item has been moved from this position (is present in a sequence no. 1)
|
|
MovedRight = 0x0002, ///< Item has been moved to this position (is present in a sequence no. 2)
|
|
Moved = 0x0004, ///< Index of item has been changed
|
|
Added = 0x0008, ///< Item has been added to a sequence no. 2
|
|
Removed = 0x0010, ///< Item has been removed from a sequence no. 1
|
|
Replaced = 0x0020, ///< Item has been replaced (or sequence of items has been replaced)
|
|
};
|
|
Q_DECLARE_FLAGS(SequenceItemFlags, SequenceItemFlag)
|
|
|
|
struct SequenceItem
|
|
{
|
|
size_t index1 = std::numeric_limits<size_t>::max();
|
|
size_t index2 = std::numeric_limits<size_t>::max();
|
|
SequenceItemFlags flags = None;
|
|
|
|
bool isLeftValid() const { return index1 != std::numeric_limits<size_t>::max(); }
|
|
bool isRightValid() const { return index2 != std::numeric_limits<size_t>::max(); }
|
|
bool isLeft() const { return isLeftValid() && !isRightValid(); }
|
|
bool isRight() const { return isRightValid() && !isLeftValid(); }
|
|
bool isMatch() const { return isLeftValid() && isRightValid(); }
|
|
bool isMovedLeft() const { return flags.testFlag(MovedLeft); }
|
|
bool isMovedRight() const { return flags.testFlag(MovedRight); }
|
|
bool isMoved() const { return flags.testFlag(Moved); }
|
|
bool isAdded() const { return flags.testFlag(Added); }
|
|
bool isRemoved() const { return flags.testFlag(Removed); }
|
|
bool isReplaced() const { return flags.testFlag(Replaced); }
|
|
bool isModified() const { return isAdded() || isRemoved() || isReplaced(); }
|
|
|
|
void markMovedLeft() { flags.setFlag(MovedLeft); }
|
|
void markMovedRight() { flags.setFlag(MovedRight); }
|
|
void markMoved() { flags.setFlag(Moved); }
|
|
void markAdded() { flags.setFlag(Added); }
|
|
void markRemoved() { flags.setFlag(Removed); }
|
|
void markReplaced() { flags.setFlag(Replaced); }
|
|
};
|
|
|
|
using Sequence = typename std::vector<SequenceItem>;
|
|
using SequenceIterator = typename Sequence::iterator;
|
|
using SequenceItemRange = typename std::pair<SequenceIterator, SequenceIterator>;
|
|
using SequenceItemRanges = typename std::vector<SequenceItemRange>;
|
|
|
|
/// Marks a sequence with set of flags representing added/removed/replaced/moved
|
|
/// items. Moved items sequences must be sorted.
|
|
/// \param sequence Sequence to be marked
|
|
/// \param movedItemsLeft Sorted sequence of left indices, which have been moved
|
|
/// \param movedItemsRight sorted sequence of right indices, which have been moved
|
|
static void markSequence(Sequence& sequence,
|
|
const std::vector<size_t>& movedItemsLeft,
|
|
const std::vector<size_t>& movedItemsRight);
|
|
|
|
/// Returns item ranges, which should be checked - for example,
|
|
/// for text modification.
|
|
/// \param sequence Sequence
|
|
static SequenceItemRanges getModifiedRanges(Sequence& sequence);
|
|
|
|
/// Collect flags from given item range
|
|
/// \param range Range
|
|
static SequenceItemFlags collectFlags(const SequenceItemRange& range);
|
|
};
|
|
|
|
/// Algorithm for computing longest common subsequence, on two sequences
|
|
/// of objects, which are implementing operator "==" (equal operator).
|
|
/// Constructor takes bidirectional iterators to the sequence. So, iterators
|
|
/// are requred to be bidirectional.
|
|
template<typename Iterator, typename Comparator>
|
|
class PDFAlgorithmLongestCommonSubsequence : public PDFAlgorithmLongestCommonSubsequenceBase
|
|
{
|
|
public:
|
|
PDFAlgorithmLongestCommonSubsequence(Iterator it1,
|
|
Iterator it1End,
|
|
Iterator it2,
|
|
Iterator it2End,
|
|
Comparator comparator);
|
|
|
|
|
|
void perform();
|
|
|
|
const Sequence& getSequence() const { return m_sequence; }
|
|
|
|
private:
|
|
Iterator m_it1;
|
|
Iterator m_it1End;
|
|
Iterator m_it2;
|
|
Iterator m_it2End;
|
|
|
|
size_t m_size1;
|
|
size_t m_size2;
|
|
size_t m_matrixSize;
|
|
|
|
Comparator m_comparator;
|
|
|
|
std::vector<bool> m_backtrackData;
|
|
Sequence m_sequence;
|
|
};
|
|
|
|
template<typename Iterator, typename Comparator>
|
|
PDFAlgorithmLongestCommonSubsequence<Iterator, Comparator>::PDFAlgorithmLongestCommonSubsequence(Iterator it1,
|
|
Iterator it1End,
|
|
Iterator it2,
|
|
Iterator it2End,
|
|
Comparator comparator) :
|
|
m_it1(std::move(it1)),
|
|
m_it1End(std::move(it1End)),
|
|
m_it2(std::move(it2)),
|
|
m_it2End(std::move(it2End)),
|
|
m_size1(0),
|
|
m_size2(0),
|
|
m_matrixSize(0),
|
|
m_comparator(std::move(comparator))
|
|
{
|
|
m_size1 = std::distance(m_it1, m_it1End) + 1;
|
|
m_size2 = std::distance(m_it2, m_it2End) + 1;
|
|
m_matrixSize = m_size1 * m_size2;
|
|
}
|
|
|
|
template<typename Iterator, typename Comparator>
|
|
void PDFAlgorithmLongestCommonSubsequence<Iterator, Comparator>::perform()
|
|
{
|
|
m_backtrackData.resize(m_matrixSize);
|
|
m_sequence.clear();
|
|
|
|
std::vector<size_t> rowTop(m_size1, size_t());
|
|
std::vector<size_t> rowBottom(m_size1, size_t());
|
|
|
|
// Jakub Melka: we will have columns consisting of it1...it1End
|
|
// and rows consisting of it2...it2End. We iterate trough rows,
|
|
// and for each row, we update longest common subsequence data.
|
|
|
|
auto it2 = m_it2;
|
|
for (size_t i2 = 1; i2 < m_size2; ++i2, ++it2)
|
|
{
|
|
auto it1 = m_it1;
|
|
for (size_t i1 = 1; i1 < m_size1; ++i1, ++it1)
|
|
{
|
|
if (m_comparator(*it1, *it2))
|
|
{
|
|
// We have match
|
|
rowBottom[i1] = rowTop[i1 - 1] + 1;
|
|
}
|
|
else
|
|
{
|
|
const size_t leftCellValue = rowBottom[i1 - 1];
|
|
const size_t upperCellValue = rowTop[i1];
|
|
bool isLeftBigger = leftCellValue > upperCellValue;
|
|
|
|
if (isLeftBigger)
|
|
{
|
|
rowBottom[i1] = leftCellValue;
|
|
m_backtrackData[i2 * m_size1 + i1] = true;
|
|
}
|
|
else
|
|
{
|
|
rowBottom[i1] = upperCellValue;
|
|
m_backtrackData[i2 * m_size1 + i1] = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Bottom row will become top row
|
|
std::swap(rowTop, rowBottom);
|
|
}
|
|
|
|
size_t i1 = m_size1 - 1;
|
|
size_t i2 = m_size2 - 1;
|
|
|
|
while (i1 > 0 && i2 > 0)
|
|
{
|
|
SequenceItem item;
|
|
|
|
const size_t index1 = i1 - 1;
|
|
const size_t index2 = i2 - 1;
|
|
|
|
auto it1 = std::next(m_it1, index1);
|
|
auto it2 = std::next(m_it2, index2);
|
|
|
|
if (m_comparator(*it1, *it2))
|
|
{
|
|
item.index1 = index1;
|
|
item.index2 = index2;
|
|
|
|
--i1;
|
|
--i2;
|
|
}
|
|
else
|
|
{
|
|
if (m_backtrackData[i2 * m_size1 + i1])
|
|
{
|
|
item.index1 = index1;
|
|
--i1;
|
|
}
|
|
else
|
|
{
|
|
item.index2 = index2;
|
|
--i2;
|
|
}
|
|
}
|
|
|
|
m_sequence.push_back(item);
|
|
}
|
|
|
|
while (i1 > 0)
|
|
{
|
|
SequenceItem item;
|
|
|
|
const size_t index1 = i1 - 1;
|
|
item.index1 = index1;
|
|
--i1;
|
|
|
|
m_sequence.push_back(item);
|
|
}
|
|
|
|
while (i2 > 0)
|
|
{
|
|
SequenceItem item;
|
|
|
|
const size_t index2 = i2 - 1;
|
|
item.index2 = index2;
|
|
--i2;
|
|
|
|
m_sequence.push_back(item);
|
|
}
|
|
|
|
std::reverse(m_sequence.begin(), m_sequence.end());
|
|
}
|
|
|
|
} // namespace pdf
|
|
|
|
#endif // PDFALGORITHMLCS_H
|