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46c263fbae
* include/abg-diff-utils.h (deep_ptr_eq_functor::operator()): Make the overloads be const. Signed-off-by: Dodji Seketeli <dodji@redhat.com>
2080 lines
62 KiB
C++
2080 lines
62 KiB
C++
// -*- Mode: C++ -*-
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//
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// Copyright (C) 2013-2015 Red Hat, Inc.
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//
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// This file is part of the GNU Application Binary Interface Generic
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// Analysis and Instrumentation Library (libabigail). This library is
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// free software; you can redistribute it and/or modify it under the
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// terms of the GNU Lesser General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option) any
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// later version.
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// General Lesser Public License for more details.
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// You should have received a copy of the GNU Lesser General Public
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// License along with this program; see the file COPYING-LGPLV3. If
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// not, see <http://www.gnu.org/licenses/>.
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/// @file
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///
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/// This file declares types and operations implementing the "O(ND)
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/// Difference Algorithm" (aka diff2) from Eugene W. Myers, to compute
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/// the difference between two sequences.
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///
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/// To understand what is going on here, one must read the paper at
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/// http://www.xmailserver.org/diff2.pdf. Throughout this file, that
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/// paper is referred to as "the paper".
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///
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/// The implementations goes as far as calculating the shortest edit
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/// script (the set of insertions and deletions) for transforming a
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/// sequence into another. The main entry point for that is the
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/// compute_diff() function.
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#ifndef __ABG_DIFF_UTILS_H__
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#define __ABG_DIFF_UTILS_H__
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#include <stdexcept>
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#include <cassert>
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#include <cstdlib>
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#include <ostream>
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#include <string>
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#include <vector>
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#include <sstream>
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#include <tr1/memory>
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namespace abigail
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{
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/// @brief Libabigail's core diffing algorithms
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///
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/// This is the namespace defining the core diffing algorithm used by
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/// libabigail @ref comparison tools. This based on the diff
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/// algorithm from Eugene Myers.
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namespace diff_utils
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{
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using std::tr1::shared_ptr;
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// Inject the names from std:: below into this namespace
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using std::string;
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using std::ostream;
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using std::vector;
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using std::abs;
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using std::ostringstream;
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/// A class representing a vertex in an edit graph, as explained in
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/// the paper. A vertex is a basically a pair of coordinates
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/// (abscissa and ordinate).
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class point
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{
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int x_;
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int y_;
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bool empty_;
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public:
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point()
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: x_(-1), y_(-1),empty_(true)
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{}
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point(int x, int y)
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: x_(x), y_(y), empty_(false)
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{}
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point(const point& p)
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: x_(p.x()), y_(p.y()), empty_(p.is_empty())
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{}
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int
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x() const
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{return x_;}
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void
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x(int x)
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{
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x_ = x;
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empty_ = false;
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}
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int
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y() const
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{return y_;}
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void
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y(int y)
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{
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y_ = y;
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empty_ = false;
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}
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void
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set(int x, int y)
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{
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x_ = x;
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y_ = y;
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empty_ = false;
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}
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void
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set(int x, int y, bool empty)
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{
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x_ = x;
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y_ = y;
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empty_ = empty;
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}
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void
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add(int ax, int ay)
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{set (x() + ax, y() + ay);}
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bool
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operator!=(const point& o) const
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{return (x() != o.x() || y() != o.y() || is_empty() != o.is_empty());}
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bool
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operator==(const point& o) const
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{return !(operator!=(o));}
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bool
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operator<(const point& o) const
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{return (x() < o.x() && y() < o.y());}
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bool
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operator>(const point& o) const
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{return (x() > o.x() && y() > o.y());}
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bool
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operator<=(const point& o) const
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{return (x() <= o.x() && y() <= o.y());}
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bool
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operator>=(const point& o) const
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{return (x() >= o.x() && y() >= o.y());}
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point
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operator+(int val) const
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{return point(x() + val, y() + val);}
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point
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operator-(int val) const
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{return point(x() - val, y() - val);}
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point&
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operator+= (int val)
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{
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set(x_ + val, y_ + val);
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return *this;
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}
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point&
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operator-= (int val)
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{return (*this) += (-val);}
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point&
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operator--()
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{return (*this) -= 1;}
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point&
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operator++()
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{return (*this) += 1;}
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point
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operator--(int)
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{
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point tmp(*this);
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(*this)--;
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return tmp;
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}
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point
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operator++(int)
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{
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point tmp(*this);
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(*this)++;
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return tmp;
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}
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point&
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operator=(int val)
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{
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set(val, val);
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return *this;
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}
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point&
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operator=(const point& p)
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{
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set(p.x(), p.y(), p.is_empty());
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return *this;
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}
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bool
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is_empty() const
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{return empty_;}
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operator bool () const
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{return !is_empty();}
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bool
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operator!() const
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{return is_empty();}
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void
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clear()
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{
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x_ = -1;
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y_ = -1;
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empty_ = true;
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}
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};// end point
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/// The abstraction of the Snake concept, from the paper.
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///
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/// In a given path from the edit graph, a snake is a non-diagonal
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/// edge followed by zero or more diagonal edges.
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///
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/// The starting poing of the non-diagonal edge is the beginning of
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/// the snake. This is given by the snake::begin() method. This point
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/// is not explicitely referenced in the paper, but we need it for
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/// some grunt implementation details of the algorithm.
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///
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/// The end point of the non-diagonal edge is the intermediate point
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/// of the snake; it's given by the snake::intermediate() method.
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/// This point is what is referred to as "the begining of the snake"
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/// in the paper.
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///
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/// The end point of the first diagonal edge is given by the
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/// snake::diagonal_start() method.
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///
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/// The end point of the last diagonal edge is given by the
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/// snake::end() method. Note that when the snake contains no
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/// diagonal edge, snake::intermediate(), and snake::end() return the
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/// same point; snake::diagonal_start() contains an empty point (i.e,
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/// a point for which point::is_empty() returns true).
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class snake
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{
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point begin_, intermediate_, diagonal_start_, end_;
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bool forward_;
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public:
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/// Default constructor for snake.
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snake()
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: forward_(false)
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{}
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/// Constructor from the beginning, intermediate and end points.
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///
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/// @param b the beginning point of the snake. That is, the
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/// starting point of the non-diagonal edge.
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///
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/// @param i the intermediate point of the snake. That is, the end
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/// point of the non-diagonal edge.
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///
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/// @param e the end point of the snake. That is the end point of
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/// the last diagonal edge.
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snake(const point& b,
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const point& i,
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const point& e)
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: begin_(b), intermediate_(i),
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end_(e), forward_(false)
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{}
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/// Constructor from the beginning, intermediate and end points.
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///
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/// @param b the beginning point of the snake. That is, the
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/// starting point of the non-diagonal edge.
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///
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/// @param i the intermediate point of the snake. That is, the end
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/// point of the non-diagonal edge.
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///
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/// @param d the beginning of the diagonal edge. That is the end of
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/// the first diagonal edge of the snake.
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///
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/// @param e the end point of the snake. That is the end point of
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/// the last diagonal edge.
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snake(const point& b,
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const point& i,
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const point& d,
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const point& e)
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: begin_(b), intermediate_(i),
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diagonal_start_(d), end_(e),
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forward_(false)
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{}
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/// Getter for the starting point of the non-diagonal edge of the
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/// snake.
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///
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/// @return the starting point of the non-diagonal edge of the snake
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const point&
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begin() const
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{return begin_;}
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/// Getter for the starting point of the non-diagonal edge of the
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/// snake, aka begin point.
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///
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///@param p the new begin point.
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void
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begin(const point& p)
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{begin_ = p;}
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/// Getter for the end point of the non-diagonal edge of the snake.
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///
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/// @return the end point of the non-diagonal edge of the snake
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const point&
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intermediate() const
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{return intermediate_;}
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/// Setter for the end point of the non-diagonal edge of the snake,
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/// aka intermediate point.
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///
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/// @param p the new intermediate point.
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void
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intermediate(const point& p)
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{intermediate_ = p;}
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/// Getter for the end point of the first diagonal edge, aka
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/// diagonal start point. Note that if the snake has no diagonal
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/// edge, this point is empty.
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///
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/// @return the end point of the first diagonal edge.
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const point&
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diagonal_start() const
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{return diagonal_start_;}
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/// Setter for the end point of the first diagonal edge, aka
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/// diagonal start point.
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///
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/// @param p the new diagonal start.d
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void
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diagonal_start(const point& p)
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{diagonal_start_ = p;}
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/// Getter for the end point of the last diagonal edge, aka snake
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/// end point. Note that if the snake has no diagonal edge, this
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/// point is equal to the intermediate point.
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///
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/// @return the end point of the last diagonal edge
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const point&
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end() const
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{return end_;}
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/// Setter for the end point of the last diagonal edge, aka snake
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/// end point. Note that if the snake has no diagonal edge, this
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/// point is equal to the intermediate point.
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void
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end(const point& p)
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{end_ = p;}
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/// Setter for the begin, intermediate and end points of the snake.
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///
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/// @param b the new snake begin point
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///
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/// @param i the new snake intermediate point
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///
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/// @param e the new snake end point
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void
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set(const point& b, const point&i, const point&e)
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{
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begin(b);
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intermediate(i);
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end(e);
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}
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/// Setter for the begin, intermediate, diagonal start and end points
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/// of the snake.
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///
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/// @param b the new snake begin point
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///
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/// @param i the new snake intermediate point
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///
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/// @param d the new diagonal start point
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///
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/// @param e the new snake end point
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void
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set(const point& b, const point&i, const point& d, const point&e)
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{
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begin(b);
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intermediate(i);
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diagonal_start(d);
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end(e);
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}
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/// @return true iff the snake is a forward snake. That is, if it
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/// was built while walking the edit graph going forward (from the
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/// top left corner to the right bottom corner.
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bool
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is_forward() const
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{return forward_;}
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/// Set to true if the snake is a forward snake; that is, if it was
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/// built while walking the edit graph going forward (from the top
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/// left corner to the right bottom corner. Set to false otherwise.
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///
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/// @param f whether the snake is a forward snake or not.
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void
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set_forward(bool f)
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{forward_ = f;}
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/// Add an offset to the abscissas of the points of the snake, and
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/// add another offset to the ordinates of these same points.
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///
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/// @param x_offset the offset to add to the abscissas of all the
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/// points of the snake.
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///
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/// @param y_offset the offset to add to the ordinates of all the
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/// points of the snake.
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void
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add(int x_offset, int y_offset)
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{
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if (is_empty())
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return;
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begin_.add(x_offset, y_offset);
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intermediate_.add(x_offset, y_offset);
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if (diagonal_start_)
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diagonal_start_.add(x_offset, y_offset);
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end_.add(x_offset, y_offset);
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}
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/// @return true iff the snake has at least one diagonal edge.
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bool
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has_diagonal_edge() const
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{return !diagonal_start().is_empty();}
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/// @return true iff the non-diagonal edge is horizontal.
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bool
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has_horizontal_edge() const
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{return (begin().y() == intermediate().y());}
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/// @return true iff the non-diagonal edge is vertical.
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bool
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has_vertical_edge() const
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{return (begin().x() == intermediate().x());}
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/// @return true iff the snake is empty, that is, if all the points
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/// it contains are empty.
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bool is_empty() const
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{return begin().is_empty() && intermediate().is_empty() && end().is_empty();}
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};// end class snake
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/// The array containing the furthest D-path end-points, for each value
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/// of K. MAX_D is the maximum value of the D-Path. That is, M+N if
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/// M is the size of the first input string, and N is the size of the
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/// second.
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class d_path_vec : public std::vector<int>
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{
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private:
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unsigned a_size_;
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unsigned b_size_;
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/// Forbid vector size modifications
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void
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push_back(const vector<int>::value_type&);
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/// Forbid default constructor.
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d_path_vec();
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bool
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over_bounds(long long index) const
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{return (index + offset()) >= (long long) size();}
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void
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check_index_against_bound(int index) const
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{
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if (over_bounds(index))
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{
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ostringstream o;
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o << "index '" << index
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<< "' out of range [-" << max_d() << ", " << max_d() << "]";
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throw std::out_of_range(o.str());
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}
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}
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public:
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/// Constructor of the d_path_vec.
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///
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/// For forward vectors, the underlying vector allocates 2 *
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/// [MAX_D+1].
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/// space, so that one can address elements in the index range
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/// [-MAX_D, MAX_D]. And MAX_D is the sum of the two sequence
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/// sizes. delta is the difference.
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///
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/// For reverse vectors, note that we need to be able to address
|
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/// [-MAX_D - delta, MAX_D + delta], with delta being the (signed)
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/// difference between the size of the two sequences. We consider
|
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/// delta being bounded by MAX_D itself; so we say we need to be
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/// able to address [-2MAX_D, 2MAX_D].
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///
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/// @param size1 the size of the first sequence we are interested
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/// in.
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///
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/// @param size2 the size of the second sequence we are interested
|
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/// in.
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d_path_vec(unsigned size1, unsigned size2)
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: vector<int>(2 * (size1 + size2 + 1 + (size1 + size2)) + 1, 0),
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a_size_(size1), b_size_(size2)
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{
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}
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std::vector<int>::const_reference
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operator[](int index) const
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||
{return at(index);}
|
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std::vector<int>::reference
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operator[](int index)
|
||
{return at(index);}
|
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std::vector<int>::reference
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at(long long index)
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{
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//check_index_against_bound(index);
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long long i = index + offset();
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return vector<int>::operator[](i);
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}
|
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|
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std::vector<int>::const_reference
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at(long long index) const
|
||
{
|
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check_index_against_bound(index);
|
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long long i = offset() + index;
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return static_cast<const vector<int>* >(this)->at(i);
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}
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unsigned
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a_size() const
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||
{return a_size_;}
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|
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unsigned
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b_size() const
|
||
{return b_size_;}
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||
|
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unsigned
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||
max_d() const
|
||
{return a_size_ + b_size_;}
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||
|
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unsigned
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offset() const
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||
{return max_d() + abs((long long) a_size() - (long long) b_size());}
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}; // end class d_path_vec
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|
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/// The abstration of an insertion of elements of a sequence B into a
|
||
/// sequence A. This is used to represent the edit script for
|
||
/// transforming a sequence A into a sequence B.
|
||
///
|
||
/// And insertion mainly encapsulates two components:
|
||
///
|
||
/// - An insertion point: this is the index (starting at 0) of the
|
||
/// element of the sequence A after which the insertion occurs.
|
||
///
|
||
/// - Inserted elements: this is a vector of indexes of elements of
|
||
/// sequence B (starting at 0) that got inserted into sequence A,
|
||
/// after the insertion point.
|
||
class insertion
|
||
{
|
||
int insertion_point_;
|
||
vector<unsigned> inserted_;
|
||
|
||
public:
|
||
|
||
insertion(int insertion_point,
|
||
const vector<unsigned>& inserted_indexes)
|
||
: insertion_point_(insertion_point),
|
||
inserted_(inserted_indexes)
|
||
{}
|
||
|
||
insertion(int insertion_point = 0)
|
||
: insertion_point_(insertion_point)
|
||
{}
|
||
|
||
int
|
||
insertion_point_index() const
|
||
{return insertion_point_;}
|
||
|
||
void
|
||
insertion_point_index(int i)
|
||
{insertion_point_ = i;}
|
||
|
||
const vector<unsigned>&
|
||
inserted_indexes() const
|
||
{return inserted_;}
|
||
|
||
vector<unsigned>&
|
||
inserted_indexes()
|
||
{return inserted_;}
|
||
};// end class insertion
|
||
|
||
/// The abstraction of the deletion of one element of a sequence A.
|
||
///
|
||
/// This encapsulates the index of the element A that got deleted.
|
||
class deletion
|
||
{
|
||
int index_;
|
||
|
||
public:
|
||
|
||
deletion(int i)
|
||
: index_(i)
|
||
{}
|
||
|
||
int
|
||
index() const
|
||
{return index_;}
|
||
|
||
void
|
||
index(int i)
|
||
{index_ = i;}
|
||
};// end class deletion
|
||
|
||
/// The abstraction of an edit script for transforming a sequence A
|
||
/// into a sequence B.
|
||
///
|
||
/// It encapsulates the insertions and deletions for transforming A
|
||
/// into B.
|
||
class edit_script
|
||
{
|
||
vector<insertion> insertions_;
|
||
vector<deletion> deletions_;
|
||
|
||
public:
|
||
|
||
edit_script()
|
||
{}
|
||
|
||
const vector<insertion>&
|
||
insertions() const
|
||
{return insertions_;}
|
||
|
||
vector<insertion>&
|
||
insertions()
|
||
{return insertions_;}
|
||
|
||
const vector<deletion>&
|
||
deletions() const
|
||
{return deletions_;}
|
||
|
||
vector<deletion>&
|
||
deletions()
|
||
{return deletions_;}
|
||
|
||
void
|
||
append(const edit_script& es)
|
||
{
|
||
insertions().insert(insertions().end(),
|
||
es.insertions().begin(),
|
||
es.insertions().end());
|
||
deletions().insert(deletions().end(),
|
||
es.deletions().begin(),
|
||
es.deletions().end());
|
||
}
|
||
|
||
void
|
||
prepend(const edit_script& es)
|
||
{
|
||
insertions().insert(insertions().begin(),
|
||
es.insertions().begin(),
|
||
es.insertions().end());
|
||
deletions().insert(deletions().begin(),
|
||
es.deletions().begin(),
|
||
es.deletions().end());
|
||
}
|
||
|
||
void
|
||
clear()
|
||
{
|
||
insertions().clear();
|
||
deletions().clear();
|
||
}
|
||
|
||
bool
|
||
is_empty() const
|
||
{return insertions().empty() && deletions().empty();}
|
||
|
||
operator bool() const
|
||
{return !is_empty();}
|
||
|
||
int
|
||
num_insertions() const
|
||
{
|
||
int l = 0;
|
||
for (vector<insertion>::const_iterator i = insertions().begin();
|
||
i != insertions().end();
|
||
++i)
|
||
l += i->inserted_indexes().size();
|
||
return l;
|
||
}
|
||
|
||
int
|
||
num_deletions() const
|
||
{return deletions().size();}
|
||
|
||
int
|
||
length() const
|
||
{return num_insertions() + num_deletions();}
|
||
};//end class edit_script
|
||
|
||
bool
|
||
point_is_valid_in_graph(point& p,
|
||
unsigned a_size,
|
||
unsigned b_size);
|
||
|
||
bool
|
||
ends_of_furthest_d_paths_overlap(const point& forward_d_path_end,
|
||
const point& reverse_d_path_end);
|
||
|
||
/// The default equality functor used by the core diffing algorithms.
|
||
struct default_eq_functor
|
||
{
|
||
/// This equality operator uses the default "==" to compare its
|
||
/// arguments.
|
||
///
|
||
/// @param a the first comparison argument.
|
||
///
|
||
/// @param b the second comparison argument.
|
||
///
|
||
/// @return true if the two arguments are equal, false otherwise.
|
||
template<typename T>
|
||
bool
|
||
operator()(const T a, const T b) const
|
||
{return a == b;}
|
||
};
|
||
|
||
|
||
/// An equality functor to deeply compare pointers.
|
||
struct deep_ptr_eq_functor
|
||
{
|
||
/// This equality operator compares pointers by comparing the
|
||
/// pointed-to objects.
|
||
///
|
||
/// @param first the first comparison argument.
|
||
///
|
||
/// @param second the second comparison argument.
|
||
///
|
||
/// @return true if the objects pointed to by the pointers are
|
||
/// equal, false otherwise.
|
||
template<typename T>
|
||
bool
|
||
operator()(const T* first,
|
||
const T* second) const
|
||
{
|
||
if (!!first != !!second)
|
||
return false;
|
||
|
||
if (!first)
|
||
return true;
|
||
|
||
return *first == *second;
|
||
}
|
||
|
||
template<typename T>
|
||
bool
|
||
operator()(const shared_ptr<T> first,
|
||
const shared_ptr<T> second) const
|
||
{return operator()(first.get(), second.get());}
|
||
};
|
||
|
||
/// Find the end of the furthest reaching d-path on diagonal k, for
|
||
/// two sequences. In the paper This is referred to as "the basic
|
||
/// algorithm".
|
||
///
|
||
/// Unlike in the paper, the coordinates of the edit graph start at
|
||
/// (-1,-1), rather than (0,0), and they end at (M-1, N-1), rather
|
||
/// than (M,N).
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param k the number of the diagonal on which we want to find the
|
||
/// end of the furthest reaching D-path.
|
||
///
|
||
/// @param d the D in D-Path. That's the number of insertions/deletions
|
||
/// (the number of changes, in other words) in the changeset. That is
|
||
/// also the number of non-diagonals in the D-Path.
|
||
///
|
||
/// @param a_begin an iterator to the beginning of the first sequence
|
||
///
|
||
/// @param a_end an iterator that points right after the last element
|
||
/// of the second sequence to consider.
|
||
///
|
||
/// @param b_begin an iterator to the beginning of the second sequence.
|
||
///
|
||
/// @param b_end an iterator that points right after the last element
|
||
/// of the second sequence to consider.
|
||
///
|
||
/// @param v the vector of furthest end points of d_paths, at (d-1).
|
||
/// It contains the abscissas of the furthest end points for different
|
||
/// values of k, at (d-1). That is, for k in [-D + 1, -D + 3, -D + 5,
|
||
/// ..., D - 1], v[k] is the abscissa of the end of the furthest
|
||
/// reaching (D-1)-path on diagonal k.
|
||
///
|
||
/// @param snak the last snake of the furthest path found. The end
|
||
/// point of the snake is the end point of the furthest path.
|
||
///
|
||
/// @return true if the end of the furthest reaching path that was
|
||
/// found was inside the boundaries of the edit graph, false
|
||
/// otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
bool
|
||
end_of_fr_d_path_in_k(int k, int d,
|
||
RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_start,
|
||
RandomAccessOutputIterator b_end,
|
||
d_path_vec& v, snake& snak)
|
||
{
|
||
int x = -1, y = -1;
|
||
point begin, intermediate, diag_start, end;
|
||
snake s;
|
||
EqualityFunctor eq;
|
||
|
||
// Let's pick the end point of the furthest reaching
|
||
// (D-1)-path. It's either v[k-1] or v[k+1]; the word
|
||
// "furthest" means we choose the one which abscissa is the
|
||
// greatest (that is, furthest from abscissa zero).
|
||
if (k == -d || ((k != d) && (v[k-1] < v[k + 1])))
|
||
// So, the abscissa of the end point of the furthest
|
||
// reaching (D-1)-path is v[k+1]. That is a diagonal that
|
||
// is above the current (k) diagonal, and on the right.
|
||
// To move to the current k diagonal, one has to move
|
||
// "down" from the diagonal k+1. So the abscissa won't
|
||
// change. Only the ordinate will. It will be given by y
|
||
// = x - k (a bit below); as k has changed from k - 1 (it
|
||
// has increased), y is going to be the new y that is
|
||
// 'down' from the previous y in k - 1.
|
||
{
|
||
x = v[k+1];
|
||
begin.set(x, x - (k + 1));
|
||
}
|
||
else
|
||
{
|
||
// So the abscissa of the end point of the furthest
|
||
// (D-1)-path is v[k-1]. That is on the left of the
|
||
// current k diagonal. To move to the current k diagonal,
|
||
// one has to move "right" from diagonal k - 1. That is,
|
||
// the y stays constant and x is incremented.
|
||
x = v[k-1];
|
||
begin.set(x, x - (k - 1));
|
||
++x;
|
||
}
|
||
|
||
// Now get the value of y from the equation k = x -y.
|
||
// This is the point where we first touch K, when we move
|
||
// from the end of the furthest reaching (D-1)-path.
|
||
y = x - k;
|
||
|
||
intermediate.x(x);
|
||
intermediate.y(y);
|
||
|
||
int last_x_index = a_end - a_begin - 1;
|
||
int last_y_index = b_end - b_start - 1;
|
||
// Now, follow the snake (aka, zero or more consecutive
|
||
// diagonals). Note that we stay on the k diagonal when we
|
||
// do this.
|
||
while ((x < last_x_index) && (y < last_y_index))
|
||
if (eq(a_begin[x + 1], b_start[y + 1]))
|
||
{
|
||
x = x + 1;
|
||
y = y + 1;
|
||
if (!diag_start)
|
||
diag_start.set(x, y);
|
||
}
|
||
else
|
||
break;
|
||
|
||
end.x(x);
|
||
end.y(y);
|
||
|
||
// Note the point that we store in v here might be outside the
|
||
// bounds of the edit graph. But we store it at this step (for a
|
||
// given D) anyway, because out of bound or not, we need this value
|
||
// at this step to be able to compute the value of the point on the
|
||
// "next" diagonal for the next D.
|
||
v[k] = x;
|
||
|
||
if (x >= (int) v.a_size()
|
||
|| y >= (int) v.b_size()
|
||
|| x < -1 || y < -1)
|
||
return false;
|
||
|
||
s.set(begin, intermediate, diag_start, end);
|
||
s.set_forward(true);
|
||
snak = s;
|
||
|
||
return true;
|
||
}
|
||
|
||
/// Find the end of the furthest reaching reverse d-path on diagonal k
|
||
/// + delta. Delta is abs(M - N), with M being the size of a and N
|
||
/// being the size of b. This is the "basic algorithm", run backward.
|
||
/// That is, starting from the point (M,N) of the edit graph.
|
||
///
|
||
/// Unlike in the paper, the coordinates of the edit graph start at
|
||
/// (-1,-1), rather than (0,0), and they end at (M-1, N-1), rather
|
||
/// than (M,N).
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param k the number of the diagonal on which we want to find the
|
||
/// end of the furthest reaching reverse D-path. Actually, we want to
|
||
/// find the end of the furthest reaching reverse D-path on diagonal (k
|
||
/// - delta).
|
||
///
|
||
/// @param d the D in D-path. That's the number of insertions/deletions
|
||
/// (the number of changes, in other words) in the changeset. That is
|
||
/// also the number of non-diagonals in the D-Path.
|
||
///
|
||
/// @param a_begin an iterator to the beginning of the first sequence
|
||
///
|
||
/// @param a_end an iterator that points right after the last element
|
||
/// of the second sequence to consider.
|
||
///
|
||
/// @param b_begin an iterator to the beginning of the second sequence.
|
||
///
|
||
/// @param b_end an iterator that points right after the last element
|
||
/// of the second sequence to consider.
|
||
///
|
||
/// @param v the vector of furthest end points of d_paths, at (d-1).
|
||
/// It contains the abscissae of the furthest end points for different
|
||
/// values of k - delta, at (d-1). That is, for k in [-D + 1, -D + 3,
|
||
/// -D + 5, ..., D - 1], v[k - delta] is the abscissa of the end of the
|
||
/// furthest reaching (D-1)-path on diagonal k - delta.
|
||
///
|
||
/// @param snak the last snake of the furthest path found. The end
|
||
/// point of the snake is the end point of the furthest path.
|
||
///
|
||
/// @return true iff the end of the furthest reaching path that was
|
||
/// found was inside the boundaries of the edit graph, false
|
||
/// otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
bool
|
||
end_of_frr_d_path_in_k_plus_delta (int k, int d,
|
||
RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
d_path_vec& v, snake& snak)
|
||
{
|
||
int a_size = a_end - a_begin;
|
||
int b_size = b_end - b_begin;
|
||
int delta = a_size - b_size;
|
||
int k_plus_delta = k + delta;
|
||
int x = -1, y = -1;
|
||
point begin, intermediate, diag_start, end;
|
||
snake s;
|
||
EqualityFunctor eq;
|
||
|
||
// Let's pick the end point of the furthest reaching (D-1)-path and
|
||
// move from there to reach the current k_plus_delta-line. That end
|
||
// point of the furthest reaching (D-1)-path is either on
|
||
// v[k_plus_delta-1] or on v[k_plus_delta+1]; the word "furthest"
|
||
// means we choose the one which abscissa is the lowest (that is,
|
||
// furthest from abscissa M).
|
||
if (k_plus_delta == -d + delta
|
||
|| ((k_plus_delta != d + delta)
|
||
&& (v[k_plus_delta + 1] <= v[k_plus_delta - 1])))
|
||
{
|
||
// We move left, that means ordinate won't change ...
|
||
x = v[k_plus_delta + 1];
|
||
y = x - (k_plus_delta + 1);
|
||
begin.set(x, y);
|
||
// ... and abscissa decreases.
|
||
x = x - 1;
|
||
}
|
||
else
|
||
{
|
||
// So the furthest end point is on the k_plus_delta - 1
|
||
// diagonal. That is a diagonal that is 'below' the
|
||
// k_plus_delta current diagonal. So to join the current
|
||
// diagonal from the k_plus_delta - 1 one, we need to move up.
|
||
|
||
// So moving up means abscissa won't change ...
|
||
x = v[k_plus_delta - 1];
|
||
begin.set(x, x - (k_plus_delta - 1));
|
||
// ... and that ordinate decreases.
|
||
y = x - (k_plus_delta - 1) - 1;
|
||
}
|
||
|
||
intermediate.set(x, y);
|
||
|
||
// Now, follow the snake. Note that we stay on the k_plus_delta
|
||
// diagonal when we do this.
|
||
while (x >= 0 && y >= 0)
|
||
if (eq(a_begin[x], b_begin[y]))
|
||
{
|
||
if (!diag_start)
|
||
diag_start.set(x, y);
|
||
x = x - 1;
|
||
y = y - 1;
|
||
}
|
||
else
|
||
break;
|
||
|
||
end.set(x, y);
|
||
|
||
// Note the point that we store in v here might be outside the
|
||
// bounds of the edit graph. But we store it at this step (for a
|
||
// given D) anyway, because out of bound or not, we need this value
|
||
// at this step to be able to compute the value of the point on the
|
||
// "next" diagonal for the next D.
|
||
v[k_plus_delta] = x;
|
||
|
||
if (x == -1 && y == -1)
|
||
;
|
||
else if (x < -1 || y < -1)
|
||
return false;
|
||
|
||
s.set(begin, intermediate, diag_start, end);
|
||
s.set_forward(false);
|
||
snak = s;
|
||
|
||
return true;
|
||
}
|
||
|
||
/// Tests if a given point is a match point in an edit graph.
|
||
///
|
||
/// @param a_begin the begin iterator of the first input sequence of
|
||
/// the edit graph.
|
||
///
|
||
/// @param a_end the end iterator of the first input sequence of the
|
||
/// edit graph. This points to one element passed the end of the
|
||
/// sequence.
|
||
///
|
||
/// @param b_begin the begin iterator of the second input sequence of
|
||
/// the edit graph.
|
||
///
|
||
/// @param b_end the end iterator of the second input sequence of the
|
||
/// edit graph. This points the one element passed the end of the
|
||
/// sequence.
|
||
///
|
||
/// @param point the point to test for being a match point.
|
||
///
|
||
/// @return true iff \a point is a match point.
|
||
template<typename RandomAccessOutputIterator>
|
||
bool
|
||
is_match_point(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
const point& point)
|
||
{
|
||
int a_size = a_end - a_begin, b_size = b_end - b_begin;
|
||
|
||
if (point.x() < 0
|
||
|| point.x () >= a_size
|
||
|| point.y() < 0
|
||
|| point.y() >= b_size)
|
||
return false;
|
||
|
||
return (a_begin[point.x()] == b_begin[point.y()]);
|
||
}
|
||
|
||
/// Returns the middle snake of two sequences A and B, as well as the
|
||
/// length of their shortest editing script.
|
||
///
|
||
/// This uses the "linear space refinement" algorithm presented in
|
||
/// section 4b in the paper. As the paper says, "The idea for doing
|
||
/// so is to simultaneously run the basic algorithm in both the
|
||
/// forward and reverse directions until furthest reaching forward and
|
||
/// reverse paths starting at opposing corners ‘‘overlap’’."
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_begin an iterator pointing to the begining of sequence A.
|
||
///
|
||
/// @param a_end an iterator pointing to the end of sequence A. Note
|
||
/// that this points right /after/ the end of vector A.
|
||
///
|
||
/// @param b_begin an iterator pointing to the begining of sequence B.
|
||
///
|
||
/// @param b_end an iterator pointing to the end of sequence B. Note
|
||
/// that this points right /after/ the end of vector B
|
||
///
|
||
/// @param snak out parameter. This is the snake current when the two
|
||
/// paths overlapped. This is set iff the function returns true;
|
||
/// otherwise, this is not touched.
|
||
///
|
||
/// @return true is the snake was found, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
bool
|
||
compute_middle_snake(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
snake& snak, int& ses_len)
|
||
{
|
||
int a_size = a_end - a_begin;
|
||
int N = a_size;
|
||
int b_size = b_end - b_begin;
|
||
int M = b_size;
|
||
int delta = N - M;
|
||
d_path_vec forward_d_paths(a_size, b_size);
|
||
d_path_vec reverse_d_paths(a_size, b_size);
|
||
// These points below are the top leftmost point and bottom
|
||
// right-most points of the edit graph.
|
||
point first_point(-1, -1), last_point(a_size -1, b_size -1), point_zero(0, 0);
|
||
|
||
// We want the initial step (D = 0, k = 0 in the paper) to find a
|
||
// furthest reaching point on diagonal k == 0; For that, we need the
|
||
// value of x for k == 1; So let's set that value to -1; that is for
|
||
// k == 1 (diagonal 1), the point in the edit graph is (-1,-2).
|
||
// That way, to get the furthest reaching point on diagonal 0 (k ==
|
||
// 0), we go down from (-1,-2) on diagonal 1 and we hit diagonal 0
|
||
// on (-1,-1); that is the starting value that the algorithm expects
|
||
// for k == 0.
|
||
forward_d_paths[1] = -1;
|
||
|
||
// Similarly for the reverse paths, for diagonal delta + 1 (note
|
||
// that diagonals are centered on delta, unlike for forward paths
|
||
// where they are centered on zero), we set the initial point to
|
||
// (a_size, b_size - 1). That way, at step D == 0 and k == delta,
|
||
// to reach diagonal delta from the point (a_size, b_size - 1) on
|
||
// diagonal delta + 1, we just have to move left, and we hit
|
||
// diagonal delta on (a_size - 1, b_size -1); that is the starting
|
||
// point value the algorithm expects for k == 0 in the reverse case.
|
||
reverse_d_paths[delta + 1] = a_size;
|
||
|
||
int d_max = (M + N) / 2 + 1;
|
||
for (int d = 0; d <= d_max; ++d)
|
||
{
|
||
// First build forward paths.
|
||
for (int k = -d; k <= d; k += 2)
|
||
{
|
||
snake s;
|
||
bool found =
|
||
end_of_fr_d_path_in_k<RandomAccessOutputIterator,
|
||
EqualityFunctor>(k, d,
|
||
a_begin, a_end,
|
||
b_begin, b_end,
|
||
forward_d_paths, s);
|
||
if (!found)
|
||
continue;
|
||
|
||
// As the paper says in 4b while explaining the middle snake
|
||
// algorithm:
|
||
//
|
||
// "Thus when delta is odd, check for overlap only while
|
||
// extending forward paths ..."
|
||
if ((delta % 2)
|
||
&& (k >= (delta - (d - 1))) && (k <= (delta + (d - 1))))
|
||
{
|
||
point reverse_end;
|
||
reverse_end.x(reverse_d_paths[k]);
|
||
reverse_end.y(reverse_end.x() - k);
|
||
if (ends_of_furthest_d_paths_overlap(s.end(), reverse_end))
|
||
{
|
||
ses_len = 2 * d - 1;
|
||
snak = s;
|
||
return true;
|
||
}
|
||
}
|
||
}
|
||
|
||
// Now build reverse paths.
|
||
for (int k = -d; k <= d; k += 2)
|
||
{
|
||
snake s;
|
||
bool found =
|
||
end_of_frr_d_path_in_k_plus_delta<RandomAccessOutputIterator,
|
||
EqualityFunctor>(k, d,
|
||
a_begin, a_end,
|
||
b_begin, b_end,
|
||
reverse_d_paths,
|
||
s);
|
||
|
||
if (!found)
|
||
continue;
|
||
|
||
// And the paper continues by saying:
|
||
//
|
||
// "... and when delta is even, check for overlap only while
|
||
// extending reverse paths."
|
||
int k_plus_delta = k + delta;
|
||
if (!(delta % 2)
|
||
&& (k_plus_delta >= -d) && (k_plus_delta <= d))
|
||
{
|
||
point forward_end;
|
||
forward_end.x(forward_d_paths[k_plus_delta]);
|
||
forward_end.y(forward_end.x() - k_plus_delta);
|
||
if (ends_of_furthest_d_paths_overlap(forward_end, s.end()))
|
||
{
|
||
ses_len = 2 * d;
|
||
snak = s;
|
||
return true;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
return false;
|
||
}
|
||
|
||
bool
|
||
compute_middle_snake(const char* str1, const char* str2,
|
||
snake& s, int& ses_len);
|
||
|
||
/// This prints the middle snake of two strings.
|
||
///
|
||
/// @param a_begin the beginning of the first string.
|
||
///
|
||
/// @param b_begin the beginning of the second string.
|
||
///
|
||
/// @param s the snake to print.
|
||
///
|
||
/// @param out the output stream to print the snake to.
|
||
template<typename RandomAccessOutputIterator>
|
||
void
|
||
print_snake(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator b_begin,
|
||
const snake s, ostream& out)
|
||
{
|
||
if (s.is_empty())
|
||
return;
|
||
|
||
out << "snake start: ";
|
||
out << "(" << s.begin().x() << ", " << s.end().y() << ")\n";
|
||
|
||
out << "snake intermediate: ";
|
||
out << "(" << s.intermediate().x() << ", " << s.intermediate().y() << ")\n";
|
||
|
||
out << "diagonal point(s): ";
|
||
if (s.has_diagonal_edge())
|
||
for (int x = s.intermediate().x(), y = s.intermediate().y();
|
||
x <= s.end().x() && y <= s.end().y();
|
||
++x, ++y)
|
||
{
|
||
assert(a_begin[x] == b_begin[y]);
|
||
out << "(" << x << "," << y << ") ";
|
||
}
|
||
out << "\n";
|
||
|
||
out << "snake end: ";
|
||
out << "(" << s.end().x() << ", " << s.end().y() << ")\n";
|
||
}
|
||
|
||
/// Compute the length of the shortest edit script for two sequences a
|
||
/// and b. This is done using the "Greedy LCS/SES" of figure 2 in the
|
||
/// paper. It can walk the edit graph either foward (when reverse is
|
||
/// false) or backward starting from the end (when reverse is true).
|
||
///
|
||
/// Here, note that the real content of a and b should start at index
|
||
/// 1, for this implementatikon algorithm to match the paper's
|
||
/// algorithm in a straightforward manner. So pleast make sure that
|
||
/// at index 0, we just get some non-used value.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a the first sequence we care about.
|
||
///
|
||
/// @param b the second sequence we care about.
|
||
///
|
||
/// @param v the vector that contains the end points of the furthest
|
||
/// reaching d-path and (d-1)-path.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
int
|
||
ses_len(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
d_path_vec& v, bool reverse)
|
||
{
|
||
unsigned a_size = a_end - a_begin;
|
||
unsigned b_size = b_end - b_begin;
|
||
snake snak;
|
||
|
||
assert(v.max_d() == a_size + b_size);
|
||
|
||
int delta = a_size - b_size;
|
||
|
||
if (reverse)
|
||
// Set a fictitious (M, N-1) into v[1], to find the furthest
|
||
// reaching reverse 0-path (i.e, when we are at d == 0 and k == 0).
|
||
v[delta + 1] = a_size - 1;
|
||
else
|
||
// Set a fictitious (-1,-2) point into v[1], to find the furthest
|
||
// reaching forward 0-path (i.e, when we are at d == 0 and k == 0).
|
||
v[1] = -1;
|
||
|
||
for (unsigned d = 0; d <= v.max_d(); ++d)
|
||
{
|
||
for (int k = -d; k <= (int) d; k += 2)
|
||
{
|
||
point end;
|
||
if (reverse)
|
||
{
|
||
bool found =
|
||
end_of_frr_d_path_in_k_plus_delta<RandomAccessOutputIterator,
|
||
EqualityFunctor>(k, d,
|
||
a_begin, a_end,
|
||
b_begin, b_end,
|
||
v, snak);
|
||
// If we reached the upper left corner of the edit graph then
|
||
// we are done.
|
||
if (found && snak.end().x() == -1 && snak.end().y() == -1)
|
||
return d;
|
||
}
|
||
else
|
||
{
|
||
end_of_fr_d_path_in_k<RandomAccessOutputIterator,
|
||
EqualityFunctor>(k, d,
|
||
a_begin, a_end,
|
||
b_begin, b_end,
|
||
v, snak);
|
||
// If we reached the lower right corner of the edit
|
||
// graph then we are done.
|
||
if ((snak.end().x() == (int) a_size - 1)
|
||
&& (snak.end().y() == (int) b_size - 1))
|
||
return d;
|
||
}
|
||
}
|
||
}
|
||
return 0;
|
||
}
|
||
|
||
/// Compute the length of the shortest edit script for two sequences a
|
||
/// and b. This is done using the "Greedy LCS/SES" of figure 2 in the
|
||
/// paper. It can walk the edit graph either foward (when reverse is
|
||
/// false) or backward starting from the end (when reverse is true).
|
||
///
|
||
/// Here, note that the real content of a and b should start at index
|
||
/// 1, for this implementatikon algorithm to match the paper's
|
||
/// algorithm in a straightforward manner. So pleast make sure that
|
||
/// at index 0, we just get some non-used value.
|
||
///
|
||
/// Note that the equality operator used to compare the elements
|
||
/// passed in argument to this function is the default "==" operator.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @param a the first sequence we care about.
|
||
///
|
||
/// @param b the second sequence we care about.
|
||
///
|
||
/// @param v the vector that contains the end points of the furthest
|
||
/// reaching d-path and (d-1)-path.
|
||
template<typename RandomAccessOutputIterator>
|
||
int
|
||
ses_len(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
d_path_vec& v, bool reverse)
|
||
{
|
||
return ses_len<RandomAccessOutputIterator, default_eq_functor>(a_begin, a_end,
|
||
b_begin, b_end,
|
||
v, reverse);
|
||
}
|
||
|
||
int
|
||
ses_len(const char* str1,
|
||
const char* str2,
|
||
bool reverse = false);
|
||
|
||
bool
|
||
snake_end_points(const snake& s, point&, point&);
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// A sequence is determined by a base, a beginning offset and an end
|
||
/// offset. The base always points to the container that contains the
|
||
/// sequence to consider. The beginning offset is an iterator that
|
||
/// points the beginning of the sub-region of the sequence that we
|
||
/// actually want to consider. The end offset is an iterator that
|
||
/// points to the end of the sub-region of the sequence that we
|
||
/// actually want to consider.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_base the iterator to the base of the first sequence.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the sub-region
|
||
/// of the first sequence to actually consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the sub-region of the first
|
||
/// sequence to consider.
|
||
///
|
||
///@param b_base an iterator to the base of the second sequence to
|
||
///consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the sub-region
|
||
/// of the second sequence to actually consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the sub-region of the
|
||
/// second sequence to actually consider.
|
||
///
|
||
/// @param lcs the resulting lcs. This is set iff the function
|
||
/// returns true.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @param ses_len the length of the ses above. Normally this can be
|
||
/// retrieved from ses.length(), but this parameter is here for sanity
|
||
/// check purposes. The function computes the length of the ses in
|
||
/// two redundant ways and ensures that both methods lead to the same
|
||
/// result.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_base,
|
||
RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_base,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
vector<point>& lcs,
|
||
edit_script& ses,
|
||
int& ses_len)
|
||
{
|
||
int a_size = a_end - a_begin;
|
||
int b_size = b_end - b_begin;
|
||
unsigned a_offset = a_begin - a_base, b_offset = b_begin - b_base;
|
||
|
||
if (a_size == 0 || b_size == 0)
|
||
{
|
||
if (a_size > 0 && b_size == 0)
|
||
// All elements of the first sequences have been deleted. So add
|
||
// the relevant deletions to the edit script.
|
||
for (RandomAccessOutputIterator i = a_begin; i < a_end; ++i)
|
||
ses.deletions().push_back(deletion(i - a_base));
|
||
|
||
if (b_size > 0 && a_size == 0)
|
||
{
|
||
// All elements present in the second sequence are part of
|
||
// an insertion into the first sequence at a_end. So add
|
||
// that insertion to the edit script.
|
||
int a_full_size = a_end - a_base;
|
||
int insertion_index = a_full_size ? a_full_size - 1 : -1;
|
||
insertion ins(insertion_index);
|
||
for (RandomAccessOutputIterator i = b_begin; i < b_end; ++i)
|
||
ins.inserted_indexes().push_back(i - b_base);
|
||
|
||
ses.insertions().push_back(ins);
|
||
}
|
||
|
||
ses_len = a_size + b_size;
|
||
return;
|
||
}
|
||
|
||
int d = 0;
|
||
snake snak;
|
||
vector<point> trace; // the trace of the edit graph. Read the paper
|
||
// to understand what a trace is.
|
||
bool has_snake =
|
||
compute_middle_snake<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_begin, a_end,
|
||
b_begin, b_end,
|
||
snak, d);
|
||
if (has_snake)
|
||
{
|
||
// So middle_{begin,end} are expressed wrt a_begin and b_begin.
|
||
// Let's express them wrt a_base and b_base.
|
||
snak.add(a_offset, b_offset);
|
||
ses_len = d;
|
||
}
|
||
|
||
if (has_snake)
|
||
{
|
||
if ( snak.has_diagonal_edge())
|
||
for (int x = snak.diagonal_start().x(), y = snak.diagonal_start().y();
|
||
x <= snak.end().x() && y <= snak.end().y();
|
||
++x, ++y)
|
||
{
|
||
point p(x, y);
|
||
trace.push_back(p);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
// So there is no middle snake. That means there is no lcs, so
|
||
// the two sequences are different.
|
||
|
||
// In other words, all the elements of the first sequence have
|
||
// been deleted ...
|
||
for (RandomAccessOutputIterator i = a_begin; i < a_end; ++i)
|
||
ses.deletions().push_back(deletion(i - a_base));
|
||
|
||
// ... and all the elements of the second sequence are insertions
|
||
// that happen at the beginning of the first sequence.
|
||
insertion ins(a_begin - a_base);
|
||
for (RandomAccessOutputIterator i = b_begin; i < b_end; ++i)
|
||
ins.inserted_indexes().push_back(i - b_base);
|
||
ses.insertions().push_back(ins);
|
||
|
||
ses_len = a_size + b_size;
|
||
assert(ses_len == ses.length());
|
||
return;
|
||
}
|
||
|
||
if (d > 1)
|
||
{
|
||
int tmp_ses_len0 = 0;
|
||
edit_script tmp_ses0;
|
||
point px, pu;
|
||
snake_end_points(snak, px, pu);
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_base, a_begin, a_base + px.x() + 1,
|
||
b_base, b_begin, b_base + px.y() + 1,
|
||
lcs, tmp_ses0, tmp_ses_len0);
|
||
|
||
lcs.insert(lcs.end(), trace.begin(), trace.end());
|
||
|
||
int tmp_ses_len1 = 0;
|
||
edit_script tmp_ses1;
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_base, a_base + pu.x() + 1, a_end,
|
||
b_base, b_base + pu.y() + 1, b_end,
|
||
lcs, tmp_ses1, tmp_ses_len1);
|
||
assert(tmp_ses0.length() + tmp_ses1.length() == d);
|
||
assert(tmp_ses_len0 + tmp_ses_len1 == d);
|
||
ses.append(tmp_ses0);
|
||
ses.append(tmp_ses1);
|
||
}
|
||
else if (d == 1)
|
||
{
|
||
if (snak.has_diagonal_edge())
|
||
{
|
||
for (int x = snak.diagonal_start().x(), y = snak.diagonal_start().y();
|
||
x <= snak.end().x() && y <= snak.end().y();
|
||
++x, ++y)
|
||
{
|
||
point p(x, y);
|
||
trace.push_back(p);
|
||
}
|
||
}
|
||
|
||
if (snak.has_vertical_edge())
|
||
{
|
||
point p = snak.intermediate();
|
||
insertion ins(p.x());
|
||
ins.inserted_indexes().push_back(p.y());
|
||
ses.insertions().push_back(ins);
|
||
}
|
||
else if (snak.has_horizontal_edge())
|
||
{
|
||
if (snak.is_forward())
|
||
{
|
||
deletion del(snak.intermediate().x());
|
||
ses.deletions().push_back(del);
|
||
}
|
||
else
|
||
{
|
||
deletion del(snak.begin().x());
|
||
ses.deletions().push_back(del);
|
||
}
|
||
}
|
||
}
|
||
else if (d == 0)
|
||
{
|
||
// Obviously on the middle snake is part of the solution, as
|
||
// there is no edit script; iow, the two sequences are
|
||
// identical.
|
||
lcs.insert(lcs.end(), trace.begin(), trace.end());
|
||
ses_len = 0;
|
||
}
|
||
|
||
assert(ses_len == ses.length());
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the first sequence
|
||
/// to consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the first sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the second sequence
|
||
/// to consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param lcs the resulting lcs. This is set iff the function
|
||
/// returns true.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @param ses_len the length of the ses above. Normally this can be
|
||
/// retrieved from ses.length(), but this parameter is here for sanity
|
||
/// check purposes. The function computes the length of the ses in
|
||
/// two redundant ways and ensures that both methods lead to the same
|
||
/// result.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
vector<point>& lcs,
|
||
edit_script& ses,
|
||
int& ses_len)
|
||
{
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_begin, a_begin, a_end,
|
||
b_begin, b_begin, b_end,
|
||
lcs, ses, ses_len);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// A sequence is determined by a base, a beginning offset and an end
|
||
/// offset. The base always points to the container that contains the
|
||
/// sequence to consider. The beginning offset is an iterator that
|
||
/// points the beginning of the sub-region of the sequence that we
|
||
/// actually want to consider. The end offset is an iterator that
|
||
/// points to the end of the sub-region of the sequence that we
|
||
/// actually want to consider.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_base the iterator to the base of the first sequence.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the sub-region
|
||
/// of the first sequence to actually consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the sub-region of the first
|
||
/// sequence to consider.
|
||
///
|
||
///@param b_base an iterator to the base of the second sequence to
|
||
///consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the sub-region
|
||
/// of the second sequence to actually consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the sub-region of the
|
||
/// second sequence to actually consider.
|
||
///
|
||
/// @param lcs the resulting lcs. This is set iff the function
|
||
/// returns true.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_base,
|
||
RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_base,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
vector<point>& lcs,
|
||
edit_script& ses)
|
||
{
|
||
int ses_len = 0;
|
||
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_base, a_begin, a_end,
|
||
b_base, b_begin, b_end,
|
||
lcs, ses, ses_len);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the first sequence
|
||
/// to consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the first sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the sequence to
|
||
/// actually consider.
|
||
///
|
||
/// @param b_end an iterator to the end of second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param lcs the resulting lcs. This is set iff the function
|
||
/// returns true.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
vector<point>& lcs,
|
||
edit_script& ses)
|
||
{
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_begin, a_begin, a_end,
|
||
b_begin, b_begin, b_end,
|
||
lcs, ses);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the first sequence
|
||
/// to consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the first sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the sequence to
|
||
/// actually consider.
|
||
///
|
||
/// @param b_end an iterator to the end of second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param lcs the resulting lcs. This is set iff the function
|
||
/// returns true.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
vector<point>& lcs,
|
||
edit_script& ses)
|
||
{
|
||
compute_diff<RandomAccessOutputIterator,
|
||
default_eq_functor>(a_begin, a_end, b_begin, b_end, lcs, ses);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// A sequence is determined by a base, a beginning offset and an end
|
||
/// offset. The base always points to the container that contains the
|
||
/// sequence to consider. The beginning offset is an iterator that
|
||
/// points the beginning of the sub-region of the sequence that we
|
||
/// actually want to consider. The end offset is an iterator that
|
||
/// points to the end of the sub-region of the sequence that we
|
||
/// actually want to consider.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_base the iterator to the base of the first sequence.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the sub-region
|
||
/// of the first sequence to actually consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the sub-region of the first
|
||
/// sequence to consider.
|
||
///
|
||
/// @param b_base an iterator to the base of the second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the sub-region
|
||
/// of the second sequence to actually consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the sub-region of the
|
||
/// second sequence to actually consider.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_base,
|
||
RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_base,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
edit_script& ses)
|
||
{
|
||
vector<point> lcs;
|
||
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_base, a_begin, a_end,
|
||
b_base, b_begin, b_end,
|
||
lcs, ses);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @tparm EqualityFunctor this must be a class that declares a public
|
||
/// call operator member returning a boolean and taking two arguments
|
||
/// that must be of the same type as the one pointed to by the @ref
|
||
/// RandomAccessOutputIterator template parameter. This functor is
|
||
/// used to compare the elements referred to by the iterators pased in
|
||
/// argument to this function.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the first sequence
|
||
/// to consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the first sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the second sequence
|
||
/// to consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator,
|
||
typename EqualityFunctor>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
edit_script& ses)
|
||
{
|
||
compute_diff<RandomAccessOutputIterator,
|
||
EqualityFunctor>(a_begin, a_begin, a_end,
|
||
b_begin, b_begin, b_end,
|
||
ses);
|
||
}
|
||
|
||
/// Compute the longest common subsequence of two (sub-regions of)
|
||
/// sequences as well as the shortest edit script from transforming
|
||
/// the first (sub-region of) sequence into the second (sub-region of)
|
||
/// sequence.
|
||
///
|
||
/// This uses the LCS algorithm of the paper at section 4b.
|
||
///
|
||
/// @tparm RandomAccessOutputIterator the type of iterators passed to
|
||
/// this function. It must be a random access output iterator kind.
|
||
///
|
||
/// @param a_start an iterator to the beginning of the first sequence
|
||
/// to consider.
|
||
///
|
||
/// @param a_end an iterator to the end of the first sequence to
|
||
/// consider.
|
||
///
|
||
/// @param b_start an iterator to the beginning of the second sequence
|
||
/// to consider.
|
||
///
|
||
/// @param b_end an iterator to the end of the second sequence to
|
||
/// consider.
|
||
///
|
||
/// @param ses the resulting shortest editing script.
|
||
///
|
||
/// @return true upon successful completion, false otherwise.
|
||
template<typename RandomAccessOutputIterator>
|
||
void
|
||
compute_diff(RandomAccessOutputIterator a_begin,
|
||
RandomAccessOutputIterator a_end,
|
||
RandomAccessOutputIterator b_begin,
|
||
RandomAccessOutputIterator b_end,
|
||
edit_script& ses)
|
||
{
|
||
compute_diff<RandomAccessOutputIterator, default_eq_functor>(a_begin, a_end,
|
||
b_begin, b_end,
|
||
ses);
|
||
}
|
||
|
||
void
|
||
compute_lcs(const char* str1, const char* str2, int &ses_len, string& lcs);
|
||
|
||
void
|
||
compute_ses(const char* str1, const char* str2, edit_script& ses);
|
||
|
||
/// Display an edit script on standard output.
|
||
///
|
||
/// @param es the edit script to display
|
||
///
|
||
/// @param str1_base the first string the edit script is about.
|
||
///
|
||
/// @pram str2_base the second string the edit script is about.
|
||
template<typename RandomAccessOutputIterator>
|
||
void
|
||
display_edit_script(const edit_script& es,
|
||
const RandomAccessOutputIterator str1_base,
|
||
const RandomAccessOutputIterator str2_base,
|
||
ostream& out)
|
||
{
|
||
if (es.num_deletions() == 0)
|
||
out << "no deletion:\n";
|
||
else if (es.num_deletions() == 1)
|
||
{
|
||
out << "1 deletion:\n"
|
||
<< "\t happened at index: ";;
|
||
}
|
||
else
|
||
{
|
||
out << es.num_deletions() << " deletions:\n"
|
||
<< "\t happened at indexes: ";
|
||
}
|
||
|
||
for (vector<deletion>::const_iterator i = es.deletions().begin();
|
||
i != es.deletions().end();
|
||
++i)
|
||
{
|
||
if (i != es.deletions().begin())
|
||
out << ", ";
|
||
out << i->index() << " (" << str1_base[i->index()] << ")";
|
||
}
|
||
out << "\n\n";
|
||
|
||
if (es.num_insertions() == 0)
|
||
out << "no insertion\n";
|
||
else if (es.num_insertions() == 1)
|
||
out << "1 insertion\n";
|
||
else
|
||
out << es.num_insertions() << " insertions:\n";
|
||
for (vector<insertion>::const_iterator i = es.insertions().begin();
|
||
i != es.insertions().end();
|
||
++i)
|
||
{
|
||
int idx = i->insertion_point_index();
|
||
if (idx < 0)
|
||
out << "\t before index of first sequence: " << idx + 1
|
||
<< " (" << str1_base[idx + 1] << ")\n";
|
||
else
|
||
out << "\t after index of first sequence: " << idx
|
||
<< " (" << str1_base[idx] << ")\n";
|
||
|
||
if (!i->inserted_indexes().empty())
|
||
out << "\t\t inserted indexes from second sequence: ";
|
||
|
||
for (vector<unsigned>::const_iterator j = i->inserted_indexes().begin();
|
||
j != i->inserted_indexes().end();
|
||
++j)
|
||
{
|
||
if (j != i->inserted_indexes().begin())
|
||
out << ", ";
|
||
out << *j << " (" << str2_base[*j] << ")";
|
||
}
|
||
out << "\n";
|
||
}
|
||
out << "\n\n";
|
||
}
|
||
|
||
}//end namespace diff_utils
|
||
|
||
}//end namespace abigail
|
||
#endif // __ABG_DIFF_UTILS_H__
|