Ichthyostega
25459028cc
This helper was drafted for the Job / JobPlanning and Scheduler interface in 2013, but seemingly not yet put into action. While in the original use case, we have a genuine measuerment for the tree depth (given by the depth of the processing stack), in other use cases we want to use to offset embedded within the indicator itself for keeping track of the depth. Thus I add a second mark operation, which usess the current offset to set a new reference level. This has the consequence that the offset has now to reflect the new reference point immediately
132 lines
3.4 KiB
C++
132 lines
3.4 KiB
C++
/*
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HIERARCHY-ORIENTATION-INDICATOR.hpp - helper to mark level on tree navigation
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Copyright (C) Lumiera.org
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2013, Hermann Vosseler <Ichthyostega@web.de>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/** @file hierarchy-orientation-indicator.hpp
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** Helper to support navigating a tree structure.
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** The OrientationIndicator records reference levels (depth into the tree)
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** and can then be used to determine the relative orientation between the
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** previously marked reference level and the current reference level.
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** This simple state capturing mechanism can be used to track the path
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** of a tree visitation, or to sync an external stack with a currently
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** investigated tree level.
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**
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** The relative orientation value can be retrieved through an int conversion;
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** to ease recursive programming, this statefull value can be incremented and
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** decremented without influencing the captured reference level.
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**
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** @see job-ticket.hpp usage example
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** @see HierarchyOrientationIndicator_test
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**
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*/
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#ifndef HIERARCHY_ORIENTATION_INDICATOR_H
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#define HIERARCHY_ORIENTATION_INDICATOR_H
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#include <cstddef>
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#include <limits>
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#include <string>
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namespace lib {
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using std::string;
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class OrientationIndicator
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{
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size_t refLevel_;
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ptrdiff_t offset_;
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public:
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OrientationIndicator()
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: refLevel_(0)
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, offset_(0)
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{ }
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// using default copy/assignment
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operator ptrdiff_t() const
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{
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return offset_;
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}
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void
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markRefLevel (size_t newRefLevel)
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{
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REQUIRE (newRefLevel < size_t(std::numeric_limits<ptrdiff_t>::max()) );
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offset_ -= newRefLevel - refLevel_;
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refLevel_ = newRefLevel;
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}
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/** define the current offset as new reference point */
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OrientationIndicator&
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markRefLevel ()
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{
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markRefLevel (refLevel_ + offset_);
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ENSURE (offset_ == 0);
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return *this;
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}
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OrientationIndicator&
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resetToRef ()
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{
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offset_ = 0;
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return *this;
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}
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OrientationIndicator&
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operator+= (int adj)
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{
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offset_ += adj;
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return *this;
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}
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OrientationIndicator&
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operator-= (int adj)
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{
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offset_ -= adj;
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return *this;
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}
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OrientationIndicator&
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operator++ ()
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{
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this->operator +=(1);
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return *this;
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}
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OrientationIndicator&
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operator-- ()
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{
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this->operator -=(1);
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return *this;
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}
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};
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} // namespace lib
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#endif /*HIERARCHY_ORIENTATION_INDICATOR_HPP_*/
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