Ichthyostega
806db414dd
* Lumiera source code always was copyrighted by individual contributors * there is no entity "Lumiera.org" which holds any copyrights * Lumiera source code is provided under the GPL Version 2+ == Explanations == Lumiera as a whole is distributed under Copyleft, GNU General Public License Version 2 or above. For this to become legally effective, the ''File COPYING in the root directory is sufficient.'' The licensing header in each file is not strictly necessary, yet considered good practice; attaching a licence notice increases the likeliness that this information is retained in case someone extracts individual code files. However, it is not by the presence of some text, that legally binding licensing terms become effective; rather the fact matters that a given piece of code was provably copyrighted and published under a license. Even reformatting the code, renaming some variables or deleting parts of the code will not alter this legal situation, but rather creates a derivative work, which is likewise covered by the GPL! The most relevant information in the file header is the notice regarding the time of the first individual copyright claim. By virtue of this initial copyright, the first author is entitled to choose the terms of licensing. All further modifications are permitted and covered by the License. The specific wording or format of the copyright header is not legally relevant, as long as the intention to publish under the GPL remains clear. The extended wording was based on a recommendation by the FSF. It can be shortened, because the full terms of the license are provided alongside the distribution, in the file COPYING.
216 lines
8.7 KiB
C++
216 lines
8.7 KiB
C++
/*
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IterChainSearch(Test) - verify chained search operations with backtracking
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Copyright (C)
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2018, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file iter-chain-search-test.cpp
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** unit test \ref IterChainSearch_test
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*/
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#include "lib/test/run.hpp"
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#include "lib/test/test-helper.hpp"
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#include "lib/format-util.hpp"
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#include "lib/iter-chain-search.hpp"
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#include "lib/iter-cursor.hpp"
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#include "lib/util.hpp"
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#include <vector>
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#include <string>
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namespace lib {
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namespace iter{
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namespace test{
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using ::Test;
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using util::join;
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using util::isnil;
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using util::startsWith;
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using util::isSameObject;
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using std::vector;
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using std::string;
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using LERR_(ITER_EXHAUST);
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namespace { // test fixture
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using Spam = vector<string>;
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const Spam SPAM{"spam"
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,"sausage"
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,"spam"
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,"spam"
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,"bacon"
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,"spam"
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,"tomato"
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,"and"
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,"spam"
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};
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/** Diagnostic helper: join all the elements from a _copy_ of the iterator */
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template<class II>
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inline string
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materialise (II&& ii)
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{
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return util::join (std::forward<II> (ii), "-");
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}
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}// (END)fixture
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/*****************************************************************//**
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* @test verify a setup for consecutive searches with backtracking.
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* - demonstrate simple consecutive matches and iterator behaviour
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* - clear the filter underway and thus return to simple iteration
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* - set up two conditions, the second one capturing state at the
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* point where the first one matches
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* - wrap a lib::IterCursor, which allows to toggle the search
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* direction underway; this creates a situation where the
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* first options picked do not lead to a successful solution,
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* so the search has to track back, try further options and
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* in each case re-apply all the following consecutive
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* search conditions.
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*
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* @see iter-chain-search.hpp
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* @see iter-cursor.hpp
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* @see [usage example](\ref event-log.hpp)
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*/
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class IterChainSearch_test : public Test
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{
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virtual void
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run (Arg)
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{
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simpleSearch();
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chainedIteration();
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backtracking();
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}
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/** @test simple basic use case. */
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void
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simpleSearch ()
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{
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auto search = chainSearch(SPAM)
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.search("bacon")
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.search("tomato");
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CHECK (search);
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CHECK (not isnil(search));
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CHECK ("tomato" == *search);
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CHECK (isSameObject (*search, SPAM[6]));
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search.clearFilter();
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CHECK ("tomato" == *search);
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++search;
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CHECK ("and" == *search);
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search.search("spam");
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CHECK ("spam" == *search);
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CHECK (isSameObject (*search, SPAM[8]));
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++search;
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CHECK (not search);
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CHECK (isnil (search));
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VERIFY_ERROR (ITER_EXHAUST, *search);
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}
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/** @test verify consecutive application of several functors on the underlying filter.
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* In the general case, each step in the chain is a function working on a copy of the
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* current filter state. Since each such step configures its own copy of the complete
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* pipeline, it may reconfigure this filter pipeline in arbitrary ways. After exhausting
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* the last layer, the evaluation returns to the previous layer, but immediately re-applies
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* the configuration step on the then next element.
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*/
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void
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chainedIteration ()
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{
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auto search = chainSearch(SPAM) // Note: 1st filter step picks all s-words
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.search([](string const& str){ return startsWith (str, "s"); });
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CHECK (materialise (search) =="spam-sausage-spam-spam-spam-spam");
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CHECK ("spam" == *search);
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search.addStep([](auto& filter)
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{ // Note: pick the current value at the point
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string currVal = *filter; // where the 2nd filter step is (re)applied
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filter.setNewFilter ([=](string const& val) // ...and bake this value into the lambda closure
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{
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return val != currVal;
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});
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});
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CHECK ("sausage" == *search);
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CHECK (materialise (search)
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== "sausage-bacon-tomato-and-" // everything in the rest, which is not "spam"
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"spam-spam-bacon-spam-tomato-and-spam-" // everything starting at "sausage" which is not "sausage"
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"bacon-tomato-and-" // any non-spam behind the 2nd spam
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"bacon-tomato-and-" // any non-spam behind the 3rd spam
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"tomato-and" // any non-spam behind the 4th spam
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""); // and any non-spam behind the final spam
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}
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/** @test verify a complex search with backtracking.
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* This becomes relevant when a given search condition can be "too greedy" for the
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* complete chain to succeed. Most notably this is the case when the search is fundamentally
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* reconfigured in some steps, e.g. by switching the search orientation. To demonstrate this,
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* we use a "gear switching" iterator, which allows us to reverse the direction and to search
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* backwards from the current position. We configure the second condition in the chain such
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* that it can not succeed when starting from the first match on the first condition
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*/
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void
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backtracking ()
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{
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using Cursor = IterCursor<decltype(SPAM.begin())>;
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auto search = chainSearch(Cursor{SPAM.begin(), SPAM.end()})
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.search("spam")
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.addStep([](auto& filter)
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{
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filter.switchBackwards(); // switch search direction without moving the cursor
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filter.flipFilter(); // flip from match on "spam" to match on non-spam
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})
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.addStep([](auto& filter)
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{ // filter is still configured to search non-spam backwards
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++filter; // just "advance" this filter by one step (backward)
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});
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CHECK (materialise (search) // Layer-0: 1-3 spam fail altogether, too greedy. Try 4rd spam....
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// Layer-1: turn back, toggle to non-spam, find bacon
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== "sausage-" // Layer-2: non-spam and one step further backwards yields sausage
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//
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// BACKTRACK to Layer-0: pick 5th (and last) spam...
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// Layer-1: turn back, toggle to non-spam, find "and"
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"tomato-bacon-sausage-" // Layer-2: non-spam and one step back yields tomato, next bacon, next sausage.
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// BACKTRACK to Layer-1: take previous one, which is tomato
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"bacon-sausage-" // Layer-2: non-spam and one step further back yields bacon, then next sausage.
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// BACKTRACK to Layer-1: take previous non-spam, which is bacon
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"sausage" // Layer-2: non-spam and one step further back yields sausage.
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""); // BACKTRACK to Layer-1: exhausted, BACKTRACK to Layer-0: exhausted. Done.
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}
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};
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LAUNCHER (IterChainSearch_test, "unit common");
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}}} // namespace lib::iter::test
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