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Segmentation: code up the algorithm according to spec

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...derive the implementation mostly by logical reasoning
...indicate positions by Iterators of a random-access list
This commit is contained in:
Fischlurch 2023-05-03 03:32:49 +02:00
parent bf978fcda1
commit 2378be5d86
2 changed files with 233 additions and 31 deletions
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202
src/steam/fixture/segmentation.cpp
View file

@ -31,7 +31,7 @@
//#include "steam/mobject/builder/fixture-change-detector.hpp" ///////////TODO
#include "lib/time/timevalue.hpp"
#include <tuple>
#include <array>
namespace steam {
@ -53,6 +53,7 @@ namespace fixture {
namespace {// Implementation of Split-Splice algorithm
using lib::time::Time;
using lib::time::TimeVar;
using OptTime = std::optional<Time>;
using Iter = typename list<Segment>::iterator;
@ -74,14 +75,11 @@ namespace fixture {
, SEAMLESS
};
Verb opPred = NIL,
opSucc = NIL;
Verb opPred_ = NIL,
opSucc_ = NIL;
Iter pred{};
Iter succ{};
Time start = Time::NEVER,
after = Time::NEVER;
Iter pred_, succ_;
Time start_, after_;
/* ======= elementary operations ======= */
@ -89,37 +87,197 @@ namespace fixture {
Time getAfter (Iter elm) { return elm->after(); }
Iter
createElm (Time start, Time after)
createSeg (Iter pos, Time start, Time after)
{
UNIMPLEMENTED ("create new Segment");
}
Iter
cloneElm (Iter elm, Time start, Time after)
emptySeg (Iter pos, Time start, Time after)
{
UNIMPLEMENTED ("create new Segment");
}
Iter
cloneSeg (Iter pos, Time start, Time after, Iter src)
{
UNIMPLEMENTED ("clone Segment and modify time");
}
public:
void
establishSplitPoint (Iter startAll, Iter afterAll
,OptTime start, OptTime after)
Iter
discard (Iter start, Iter after)
{
UNIMPLEMENTED ("Stage-1 and Stage-2");
UNIMPLEMENTED ("discard Segments");
}
public:
/**
* @param startAll (forward) iterator pointing at the overall Segmentation begin
* @param afterAll (forward) iterator indicating point-after-end of Segmentation
* @param start (optional) specification of new segment's start point
* @param after (optional) specification of new segment's end point
*/
SplitSpliceAlgo (Iter startAll, Iter afterAll
,OptTime start, OptTime after)
{
auto [start_,after_] = establishSplitPoint (startAll,afterAll, start,after);
// Postcondition: ordered start and end times
ENSURE (pred_ != afterAll);
ENSURE (succ_ != afterAll);
ENSURE (start_ < after_);
ENSURE (getStart(pred_) <= start_);
ENSURE (start_ <= getStart(succ_) or pred_ == succ_);
}
/**
* Stage-1 and Stage-2 of the algorithm determine the insert point
* and establish the actual start and end point of the new segment
* @return
*/
std::pair<Time,Time>
establishSplitPoint (Iter startAll, Iter afterAll
,OptTime start, OptTime after)
{ // nominal break point
Time sep = start? *start
: after? *after
: Time::NEVER;
// find largest Predecessor with start before separator
for (succ_ = startAll, pred_ = afterAll
;succ_ != afterAll and getStart(succ_) < sep
;++succ_)
{
pred_ = succ_;
}
REQUIRE (pred_ != succ_, "non-empty segmentation required");
if (succ_ == afterAll) succ_=pred_;
if (pred_ == afterAll) pred_=succ_; // separator touches bounds
// Stage-2 : establish start and end point of new segment
Time startSeg = start? *start
: getAfter(pred_) < sep? getAfter(pred_)
: getStart(pred_);
Time afterSeg = after? *after
: getStart(succ_) > sep? getStart(succ_)
: getAfter(succ_);
ENSURE (startSeg != afterSeg);
if (startSeg < afterSeg)
return {startSeg,afterSeg};
else
return {afterSeg,startSeg};
}
/**
* Stage-3 of the algorithm works out the precise relation of the
* predecessor and successor segments to determine necessary adjustments
*/
void
determineRelations()
{
UNIMPLEMENTED ("Stage-3");
Time startPred = getStart (pred_),
afterPred = getAfter (pred_);
if (startPred < start_)
{
if (afterPred < start_) opPred_ = INS_NOP;
else
if (afterPred == start_) opPred_ = SEAMLESS;
else
{
opPred_ = TRUNC;
if (afterPred > after_)
{ // predecessor actually spans the new segment
// thus use it also as successor and truncate both (=SPLIT)
succ_ = pred_;
opSucc_ = TRUNC;
return;
} } }
else
{
REQUIRE (startPred == start_, "predecessor does not precede start point");
opPred_ = DROP;
if (after_ < afterPred )
{ // predecessor coincides with start of new segment
// thus use it rather as successor and truncate at start
succ_ = pred_;
opSucc_ = TRUNC;
return;
} }
TimeVar startSucc = getStart (succ_),
afterSucc = getAfter (succ_);
if (startSucc < after_)
{
while (afterSucc < after_)
{
++succ_;
startSucc = getStart (succ_);
afterSucc = getAfter (succ_);
}
ASSERT (startSucc < after_ // in case we dropped a successor completely spanned,
,"seamless segmentation"); // even the next one must start within the new segment
if (after_ == afterSucc) opSucc_ = DROP;
else
if (after_ < afterSucc) opSucc_ = TRUNC;
}
else
{
if (after_ == startSucc) opSucc_ = SEAMLESS;
else opSucc_ = INS_NOP;
}
}
std::pair<Iter, Iter>
/**
* Stage-4 of the algorithm performs the actual insert and deleting of segments
* @return `(s,n,e)` to indicate where changes happened
* - s the first changed element
* - n the new main segment (may be identical to s)
* - e the first unaltered element after the changed range (may be `end()`)
*/
std::array<Iter, 3>
performSplitSplice()
{
UNIMPLEMENTED ("Stage-4 - doIT");
Iter refPred = pred_, refSucc = succ_;
REQUIRE (opPred_ != NIL and opSucc_ != NIL);
// deletions are done by skipping the complete range around the insertion point;
// thus to retain a predecessor or successor, this range has to be reduced
if (opPred_ == INS_NOP or opPred_ == SEAMLESS)
++pred_;
if (opSucc_ == DROP or opSucc_ == TRUNC)
++succ_;
// insert the new elements /before/ the range to be dropped, i.e. at pred_
Iter n = createSeg (pred_, start_, after_);
Iter s = n;
//
// possibly adapt the predecessor
if (opPred_ == INS_NOP)
s = emptySeg (n, getAfter(refPred), start_);
else
if (opPred_ == TRUNC)
s = cloneSeg (n, getStart(refPred), start_, refPred);
//
// possibly adapt the successor
if (opSucc_ == INS_NOP)
emptySeg (pred_, after_, getStart(refSucc));
else
if (opPred_ == TRUNC)
cloneSeg (pred_, after_, getAfter(refSucc), refSucc);
// finally discard superseded segments
Iter e = discard (pred_, succ_);
// indicate the range where changes happened
return {s,n,e};
}
};
}//(End)SlitSplice impl
@ -148,10 +306,10 @@ namespace fixture {
Segment const&
Segmentation::splitSplice (OptTime start, OptTime after, const engine::JobTicket* jobTicket)
{
SplitSpliceAlgo splicr;
splicr.establishSplitPoint (segments_.begin(),segments_.end(), start,after);
SplitSpliceAlgo splicr{segments_.begin(),segments_.end(), start,after};
splicr.determineRelations();
splicr.performSplitSplice();
auto [s,n,e] = splicr.performSplitSplice();
return *n;
}

62
wiki/thinkPad.ichthyo.mm
View file

@ -70022,7 +70022,7 @@
<node BACKGROUND_COLOR="#e0ceaa" COLOR="#690f14" CREATED="1682627110771" ID="ID_183754275" MODIFIED="1682627133820" TEXT="Invariante: l&#xfc;ckenlose Abdeckung">
<icon BUILTIN="messagebox_warning"/>
</node>
<node BACKGROUND_COLOR="#fdfdcf" COLOR="#ff0000" CREATED="1682985654543" ID="ID_433290925" MODIFIED="1682993072525" TEXT="Algorithmus">
<node COLOR="#435e98" CREATED="1682985654543" ID="ID_433290925" MODIFIED="1683076777480" TEXT="Algorithmus">
<icon BUILTIN="info"/>
<node CREATED="1682987424458" ID="ID_419424512" MODIFIED="1682987433683" TEXT="Invariante">
<font BOLD="true" NAME="SansSerif" SIZE="12"/>
@ -70145,11 +70145,11 @@
</node>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1682993086565" ID="ID_469257294" MODIFIED="1682993090645" TEXT="Implementierung">
<icon BUILTIN="flag-yellow"/>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1683042576253" ID="ID_1878728765" MODIFIED="1683042587092" TEXT="Konzept">
<node BACKGROUND_COLOR="#eef0c5" COLOR="#990000" CREATED="1682993086565" ID="ID_469257294" MODIFIED="1683076810216" TEXT="Implementierung">
<icon BUILTIN="pencil"/>
<node COLOR="#435e98" CREATED="1683042576253" ID="ID_1878728765" MODIFIED="1683076796339" TEXT="Konzept">
<icon BUILTIN="yes"/>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1683042638127" ID="ID_1570983964" MODIFIED="1683042656744" TEXT="Deskriptor SpliceAct">
<node COLOR="#435e98" CREATED="1683042638127" ID="ID_1570983964" MODIFIED="1683076788355" TEXT="Deskriptor SpliceAct">
<icon BUILTIN="idea"/>
</node>
<node COLOR="#5b280f" CREATED="1683042697806" ID="ID_1462476322" MODIFIED="1683043770315" TEXT="Task-Record">
@ -70164,7 +70164,7 @@
</node>
</node>
</node>
<node CREATED="1683043806248" ID="ID_358437836" MODIFIED="1683043811748" TEXT="Enum als verb">
<node COLOR="#435e98" CREATED="1683043806248" ID="ID_358437836" MODIFIED="1683076789875" TEXT="Enum als verb">
<node CREATED="1683043814387" ID="ID_312010971" MODIFIED="1683043834772" TEXT="jeweils separat f&#xfc;r pred und succ"/>
<node CREATED="1683043835634" ID="ID_1729162283" MODIFIED="1683043837062" TEXT="F&#xe4;lle">
<node CREATED="1683043887635" ID="ID_1329437740" MODIFIED="1683043891434" TEXT="SEAMLESS"/>
@ -70183,14 +70183,58 @@
</node>
</node>
</node>
<node CREATED="1683045976036" ID="ID_1600965970" MODIFIED="1683045990086" TEXT="Predecessor und Successor per Iterator referenzieren"/>
<node COLOR="#338800" CREATED="1683045976036" ID="ID_1600965970" MODIFIED="1683076793754" TEXT="Predecessor und Successor per Iterator referenzieren">
<icon BUILTIN="button_ok"/>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1683046583116" ID="ID_133574091" MODIFIED="1683046722114" TEXT="lokale Umsetzung">
<icon BUILTIN="flag-yellow"/>
</node>
<node COLOR="#338800" CREATED="1683046583116" ID="ID_133574091" MODIFIED="1683076802821" TEXT="lokale Umsetzung">
<icon BUILTIN="button_ok"/>
<node CREATED="1683046618535" ID="ID_545931815" MODIFIED="1683046633053" TEXT="den Deskriptor als lokale/anonyme Klasse"/>
<node CREATED="1683046633701" ID="ID_1909003590" MODIFIED="1683046644503" TEXT="die Schritte des Algo als Methoden"/>
<node CREATED="1683046648011" ID="ID_884620601" MODIFIED="1683046664621" TEXT="Arbeitsdaten als Member"/>
<node CREATED="1683046711054" ID="ID_815326523" MODIFIED="1683046719941" TEXT="Integration als statische Funktion"/>
<node COLOR="#435e98" CREATED="1683076903128" ID="ID_1277889001" MODIFIED="1683077356643" TEXT="einige Vereinfachungen">
<richcontent TYPE="NOTE"><html>
<head>
</head>
<body>
<p>
Nach logischer Analyse der spezifiziereten F&#228;lle lassen sich einige Verzweigungen verk&#252;rzen
</p>
<ul>
<li>
die Suche nach dem Split-Punkt und das Festsetzen der Start/Endpunkte fasse ich zusammen in den Konstruktor; danach sind Start/Endzeit <i>immutable</i>
</li>
<li>
sichere die Verk&#252;rzungen m&#246;glichst durch Assertions ab
</li>
<li>
der SPLIT und SWAP-Fall wird dargestellt, indem ich den Predecessor auch als Successor verwende, und lediglich f&#252;r beide verschiedene Operationen codiere
</li>
<li>
sofern f&#252;r beide bereits eine Operation definiert wurde, kann man die gesamte Untersuchung des Successors &#252;berspringen
</li>
<li>
in dem Fall, in dem ggfs. mehrere &#252;berdeckte Successoren &#252;bersprungen werden, schiebe ich lediglich die Variablen
</li>
<li>
den Umstand, da&#223; Predecessor/Successor verworfen werden, oder eben nicht, setze ich direkt durch Justieren des Iterator-Bereichs um
</li>
<li>
anschlie&#223;end werden <i>zuerst</i>&#160;die neuen Elemente <i>davorgeh&#228;ngt</i>&#160;und dann der zu verwerfende Bereich gel&#246;scht
</li>
<li>
als Ergebnis gebe ich die bezeichneten Iterator-Positionen zur&#252;ck
</li>
<li>
alle Mutator-Operationen arbeiten auf Iteratoren (d.h. setzen eine nicht-invalidierende random-access-Liste vorraus)
</li>
</ul>
</body>
</html></richcontent>
<icon BUILTIN="idea"/>
</node>
</node>
<node BACKGROUND_COLOR="#eee5c3" COLOR="#990000" CREATED="1683046722945" ID="ID_113209914" MODIFIED="1683046727395" TEXT="Generalisierung">
<icon BUILTIN="flag-yellow"/>