Completed
Push — issue_187 ( fb1b49...8952f9 )
by Doug
158:46 queued 155:58
created

VolumePacker::pack()   A

Complexity

Conditions 4
Paths 8

Size

Total Lines 20
Code Lines 10

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 11
CRAP Score 4

Importance

Changes 6
Bugs 0 Features 0
Metric Value
cc 4
eloc 10
c 6
b 0
f 0
nc 8
nop 0
dl 0
loc 20
ccs 11
cts 11
cp 1
crap 4
rs 9.9332
1
<?php
2
/**
3
 * Box packing (3D bin packing, knapsack problem).
4
 *
5
 * @author Doug Wright
6
 */
7
declare(strict_types=1);
8
9
namespace DVDoug\BoxPacker;
10
11
use function count;
12
use function max;
13
use function min;
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use Psr\Log\LoggerAwareInterface;
15
use Psr\Log\LoggerInterface;
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use Psr\Log\NullLogger;
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18
/**
19
 * Actual packer.
20
 *
21
 * @author Doug Wright
22
 */
23
class VolumePacker implements LoggerAwareInterface
24
{
25
    /**
26
     * The logger instance.
27
     *
28
     * @var LoggerInterface
29
     */
30
    protected $logger;
31
32
    /**
33
     * Box to pack items into.
34
     *
35
     * @var Box
36
     */
37
    protected $box;
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39
    /**
40
     * @var int
41
     */
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    protected $boxWidth;
43
44
    /**
45
     * @var int
46
     */
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    protected $boxLength;
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49
    /**
50
     * List of items to be packed.
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     *
52
     * @var ItemList
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     */
54
    protected $items;
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56
    /**
57
     * List of items temporarily skipped to be packed.
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     *
59
     * @var array
60
     */
61
    protected $skippedItems = [];
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63
    /**
64
     * Remaining weight capacity of the box.
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     *
66
     * @var int
67
     */
68
    protected $remainingWeight;
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70
    /**
71
     * Whether the box was rotated for packing.
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     *
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     * @var bool
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     */
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    protected $boxRotated = false;
76
77
    /**
78
     * @var PackedLayer[]
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     */
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    protected $layers = [];
81
82
    /**
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     * Whether the packer is in look-ahead mode (i.e. working ahead of the main packing).
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     *
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     * @var bool
86
     */
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    protected $lookAheadMode = false;
88
89
    /**
90
     * @var OrientatedItemFactory
91
     */
92
    private $orientatedItemFactory;
93
94
    /**
95
     * Constructor.
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     */
97 22
    public function __construct(Box $box, ItemList $items)
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    {
99 22
        $this->box = $box;
100 22
        $this->items = $items;
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102 22
        $this->boxWidth = max($this->box->getInnerWidth(), $this->box->getInnerLength());
103 22
        $this->boxLength = min($this->box->getInnerWidth(), $this->box->getInnerLength());
104 22
        $this->remainingWeight = $this->box->getMaxWeight() - $this->box->getEmptyWeight();
105 22
        $this->logger = new NullLogger();
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107
        // we may have just rotated the box for packing purposes, record if we did
108 22
        if ($this->box->getInnerWidth() !== $this->boxWidth || $this->box->getInnerLength() !== $this->boxLength) {
109 4
            $this->boxRotated = true;
110
        }
111
112 22
        $this->orientatedItemFactory = new OrientatedItemFactory($this->box);
113 22
    }
114
115
    /**
116
     * Sets a logger.
117
     */
118 7
    public function setLogger(LoggerInterface $logger): void
119
    {
120 7
        $this->logger = $logger;
121 7
        $this->orientatedItemFactory->setLogger($logger);
122 7
    }
123
124
    /**
125
     * @internal
126
     */
127 3
    public function setLookAheadMode(bool $lookAhead): void
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    {
129 3
        $this->lookAheadMode = $lookAhead;
130 3
    }
131
132
    /**
133
     * Pack as many items as possible into specific given box.
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     *
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     * @return PackedBox packed box
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     */
137 22
    public function pack(): PackedBox
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    {
139 22
        $this->logger->debug("[EVALUATING BOX] {$this->box->getReference()}", ['box' => $this->box]);
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141 22
        while ($this->items->count() > 0) {
142 22
            $layerStartDepth = $this->getCurrentPackedDepth();
143 22
            $this->packLayer($layerStartDepth, $this->boxWidth, $this->boxLength, $this->box->getInnerDepth() - $layerStartDepth);
144
        }
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146 22
        if ($this->boxRotated) {
147 4
            $this->rotateLayersNinetyDegrees();
148
        }
149
150 22
        if (!$this->lookAheadMode) {
151 22
            $this->stabiliseLayers();
152
        }
153
154 22
        $this->logger->debug('done with this box');
155
156 22
        return new PackedBox($this->box, $this->getPackedItemList());
157
    }
158
159
    /**
160
     * Pack items into an individual vertical layer.
161
     */
162 22
    protected function packLayer(int $startDepth, int $widthLeft, int $lengthLeft, int $depthLeft): void
163
    {
164 22
        $this->layers[] = $layer = new PackedLayer();
165 22
        $prevItem = null;
166 22
        $x = $y = $rowWidth = $rowLength = $layerDepth = 0;
167
168 22
        while ($this->items->count() > 0) {
169 22
            $itemToPack = $this->items->extract();
170
171
            //skip items that are simply too heavy or too large
172 22
            if (!$this->checkNonDimensionalConstraints($itemToPack)) {
173 3
                continue;
174
            }
175
176 22
            $orientatedItem = $this->getOrientationForItem($itemToPack, $prevItem, $this->items, !$this->hasItemsLeftToPack(), $widthLeft, $lengthLeft, $depthLeft, $rowLength, $x, $y, $startDepth);
177
178 22
            if ($orientatedItem instanceof OrientatedItem) {
179 22
                $packedItem = PackedItem::fromOrientatedItem($orientatedItem, $x, $y, $startDepth);
180 22
                $layer->insert($packedItem);
181 22
                $this->remainingWeight -= $orientatedItem->getItem()->getWeight();
182 22
                $widthLeft -= $orientatedItem->getWidth();
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184 22
                $rowWidth += $orientatedItem->getWidth();
185 22
                $rowLength = max($rowLength, $orientatedItem->getLength());
186 22
                $layerDepth = max($layerDepth, $orientatedItem->getDepth());
187
188
                //allow items to be stacked in place within the same footprint up to current layer depth
189 22
                $stackableDepth = $layerDepth - $orientatedItem->getDepth();
190 22
                $this->tryAndStackItemsIntoSpace($layer, $prevItem, $this->items, $orientatedItem->getWidth(), $orientatedItem->getLength(), $stackableDepth, $x, $y, $startDepth + $orientatedItem->getDepth(), $rowLength);
191 22
                $x += $orientatedItem->getWidth();
192
193 22
                $prevItem = $packedItem;
194 22
                if ($this->items->count() === 0) {
195 22
                    $this->rebuildItemList();
196
                }
197 19
            } elseif (count($layer->getItems()) === 0) { // zero items on layer
198 5
                $this->logger->debug("doesn't fit on layer even when empty, skipping for good");
199 5
                continue;
200 18
            } elseif ($widthLeft > 0 && $this->items->count() > 0) { // skip for now, move on to the next item
201 14
                $this->logger->debug("doesn't fit, skipping for now");
202 14
                $this->skippedItems[] = $itemToPack;
203
                // abandon here if next item is the same, no point trying to keep going. Last time is not skipped, need that to trigger appropriate reset logic
204 14
                while ($this->items->count() > 2 && $this->orientatedItemFactory->isSameDimensions($itemToPack, $this->items->top())) {
205 4
                    $this->skippedItems[] = $this->items->extract();
206
                }
207 18
            } elseif ($x > 0 && $lengthLeft >= min($itemToPack->getWidth(), $itemToPack->getLength(), $itemToPack->getDepth())) {
208 18
                $this->logger->debug('No more fit in width wise, resetting for new row');
209 18
                $widthLeft += $rowWidth;
210 18
                $lengthLeft -= $rowLength;
211 18
                $y += $rowLength;
212 18
                $x = $rowWidth = $rowLength = 0;
213 18
                $this->skippedItems[] = $itemToPack;
214 18
                $this->rebuildItemList();
215 18
                $prevItem = null;
216 18
                continue;
217
            } else {
218 16
                $this->logger->debug('no items fit, so starting next vertical layer');
219 16
                $this->skippedItems[] = $itemToPack;
220 16
                $this->rebuildItemList();
221
222 16
                return;
223
            }
224
        }
225 22
    }
226
227
    /**
228
     * During packing, it is quite possible that layers have been created that aren't physically stable
229
     * i.e. they overhang the ones below.
230
     *
231
     * This function reorders them so that the ones with the greatest surface area are placed at the bottom
232
     */
233 22
    public function stabiliseLayers(): void
234
    {
235 22
        $stabiliser = new LayerStabiliser();
236 22
        $this->layers = $stabiliser->stabilise($this->layers);
237 22
    }
238
239 22
    protected function getOrientationForItem(
240
        Item $itemToPack,
241
        ?PackedItem $prevItem,
242
        ItemList $nextItems,
243
        bool $isLastItem,
244
        int $maxWidth,
245
        int $maxLength,
246
        int $maxDepth,
247
        int $rowLength,
248
        int $x,
249
        int $y,
250
        int $z
251
    ): ?OrientatedItem {
252 22
        $this->logger->debug(
253 22
            "evaluating item {$itemToPack->getDescription()} for fit",
254
            [
255 22
                'item' => $itemToPack,
256
                'space' => [
257 22
                    'maxWidth' => $maxWidth,
258 22
                    'maxLength' => $maxLength,
259 22
                    'maxDepth' => $maxDepth,
260
                ],
261
            ]
262
        );
263
264 22
        $prevOrientatedItem = $prevItem ? $prevItem->toOrientatedItem() : null;
265 22
        $prevPackedItemList = $itemToPack instanceof ConstrainedPlacementItem ? $this->getPackedItemList() : new PackedItemList(); // don't calculate it if not going to be used
266
267 22
        $orientatedItemDecision = $this->orientatedItemFactory->getBestOrientation($itemToPack, $prevOrientatedItem, $nextItems, $isLastItem, $maxWidth, $maxLength, $maxDepth, $rowLength, $x, $y, $z, $prevPackedItemList);
268
269 22
        return $orientatedItemDecision;
270
    }
271
272
    /**
273
     * Figure out if we can stack the next item vertically on top of this rather than side by side
274
     * Used when we've packed a tall item, and have just put a shorter one next to it.
275
     */
276 22
    protected function tryAndStackItemsIntoSpace(
277
        PackedLayer $layer,
278
        ?PackedItem $prevItem,
279
        ItemList $nextItems,
280
        int $maxWidth,
281
        int $maxLength,
282
        int $maxDepth,
283
        int $x,
284
        int $y,
285
        int $z,
286
        int $rowLength
287
    ): void {
288 22
        while ($this->items->count() > 0 && $this->checkNonDimensionalConstraints($this->items->top())) {
289 21
            $stackedItem = $this->getOrientationForItem(
290 21
                $this->items->top(),
291
                $prevItem,
292
                $nextItems,
293 21
                $this->items->count() === 1,
294
                $maxWidth,
295
                $maxLength,
296
                $maxDepth,
297
                $rowLength,
298
                $x,
299
                $y,
300
                $z
301
            );
302 21
            if ($stackedItem) {
303 3
                $this->remainingWeight -= $this->items->top()->getWeight();
304 3
                $layer->insert(PackedItem::fromOrientatedItem($stackedItem, $x, $y, $z));
305 3
                $this->items->extract();
306 3
                $maxDepth -= $stackedItem->getDepth();
307 3
                $z += $stackedItem->getDepth();
308
            } else {
309 21
                break;
310
            }
311
        }
312 22
    }
313
314
    /**
315
     * As well as purely dimensional constraints, there are other constraints that need to be met
316
     * e.g. weight limits or item-specific restrictions (e.g. max <x> batteries per box).
317
     */
318 22
    protected function checkNonDimensionalConstraints(Item $itemToPack): bool
319
    {
320 22
        $weightOK = $itemToPack->getWeight() <= $this->remainingWeight;
321
322 22
        if ($itemToPack instanceof ConstrainedItem) {
323
            return $weightOK && $itemToPack->canBePackedInBox($this->getPackedItemList(), $this->box);
324
        }
325
326 22
        return $weightOK;
327
    }
328
329
    /**
330
     * Reintegrate skipped items into main list.
331
     */
332 22
    protected function rebuildItemList(): void
333
    {
334 22
        $this->items = ItemList::fromArray(array_merge($this->skippedItems, iterator_to_array($this->items)), true);
335 22
        $this->skippedItems = [];
336 22
    }
337
338
    /**
339
     * Swap back width/length of the packed items to match orientation of the box if needed.
340
     */
341 4
    protected function rotateLayersNinetyDegrees(): void
342
    {
343 4
        foreach ($this->layers as $i => $originalLayer) {
344 4
            $newLayer = new PackedLayer();
345 4
            foreach ($originalLayer->getItems() as $item) {
346 4
                $packedItem = new PackedItem($item->getItem(), $item->getY(), $item->getX(), $item->getZ(), $item->getLength(), $item->getWidth(), $item->getDepth());
347 4
                $newLayer->insert($packedItem);
348
            }
349 4
            $this->layers[$i] = $newLayer;
350
        }
351 4
    }
352
353
    /**
354
     * Are there items left to pack?
355
     */
356 22
    protected function hasItemsLeftToPack(): bool
357
    {
358 22
        return count($this->skippedItems) + $this->items->count() > 0;
359
    }
360
361
    /**
362
     * Generate a single list of items packed.
363
     */
364 22
    protected function getPackedItemList(): PackedItemList
365
    {
366 22
        $packedItemList = new PackedItemList();
367 22
        foreach ($this->layers as $layer) {
368 22
            foreach ($layer->getItems() as $packedItem) {
369 22
                $packedItemList->insert($packedItem);
370
            }
371
        }
372
373 22
        return $packedItemList;
374
    }
375
376
    /**
377
     * Return the current packed depth.
378
     */
379 22
    protected function getCurrentPackedDepth(): int
380
    {
381 22
        $depth = 0;
382 22
        foreach ($this->layers as $layer) {
383 16
            $depth += $layer->getDepth();
384
        }
385
386 22
        return $depth;
387
    }
388
}
389