graph-tools-php

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<?php
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namespace Smoren\GraphTools\Helpers;
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use Generator;
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use Smoren\GraphTools\Models\Interfaces\VertexInterface;
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use Smoren\GraphTools\Structs\Interfaces\TraverseContextInterface;
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/**
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 * Helper for getting traversing results
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 * @author Smoren <ofigate@gmail.com>
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 */
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class TraverseHelper
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{
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    /**
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     * Returns branches of traversing (every branch as array of Vertex objects)
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     * @param Generator<TraverseContextInterface> $contexts traverse contexts' iterator
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     * @param callable|null $callback action to do for each context
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     * @return array<int, array<VertexInterface>> branch list
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     */
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    public static function getBranches(Generator $contexts, ?callable $callback = null): array
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    {
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        $branchMap = [];
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        foreach($contexts as $context) {
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            if(is_callable($callback)) {
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                $callback($context, $contexts);
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            }
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            $branchContext = $context->getBranchContext();
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            $branchIndex = $branchContext->getIndex();
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            $parentBranchIndex = $context->getBranchContext()->getParentIndex();
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            $vertex = $context->getVertex();
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            if(!isset($branchMap[$branchIndex])) {
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                if(isset($branchMap[$parentBranchIndex])) {
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                    $parentBranch = $branchMap[$parentBranchIndex];
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                    $key = array_search($branchContext->getStart(), $parentBranch);
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                    $branchMap[$branchIndex] = array_slice($parentBranch, 0, $key+1);
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                } else {
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                    $branchMap[$branchIndex] = [];
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                }
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            }
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            $branchMap[$branchIndex][] = $vertex;
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        }
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        return $branchMap;
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    }
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}
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