Improve IteratorProvider::cycle() implement

Author: emonkak

benchmarks/CycleEvent.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace Emonkak\Collection\Benchmarks;
+
+use Athletic\AthleticEvent;
+use Emonkak\Collection\Collection;
+
+class CycleEvent extends AthleticEvent
+{
+    use CollectionBenchmark;
+
+    public function setUp()
+    {
+        $this->data = Collection::from(range(0, 10));
+    }
+
+    protected function execute($xs)
+    {
+        foreach ($xs->cycle(100) as $x);
+    }
+}

src/Iterator/CycleIterator.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Emonkak\Collection\Iterator;
+
+class CycleIterator implements \Iterator
+{
+    private $it;
+    private $n;
+    private $i;
+
+    public function __construct(\Iterator $it, $n)
+    {
+        $this->it = $it;
+        $this->n = $n;
+    }
+
+    public function current()
+    {
+        return $this->it->current();
+    }
+
+    public function key()
+    {
+        return $this->it->key();
+    }
+
+    public function next()
+    {
+        $this->it->next();
+
+        if (!$this->it->valid()) {
+            $this->i++;
+            $this->it->rewind();
+        }
+    }
+
+    public function rewind()
+    {
+        $this->i = 0;
+        $this->it->rewind();
+    }
+
+    public function valid()
+    {
+        return $this->i < $this->n && $this->it->valid();
+    }
+}

src/Provider/IteratorProvider.php

@@ -4,6 +4,7 @@
 
 use Emonkak\Collection\Comparer\EqualityComparer;
 use Emonkak\Collection\Iterator\ConcatMapIterator;
+use Emonkak\Collection\Iterator\CycleIterator;
 use Emonkak\Collection\Iterator\DropWhileIterator;
 use Emonkak\Collection\Iterator\FlattenIterator;
 use Emonkak\Collection\Iterator\GroupJoinIterator;
@@ -45,8 +46,8 @@ public function map($xs, callable $valueSelector, callable $keySelector)
      */
     public function concatMap($xs, callable $selector)
     {
-        $inner = new ConcatMapIterator(Iterators::create($xs), $selector);
-        return new \RecursiveIteratorIterator($inner);
+        $it = new ConcatMapIterator(Iterators::create($xs), $selector);
+        return new \RecursiveIteratorIterator($it);
     }
 
     /**
@@ -186,8 +187,8 @@ public function dropWhile($xs, callable $predicate)
      */
     public function flatten($xs, $shallow)
     {
-        $inner = new FlattenIterator(Iterators::create($xs), $shallow);
-        return new \RecursiveIteratorIterator($inner);
+        $it = new FlattenIterator(Iterators::create($xs), $shallow);
+        return new \RecursiveIteratorIterator($it);
     }
 
     /**
@@ -243,16 +244,11 @@ public function concat($xss)
      */
     public function cycle($xs, $n)
     {
-        $inner = Iterators::create($xs);
-        if ($n === null) {
-            return new \InfiniteIterator($inner);
+        $it = Iterators::create($xs);
+        if ($n !== null) {
+            return new CycleIterator($it, $n);
         } else {
-            // TODO: Implement CycleIterator
-            $it = new \AppendIterator();
-            while ($n-- > 0) {
-                $it->append($inner);
-            }
-            return $it;
+            return new \InfiniteIterator($it);
         }
     }
 
@@ -269,10 +265,10 @@ public function range($start, $stop, $step)
      */
     public function repeat($value, $n)
     {
-        if ($n === null) {
-            return new \InfiniteIterator(new \ArrayIterator([$value]));
-        } else {
+        if ($n !== null) {
             return new RepeatIterator($value, $n);
+        } else {
+            return new \InfiniteIterator(new \ArrayIterator([$value]));
         }
     }