Support iterator state pattern

composer.json

@@ -3,7 +3,7 @@
   "description": "Collections library for php language",
   "minimum-stability": "dev",
   "license": "MIT",
-  "version": "1.1.1",
+  "version": "1.1.2",
   "authors": [
     {
       "name": "Maxim Sokolovsky",

src/WS/Utils/Collections/CollectionFactory.php

@@ -5,7 +5,10 @@
 
 namespace WS\Utils\Collections;
 
+use Iterator;
+use IteratorAggregate;
 use RuntimeException;
+use WS\Utils\Collections\Exception\UnsupportedException;
 
 class CollectionFactory
 {
@@ -37,7 +40,7 @@ public static function generate(int $times, ?callable $generator = null): Collec
     /**
      * Generate collection of int numbers between $from and $to. If $to arg is absent $from - is count of numbers
      * @param int $from
-     * @param int $to
+     * @param int|null $to
      * @return Collection
      */
     public static function numbers(int $from, ?int $to = null): Collection
@@ -68,8 +71,21 @@ public static function fromStrict(array $values): Collection
         return new ArrayStrictList($values);
     }
 
+    /**
+     * @throws UnsupportedException
+     */
     public static function fromIterable(iterable $iterable): Collection
     {
+        if (self::isStatePatternIterator($iterable)) {
+            if ($iterable instanceof IteratorAggregate) {
+                /** @noinspection PhpUnhandledExceptionInspection */
+                $iterable = $iterable->getIterator();
+            }
+            if (!$iterable instanceof Iterator) {
+                throw new UnsupportedException('Only Iterator interface can be applied to IteratorCollection');
+            }
+            return new IteratorCollection($iterable);
+        }
         $list = ArrayList::of();
         foreach ($iterable as $item) {
             $list->add($item);
@@ -82,4 +98,21 @@ public static function empty(): Collection
     {
         return ArrayList::of();
     }
+
+    private static function isStatePatternIterator(iterable $iterable): bool
+    {
+        $i = 2;
+        $lastItem = null;
+        foreach ($iterable as $item) {
+            if ($i === 0) {
+                break;
+            }
+            if (is_object($item) && $item === $lastItem) {
+                return true;
+            }
+            $lastItem = $item;
+            $i--;
+        }
+        return false;
+    }
 }

src/WS/Utils/Collections/Exception/UnsupportedException.php

@@ -0,0 +1,9 @@
+<?php
+
+namespace WS\Utils\Collections\Exception;
+
+use RuntimeException;
+
+class UnsupportedException extends RuntimeException
+{
+}

src/WS/Utils/Collections/IteratorCollection.php

@@ -0,0 +1,135 @@
+<?php
+
+namespace WS\Utils\Collections;
+
+use Iterator;
+use WS\Utils\Collections\Exception\UnsupportedException;
+
+/**
+ * Collection which support Traversable interface
+ */
+class IteratorCollection implements Collection
+{
+
+    /**
+     * @var Iterator
+     */
+    private $iterator;
+
+    public function __construct(Iterator $iterator)
+    {
+        $this->iterator = $iterator;
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function add($element): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function addAll(iterable $elements): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function merge(Collection $collection): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function clear(): void
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function remove($element): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function contains($element): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @throws UnsupportedException
+     * @codeCoverageIgnore
+     */
+    public function equals(Collection $collection): bool
+    {
+        throw new UnsupportedException();
+    }
+
+    public function size(): int
+    {
+        $this->iterator->rewind();
+        $count = 0;
+        while ($this->iterator->valid()) {
+            $this->iterator->next();
+            $count++;
+        }
+
+        return $count;
+    }
+
+    /**
+     * @codeCoverageIgnore
+     * @return bool
+     */
+    public function isEmpty(): bool
+    {
+        return $this->size() === 0;
+    }
+
+    public function stream(): Stream
+    {
+        return new IteratorStream($this);
+    }
+
+    /**
+     * @codeCoverageIgnore
+     * @return array
+     */
+    public function toArray(): array
+    {
+        throw new UnsupportedException();
+    }
+
+    /**
+     * @codeCoverageIgnore
+     * @return Collection
+     */
+    public function copy(): Collection
+    {
+        throw new UnsupportedException();
+    }
+
+    public function getIterator()
+    {
+        return $this->iterator;
+    }
+}