installed plugin W3 Total Cache version 2.3.2

wp-content/plugins/w3-total-cache/vendor/aws/aws-sdk-php/src/PhpHash.php

@@ -0,0 +1,81 @@
+<?php
+namespace Aws;
+
+/**
+ * Incremental hashing using PHP's hash functions.
+ */
+class PhpHash implements HashInterface
+{
+    /** @var resource|\HashContext */
+    private $context;
+
+    /** @var string */
+    private $algo;
+
+    /** @var array */
+    private $options;
+
+    /** @var string */
+    private $hash;
+
+    /**
+     * @param string $algo Hashing algorithm. One of PHP's hash_algos()
+     *     return values (e.g. md5, sha1, etc...).
+     * @param array  $options Associative array of hashing options:
+     *     - key: Secret key used with the hashing algorithm.
+     *     - base64: Set to true to base64 encode the value when complete.
+     */
+    public function __construct($algo, array $options = [])
+    {
+        $this->algo = $algo;
+        $this->options = $options;
+    }
+
+    public function update($data)
+    {
+        if ($this->hash !== null) {
+            $this->reset();
+        }
+
+        hash_update($this->getContext(), $data);
+    }
+
+    public function complete()
+    {
+        if ($this->hash) {
+            return $this->hash;
+        }
+
+        $this->hash = hash_final($this->getContext(), true);
+
+        if (isset($this->options['base64']) && $this->options['base64']) {
+            $this->hash = base64_encode($this->hash);
+        }
+
+        return $this->hash;
+    }
+
+    public function reset()
+    {
+        $this->context = $this->hash = null;
+    }
+
+    /**
+     * Get a hash context or create one if needed
+     *
+     * @return resource|\HashContext 
+     */
+    private function getContext()
+    {
+        if (!$this->context) {
+            $key = isset($this->options['key']) ? $this->options['key'] : null;
+            $this->context = hash_init(
+                $this->algo,
+                $key ? HASH_HMAC : 0,
+                $key
+            );
+        }
+
+        return $this->context;
+    }
+}