first commit

pgserver/vendor/mdanter/ecc/src/Util/BinaryString.php

@@ -0,0 +1,66 @@
+<?php
+declare(strict_types=1);
+
+namespace Mdanter\Ecc\Util;
+
+class BinaryString
+{
+    /**
+     * Multi-byte-safe string length calculation
+     *
+     * @param string $str
+     * @return int
+     */
+    public static function length(string $str): int
+    {
+        // Premature optimization: cache the function_exists() result
+        static $exists = null;
+        if ($exists === null) {
+            $exists = function_exists('mb_strlen');
+        }
+
+        // If it exists, we need to make sure we're using 8bit mode
+        if ($exists) {
+            return mb_strlen($str, '8bit');
+        }
+        return strlen($str);
+    }
+
+    /**
+     * Multi-byte-safe substring calculation
+     *
+     * @param string $str
+     * @param int $start
+     * @param int $length (optional)
+     * @return string
+     */
+    public static function substring(string $str, int $start = 0, int $length = null): string
+    {
+        // Premature optimization: cache the function_exists() result
+        static $exists = null;
+        if ($exists === null) {
+            $exists = function_exists('mb_substr');
+        }
+
+        // If it exists, we need to make sure we're using 8bit mode
+        if ($exists) {
+            return mb_substr($str, $start, $length, '8bit');
+        } elseif ($length !== null) {
+            return substr($str, $start, $length);
+        }
+        return substr($str, $start);
+    }
+    
+    /**
+     * Equivalent to hash_equals() in PHP 5.6
+     *
+     * @param string $knownString
+     * @param string $userString
+     *
+     * @return bool
+     */
+    public static function constantTimeCompare(string $knownString, string $userString): bool
+    {
+        return hash_equals($knownString, $userString);
+    }
+}