diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index aa68ef4..defda12 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -23,16 +23,10 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php-version: ["7.2", "7.3", "7.4", "8.0", "8.1", "8.2"]
+                php-version: ["8.0", "8.1", "8.2"]
                 experimental: [false]
                 os: [ubuntu-latest]
                 coverage-extension: [pcov]
-                include:
-                    #- { php-version: '5.3', experimental: false, os: ubuntu-latest, coverage-extension: 'xdebug' }
-                    #- { php-version: '5.4', experimental: false, os: ubuntu-latest, coverage-extension: 'xdebug' }
-                    - { php-version: '5.5', experimental: false, os: ubuntu-latest, coverage-extension: 'xdebug' }
-                    - { php-version: '5.6', experimental: false, os: ubuntu-latest, coverage-extension: 'xdebug' }
-                    - { php-version: '7.1', experimental: false, os: ubuntu-latest, coverage-extension: 'xdebug' }
         steps:
             - uses: actions/checkout@v4
             - name: Use php ${{ matrix.php-version }}
diff --git a/.gitignore b/.gitignore
index 291bb86..4dd7d5e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,10 +7,14 @@
 **/.vagrant
 **/auth.json
 **/nbproject
+**/temp.php
+**/test.php
 .phpdoc
 .phpunit.cache
 .phpunit.result.cache
 composer.lock
+ecs.php
 phpunit.xml
+rector.php
 target
 vendor
diff --git a/README.md b/README.md
index 1cd5595..aa318b6 100644
--- a/README.md
+++ b/README.md
@@ -62,7 +62,7 @@ All artifacts are generated in the target directory.
 
 Examples are located in the `example` directory.
 
-Start a development server (requires PHP 5.4) using the command:
+Start a development server (requires PHP 8.0+) using the command:
 
 ```
 make server
@@ -78,7 +78,7 @@ Create a composer.json in your projects root-directory:
 ```json
 {
     "require": {
-        "tecnickcom/tc-lib-file": "^1.6"
+        "tecnickcom/tc-lib-file": "^2.0"
     }
 }
 ```
@@ -86,7 +86,7 @@ Create a composer.json in your projects root-directory:
 Or add to an existing project with: 
 
 ```bash
-composer require tecnickcom/tc-lib-file ^1.6
+composer require tecnickcom/tc-lib-file ^2.0
 ```
 
 ## Packaging
diff --git a/VERSION b/VERSION
index c0b0d22..157e54f 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.7.39
+2.0.6
diff --git a/composer.json b/composer.json
index 99eb6ce..cc1a135 100644
--- a/composer.json
+++ b/composer.json
@@ -22,15 +22,15 @@
     }
   ],
   "require": {
-    "php": ">=5.4",
+    "php": ">=8.0",
     "ext-curl": "*",
     "ext-pcre": "*"
   },
   "require-dev": {
     "pdepend/pdepend": "2.13.0",
     "phpmd/phpmd": "2.13.0",
-    "phpunit/phpunit": "10.1.2 || 9.6.7 || 8.5.31 || 7.5.20 || 6.5.14 || 5.7.27 || 4.8.36",
-    "squizlabs/php_codesniffer": "3.7.2 || 2.9.2"
+    "phpunit/phpunit": "10.1.2 || 9.6.13",
+    "squizlabs/php_codesniffer": "3.7.2"
   },
   "autoload": {
     "psr-4": {
diff --git a/phpstan.neon b/phpstan.neon
index c42b364..bf592ce 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,5 +1,5 @@
 parameters:
-  level: 5
+  level: max
   paths:
     - src
     - test
diff --git a/resources/debian/control b/resources/debian/control
index ccfee43..0db9edd 100644
--- a/resources/debian/control
+++ b/resources/debian/control
@@ -10,6 +10,6 @@ Vcs-Git: https://github.com/~#VENDOR#~/~#PROJECT#~.git
 Package: ~#PKGNAME#~
 Provides: php-~#PROJECT#~
 Architecture: all
-Depends: php (>= 5.4.0), php-curl, ${misc:Depends}
+Depends: php (>= 8.0.0), php-curl, ${misc:Depends}
 Description: PHP Color library
  This library includes PHP classes to read byte-level data from files
diff --git a/resources/rpm/rpm.spec b/resources/rpm/rpm.spec
index 82c6098..ec90d3d 100644
--- a/resources/rpm/rpm.spec
+++ b/resources/rpm/rpm.spec
@@ -16,7 +16,7 @@ URL:       https://github.com/%{gh_owner}/%{gh_project}
 BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-%(%{__id_u} -n)
 BuildArch: noarch
 
-Requires:  php(language) >= 5.4.0
+Requires:  php(language) >= 8.0.0
 Requires:  php-curl
 Requires:  php-pcre
 
diff --git a/src/Byte.php b/src/Byte.php
index 36b1740..6cd52e6 100644
--- a/src/Byte.php
+++ b/src/Byte.php
@@ -3,13 +3,13 @@
 /**
  * Byte.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
@@ -21,31 +21,27 @@
  *
  * Function to read byte-level data
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class Byte
 {
-    /**
-     * String to process
-     *
-     * @var string
-     */
-    protected $str = '';
-
     /**
      * Initialize a new string to be processed
      *
      * @param string $str String from where to extract values
      */
-    public function __construct($str)
-    {
-        $this->str = $str;
+    public function __construct(
+        /**
+         * String to process
+         */
+        protected string $str
+    ) {
     }
 
     /**
@@ -54,12 +50,11 @@ public function __construct($str)
      * @param int $offset Point from where to read the data.
      *
      * @return int 8 bit value
-     *
      */
-    public function getByte($offset)
+    public function getByte(int $offset): int
     {
         $val = unpack('Ci', substr($this->str, $offset, 1));
-        return $val['i'];
+        return $val === false ? 0 : $val['i'];
     }
 
     /**
@@ -69,10 +64,10 @@ public function getByte($offset)
      *
      * @return int 32 bit value
      */
-    public function getULong($offset)
+    public function getULong(int $offset): int
     {
         $val = unpack('Ni', substr($this->str, $offset, 4));
-        return $val['i'];
+        return $val === false ? 0 : $val['i'];
     }
 
     /**
@@ -82,10 +77,10 @@ public function getULong($offset)
      *
      * @return int 16 bit value
      */
-    public function getUShort($offset)
+    public function getUShort(int $offset): int
     {
         $val = unpack('ni', substr($this->str, $offset, 2));
-        return $val['i'];
+        return $val === false ? 0 : $val['i'];
     }
 
     /**
@@ -95,10 +90,10 @@ public function getUShort($offset)
      *
      * @return int 16 bit value
      */
-    public function getShort($offset)
+    public function getShort(int $offset): int
     {
         $val = unpack('si', substr($this->str, $offset, 2));
-        return $val['i'];
+        return $val === false ? 0 : $val['i'];
     }
 
     /**
@@ -108,7 +103,7 @@ public function getShort($offset)
      *
      * @return int 16 bit value
      */
-    public function getUFWord($offset)
+    public function getUFWord(int $offset): int
     {
         return $this->getUShort($offset);
     }
@@ -120,12 +115,13 @@ public function getUFWord($offset)
      *
      * @return int 16 bit value
      */
-    public function getFWord($offset)
+    public function getFWord(int $offset): int
     {
         $val = $this->getUShort($offset);
         if ($val > 0x7fff) {
             $val -= 0x10000;
         }
+
         return $val;
     }
 
@@ -133,13 +129,10 @@ public function getFWord($offset)
      * Get FIXED from string (32-bit signed fixed-point number (16.16).
      *
      * @param int $offset Point from where to read the data.
-     *
-     * @return float
-     *
      */
-    public function getFixed($offset)
+    public function getFixed(int $offset): float
     {
         // mantissa.fraction
-        return (float)($this->getFWord($offset) . '.' . $this->getUShort($offset + 2));
+        return (float) ($this->getFWord($offset) . '.' . $this->getUShort($offset + 2));
     }
 }
diff --git a/src/Cache.php b/src/Cache.php
index c282e1e..8189e42 100644
--- a/src/Cache.php
+++ b/src/Cache.php
@@ -3,13 +3,13 @@
 /**
  * Cache.php
  *
- * @since       2011-05-23
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2011-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-pdf-filecache
+ * @since     2011-05-23
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2011-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-pdf-filecache
  *
  * This file is part of tc-lib-pdf-filecache software library.
  */
@@ -19,13 +19,13 @@
 /**
  * Com\Tecnick\Pdf\File\Cache
  *
- * @since       2011-05-23
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2011-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-pdf-filecache
+ * @since     2011-05-23
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2011-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-pdf-filecache
  */
 class Cache
 {
@@ -38,10 +38,8 @@ class Cache
 
     /**
      * File prefix
-     *
-     * @var string
      */
-    protected static $prefix;
+    protected static string $prefix;
 
     /**
      * Set the file prefix (common name)
@@ -53,17 +51,16 @@ public function __construct($prefix = null)
         $this->defineSystemCachePath();
         $this->setCachePath();
         if ($prefix === null) {
-            $prefix = rtrim(base64_encode(pack('H*', md5(uniqid((string)rand(), true)))), '=');
+            $prefix = rtrim(base64_encode(pack('H*', md5(uniqid((string) random_int(0, mt_getrandmax()), true)))), '=');
         }
+
         self::$prefix = '_' . preg_replace('/[^a-zA-Z0-9_\-]/', '', strtr($prefix, '+/', '-_')) . '_';
     }
 
     /**
      * Get the cache directory path
-     *
-     * @return string
      */
-    public function getCachePath()
+    public function getCachePath(): string
     {
         return self::$path;
     }
@@ -71,24 +68,23 @@ public function getCachePath()
     /**
      * Set the default cache directory path
      *
-     * @param string|null $path Cache directory path; if null use the K_PATH_CACHE value
+     * @param ?string $path Cache directory path; if null use the K_PATH_CACHE value
      */
-    public function setCachePath($path = null)
+    public function setCachePath(?string $path = null): void
     {
-        if (($path === null) || !is_writable($path)) {
+        if (($path === null) || ! is_writable($path)) {
             /* @phpstan-ignore-next-line */
             self::$path = K_PATH_CACHE;
             return;
         }
+
         self::$path = $this->normalizePath($path);
     }
 
     /**
      * Get the file prefix
-     *
-     * @return string
      */
-    public function getFilePrefix()
+    public function getFilePrefix(): string
     {
         return self::$prefix;
     }
@@ -99,9 +95,9 @@ public function getFilePrefix()
      * @param string $type Type of file
      * @param string $key  File key (used to retrieve file from cache)
      *
-     * @return string filename
+     * @return string|false filename
      */
-    public function getNewFileName($type = 'tmp', $key = '0')
+    public function getNewFileName(string $type = 'tmp', string $key = '0'): string|bool
     {
         return tempnam(self::$path, self::$prefix . $type . '_' . $key . '_');
     }
@@ -109,11 +105,10 @@ public function getNewFileName($type = 'tmp', $key = '0')
     /**
      * Delete cached files
      *
-     * @param string $type Type of files to delete
-     * @param string $key  Specific file key to delete
-     *
+     * @param ?string $type Type of files to delete
+     * @param ?string $key  Specific file key to delete
      */
-    public function delete($type = null, $key = null)
+    public function delete(?string $type = null, ?string $key = null): void
     {
         $path = self::$path . self::$prefix;
         if ($type !== null) {
@@ -122,22 +117,30 @@ public function delete($type = null, $key = null)
                 $path .= $key . '_';
             }
         }
+
         $path .= '*';
         $files = glob($path);
-        if (!empty($files)) {
-            array_map('unlink', $files);
+        if ($files === []) {
+            return;
         }
+
+        if ($files === false) {
+            return;
+        }
+
+        array_map('unlink', $files);
     }
 
     /**
      * Set the K_PATH_CACHE constant (if not set) to the default system directory for temporary files
      */
-    protected function defineSystemCachePath()
+    protected function defineSystemCachePath(): void
     {
         if (defined('K_PATH_CACHE')) {
             return;
         }
-        $kPathCache = ini_get('upload_tmp_dir') ? ini_get('upload_tmp_dir') : sys_get_temp_dir();
+
+        $kPathCache = ini_get('upload_tmp_dir') ?: sys_get_temp_dir();
         define('K_PATH_CACHE', $this->normalizePath($kPathCache));
     }
 
@@ -145,15 +148,18 @@ protected function defineSystemCachePath()
      * Normalize cache path
      *
      * @param string $path Path to normalize
-     *
-     * @return string
      */
-    protected function normalizePath($path)
+    protected function normalizePath(string $path): string
     {
-        $path = realpath($path);
-        if (substr($path, -1) != '/') {
-            $path .= '/';
+        $rpath = realpath($path);
+        if ($rpath === false) {
+            return '';
+        }
+
+        if (! str_ends_with($rpath, '/')) {
+            $rpath .= '/';
         }
-        return $path;
+
+        return $rpath;
     }
 }
diff --git a/src/Dir.php b/src/Dir.php
index 7313fd4..11657e6 100644
--- a/src/Dir.php
+++ b/src/Dir.php
@@ -3,13 +3,13 @@
 /**
  * Dir.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
@@ -21,13 +21,13 @@
  *
  * Function to read byte-level data
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class Dir
 {
@@ -39,21 +39,25 @@ class Dir
      *
      * @return string Directory name
      */
-    public function findParentDir($name, $dir = __DIR__)
+    public function findParentDir(string $name, string $dir = __DIR__): string
     {
-        while (!empty($dir)) {
-            if ($dir == dirname($dir)) {
+        while ($dir !== '') {
+            if ($dir === dirname($dir)) {
                 $dir = '';
             }
+
             if (@is_writable($dir . DIRECTORY_SEPARATOR . $name)) {
                 $dir = $dir . DIRECTORY_SEPARATOR . $name;
                 break;
             }
+
             $dir = dirname($dir);
         }
+
         if (substr($dir, -1) !== DIRECTORY_SEPARATOR) {
             $dir .= DIRECTORY_SEPARATOR;
         }
+
         return $dir;
     }
 }
diff --git a/src/Exception.php b/src/Exception.php
index 50bab83..ddf214c 100644
--- a/src/Exception.php
+++ b/src/Exception.php
@@ -3,13 +3,13 @@
 /**
  * Exception.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
@@ -21,13 +21,13 @@
  *
  * Custom Exception class
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class Exception extends \Exception
 {
diff --git a/src/File.php b/src/File.php
index be1454a..2439cb3 100644
--- a/src/File.php
+++ b/src/File.php
@@ -3,13 +3,13 @@
 /**
  * File.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
@@ -23,13 +23,13 @@
  *
  * Function to read byte-level data
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * @SuppressWarnings(PHPMD.ExcessiveClassComplexity)
  */
@@ -45,31 +45,38 @@ class File
      *
      * @throws FileException in case of error
      */
-    public function fopenLocal($filename, $mode)
+    public function fopenLocal(string $filename, string $mode): mixed
     {
-        if (strpos($filename, '://') === false) {
+        if (! str_contains($filename, '://')) {
             $filename = 'file://' . $filename;
-        } elseif (strpos($filename, 'file://') !== 0) {
+        } elseif (! str_starts_with($filename, 'file://')) {
             throw new FileException('this is not a local file');
         }
+
         $handler = @fopen($filename, $mode);
         if ($handler === false) {
             throw new FileException('unable to open the file: ' . $filename);
         }
+
         return $handler;
     }
 
     /**
      * Read a 4-byte (32 bit) integer from file.
      *
-     * @param resource $handle A file system pointer resource that is typically created using fopen().
+     * @param resource $resource A file system pointer resource that is typically created using fopen().
      *
      * @return int 4-byte integer
      */
-    public function fReadInt($handle)
+    public function fReadInt(mixed $resource): int
     {
-        $val = unpack('Ni', fread($handle, 4));
-        return $val['i'];
+        $data = fread($resource, 4);
+        if ($data === false) {
+            throw new FileException('unable to read the file');
+        }
+
+        $val = unpack('Ni', $data);
+        return $val === false ? 0 : $val['i'];
     }
 
     /**
@@ -78,29 +85,30 @@ public function fReadInt($handle)
      * Reading stops as soon as one of the following conditions is met:
      * length bytes have been read; EOF (end of file) is reached.
      *
-     * @param resource $handle A file system pointer resource that is typically created using fopen().
-     * @param int      $length Number of bytes to read.
-     *
-     * @return string
+     * @param ?resource  $resource A file system pointer resource that is typically created using fopen().
+     * @param int<0, max> $length   Number of bytes to read.
      *
      * @throws FileException in case of error
      */
-    public function rfRead($handle, $length)
+    public function rfRead(mixed $resource, int $length): string
     {
         $data = false;
-        if (is_resource($handle)) {
-            $data = @fread($handle, $length);
+        if (is_resource($resource)) {
+            $data = @fread($resource, $length);
         }
-        if ($data === false) {
+
+        if (($data === false) || ($resource === null)) {
             throw new FileException('unable to read the file');
         }
+
         $rest = ($length - strlen($data));
-        if (($rest > 0) && !feof($handle)) {
-            $stream_meta_data = stream_get_meta_data($handle);
+        if (($rest > 0) && ! feof($resource)) {
+            $stream_meta_data = stream_get_meta_data($resource);
             if ($stream_meta_data['unread_bytes'] > 0) {
-                $data .= $this->rfRead($handle, $rest);
+                $data .= $this->rfRead($resource, $rest);
             }
         }
+
         return $data;
     }
 
@@ -109,10 +117,8 @@ public function rfRead($handle, $length)
      * The file can be also an URL.
      *
      * @param string $file Name of the file or URL to read.
-     *
-     * @return string File content
      */
-    public function fileGetContents($file)
+    public function fileGetContents(string $file): string
     {
         $alt = $this->getAltFilePaths($file);
         foreach ($alt as $path) {
@@ -121,6 +127,7 @@ public function fileGetContents($file)
                 return $ret;
             }
         }
+
         throw new FileException('unable to read the file: ' . $file);
     }
 
@@ -130,14 +137,15 @@ public function fileGetContents($file)
      *
      * @param string $file Name of the file or URL to read.
      *
-     * @return string File content or FALSE in case the file is unreadable
+     * @return string|false File content or FALSE in case the file is unreadable
      */
-    public function getFileData($file)
+    public function getFileData(string $file): string|false
     {
         $ret = @file_get_contents($file);
         if ($ret !== false) {
             return $ret;
         }
+
         // try to use CURL for URLs
         return $this->getUrlData($file);
     }
@@ -147,38 +155,46 @@ public function getFileData($file)
      *
      * @param string $url URL to read.
      *
-     * @return string|bool
+     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      */
-    public function getUrlData($url)
+    public function getUrlData(string $url): string|false
     {
         if (
-            (ini_get('allow_url_fopen') && !defined('FORCE_CURL'))
-            || !function_exists('curl_init')
-            || !preg_match('%^(https?|ftp)://%', $url)
+            (ini_get('allow_url_fopen') && ! defined('FORCE_CURL'))
+            || (! function_exists('curl_init'))
+            || preg_match('%^(https?|ftp)://%', $url) === 0
+            || preg_match('%^(https?|ftp)://%', $url) === false
         ) {
             return false;
         }
+
         // try to get remote file data using cURL
-        $crs = curl_init();
-        curl_setopt($crs, CURLOPT_URL, $url);
-        curl_setopt($crs, CURLOPT_BINARYTRANSFER, true);
-        curl_setopt($crs, CURLOPT_FAILONERROR, true);
-        curl_setopt($crs, CURLOPT_RETURNTRANSFER, true);
-        if ((ini_get('open_basedir') == '') && (!ini_get('safe_mode'))) {
-            curl_setopt($crs, CURLOPT_FOLLOWLOCATION, true);
+        $curlHandle = curl_init();
+        curl_setopt($curlHandle, CURLOPT_URL, $url);
+        curl_setopt($curlHandle, CURLOPT_BINARYTRANSFER, true);
+        curl_setopt($curlHandle, CURLOPT_FAILONERROR, true);
+        curl_setopt($curlHandle, CURLOPT_RETURNTRANSFER, true);
+        if ((ini_get('open_basedir') == '') && (ini_get('safe_mode') === '' || ini_get('safe_mode') === false)) {
+            curl_setopt($curlHandle, CURLOPT_FOLLOWLOCATION, true);
         }
-        curl_setopt($crs, CURLOPT_CONNECTTIMEOUT, 5);
-        curl_setopt($crs, CURLOPT_TIMEOUT, 30);
-        curl_setopt($crs, CURLOPT_SSL_VERIFYPEER, false);
-        curl_setopt($crs, CURLOPT_SSL_VERIFYHOST, false);
-        curl_setopt($crs, CURLOPT_USERAGENT, 'tc-lib-file');
-        curl_setopt($crs, CURLOPT_MAXREDIRS, 5);
+
+        curl_setopt($curlHandle, CURLOPT_CONNECTTIMEOUT, 5);
+        curl_setopt($curlHandle, CURLOPT_TIMEOUT, 30);
+        curl_setopt($curlHandle, CURLOPT_SSL_VERIFYPEER, false);
+        curl_setopt($curlHandle, CURLOPT_SSL_VERIFYHOST, false);
+        curl_setopt($curlHandle, CURLOPT_USERAGENT, 'tc-lib-file');
+        curl_setopt($curlHandle, CURLOPT_MAXREDIRS, 5);
         if (defined('CURLOPT_PROTOCOLS')) {
-            curl_setopt($crs, CURLOPT_PROTOCOLS, CURLPROTO_HTTPS | CURLPROTO_HTTP |  CURLPROTO_FTP | CURLPROTO_FTPS);
+            curl_setopt(
+                $curlHandle,
+                CURLOPT_PROTOCOLS,
+                CURLPROTO_HTTPS | CURLPROTO_HTTP | CURLPROTO_FTP | CURLPROTO_FTPS
+            );
         }
-        $ret = curl_exec($crs);
-        curl_close($crs);
-        return $ret;
+
+        $ret = curl_exec($curlHandle);
+        curl_close($curlHandle);
+        return $ret === true ? '' : $ret;
     }
 
     /**
@@ -186,11 +202,11 @@ public function getUrlData($url)
      *
      * @param string $file Name of the file or URL to read.
      *
-     * @return array
+     * @return array<string> List of possible alternative file paths or URLs.
      */
-    public function getAltFilePaths($file)
+    public function getAltFilePaths(string $file): array
     {
-        $alt = array($file);
+        $alt = [$file];
         $alt[] = $this->getAltLocalUrlPath($file);
         $url = $this->getAltMissingUrlProtocol($file);
         $alt[] = $url;
@@ -203,23 +219,22 @@ public function getAltFilePaths($file)
      * Replace URL relative path with full real server path
      *
      * @param string $file Relative URL path
-     *
-     * @return string
      */
-    protected function getAltLocalUrlPath($file)
+    protected function getAltLocalUrlPath(string $file): string
     {
         if (
             (strlen($file) > 1)
             && ($file[0] === '/')
             && ($file[1] !== '/')
-            && !empty($_SERVER['DOCUMENT_ROOT'])
+            && ! empty($_SERVER['DOCUMENT_ROOT'])
             && ($_SERVER['DOCUMENT_ROOT'] !== '/')
         ) {
-            $findroot = strpos($file, $_SERVER['DOCUMENT_ROOT']);
+            $findroot = strpos($file, (string) $_SERVER['DOCUMENT_ROOT']);
             if (($findroot === false) || ($findroot > 1)) {
                 $file = htmlspecialchars_decode(urldecode($_SERVER['DOCUMENT_ROOT'] . $file));
             }
         }
+
         return $file;
     }
 
@@ -230,25 +245,25 @@ protected function getAltLocalUrlPath($file)
      *
      * @return string local path or original $file
      */
-    protected function getAltMissingUrlProtocol($file)
+    protected function getAltMissingUrlProtocol(string $file): string
     {
-        if (preg_match('%^//%', $file) && !empty($_SERVER['HTTP_HOST'])) {
+        if (preg_match('%^//%', $file) && ! empty($_SERVER['HTTP_HOST'])) {
             $file = $this->getDefaultUrlProtocol() . ':' . str_replace(' ', '%20', $file);
         }
+
         return htmlspecialchars_decode($file);
     }
 
     /**
      * Get the default URL protocol (http or https)
-     *
-     * @return string
      */
-    protected function getDefaultUrlProtocol()
+    protected function getDefaultUrlProtocol(): string
     {
         $protocol = 'http';
-        if (!empty($_SERVER['HTTPS']) && (strtolower($_SERVER['HTTPS']) != 'off')) {
+        if (! empty($_SERVER['HTTPS']) && (strtolower($_SERVER['HTTPS']) != 'off')) {
             $protocol .= 's';
         }
+
         return $protocol;
     }
 
@@ -259,25 +274,29 @@ protected function getDefaultUrlProtocol()
      *
      * @return string local path or original $file
      */
-    protected function getAltPathFromUrl($url)
+    protected function getAltPathFromUrl(string $url): string
     {
         if (
-            !preg_match('%^(https?)://%', $url)
+            preg_match('%^(https?)://%', $url) === 0
+            || preg_match('%^(https?)://%', $url) === false
             || empty($_SERVER['HTTP_HOST'])
             || empty($_SERVER['DOCUMENT_ROOT'])
         ) {
             return $url;
         }
+
         $urldata = parse_url($url);
-        if (!empty($urldata['query'])) {
+        if (isset($urldata['query']) && $urldata['query'] !== '') {
             return $url;
         }
+
         $host = $this->getDefaultUrlProtocol() . '://' . $_SERVER['HTTP_HOST'];
-        if (strpos($url, $host) === 0) {
+        if (str_starts_with($url, $host)) {
             // convert URL to full server path
             $tmp = str_replace($host, $_SERVER['DOCUMENT_ROOT'], $url);
             return htmlspecialchars_decode(urldecode($tmp));
         }
+
         return $url;
     }
 
@@ -286,18 +305,25 @@ protected function getAltPathFromUrl($url)
      *
      * @param string $file File name and path
      *
-     * @return string
+     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      */
-    protected function getAltUrlFromPath($file)
+    protected function getAltUrlFromPath(string $file): string
     {
         if (
             isset($_SERVER['SCRIPT_URI'])
-            && !preg_match('%^(https?|ftp)://%', $file)
-            && !preg_match('%^//%', $file)
+            && (preg_match('%^(https?|ftp)://%', $file) === 0
+            || preg_match('%^(https?|ftp)://%', $file) === false)
+            && (preg_match('%^//%', $file) === 0
+            || preg_match('%^//%', $file) === false)
         ) {
             $urldata = @parse_url($_SERVER['SCRIPT_URI']);
+            if (! is_array($urldata) || ! isset($urldata['scheme']) || ! isset($urldata['host'])) {
+                return $file;
+            }
+
             return $urldata['scheme'] . '://' . $urldata['host'] . (($file[0] == '/') ? '' : '/') . $file;
         }
+
         return $file;
     }
 }
diff --git a/test/ByteTest.php b/test/ByteTest.php
index c50b41f..912184a 100644
--- a/test/ByteTest.php
+++ b/test/ByteTest.php
@@ -3,35 +3,33 @@
 /**
  * ByteTest.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
 
 namespace Test;
 
-use PHPUnit\Framework\TestCase;
-
 /**
  * Byte Color class test
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class ByteTest extends TestUtil
 {
-    protected function getTestObject()
+    protected function getTestObject(): \Com\Tecnick\File\Byte
     {
         $str = chr(0) . chr(0) . chr(0) . chr(0)
             . chr(1) . chr(3) . chr(7) . chr(15)
@@ -45,241 +43,259 @@ protected function getTestObject()
     /**
      * @dataProvider getByteDataProvider
      */
-    public function testGetByte($offset, $expected)
+    public function testGetByte(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getByte($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getByte($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getByteDataProvider()
+    /**
+     * @return array<array{int, int}>
+     */
+    public static function getByteDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 0),
-            array(2, 0),
-            array(3, 0),
-            array(4, 1),
-            array(5, 3),
-            array(6, 7),
-            array(7, 15),
-            array(8, 31),
-            array(9, 63),
-            array(10, 127),
-            array(11, 255),
-            array(12, 254),
-            array(13, 252),
-            array(14, 248),
-            array(15, 240),
-            array(16, 224),
-            array(17, 192),
-            array(18, 128),
-            array(19, 0),
-            array(20, 255),
-            array(21, 255),
-            array(22, 255),
-            array(23, 255)
-        );
+        return [
+            [0, 0],
+            [1, 0],
+            [2, 0],
+            [3, 0],
+            [4, 1],
+            [5, 3],
+            [6, 7],
+            [7, 15],
+            [8, 31],
+            [9, 63],
+            [10, 127],
+            [11, 255],
+            [12, 254],
+            [13, 252],
+            [14, 248],
+            [15, 240],
+            [16, 224],
+            [17, 192],
+            [18, 128],
+            [19, 0],
+            [20, 255],
+            [21, 255],
+            [22, 255],
+            [23, 255],
+        ];
     }
 
     /**
      * @dataProvider getULongDataProvider
      */
-    public function testGetULong($offset, $expected)
+    public function testGetULong(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getULong($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getULong($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getULongDataProvider()
+    /**
+     * @return array<array{int, int}>
+     */
+    public static function getULongDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 1),
-            array(2, 259),
-            array(3, 66311),
-            array(4, 16975631),
-            array(5, 50794271),
-            array(6, 118431551),
-            array(7, 253706111),
-            array(8, 524255231),
-            array(9, 1065353214),
-            array(10, 2147483388),
-            array(11, 4294900984),
-            array(12, 4277991664),
-            array(13, 4244173024),
-            array(14, 4176535744),
-            array(15, 4041261184),
-            array(16, 3770712064),
-            array(17, 3229614335),
-            array(18, 2147549183),
-            array(19, 16777215),
-            array(20, 4294967295)
-        );
+        return [
+            [0, 0],
+            [1, 1],
+            [2, 259],
+            [3, 66311],
+            [4, 16_975_631],
+            [5, 50_794_271],
+            [6, 118_431_551],
+            [7, 253_706_111],
+            [8, 524_255_231],
+            [9, 1_065_353_214],
+            [10, 2_147_483_388],
+            [11, 4_294_900_984],
+            [12, 4_277_991_664],
+            [13, 4_244_173_024],
+            [14, 4_176_535_744],
+            [15, 4_041_261_184],
+            [16, 3_770_712_064],
+            [17, 3_229_614_335],
+            [18, 2_147_549_183],
+            [19, 16_777_215],
+            [20, 4_294_967_295],
+        ];
     }
 
     /**
      * @dataProvider getUShortDataProvider
      */
-    public function testGetUShort($offset, $expected)
+    public function testGetUShort(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getUShort($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getUShort($offset);
         $this->assertEquals($expected, $res);
     }
 
     /**
      * @dataProvider getUShortDataProvider
      */
-    public function testGetUFWord($offset, $expected)
+    public function testGetUFWord(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getUFWord($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getUFWord($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getUShortDataProvider()
+    /**
+     * @return array<array{int, int}>
+     */
+    public static function getUShortDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 0),
-            array(2, 0),
-            array(3, 1),
-            array(4, 259),
-            array(5, 775),
-            array(6, 1807),
-            array(7, 3871),
-            array(8, 7999),
-            array(9, 16255),
-            array(10, 32767),
-            array(11, 65534),
-            array(12, 65276),
-            array(13, 64760),
-            array(14, 63728),
-            array(15, 61664),
-            array(16, 57536),
-            array(17, 49280),
-            array(18, 32768),
-            array(19, 255),
-            array(20, 65535),
-            array(21, 65535),
-            array(22, 65535)
-        );
+        return [
+            [0, 0],
+            [1, 0],
+            [2, 0],
+            [3, 1],
+            [4, 259],
+            [5, 775],
+            [6, 1807],
+            [7, 3871],
+            [8, 7999],
+            [9, 16255],
+            [10, 32767],
+            [11, 65534],
+            [12, 65276],
+            [13, 64760],
+            [14, 63728],
+            [15, 61664],
+            [16, 57536],
+            [17, 49280],
+            [18, 32768],
+            [19, 255],
+            [20, 65535],
+            [21, 65535],
+            [22, 65535],
+        ];
     }
 
     /**
      * @dataProvider getShortDataProvider
      */
-    public function testGetShort($offset, $expected)
+    public function testGetShort(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getShort($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getShort($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getShortDataProvider()
+    /**
+     * @return array<array{int, int}>
+     */
+    public static function getShortDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 0),
-            array(2, 0),
-            array(3, 256),
-            array(4, 769),
-            array(5, 1795),
-            array(6, 3847),
-            array(7, 7951),
-            array(8, 16159),
-            array(9, 32575),
-            array(10, -129),
-            array(11, -257),
-            array(12, -770),
-            array(13, -1796),
-            array(14, -3848),
-            array(15, -7952),
-            array(16, -16160),
-            array(17, -32576),
-            array(18, 128),
-            array(19, -256),
-            array(20, -1),
-            array(21, -1),
-            array(22, -1)
-        );
+        return [
+            [0, 0],
+            [1, 0],
+            [2, 0],
+            [3, 256],
+            [4, 769],
+            [5, 1795],
+            [6, 3847],
+            [7, 7951],
+            [8, 16159],
+            [9, 32575],
+            [10, -129],
+            [11, -257],
+            [12, -770],
+            [13, -1796],
+            [14, -3848],
+            [15, -7952],
+            [16, -16160],
+            [17, -32576],
+            [18, 128],
+            [19, -256],
+            [20, -1],
+            [21, -1],
+            [22, -1],
+        ];
     }
 
     /**
      * @dataProvider getFWordDataProvider
      */
-    public function testGetFWord($offset, $expected)
+    public function testGetFWord(int $offset, int $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getFWord($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getFWord($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getFWordDataProvider()
+    /**
+     * @return array<array{int, int}>
+     */
+    public static function getFWordDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 0),
-            array(2, 0),
-            array(3, 1),
-            array(4, 259),
-            array(5, 775),
-            array(6, 1807),
-            array(7, 3871),
-            array(8, 7999),
-            array(9, 16255),
-            array(10, 32767),
-            array(11, -2),
-            array(12, -260),
-            array(13, -776),
-            array(14, -1808),
-            array(15, -3872),
-            array(16, -8000),
-            array(17, -16256),
-            array(18, -32768),
-            array(19, 255),
-            array(20, -1),
-            array(21, -1),
-            array(22, -1)
-        );
+        return [
+            [0, 0],
+            [1, 0],
+            [2, 0],
+            [3, 1],
+            [4, 259],
+            [5, 775],
+            [6, 1807],
+            [7, 3871],
+            [8, 7999],
+            [9, 16255],
+            [10, 32767],
+            [11, -2],
+            [12, -260],
+            [13, -776],
+            [14, -1808],
+            [15, -3872],
+            [16, -8000],
+            [17, -16256],
+            [18, -32768],
+            [19, 255],
+            [20, -1],
+            [21, -1],
+            [22, -1],
+        ];
     }
 
     /**
      * @dataProvider getFixedDataProvider
      */
-    public function testGetFixed($offset, $expected)
+    public function testGetFixed(int $offset, int|float $expected): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->getFixed($offset);
+        $byte = $this->getTestObject();
+        $res = $byte->getFixed($offset);
         $this->assertEquals($expected, $res);
     }
 
-    public static function getFixedDataProvider()
+    /**
+     * @return array<array{int, float}>
+     */
+    public static function getFixedDataProvider(): array
     {
-        return array(
-            array(0, 0),
-            array(1, 0.1),
-            array(2, 0.259),
-            array(3, 1.775),
-            array(4, 259.1807),
-            array(5, 775.3871),
-            array(6, 1807.7999),
-            array(7, 3871.16255),
-            array(8, 7999.32767),
-            array(9, 16255.65534),
-            array(10, 32767.65276),
-            array(11, -2.64760),
-            array(12, -260.63728),
-            array(13, -776.61664),
-            array(14, -1808.57536),
-            array(15, -3872.49280),
-            array(16, -8000.32768),
-            array(17, -16256.255),
-            array(18, -32768.65535),
-            array(19, 255.65535),
-            array(20, -1.65535)
-        );
+        return [
+            [0, 0],
+            [1, 0.1],
+            [2, 0.259],
+            [3, 1.775],
+            [4, 259.1807],
+            [5, 775.3871],
+            [6, 1807.7999],
+            [7, 3871.16255],
+            [8, 7999.32767],
+            [9, 16255.65534],
+            [10, 32767.65276],
+            [11, -2.64760],
+            [12, -260.63728],
+            [13, -776.61664],
+            [14, -1808.57536],
+            [15, -3872.49280],
+            [16, -8000.32768],
+            [17, -16256.255],
+            [18, -32768.65535],
+            [19, 255.65535],
+            [20, -1.65535],
+        ];
     }
 }
diff --git a/test/CacheTest.php b/test/CacheTest.php
index 502bcc4..54157df 100644
--- a/test/CacheTest.php
+++ b/test/CacheTest.php
@@ -3,96 +3,100 @@
 /**
  * CacheTest.php
  *
- * @since       2011-05-23
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2011-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-pdf-filecache
+ * @since     2011-05-23
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2011-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-pdf-filecache
  *
  * This file is part of tc-lib-pdf-filecache software library.
  */
 
 namespace Test;
 
-use PHPUnit\Framework\TestCase;
-
 /**
  * Unit Test
  *
- * @since       2011-05-23
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2011-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-pdf-filecache
+ * @since     2011-05-23
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2011-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-pdf-filecache
  */
 class CacheTest extends TestUtil
 {
-    protected function getTestObject()
+    protected function getTestObject(): \Com\Tecnick\File\Cache
     {
         return new \Com\Tecnick\File\Cache('1_2-a+B/c');
     }
 
-    public function testAutoPrefix()
+    public function testAutoPrefix(): void
     {
-        $obj = new \Com\Tecnick\File\Cache();
-        $this->assertNotEmpty($obj->getFilePrefix());
+        $cache = new \Com\Tecnick\File\Cache();
+        $this->assertNotEmpty($cache->getFilePrefix());
     }
 
-    public function testGetCachePath()
+    public function testGetCachePath(): void
     {
-        $testObj = $this->getTestObject();
-        $val = $testObj->getCachePath();
-        $this->assertEquals('/', $val[0]);
-        $this->assertEquals('/', substr($val, -1));
+        $cache = $this->getTestObject();
+        $cachePath = $cache->getCachePath();
+        $this->assertEquals('/', $cachePath[0]);
+        $this->assertEquals('/', substr($cachePath, -1));
 
-        $testObj->setCachePath();
-        $this->assertEquals($val, $testObj->getCachePath());
+        $cache->setCachePath();
+        $this->assertEquals($cachePath, $cache->getCachePath());
 
         $path = '/tmp';
-        $testObj->setCachePath($path);
-        $this->assertEquals('/tmp/', $testObj->getCachePath());
+        $cache->setCachePath($path);
+        $this->assertEquals('/tmp/', $cache->getCachePath());
     }
 
-    public function testGetFilePrefix()
+    public function testGetFilePrefix(): void
     {
-        $testObj = $this->getTestObject();
-        $val = $testObj->getFilePrefix();
-        $this->assertEquals('_1_2-a-B_c_', $val);
+        $cache = $this->getTestObject();
+        $filePrefix = $cache->getFilePrefix();
+        $this->assertEquals('_1_2-a-B_c_', $filePrefix);
     }
 
-    public function testGetNewFileName()
+    public function testGetNewFileName(): void
     {
-        $testObj = $this->getTestObject();
-        $val = $testObj->getNewFileName('tst', '0123');
+        $cache = $this->getTestObject();
+        $val = $cache->getNewFileName('tst', '0123');
+        $this->assertNotFalse($val);
         $this->bcAssertMatchesRegularExpression('/_1_2-a-B_c_tst_0123_/', $val);
     }
 
-    public function testDelete()
+    public function testDelete(): void
     {
-        $testObj = $this->getTestObject();
+        $cache = $this->getTestObject();
         $idk = 0;
         for ($idx = 1; $idx <= 2; ++$idx) {
             for ($idy = 1; $idy <= 2; ++$idy) {
-                $file[$idk] = $testObj->getNewFileName($idx, $idy);
+                $file[$idk] = $cache->getNewFileName((string) $idx, (string) $idy);
+                $this->assertNotFalse($file[$idk]);
                 file_put_contents($file[$idk], '');
                 $this->assertTrue(file_exists($file[$idk]));
                 ++$idk;
             }
         }
 
-        $testObj->delete('2', '1');
+        $cache->delete('2', '1');
+        $this->assertNotFalse($file[2]);
         $this->assertFalse(file_exists($file[2]));
 
-        $testObj->delete('1');
+        $cache->delete('1');
+        $this->assertNotFalse($file[0]);
         $this->assertFalse(file_exists($file[0]));
+        $this->assertNotFalse($file[1]);
         $this->assertFalse(file_exists($file[1]));
+        $this->assertNotFalse($file[3]);
         $this->assertTrue(file_exists($file[3]));
 
-        $testObj->delete();
+        $cache->delete();
         $this->assertFalse(file_exists($file[3]));
     }
 }
diff --git a/test/DirTest.php b/test/DirTest.php
index 5cb3caf..f7b4157 100644
--- a/test/DirTest.php
+++ b/test/DirTest.php
@@ -3,35 +3,33 @@
 /**
  * DirTest.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
 
 namespace Test;
 
-use PHPUnit\Framework\TestCase;
-
 /**
  * File Color class test
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class DirTest extends TestUtil
 {
-    protected function getTestObject()
+    protected function getTestObject(): \Com\Tecnick\File\Dir
     {
         return new \Com\Tecnick\File\Dir();
     }
@@ -39,19 +37,18 @@ protected function getTestObject()
     /**
      * @dataProvider getAltFilePathsDataProvider
      */
-    public function testGetAltFilePaths($name, $expected)
+    public function testGetAltFilePaths(string $name, string $expected): void
     {
         $testObj = $this->getTestObject();
         $dir = $testObj->findParentDir($name);
         $this->bcAssertMatchesRegularExpression('#' . $expected . '#', $dir);
     }
 
-    public static function getAltFilePathsDataProvider()
+    /**
+     * @return array<array{string, string}>
+     */
+    public static function getAltFilePathsDataProvider(): array
     {
-        return array(
-            array('', '/src/'),
-            array('missing', '/'),
-            array('src', '/src/'),
-        );
+        return [['', '/src/'], ['missing', '/'], ['src', '/src/']];
     }
 }
diff --git a/test/FileTest.php b/test/FileTest.php
index d780f2e..443df28 100644
--- a/test/FileTest.php
+++ b/test/FileTest.php
@@ -3,93 +3,96 @@
 /**
  * FileTest.php
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
 
 namespace Test;
 
-use PHPUnit\Framework\TestCase;
-
 /**
  * File Color class test
  *
- * @since       2015-07-28
- * @category    Library
- * @package     File
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2015-07-28
+ * @category  Library
+ * @package   File
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class FileTest extends TestUtil
 {
-    protected function getTestObject()
+    protected function getTestObject(): \Com\Tecnick\File\File
     {
         return new \Com\Tecnick\File\File();
     }
 
-    public function testFopenLocal()
+    public function testFopenLocal(): void
     {
-        $testObj = $this->getTestObject();
-        $handle = $testObj->fopenLocal(__FILE__, 'r');
+        $file = $this->getTestObject();
+        $handle = $file->fopenLocal(__FILE__, 'r');
         $this->bcAssertIsResource($handle);
         fclose($handle);
     }
 
-    public function testFopenLocalNonLocal()
+    public function testFopenLocalNonLocal(): void
     {
-        $this->bcExpectException('\Com\Tecnick\File\Exception');
-        $testObj = $this->getTestObject();
-        $testObj->fopenLocal('http://www.example.com/test.txt', 'r');
+        $this->bcExpectException('\\' . \Com\Tecnick\File\Exception::class);
+        $file = $this->getTestObject();
+        $file->fopenLocal('http://www.example.com/test.txt', 'r');
     }
 
-    public function testFopenLocalMissing()
+    public function testFopenLocalMissing(): void
     {
-        $this->bcExpectException('\Com\Tecnick\File\Exception');
-        $testObj = $this->getTestObject();
-        $testObj->fopenLocal('/missing_error.txt', 'r');
+        $this->bcExpectException('\\' . \Com\Tecnick\File\Exception::class);
+        $file = $this->getTestObject();
+        $file->fopenLocal('/missing_error.txt', 'r');
     }
 
-    public function testfReadInt()
+    public function testfReadInt(): void
     {
-        $testObj = $this->getTestObject();
+        $file = $this->getTestObject();
         $handle = fopen(__FILE__, 'r');
-        $res = $testObj->fReadInt($handle);
+        $this->assertNotFalse($handle);
+        $res = $file->fReadInt($handle);
         // '<?ph' = 60 63 112 104 = 00111100 00111111 01110000 01101000 = 1010790504
-        $this->assertEquals(1010790504, $res);
+        $this->assertEquals(1_010_790_504, $res);
         fclose($handle);
     }
 
-    public function testRfRead()
+    public function testRfRead(): void
     {
-        $testObj = $this->getTestObject();
+        $file = $this->getTestObject();
         $handle = fopen(dirname(__DIR__) . '/src/File.php', 'rb');
-        $res = $testObj->rfRead($handle, 2);
+        $this->assertNotFalse($handle);
+        $res = $file->rfRead($handle, 2);
         $this->assertEquals('<?', $res);
-        $res = $testObj->rfRead($handle, 3);
+        $res = $file->rfRead($handle, 3);
         $this->assertEquals('php', $res);
         fclose($handle);
     }
 
-    public function testRfReadException()
+    public function testRfReadException(): void
     {
-        $this->bcExpectException('\Com\Tecnick\File\Exception');
-        $testObj = $this->getTestObject();
-        $testObj->rfRead(null, 2);
+        $this->bcExpectException('\\' . \Com\Tecnick\File\Exception::class);
+        $file = $this->getTestObject();
+        $file->rfRead(null, 2);
     }
 
     /**
+     * @param string $file     File path
+     * @param array{string, array<int, string>}  $expected Expected result
+     *
      * @dataProvider getAltFilePathsDataProvider
      */
-    public function testGetAltFilePaths($file, $expected)
+    public function testGetAltFilePaths(string $file, array $expected): void
     {
         $testObj = $this->getTestObject();
         $_SERVER['DOCUMENT_ROOT'] = '/var/www';
@@ -100,73 +103,78 @@ public function testGetAltFilePaths($file, $expected)
         $this->assertEquals($expected, $alt);
     }
 
-    public static function getAltFilePathsDataProvider()
+    /**
+     * Data provider for testGetAltFilePaths
+     *
+     * @return array<array{string, array<int, string>}>
+     */
+    public static function getAltFilePathsDataProvider(): array
     {
-        return array(
-            array(
+        return [
+            [
                 'http://www.example.com/test.txt',
-                array(
-                    0 => 'http://www.example.com/test.txt'
-                )
-            ),
-            array(
+                [
+                    0 => 'http://www.example.com/test.txt',
+                ],
+            ],
+            [
                 'https://localhost/path/test.txt',
-                array(
+                [
                     0 => 'https://localhost/path/test.txt',
-                    3 => '/var/www/path/test.txt'
-                )
-            ),
-            array(
+                    3 => '/var/www/path/test.txt',
+                ],
+            ],
+            [
                 '//www.example.com/space test.txt',
-                array(
+                [
                     0 => '//www.example.com/space test.txt',
-                    2 => 'https://www.example.com/space%20test.txt'
-                )
-            ),
-            array(
+                    2 => 'https://www.example.com/space%20test.txt',
+                ],
+            ],
+            [
                 '/path/test.txt',
-                array(
+                [
                     0 => '/path/test.txt',
                     1 => '/var/www/path/test.txt',
-                    4 => 'https://localhost/path/test.txt'
-                )
-            ),
-            array(
+                    4 => 'https://localhost/path/test.txt',
+                ],
+            ],
+            [
                 'https://localhost/path/test.php?a=0&b=1&amp;c=2;&amp;d="a+b%20c"',
-                array(
-                      0 => 'https://localhost/path/test.php?a=0&b=1&amp;c=2;&amp;d="a+b%20c"',
-                      2 => 'https://localhost/path/test.php?a=0&b=1&c=2;&d="a+b%20c"',
-                )
-            ),
-            array(
+                [
+                    0 => 'https://localhost/path/test.php?a=0&b=1&amp;c=2;&amp;d="a+b%20c"',
+                    2 => 'https://localhost/path/test.php?a=0&b=1&c=2;&d="a+b%20c"',
+                ],
+            ],
+            [
                 'path/test.txt',
-                array(
+                [
                     0 => 'path/test.txt',
-                    4 => 'https://localhost/path/test.txt'
-                )
-            ),
-        );
+                    4 => 'https://localhost/path/test.txt',
+                ],
+            ],
+        ];
     }
 
-    public function testFileGetContentsException()
+    public function testFileGetContentsException(): void
     {
-        $this->bcExpectException('\Com\Tecnick\File\Exception');
-        $testObj = $this->getTestObject();
-        $testObj->fileGetContents('missing.txt');
+        $this->bcExpectException('\\' . \Com\Tecnick\File\Exception::class);
+        $file = $this->getTestObject();
+        $file->fileGetContents('missing.txt');
     }
 
-    public function testFileGetContents()
+    public function testFileGetContents(): void
     {
-        $testObj = $this->getTestObject();
-        $res = $testObj->fileGetContents(__FILE__);
+        $file = $this->getTestObject();
+        $res = $file->fileGetContents(__FILE__);
         $this->assertEquals('<?php', substr($res, 0, 5));
     }
 
-    public function testFileGetContentsCurl()
+    public function testFileGetContentsCurl(): void
     {
-        $this->bcExpectException('\Com\Tecnick\File\Exception');
-        $testObj = $this->getTestObject();
+        $this->bcExpectException('\\' . \Com\Tecnick\File\Exception::class);
+        $file = $this->getTestObject();
         define('FORCE_CURL', true);
-        $testObj->fileGetContents('http://www.example.com/test.txt');
+        $file->fileGetContents('http://www.example.com/test.txt');
     }
 }
diff --git a/test/TestUtil.php b/test/TestUtil.php
index 60c4112..1311cbb 100644
--- a/test/TestUtil.php
+++ b/test/TestUtil.php
@@ -3,13 +3,13 @@
 /**
  * TestUtil.php
  *
- * @since       2020-12-19
- * @category    Library
- * @package     file
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2020-12-19
+ * @category  Library
+ * @package   file
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  *
  * This file is part of tc-lib-file software library.
  */
@@ -21,53 +21,40 @@
 /**
  * Test Util
  *
- * @since      2020-12-19
- * @category    Library
- * @package     file
- * @author      Nicola Asuni <info@tecnick.com>
- * @copyright   2015-2023 Nicola Asuni - Tecnick.com LTD
- * @license     http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
- * @link        https://github.com/tecnickcom/tc-lib-file
+ * @since     2020-12-19
+ * @category  Library
+ * @package   file
+ * @author    Nicola Asuni <info@tecnick.com>
+ * @copyright 2015-2023 Nicola Asuni - Tecnick.com LTD
+ * @license   http://www.gnu.org/copyleft/lesser.html GNU-LGPL v3 (see LICENSE.TXT)
+ * @link      https://github.com/tecnickcom/tc-lib-file
  */
 class TestUtil extends TestCase
 {
-    public function bcAssertEqualsWithDelta($expected, $actual, $delta = 0.01, $message = '')
-    {
-        if (\is_callable([self::class, 'assertEqualsWithDelta'])) {
-            parent::assertEqualsWithDelta($expected, $actual, $delta, $message);
-            return;
-        }
-        /* @phpstan-ignore-next-line */
-        $this->assertEquals($expected, $actual, $message, $delta);
+    public function bcAssertEqualsWithDelta(
+        mixed $expected,
+        mixed $actual,
+        float $delta = 0.01,
+        string $message = ''
+    ): void {
+        parent::assertEqualsWithDelta($expected, $actual, $delta, $message);
     }
 
-    public function bcExpectException($exception)
+    /**
+     * @param class-string<\Throwable> $exception
+     */
+    public function bcExpectException($exception): void
     {
-        if (\is_callable([self::class, 'expectException'])) {
-            parent::expectException($exception);
-            return;
-        }
-        /* @phpstan-ignore-next-line */
-        parent::setExpectedException($exception);
+        parent::expectException($exception);
     }
 
-    public function bcAssertIsResource($res)
+    public function bcAssertIsResource(mixed $res): void
     {
-        if (\is_callable([self::class, 'assertIsResource'])) {
-            parent::assertIsResource($res);
-            return;
-        }
-        /* @phpstan-ignore-next-line */
-        parent::assertInternalType('resource', $res);
+        parent::assertIsResource($res);
     }
 
-    public function bcAssertMatchesRegularExpression($pattern, $string, $message = '')
+    public function bcAssertMatchesRegularExpression(string $pattern, string $string, string $message = ''): void
     {
-        if (\is_callable([self::class, 'assertMatchesRegularExpression'])) {
-            parent::assertMatchesRegularExpression($pattern, $string, $message);
-            return;
-        }
-        /* @phpstan-ignore-next-line */
-        parent::assertRegExp($pattern, $string, $message);
+        parent::assertMatchesRegularExpression($pattern, $string, $message);
     }
 }