diff --git a/src/includes/functions.php b/src/includes/functions.php
index 09574e54..abd32e12 100644
--- a/src/includes/functions.php
+++ b/src/includes/functions.php
@@ -20,108 +20,119 @@
 
 ******************************************************************************/
 
-/**
- * Construction d'une chaine formatée
+/*
+ * LSFormat : %{[key name][:A][:B][-][! ou _][~][%}}
  *
- * Cette fonction retourne la valeur d'une chaine formatée selon le format
- * et les données passés en paramètre.
+ * Extracted fields
+ * - 0 : full string '%{...}'
+ * - 1/key : key name
+ * - 2 : :A
+ * - 3/substr_a : A
+ * - 4 : :B
+ * - 5/substr_b : B
+ * - 6/modifiers : "!" / "_" / "~" / "%"
+ */
+define(
+  'GETFDATA_REGEX',
+  "/%[{(](?P<key>[A-Za-z0-9]+)(\:(?P<substr_a>-?[0-9])+)?(\:(?P<substr_b>[0-9]+))?(?P<modifiers>[\!\_~%]*)[})]/"
+);
+
+/**
+ * Build LSformat string
+ *
+ * This function build and return a LSformat string from specified format and provided data.
  *
  * @author Benjamin Renard <brenard@easter-eggs.com>
  *
- * @param string $format Format de la chaine
- * @param string $format Les données pour composés la chaine
- *                    Ce paramètre peut être un tableau de string, une string,
- *                    une tableau d'objet ou un objet.
- * @param string $format Le nom de la methode de/des objet(s) à appeler pour
- *                         obtenir la valeur de remplacement dans la chaine formatée.
+ * @param string $format The LSformat string
+ * @param string|object|array<string|object> $data Data to build the string
+ *        This parameter could be a string, an object or an array of string or object.
+ * @param string $meth The name to the method of objet(s) to call to get the replacement value for a
+ *                     specified key
  *
- * @return string La chaine formatée
+ * @return string The builded LSformat string
  */
-function getFData($format,$data,$meth=NULL) {
-  $unique=false;
-  /*
-   * Format : %{[key name][:A][:B][! ou _][~][%}}
-   *
-   * Extracted fields
-   * - 0 : full string '%{...}'
-   * - 1 : key name
-   * - 2 : :A
-   * - 3 : A
-   * - 4 : :B
-   * - 5 : B
-   * - 6 : "!" / "_" / "~" / "%"
-   */
-  $expr="/%[{(]([A-Za-z0-9]+)(\:(-?[0-9])+)?(\:(-?[0-9]+))?([\!\_~%]*)[})]/";
+function getFData($format, $data, $meth=NULL) {
+  $unique = false;
   if(!is_array($format)) {
-    $format=array($format);
-    $unique=true;
+    $format = array($format);
+    $unique = true;
   }
-  for($i=0;$i<count($format);$i++) {
+  for($i=0; $i<count($format); $i++) {
     if(is_array($data)) {
-      if ($meth==NULL) {
-        while (preg_match($expr,$format[$i],$ch)) {
-          if (!isset($data[$ch[1]])) {
+      if (is_null($meth)) {
+        while (preg_match(GETFDATA_REGEX, $format[$i], $ch)) {
+          if (!isset($data[$ch['key']])) {
             $val = '';
           }
-          elseif (is_array($data[$ch[1]])) {
-            $val = $data[$ch[1]][0];
+          elseif (is_array($data[$ch['key']])) {
+            $val = $data[$ch['key']][0];
           }
           else {
-            $val = $data[$ch[1]];
+            $val = $data[$ch['key']];
           }
-          $val=_getFData_extractAndModify($val,$ch);
-          $format[$i]=str_replace($ch[0],$val,$format[$i]);
+          $val = _getFData_extractAndModify($val, $ch);
+          $format[$i] = str_replace($ch[0], $val, $format[$i]);
         }
       }
       else {
-        while (preg_match($expr,$format[$i],$ch)) {
-          if (method_exists($data[$ch[1]],$meth)) {
-            $value = $data[$ch[1]] -> $meth();
+        while (preg_match(GETFDATA_REGEX, $format[$i], $ch)) {
+          if (method_exists($data[$ch['key']], $meth)) {
+            $value = $data[$ch['key']] -> $meth();
             if (is_array($value)) {
               $value = $value[0];
             }
-            $value=_getFData_extractAndModify($value,$ch);
-            $format[$i]=str_replace($ch[0],$value,$format[$i]);
+            $value = _getFData_extractAndModify($value, $ch);
+            $format[$i] = str_replace($ch[0], $value, $format[$i]);
           }
           else {
-            LSerror :: addErrorCode('fct_getFData_01',array('meth' => $meth,'obj' => $ch[1]));
+            LSerror :: addErrorCode(
+              'fct_getFData_01',
+              array('meth' => $meth, 'obj' => $ch['key'])
+            );
             break;
           }
         }
       }
     }
     elseif (is_object($data)) {
-      if ($meth==NULL) {
-        while (preg_match($expr,$format[$i],$ch)) {
-          $value = $data -> $ch[1];
+      if (is_null($meth)) {
+        while (preg_match(GETFDATA_REGEX, $format[$i], $ch)) {
+          $value = $data -> $ch['key'];
           if (is_array($value)) {
             $value = $value[0];
           }
-          $value=_getFData_extractAndModify($value,$ch);
-          $format[$i]=str_replace($ch[0],$value,$format[$i]);
+          $value = _getFData_extractAndModify($value, $ch);
+          $format[$i] = str_replace($ch[0], $value, $format[$i]);
         }
       }
       else {
-        while (preg_match($expr,$format[$i],$ch)) {
-          if (method_exists($data,$meth)) {
-            $value = $data -> $meth($ch[1]);
+        while (preg_match(GETFDATA_REGEX, $format[$i], $ch)) {
+          if (method_exists($data, $meth)) {
+            $value = $data -> $meth($ch['key']);
             if (is_array($value)) {
               $value = $value[0];
             }
-            $value=_getFData_extractAndModify($value,$ch);
-            $format[$i]=str_replace($ch[0],$value,$format[$i]);
+            $value = _getFData_extractAndModify($value, $ch);
+            $format[$i] = str_replace($ch[0], $value, $format[$i]);
           }
           else {
-            LSerror :: addErrorCode(0,getFData(_("Function 'getFData' : The method %{meth} of the object %{obj} doesn't exist."),array('meth' => $meth,'obj' => get_class($data))));
+            LSerror :: addErrorCode(
+              0,
+              getFData(
+                _("Function 'getFData' : The method %{meth} of the object %{obj} doesn't exist."),
+                array('meth' => $meth, 'obj' => get_class($data))
+              )
+            );
             break;
           }
         }
       }
     }
     else {
-      while (preg_match($expr,$format[$i],$ch)) {
-        $val=_getFData_extractAndModify($data,$ch);
-        $format[$i]=str_replace($ch[0],$val,$format[$i]);
+      while (preg_match(GETFDATA_REGEX, $format[$i], $ch)) {
+        $val = _getFData_extractAndModify($data, $ch);
+        $format[$i] = str_replace($ch[0], $val, $format[$i]);
       }
     }
   }
@@ -131,100 +142,95 @@ function getFData($format,$data,$meth=NULL) {
   return $format;
 }
 
-function _getFData_extractAndModify($data,$ch) {
+function _getFData_extractAndModify($data, $ch) {
   /*
-   * Format : %{[key name][:A][:B][-][! ou _][~][%}}
-   *
-   * Extracted fields
-   * - 0 : full string '%{...}'
-   * - 1 : key name
-   * - 2 : :A
-   * - 3 : A
-   * - 4 : :B
-   * - 5 : B
-   * - 6 : "!" / "_" / "~" / "%"
+   * Handle substring parameters (substr_a & substr_b)
    */
+
   // If A
-  if($ch[3]!="") {
+  if($ch['substr_a']) {
     // If A and B
-    if ($ch[5]!="") {
+    if ($ch['substr_b']) {
       // If A and B=0
-      if ($ch[5]==0) {
+      if ($ch['substr_b'] == 0) {
         // If A<0 and B=0
-        if ($ch[3]<0) {
-          $s=strlen((string)$data)-(-1*$ch[3]);
-          $l=strlen((string)$data);
+        if ($ch['substr_a'] < 0) {
+          $s = mb_strlen(strval($data)) - (-1 * $ch['substr_a']);
+          $l = mb_strlen(strval($data));
         }
         // If A >= 0 and B
         else {
-          $s=$ch[3];
-          $l=strlen((string)$data);
+          $s = $ch['substr_a'];
+          $l = mb_strlen(strval($data));
         }
       }
       // If A and B > 0
-      elseif ($ch[5]>0) {
+      elseif ($ch['substr_b'] > 0) {
         // If A < 0 and B > 0 or A >= 0 and B > 0
-        $s=$ch[3];
-        $l=$ch[5];
+        $s = $ch['substr_a'];
+        $l = $ch['substr_b'];
       }
       // If A and B < 0
       else {
         // If A < 0 and B < 0
-        if ($ch[3]<0) {
-          $s=$ch[5];
-          $l=false;
+        if ($ch['substr_a'] < 0) {
+          $s = $ch['substr_b'];
+          $l = false;
         }
         // If A >= 0 and B < 0
         else {
-          $s=$ch[3]+$ch[5];
-          $l=abs($ch[5]);
+          $s = $ch['substr_a'] + $ch['substr_b'];
+          $l = abs($ch['substr_b']);
         }
       }
     }
     // If only A
     else {
-      if ($ch[3]<0) {
-        $s=$ch[3];
-        $l=false;
+      if ($ch['substr_a'] < 0) {
+        $s = $ch['substr_a'];
+        $l = false;
       }
       else {
-        $s=0;
-        $l=$ch[3];
+        $s = 0;
+        $l = $ch['substr_a'];
       }
     }
 
-    if ($l==false) {
-      $val=mb_substr((string)$data,$s);
+    if ($l == false) {
+      $val = mb_substr(strval($data), $s);
     }
     else {
-      $val=mb_substr((string)$data,$s, abs($l));
+      $val = mb_substr(strval($data), $s, abs($l));
     }
   }
   else {
     try {
-      $val=strval($data);
+      $val = strval($data);
     }
     catch (Exception $e) {
-      $val=_('[not string value]');
+      $val = _('[not string value]');
     }
   }
 
-  if ($ch[6]) {
+  /*
+   * Handle modifiers
+   */
+  if ($ch['modifiers']) {
     # Without Accent
-    if (strpos($ch[6], '~')!==false) {
+    if (strpos($ch['modifiers'], '~') !== false) {
       $val = withoutAccents($val);
     }
 
     # Upper / Lower case
-    if (strpos($ch[6], '!')!==false) {
-      $val=mb_strtoupper($val);
+    if (strpos($ch['modifiers'], '!') !== false) {
+      $val = mb_strtoupper($val);
     }
-    elseif (strpos($ch[6], '_')!==false) {
-      $val=mb_strtolower($val);
+    elseif (strpos($ch['modifiers'], '_') !== false) {
+      $val = mb_strtolower($val);
     }
 
     # Escape HTML entities
-    if (strpos($ch[6], '%')!==false) {
+    if (strpos($ch['modifiers'], '%') !== false) {
       $val = htmlentities($val);
     }
   }
@@ -233,11 +239,10 @@ function _getFData_extractAndModify($data,$ch) {
 }
 
 function getFieldInFormat($format) {
-  $fields=array();
-  $expr='/%[{(]([A-Za-z0-9]+)(\:(-?[0-9])+)?(\:(-?[0-9]+))?(-)?(\!|\_)?(~)?(%)?[})]/';
-  while (preg_match($expr,$format,$ch)) {
-    $fields[]=$ch[1];
-    $format=str_replace($ch[0],'',$format);
+  $fields = array();
+  while (preg_match(GETFDATA_REGEX, $format, $ch)) {
+    $fields[] = $ch['key'];
+    $format = str_replace($ch[0], '', $format);
   }
   return $fields;
 }