From 30d592636366fff783d316dba9825dcf59624475 Mon Sep 17 00:00:00 2001
From: Steffen185 <steffen.weber@gmail.com>
Date: Sun, 14 Apr 2013 13:11:03 +0300
Subject: [PATCH] Mail\Header/GenericHeader.php: Adjust regex to RFC 5322

---
 src/Header/GenericHeader.php | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Header/GenericHeader.php b/src/Header/GenericHeader.php
index 67834e93..cc48385a 100644
--- a/src/Header/GenericHeader.php
+++ b/src/Header/GenericHeader.php
@@ -76,9 +76,9 @@ public function setFieldName($fieldName)
         $fieldName = str_replace(' ', '-', ucwords(str_replace(array('_', '-'), ' ', $fieldName)));
 
         // Validate what we have
-        if (!preg_match('/^[a-z][a-z0-9-]*$/i', $fieldName)) {
+        if (!preg_match('/^[\x21-\x39\x3B-\x7E]*$/i', $fieldName)) {
             throw new Exception\InvalidArgumentException(
-                'Header name must start with a letter, and consist of only letters, numbers and dashes.'
+                'Header name must be composed of printable US-ASCII characters, except colon.'
             );
         }