From f787a8a7a70e91d9281c3e17c7d9a2322830ec75 Mon Sep 17 00:00:00 2001
From: Ray Vincent <rayhvincent@gmail.com>
Date: Tue, 24 Aug 2021 13:51:32 -0700
Subject: [PATCH] Update urn regex to match widely accepted expression

---
 include/valijson/internal/uri.hpp | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/include/valijson/internal/uri.hpp b/include/valijson/internal/uri.hpp
index 6adc1e7..91b3fae 100644
--- a/include/valijson/internal/uri.hpp
+++ b/include/valijson/internal/uri.hpp
@@ -26,9 +26,7 @@ inline bool isUriAbsolute(const std::string &documentUri)
  */
 inline bool isUrn(const std::string &documentUri) {
   static const std::regex pattern(
-      "^((urn)|(URN)):[a-zA-Z0-9]+[-]{0,1}[a-zA-Z0-9]+(:[-a-zA-Z0-9\\\\._~%!"
-      "$&'()\\/*+,;=]+)+(\\?[-a-zA-Z0-9\\\\._~%!$&'()\\/"
-      "*+,;:=]+){0,1}(#[-a-zA-Z0-9\\\\._~%!$&'()\\/*+,;:=]+){0,1}$");
+      "^(?i:urn:(?!urn:)([a-z0-9][a-z0-9-]{1,31}):((?:[-a-z0-9()+,.:=@;$_!*'&~\\/]|%[0-9a-f]{2})+)(?:\\?\\+(.*?))?(?:\\?=(.*?))?(?:#(.*?))?)$");
 
   return std::regex_match(documentUri, pattern);
 }