From 77420b94d0e49469b20df43d7913150f9668e6ac Mon Sep 17 00:00:00 2001
From: Geoff McLane <ubuntu@geoffair.info>
Date: Mon, 8 May 2017 18:37:04 +0200
Subject: [PATCH] Fix for 'isalnum' in Windows

According to the MSN documentation 'isalnum(c)' is only valid when c equals
EOF, or is in the range 0 to 255 inclusive. It states the behavior is
undefined outside this range, and in Debug mode triggers an assert dialog.
---
 src/attrs.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/attrs.c b/src/attrs.c
index cbcb6a9..4f1c449 100644
--- a/src/attrs.c
+++ b/src/attrs.c
@@ -1475,13 +1475,21 @@ static void CheckLowerCaseAttrValue( TidyDocImpl* doc, Node *node, AttVal *attva
 }
 
 /* methods for checking value of a specific attribute */
+#ifdef _WIN32
+#define ISUPPER(a) ((a >= 'A') && (a <= 'Z'))
+#define ISLOWER(a) ((a >= 'a') && (a <= 'z'))
+#define ISNUMERIC(a) ((a >= '0') && (a <= '9'))
+#define ISALNUM(a) (ISUPPER(a) || ISLOWER(a) || ISNUMERIC(a))
+#else
+#define ISALNUM(a)  isalnum(a)
+#endif
 
 static Bool IsURLCodePoint( ctmbstr p, uint *increment )
 {
     uint c;
     *increment = TY_(GetUTF8)( p, &c ) + 1;
 
-    return isalnum( c ) ||
+    return ISALNUM( c ) ||
         c == '%' ||    /* not a valid codepoint, but an escape sequence */
         c == '#' ||    /* not a valid codepoint, but a delimiter */
         c == '!' ||