degesch: support CASEMAPPING=rfc1459-strict

common.c

@@ -58,6 +58,16 @@
 		(link)->next = (following);                                            \
 	BLOCK_END
 
+#define TRIVIAL_STRXFRM(name, fn)                                              \
+	static size_t                                                              \
+	name (char *dest, const char *src, size_t n)                               \
+	{                                                                          \
+		size_t len = strlen (src);                                             \
+		while (n-- && (*dest++ = (fn) (*src++)))                               \
+			;                                                                  \
+		return len;                                                            \
+	}
+
 static void
 transform_str (char *s, int (*tolower) (int c))
 {
@@ -103,6 +113,17 @@ strncasecmp_ascii (const char *a, const char *b, size_t n)
 	return 0;
 }
 
+static int
+irc_tolower_strict (int c)
+{
+	if (c == '[')   return '{';
+	if (c == ']')   return '}';
+	if (c == '\\')  return '|';
+	return c >= 'A' && c <= 'Z' ? c + ('a' - 'A') : c;
+}
+
+TRIVIAL_STRXFRM (irc_strxfrm_strict, irc_tolower_strict)
+
 static char *
 resolve_relative_runtime_filename (const char *filename)
 {