Add inv_strpbrk() function and convert equivalent sindex() calls

inv_strpbrk() is the inverse of the standard function strpbrk().

Calls to sindex() where both strings are not NULL and the second string begins with ^ are equivalent
to calls to inv_strpbrk() (but without the ^).  Convert those calls.

include/ircaux.h

@@ -28,6 +28,7 @@ char *	BX_last_arg 		(char **);
 char *	BX_expand_twiddle 		(char *);
 char *	BX_upper 			(char *);
 char *	BX_lower 			(char *);
+char *inv_strpbrk(const char *s, const char *reject);
 char *	BX_sindex			(const char *, const char *);
 char *	BX_rsindex 		(const char *, const char *, const char *, int);
 char *	BX_path_search 		(char *, char *);

source/commands.c

@@ -3526,7 +3526,7 @@ BUILT_IN_COMMAND(untopic)
 	ChannelList *chan;
 	int server;
 	
-	args = sindex(args, "^ ");
+	args = inv_strpbrk(args, " ");
 
 	if (is_channel(args))
 		channel = next_arg(args, &args);
@@ -3543,12 +3543,12 @@ BUILT_IN_COMMAND(e_topic)
 	ChannelList *chan;
 	int server;
 
-	args = sindex(args, "^ ");
+	args = inv_strpbrk(args, " ");
 
 	if (is_channel(args))
 	{
 		channel = next_arg(args, &args);
-		args = sindex(args, "^ ");
+		args = inv_strpbrk(args, " ");
 	}
 
 	if (!(chan = prepare_command(&server, channel, args ? PC_TOPIC : NO_OP)))

source/ircaux.c

@@ -467,7 +467,7 @@ char *BX_next_arg(char *str, char **new_ptr)
 	if (!str)
 		return NULL;
 
-	if ((ptr = sindex(str, "^ ")) != NULL)
+	if ((ptr = inv_strpbrk(str, " ")) != NULL)
 	{
 		if ((str = strchr(ptr, ' ')) != NULL)
 			*str++ = 0;
@@ -614,7 +614,7 @@ char	*safe_new_next_arg (char *str, char **new_ptr)
 	if (!str || !*str)
 		return empty_string;
 
-	if ((ptr = sindex(str, "^ \t")) != NULL)
+	if ((ptr = inv_strpbrk(str, " \t")) != NULL)
 	{
 		if (*ptr == '"')
 		{
@@ -666,7 +666,7 @@ char	*BX_new_new_next_arg (char *str, char **new_ptr, char *type)
 	if (!str || !*str)
 		return NULL;
 
-	if ((ptr = sindex(str, "^ \t")) != NULL)
+	if ((ptr = inv_strpbrk(str, " \t")) != NULL)
 	{
 		if ((*ptr == '"') || (*ptr == '\''))
 		{
@@ -1066,6 +1066,23 @@ char	*BX_check_nickname (char *nick)
 	return *nick ? nick : NULL;
 }
 
+/* inv_strcpbrk()
+ *
+ * Returns a pointer to the first character in a string which is NOT found
+ * in 'reject'.
+ *
+ * This is the inverse of the standard function strpbrk().
+ */
+char *inv_strpbrk(const char *s, const char *reject)
+{
+	s += strspn(s, reject);
+
+	if (!*s)
+		return NULL;
+
+	return (char *)s;
+}
+
 /* sindex()
  *
  * Returns a pointer to the first matching character in a string, or NULL if
@@ -1081,18 +1098,9 @@ char *BX_sindex(const char *string, const char *group)
 		return NULL;
 
 	if (*group == '^')
-	{
+		return inv_strpbrk(string, group + 1);
-		string += strspn(string, group + 1);
-	}
 	else
-	{
+		return strpbrk(string, group);
-		string += strcspn(string, group);
-	}
-
-	if (*string)
-		return (char *)string;
-	else
-		return NULL;
 }
 
 /* rsindex()