commit 569a3269311f1554be345fefdeffe6f7b374a56f
parent d1ef7e0ec6f0b3c40a4abedb3f79a3eaabe01631
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 19 Sep 2006 11:06:22 -0300
small optimization for ""..x
Diffstat:
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.67 2006/09/11 14:07:24 roberto Exp roberto $
+** $Id: lvm.c,v 2.68 2006/09/19 13:57:50 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -281,8 +281,12 @@ void luaV_concat (lua_State *L, int total, int last) {
if (!tostring(L, top-2) || !tostring(L, top-1)) {
if (!call_binTM(L, top-2, top-1, top-2, TM_CONCAT))
luaG_concaterror(L, top-2, top-1);
- } else if (tsvalue(top-1)->len > 0) { /* if len=0, do nothing */
- /* at least two string values; get as many as possible */
+ } else if (tsvalue(top-1)->len == 0) { /* second operand is empty? */
+ /* do nothing; result is already first operand */ ;
+ } else if (tsvalue(top-2)->len == 0) { /* fist operand is empty? */
+ setsvalue2s(L, top-2, rawtsvalue(top-1)); /* result is second op. */
+ } else {
+ /* at least two (non-empty) string values; get as many as possible */
size_t tl = tsvalue(top-1)->len;
char *buffer;
int i;