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small optimization for ""..x

This commit is contained in:
Roberto Ierusalimschy 2006-09-19 11:06:45 -03:00
parent d1ef7e0ec6
commit 569a326931
1 changed files with 7 additions and 3 deletions
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10
lvm.c
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@ -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;