'if' to avoid empty 'memcpy' (may be expensive)

This commit is contained in:
Roberto Ierusalimschy 2012-04-03 16:06:19 -03:00
parent cfbe2333a4
commit 462375ba47
1 changed files with 4 additions and 2 deletions

View File

@ -1,5 +1,5 @@
/*
** $Id: lstrlib.c,v 1.172 2011/10/25 12:01:20 roberto Exp roberto $
** $Id: lstrlib.c,v 1.173 2011/11/30 18:24:56 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
@ -119,7 +119,9 @@ static int str_rep (lua_State *L) {
char *p = luaL_buffinitsize(L, &b, totallen);
while (n-- > 1) { /* first n-1 copies (followed by separator) */
memcpy(p, s, l * sizeof(char)); p += l;
memcpy(p, sep, lsep * sizeof(char)); p += lsep;
if (lsep > 0) { /* avoid empty 'memcpy' (may be expensive) */
memcpy(p, sep, lsep * sizeof(char)); p += lsep;
}
}
memcpy(p, s, l * sizeof(char)); /* last copy (not followed by separator) */
luaL_pushresultsize(&b, totallen);