util.strbitop: Create buffer in the correct size (optimization)
This avoids dynamically growing the buffer as Lua does when luaL_addchar
is used, thus saving on realloc calls.
--- a/util-src/strbitop.c Thu Oct 15 16:41:51 2020 +0200
+++ b/util-src/strbitop.c Thu Oct 15 16:43:30 2020 +0200
@@ -2,7 +2,7 @@
* This project is MIT licensed. Please see the
* COPYING file in the source package for more information.
*
- * Copyright (C) 2016 Kim Alvefur
+ * Copyright (C) 2016-2020 Kim Alvefur
*/
#include <lua.h>
@@ -27,10 +27,13 @@
return 1;
}
+ char *cbuf = luaL_buffinitsize(L, &buf, a);
+
for(i = 0; i < a; i++) {
- luaL_addchar(&buf, str_a[i] & str_b[i % b]);
+ cbuf[i] = str_a[i] & str_b[i % b];
}
+ luaL_addsize(&buf, a);
luaL_pushresult(&buf);
return 1;
}
@@ -48,10 +51,13 @@
return 1;
}
+ char *cbuf = luaL_buffinitsize(L, &buf, a);
+
for(i = 0; i < a; i++) {
- luaL_addchar(&buf, str_a[i] | str_b[i % b]);
+ cbuf[i] = str_a[i] | str_b[i % b];
}
+ luaL_addsize(&buf, a);
luaL_pushresult(&buf);
return 1;
}
@@ -62,17 +68,18 @@
const char *str_a = luaL_checklstring(L, 1, &a);
const char *str_b = luaL_checklstring(L, 2, &b);
- luaL_buffinit(L, &buf);
-
if(a == 0 || b == 0) {
lua_settop(L, 1);
return 1;
}
+ char *cbuf = luaL_buffinitsize(L, &buf, a);
+
for(i = 0; i < a; i++) {
- luaL_addchar(&buf, str_a[i] ^ str_b[i % b]);
+ cbuf[i] = str_a[i] ^ str_b[i % b];
}
+ luaL_addsize(&buf, a);
luaL_pushresult(&buf);
return 1;
}