1 files changed, 21 insertions, 16 deletions

diff --git a/src/lib_os.c b/src/lib_os.c
index 0a784129..de2bc623 100644
--- a/src/lib_os.c
+++ b/src/lib_os.c
@@ -18,7 +18,10 @@
 #include "lualib.h"
 
 #include "lj_obj.h"
+#include "lj_gc.h"
 #include "lj_err.h"
+#include "lj_buf.h"
+#include "lj_str.h"
 #include "lj_lib.h"
 
 #if LJ_TARGET_POSIX
@@ -185,7 +188,7 @@ LJLIB_CF(os_date)
 #endif
   }
   if (stm == NULL) {  /* Invalid date? */
-    setnilV(L->top-1);
+    setnilV(L->top++);
   } else if (strcmp(s, "*t") == 0) {
     lua_createtable(L, 0, 9);  /* 9 = number of fields */
     setfield(L, "sec", stm->tm_sec);
@@ -197,23 +200,25 @@ LJLIB_CF(os_date)
     setfield(L, "wday", stm->tm_wday+1);
     setfield(L, "yday", stm->tm_yday+1);
     setboolfield(L, "isdst", stm->tm_isdst);
-  } else {
-    char cc[3];
-    luaL_Buffer b;
-    cc[0] = '%'; cc[2] = '\0';
-    luaL_buffinit(L, &b);
-    for (; *s; s++) {
-      if (*s != '%' || *(s + 1) == '\0') {  /* No conversion specifier? */
-        luaL_addchar(&b, *s);
-      } else {
-        size_t reslen;
-        char buff[200];  /* Should be big enough for any conversion result. */
-        cc[1] = *(++s);
-        reslen = strftime(buff, sizeof(buff), cc, stm);
-        luaL_addlstring(&b, buff, reslen);
+  } else if (*s) {
+    SBuf *sb = &G(L)->tmpbuf;
+    MSize sz = 0;
+    const char *q;
+    for (q = s; *q; q++)
+      sz += (*q == '%') ? 30 : 1;  /* Overflow doesn't matter. */
+    setsbufL(sb, L);
+    for (;;) {
+      char *buf = lj_buf_need(sb, sz);
+      size_t len = strftime(buf, sbufsz(sb), s, stm);
+      if (len) {
+        setstrV(L, L->top++, lj_str_new(L, buf, len));
+        lj_gc_check(L);
+        break;
       }
+      sz += (sz|1);
     }
-    luaL_pushresult(&b);
+  } else {
+    setstrV(L, L->top++, &G(L)->strempty);
   }
   return 1;
 }