tonumber() in Lua3.2.1

[Yutaka Ueno <ueno@...>]

While using Lua3.2.1 for a very large (>2MB) file processing,
tonumber("  ") sometimes returns 0 instead of nil.
It was fixed by following patch:

--- org/src/lvm.c       Wed Jun 23 05:37:23 1999
+++ src/lvm.c   Fri Oct  6 10:17:06 2000
@@ -62,6 +62,9 @@
       sig = -1;
     }
     else if (*e == '+') e++;
+               /** avoid checking *(e+1) **/
+    if(*e==NULL)
+       return 2;
     /* no digit before or after decimal point? */
     if (!isdigit((unsigned char)*e) && !isdigit((unsigned char)*(e+1)))
       return 2;

When *e is a empty string, *(e+1) is a problem. It may not happen,
depending on C library and how the Lua program reuses string data.
Lua 4.0 beta seems to be ok.

We may needs another patch for:

Dave Bollinger <DBollinger@compuserve.com> wrote :
>  Third, erroneous zero returns:  tonumber() should handle the
>zero-as-error return of strtol().  The empty string is the only example
>that I'm aware of, which could be checked for in advance or check the
>endptr return value against the original string pointer for equality. 
>Example:
>
>  print(tonumber("",8))
>  > 0
>
>  should have returned nil according to all documentation since "" is
>neither a number or convertible string.

--- org/src/lbuiltin.c  Fri Jun 18 02:04:03 1999
+++ src/lbuiltin.c      Fri Oct  6 11:03:17 2000
@@ -149,6 +149,12 @@
     char *s = luaL_check_string(1);
     long n;
     luaL_arg_check(0 <= base && base <= 36, 2, "base out of range");
+       /** bug fix **/
+    while (isspace((unsigned char)*s)) s++;  /* skip heading spaces */
+    if(*s==NULL) {
+       lua_pushnil();
+       return;
+    }
     n = strtol(s, &s, base);
     while (isspace((unsigned char)*s)) s++;  /* skip trailing spaces */
     if (*s) lua_pushnil();  /* invalid format: return nil */

---ueno