[tarantool-patches] Re: [PATCH v1 1/1] lua: fix strange behaviour of tonumber64
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Mon Jul 16 13:23:36 MSK 2018
Thanks for the patch! See 4 comments below.
On 13/07/2018 14:21, Kirill Shcherbatov wrote:
> Function tonumber64 has worked incorrectly with values less
> than LLONG_MIN.
> Now it works in the interval [LLONG_MIN, ULLONG_MAX] returning
> nil otherwise.
>
> Closes #3466.
> ---
> Branch: https://github.com/tarantool/tarantool/compare/kshch/gh-3466-tonumber64-strange-behaviour
> Issue: https://github.com/tarantool/tarantool/issues/3466
>
> src/lua/init.c | 6 +++++-
> test/box/misc.result | 19 +++++++++++++++++++
> test/box/misc.test.lua | 8 ++++++++
> 3 files changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/src/lua/init.c b/src/lua/init.c
> index 9a96030..4b5285d 100644
> --- a/src/lua/init.c
> +++ b/src/lua/init.c
> @@ -222,7 +222,11 @@ lbox_tonumber64(struct lua_State *L)
> if (argl == 0) {
> lua_pushnil(L);
> } else if (negative) {
> - luaL_pushint64(L, -1 * (long long )result);
> + if (result > -((unsigned long long )LLONG_MIN)) {
1. Please, do not enclose one-line bodies into {}.
2. How can you cast LLONG_MIN (that is negative) to the unsigned type?
3. Why not 'result > LLONG_MAX'? As I understand, abs(LLONG_MAX) == abs(LLONG_MIN),
it is not? (http://www.cplusplus.com/reference/climits/)
4. Why the function is named to64, but we use non-explicitly sized types?
I mean, why not to use uint64_t result, compare with INT64_MAX etc. According to
the C standard, LLONG_MAX is not restricted with 64 bits.
> + lua_pushnil(L);
> + } else {
> + luaL_pushint64(L, -result);
> + }
> } else {
> luaL_pushuint64(L, result);
> }
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