On 16/07/2018 15:49, Alexander Turenko wrote:
Hi, Vlad!
That is interesting discussion. Hope you don't mind my participation.
WBR, Alexander Turenko.
On Mon, Jul 16, 2018 at 01:23:36PM +0300, Vladislav Shpilevoy wrote:
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?
Cast does not change bits. It is legal.
3. Why not 'result > LLONG_MAX'? As I understand, abs(LLONG_MAX) ==
abs(LLONG_MIN),
it is not? (http://www.cplusplus.com/reference/climits/)
No, LLONG_MAX is 2^63-1, but LLONG_MIN is -2^63. We want to compare
result with 2^63. We are trying to do so in platform-independent way
(hovewer unsiged unary nimus equivalence with signed one is likely
two-complement number representation property and can be violated on
other platforms).
Are you think we should introduce our own constant
9223372036854775808ULL (2^63) and avoid that complex assumptions set? It
would be explicitly number-representation-dependent, so maybe it is
better.
