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Date: Thu, 15 Aug 2019 01:21:10 +0300
From: Konstantin Osipov <kostja@tarantool.org>
Subject: Re: [tarantool-patches] [PATCH v2 2/8] decimal: fix encoding numbers
 with positive exponent.
Message-ID: <20190814222110.GE28533@atlas>
References: <cover.1565263272.git.sergepetrenko@tarantool.org>
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To: Serge Petrenko <sergepetrenko@tarantool.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>, tarantool-patches@freelists.org
List-ID: <tarantool-patches.dev.tarantool.org>

* Serge Petrenko <sergepetrenko@tarantool.org> [19/08/13 12:03]:
> Similar code is already used in
> mp_encode_extl/mp_decode_extl()
> (yes, it was also introduced by me, but it passed the review):
> 
> (the type of ’type’ is int8_t)
>          data = mp_store_u8(data, type);
> …
>          *type = mp_load_u8(data);

The problem with this approach is that you lost sign in your
storage representation. Imagine this data format is read by a code
which is different from the one you wrote, and relies on msgpack
format specifiers alone. It will honestly believe that the value
is always positive.

Basically, you should follow MsgPack guidelines for choosing
format specifiers.


-- 
Konstantin Osipov, Moscow, Russia