Received-SPF: pass (google.com: best guess record for domain of linux-ext4-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [RFC] Thing 1: Shardmap fox Ext4
To:     "Theodore Y. Ts'o" <tytso@mit.edu>
Cc:     linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
References: <176a1773-f5ea-e686-ec7b-5f0a46c6f731@phunq.net>
 <20191127142508.GB5143@mit.edu>
 <c3636a43-6ae9-25d4-9483-34770b6929d0@phunq.net>
 <20191128022817.GE22921@mit.edu>
From:   Daniel Phillips <daniel@phunq.net>
Message-ID: <3b4d380f-cb33-b0fb-2426-67109875ce77@phunq.net>
Date:   Sun, 8 Dec 2019 02:25:22 -0800
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.9.0
MIME-Version: 1.0
In-Reply-To: <20191128022817.GE22921@mit.edu>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-ext4-owner@vger.kernel.org
Precedence: bulk

On 2019-11-27 6:28 p.m., Theodore Y. Ts'o wrote:
> The use of C++ with templates is presumably one of the "less so"
> parts, and it was that which I had in mind when I said,
> "reimplementing from scratch".

The templates were removed without reimplementing from scratch:

   https://github.com/danielbot/Shardmap/blob/master/shardmap.h#L88
   https://github.com/danielbot/Shardmap/blob/master/shardmap.cc#L82

The duopack/tripack facility, central to Shardmap efficient scalability, are
now just ordinary C code that happens to be compiled by a C++ compiler. I
think the machine code should be identical to what the templates produced,
though I did not verify.

This was a strictly mechanical conversion, less error prone than
reimplementing from scratch I would think. I expect the rest of the
back conversions to be similarly mechanical.

Regards,

Daniel