- From: RUELLAN Herve <Herve.Ruellan@crf.canon.fr>
- Date: Fri, 29 Aug 2014 16:51:16 +0000
- To: Pavel Rappo <pavel.rappo@gmail.com>, Mark Nottingham <mnot@mnot.net>
- CC: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
I made some more modifications to 6.1, to describe how variable length integer works, but I think this could be further improved. I'll try to add some drawings to this. Hervé. > -----Original Message----- > From: Pavel Rappo [mailto:pavel.rappo@gmail.com] > Sent: vendredi 29 août 2014 17:11 > To: Mark Nottingham > Cc: Tatsuhiro Tsujikawa; ietf-http-wg@w3.org > Subject: Re: HPACK, Draft 09, Integer Representation > > It looks like I'm not too familiar with the spec language after all :) > Anyway, I believe "6.1." it should be as visual as it is in > Wikipedia's article and at the same time a lot more concise. > > On Fri, Aug 29, 2014 at 1:47 AM, Mark Nottingham <mnot@mnot.net> wrote: > > See: > > https://github.com/http2/http2-spec/issues/595 > > > > I tend to think we need some text to replace it... any volunteers? > > > > > > On 29 Aug 2014, at 2:12 am, Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com> > wrote: > > > >> > >> > >> > >> On Fri, Aug 29, 2014 at 1:00 AM, Pavel Rappo <pavel.rappo@gmail.com> > wrote: > >> > HPACK uses little endian. > >> > >> I think this difference should be mentioned explicitly. > >> > >> > >> FYI, wikipedia reference was deleted. > >> https://github.com/http2/http2- > spec/commit/bd8d7688a9dd8708bae543a9abe889ea7797e139 > >> > >> > >> > "I" is updated while loop: > >> > > >> > repeat > >> > B = next octet > >> > I = I + (B & 127) * 2^M > >> > > >> > ~~~~~~~~~~~~~~~~~~~~~ > >> > M = M + 7 > >> > while B & 128 == 128 > >> > > >> > So, initial "I" is not forgotten. > >> > >> Thanks, Tatsuhiro! It's indeed updated. I overlooked it. > >> > >> > "I" comes from next N bits as algorithm exactly says: > >> > > >> > > >> > decode I from the next N bits > >> > > >> > HPACK integer encoding uses specific prefix bits, which is described as N > >> > here in algorithm. > >> > So when decoding integer encoded with 7 prefix bits, decode initial "I" > from > >> > next 7 bits. > >> > >> The only thing then, the meaning of "I" is different for the encoding > >> and decoding parts. Isn't it? > >> "The algorithm to represent an integer I is as follows:" and "For > >> informational purpose, the algorithm to decode an integer I is as > >> follows:". i.e. same "I" different meanings. > >> > >> > >> If integer X is encoded to some byte string B and then B is decoded to > integer Y, then X should be equal to Y, so in that sense, both "I" mean same > integer. > >> For decoding algorithm, "I" in the sentence you quoted means the result of > the algorithm, and not just the first N bits. > >> > >> Best regards, > >> Tatsuhiro Tsujikawa > >> > >> > >> > >> > > > > -- > > Mark Nottingham https://www.mnot.net/ > >
Received on Friday, 29 August 2014 16:51:49 UTC