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Groups > comp.lang.python > #48073
| From | Nick the Gr33k <support@superhost.gr> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: A few questiosn about encoding |
| Date | 2013-06-14 10:28 +0300 |
| Organization | National Technical University of Athens, Greece |
| Message-ID | <kpegmv$p37$4@news.ntua.gr> (permalink) |
| References | (1 earlier) <mailman.2923.1370797972.3114.python-list@python.org> <kp9drh$1o0t$1@news.ntua.gr> <mailman.3238.1371163584.3114.python-list@python.org> <kpea1c$p37$1@news.ntua.gr> <mailman.3253.1371189687.3114.python-list@python.org> |
On 14/6/2013 9:00 πμ, Zero Piraeus wrote: > : > > On 14 June 2013 01:34, Nick the Gr33k <support@superhost.gr> wrote: >> Why doesn't it work like this? >> >> leading 0 = 1 byte flag >> leading 1 = 2 bytes flag >> leading 00 = 3 bytes flag >> leading 01 = 4 bytes flag >> leading 10 = 5 bytes flag >> leading 11 = 6 bytes flag >> >> Wouldn't it be more logical? > > Think about it. Let's say that, as per your scheme, a leading 0 > indicates "1 byte" (as is indeed the case in UTF8). What things could > follow that leading 0? How does that impact your choice of a leading > 00 or 01 for other numbers of bytes? > > ... okay, you're obviously going to need to be spoon-fed a little more > than that. Here's a byte: > > 01010101 > > Is that a single byte representing a code point in the 0-127 range, or > the first of 4 bytes representing something else, in your proposed > scheme? How can you tell? Indeed. You cannot tell if it stands for 1 byte or a 4 byte sequence: 0 + 1010101 = leading 0 stands for 1byte representation of a code-point 01 + 010101 = leading 01 stands for 4byte representation of a code-point the problem here in my scheme of how utf8 encoding works is that you cannot tell whether the flag is '0' or '01' Same happen with leading '1' and '11'. You cannot tell what the flag is, so you cannot know if the Unicode code-point is being represented as 2-byte sequence or 6 bye sequence Understood > Now look at the way UTF8 does it: > <http://en.wikipedia.org/wiki/Utf-8#Description> > > Really, follow the link and study the table carefully. Don't continue > reading this until you believe you understand the choices that the > designers of UTF8 made, and why they made them. > > Pay particular attention to the possible values for byte 1. Do you > notice the difference between that scheme, and yours: > > 0xxxxxxx > 1xxxxxxx > 00xxxxxx > 01xxxxxx > 10xxxxxx > 11xxxxxx > > If you don't see it, keep looking until you do ... this email gives > you more than enough hints to work it out. Don't ask someone here to > explain it to you. If you want to become competent, you must use your > brain. 0xxxxxxx 110xxxxx 10xxxxxx 1110xxxx 10xxxxxx 10xxxxxx 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx I did read the link but i still cannot see why 1. '110' is the flag for 2-byte code-point 2. why the in the 2nd byte and every subsequent byte leading flag has to be '10' -- What is now proved was at first only imagined!
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A few questiosn about encoding Νικόλαος Κούρας <nikos.gr33k@gmail.com> - 2013-06-09 03:44 -0700
Re: A few questiosn about encoding Fábio Santos <fabiosantosart@gmail.com> - 2013-06-09 13:18 +0100
Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-09 18:01 +0100
Re: A few questiosn about encoding Chris “Kwpolska” Warrick <kwpolska@gmail.com> - 2013-06-09 19:12 +0200
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-12 09:09 +0000
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-12 09:24 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-12 14:23 +0300
Re: A few questiosn about encoding Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2013-06-12 14:52 +0200
Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-12 21:30 +0100
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 01:40 +0000
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 12:01 +1000
Re: A few questiosn about encoding Nobody <nobody@nowhere.com> - 2013-06-13 11:02 +0100
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 09:21 +0300
Re: A few questiosn about encoding jmfauth <wxjmfauth@gmail.com> - 2013-06-12 23:28 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 16:48 +1000
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 00:13 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 09:09 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 07:11 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 10:42 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 17:58 +1000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 11:08 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-13 18:20 +1000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 12:41 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-13 11:49 +0000
Re: A few questiosn about encoding Νικόλαος Κούρας <support@superhost.gr> - 2013-06-13 17:19 +0300
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 11:00 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 09:59 +0300
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 20:14 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 16:58 +0300
Re: A few questiosn about encoding Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-14 11:21 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 18:26 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-15 03:03 +1000
Re: A few questiosn about encoding Walter Hurry <walterhurry@lavabit.com> - 2013-06-14 23:32 +0000
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-15 10:26 +1000
Re: A few questiosn about encoding Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-15 06:34 +0000
Re: A few questiosn about encoding Grant Edwards <invalid@invalid.invalid> - 2013-06-15 14:44 +0000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 17:49 +0300
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-15 15:30 +0000
Re: A few questiosn about encoding Roy Smith <roy@panix.com> - 2013-06-15 10:59 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 18:14 +0300
Re: A few questiosn about encoding Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-15 11:35 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-15 22:26 +0300
Re: A few questiosn about encoding Benjamin Schollnick <benjamin@schollnick.net> - 2013-06-15 16:35 -0400
Re: A few questiosn about encoding Chris “Kwpolska” Warrick <kwpolska@gmail.com> - 2013-06-16 15:45 +0200
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 09:36 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 10:49 +0300
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 10:22 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 11:37 +0300
Don't feed the troll... (was: Re: A few questiosn about encoding) Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 11:06 +0200
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 12:32 +0300
Re: Don't feed the troll... Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 13:09 +0200
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:36 +0300
Re: Don't feed the troll... Joel Goldstick <joel.goldstick@gmail.com> - 2013-06-14 08:44 -0400
Re: Don't feed the troll... Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 15:25 +0200
Re: Don't feed the troll... Neil Cerutti <neilc@norwich.edu> - 2013-06-14 15:54 +0000
Re: Don't feed the troll... Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 12:15 +0200
Re: Don't feed the troll... Guy Scree <nobody@nowhere.com> - 2013-06-14 18:50 -0400
Re: Don't feed the troll... Denis McMahon <denismfmcmahon@gmail.com> - 2013-06-15 06:31 +0000
Re: Don't feed the troll... Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-15 13:04 -0400
Re: Don't feed the troll... Guy Scree <nobody@nowhere.com> - 2013-06-17 16:15 -0400
Re: Don't feed the troll... Chris Angelico <rosuav@gmail.com> - 2013-06-18 07:46 +1000
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-14 20:19 +1000
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:41 +0300
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 11:20 +0100
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) rusi <rustompmody@gmail.com> - 2013-06-14 04:51 -0700
Re: Don't feed the help-vampire rusi <rustompmody@gmail.com> - 2013-06-14 05:09 -0700
Re: Don't feed the help-vampire Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 14:31 +0200
Re: Don't feed the help-vampire Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-14 10:51 -0600
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:50 +0300
Re: Don't feed the troll... Zero Piraeus <schesis@gmail.com> - 2013-06-14 09:33 -0400
Re: Don't feed the troll... Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:45 +0300
Re: Don't feed the troll... Heiko Wundram <modelnine@modelnine.org> - 2013-06-14 14:58 +0200
Re: Don't feed the troll... Fábio Santos <fabiosantosart@gmail.com> - 2013-06-14 14:25 +0100
Re: Don't feed the troll... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-14 17:12 +0100
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 12:50 +0200
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 15:59 +0300
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-14 15:52 +0200
Re: A few questiosn about encoding Cameron Simpson <cs@zip.com.au> - 2013-06-15 10:28 +1000
Re: A few questiosn about encoding Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-17 08:49 +0200
Re: Don't feed the troll... Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-14 12:57 +0100
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 13:13 -0400
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Chris Angelico <rosuav@gmail.com> - 2013-06-15 03:31 +1000
Re: Don't feed the troll... (was: Re: A few questiosn about encoding) Grant Edwards <invalid@invalid.invalid> - 2013-06-14 19:40 +0000
Re: Don't feed the troll "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 13:56 -0400
Re: Don't feed the troll Tim Chase <python.list@tim.thechases.com> - 2013-06-14 14:00 -0500
Re: Don't feed the troll "D'Arcy J.M. Cain" <darcy@druid.net> - 2013-06-14 15:17 -0400
Re: Don't feed the troll... Ben Finney <ben+python@benfinney.id.au> - 2013-06-15 10:42 +1000
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-19 18:46 -0700
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-20 06:26 +0000
Re: A few questiosn about encoding MRAB <python@mrabarnett.plus.com> - 2013-06-20 12:43 +0100
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-20 09:27 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 02:37 +1000
Re: A few questiosn about encoding MRAB <python@mrabarnett.plus.com> - 2013-06-20 18:17 +0100
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-23 08:51 -0700
Re: A few questiosn about encoding Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 16:30 +0000
Re: A few questiosn about encoding wxjmfauth@gmail.com - 2013-06-25 13:16 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 03:21 +1000
Re: A few questiosn about encoding Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-06-20 20:43 +0100
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-20 06:40 -0700
Re: A few questiosn about encoding Andrew Berg <robotsondrugs@gmail.com> - 2013-06-20 09:04 -0500
Re: A few questiosn about encoding Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-20 08:12 -0700
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 01:26 +1000
Re: A few questiosn about encoding Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2013-06-20 20:25 +0300
Re: A few questiosn about encoding Chris Angelico <rosuav@gmail.com> - 2013-06-21 01:28 +1000
Re: A few questiosn about encoding Andreas Perstinger <andipersti@gmail.com> - 2013-06-20 19:08 +0200
Re: A few questiosn about encoding Dave Angel <davea@davea.name> - 2013-06-12 08:43 -0400
Re: A few questiosn about encoding Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2013-06-13 18:46 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 08:34 +0300
Re: A few questiosn about encoding Zero Piraeus <schesis@gmail.com> - 2013-06-14 02:00 -0400
Re: A few questiosn about encoding Nick the Gr33k <support@superhost.gr> - 2013-06-14 10:28 +0300
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