From: Johannes Schindelin <Johannes.Schindelin@gmx.de>
To: Reece Dunn <msclrhd@googlemail.com>
Cc: Mike Hommey <mh@glandium.org>, Junio C Hamano <gitster@pobox.com>,
Johannes Sixt <johannes.sixt@telecom.at>,
git@vger.kernel.org
Subject: Re: [PATCH 1/2] Add strbuf_initf()
Date: Thu, 6 Mar 2008 13:52:57 +0100 (CET) [thread overview]
Message-ID: <alpine.LSU.1.00.0803061319590.15786@racer.site> (raw)
In-Reply-To: <3f4fd2640803060353w70651522w4b3896b8106b01c0@mail.gmail.com>
Hi,
On Thu, 6 Mar 2008, Reece Dunn wrote:
> On 06/03/2008, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
>
> > On Thu, 6 Mar 2008, Reece Dunn wrote:
> >
> > > On 06/03/2008, Mike Hommey <mh@glandium.org> wrote:
> > > > On Thu, Mar 06, 2008 at 02:14:43AM +0100, Johannes Schindelin wrote:
> > > > >
> > > > > The most common use of addf() was to init a strbuf and addf()
> > > > > right away. Since it is so common, it makes sense to have a
> > > > > function strbuf_initf() to wrap both calls into one.
> > > > >
> > > > > Unfortunately, C (and cpp) has no way to make this easy
> > > > > without code duplication, as we need to va_init() in
> > > > > strbuf_addf() possibly a few times. So the code for addf() is
> > > > > copied. Fortunately, the code is pretty short, so not too
> > > > > much had to be copied as-is.
> > >
> > > Why not have a strbuf_vaddf and strbuf_vinitf that take a va_arg as
> > > a parameter. This would mean that you don't have code duplication,
> > > and it is flexible enough if you want to add more customisations in
> > > the future. No macro needed. This is what the printf/scanf family
> > > of functions do.
>
> Is it possible to pass a void * to a strbuf_vaddf function that you can
> pass to va_start, so you can then restart the va_list?
AFAIU va_list() works on the stack (on less register-challenged systems
than x86, the first parameters are possibly passed as registers, too, but
it has to resort to the stack at a certain number of parameters).
Since the stack is also used (at least on register-challenged yadda yadda)
to store the return address, va_list() would most likely pick that up,
too.
Now, that just _might_ still work, since the printf() family determines
the number of arguments from the format string.
But then there are machines which are _not_ completely stack-based, for
example SPARC. IIRC the first 8 parameters are passed by a so-called
register window, which changes with each function call.
So no, I think there is no portable way to pass them around.
Of course, having a simple implementation for addf() _not_ using
vsnprintf() could help, too (and make the process more efficient,
probably).
I thought.
The formats we'd have to support are:
$ git grep strbuf_addf |
sed -e 's/^[^"]*"\([^"]*\)".*$/\1/' -e 's/%%//g' -e 's/%/\
&/g' | sed -n -e 's/\(%[^a-zA-Z]*[a-zA-Z]\).*/\1/p' | sort | uniq
%02X
%06o
%c
%d
%l
%o
%s
%.*s
%u
So it does not look too bad. 'X', 'o', 'd', 'l' and 'u', possibly with a
size specifier (left 0-padded), 'c' and 's' (possibly with a length
parameter).
The implementation wouldn't be _too_ short, I'd say, but doable.
Ciao,
Dscho
next prev parent reply other threads:[~2008-03-06 12:53 UTC|newest]
Thread overview: 138+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-27 18:54 [PATCH 00/40] MinGW port Johannes Sixt
2008-02-27 18:54 ` [PATCH 01/40] Add compat/regex.[ch] and compat/fnmatch.[ch] Johannes Sixt
2008-02-27 23:43 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 02/40] Compile some programs only conditionally Johannes Sixt
2008-02-28 11:57 ` Johannes Schindelin
2008-02-28 20:30 ` Johannes Sixt
2008-02-29 0:47 ` Johannes Schindelin
2008-02-29 20:58 ` Johannes Sixt
2008-02-29 21:53 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 03/40] Add target architecture MinGW Johannes Sixt
2008-02-28 12:05 ` Johannes Schindelin
2008-02-28 12:57 ` Paolo Bonzini
2008-02-28 14:56 ` Johannes Schindelin
2008-02-28 20:40 ` Johannes Sixt
2008-02-29 1:07 ` Johannes Schindelin
2008-02-29 21:03 ` Johannes Sixt
2008-02-29 21:54 ` Johannes Schindelin
2008-03-05 21:21 ` Johannes Sixt
2008-03-05 22:18 ` Johannes Schindelin
2008-03-05 22:22 ` Junio C Hamano
2008-03-05 22:28 ` Johannes Schindelin
2008-03-05 22:51 ` Junio C Hamano
2008-03-06 0:11 ` Johannes Schindelin
2008-03-06 1:14 ` [PATCH 1/2] Add strbuf_initf() Johannes Schindelin
2008-03-06 6:33 ` Mike Hommey
2008-03-06 9:03 ` Reece Dunn
2008-03-06 10:55 ` Johannes Schindelin
2008-03-06 11:53 ` Reece Dunn
2008-03-06 12:52 ` Johannes Schindelin [this message]
2008-03-06 16:29 ` [PATCH 1/2 v2] Add strbuf_vaddf(), use it in strbuf_addf(), and add strbuf_initf() Johannes Schindelin
2008-03-06 16:38 ` Johannes Sixt
2008-03-06 16:47 ` Johannes Sixt
2008-03-06 16:59 ` Johannes Schindelin
2008-03-06 18:18 ` [PATCH 1/2] Add strbuf_initf() Kristian Høgsberg
2008-03-06 18:26 ` Johannes Schindelin
2008-03-06 18:35 ` Kristian Høgsberg
2008-03-06 19:10 ` Mike Hommey
2008-03-06 10:53 ` Johannes Schindelin
2008-03-06 12:09 ` Jeff King
2008-03-06 1:15 ` [PATCH 2/2] format-patch: add --reviewed-by=<ident> Johannes Schindelin
2008-03-06 2:40 ` Junio C Hamano
2008-03-06 10:40 ` Johannes Schindelin
2008-03-06 20:38 ` [PATCH 03/40] Add target architecture MinGW Johannes Sixt
2008-03-11 21:30 ` Johannes Sixt
2008-03-11 23:28 ` Johannes Schindelin
2008-03-12 22:59 ` Johannes Sixt
2008-03-12 23:06 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 04/40] Windows: Use the Windows style PATH separator ';' Johannes Sixt
2008-02-28 9:25 ` Paolo Bonzini
2008-02-28 20:43 ` Johannes Sixt
2008-02-29 1:09 ` Johannes Schindelin
2008-02-29 7:57 ` Paolo Bonzini
2008-02-29 12:19 ` Johannes Schindelin
2008-02-29 12:45 ` Paolo Bonzini
2008-02-29 12:59 ` Johannes Schindelin
2008-02-28 17:57 ` Junio C Hamano
2008-02-27 18:54 ` [PATCH 05/40] Windows: Strip ".exe" from the program name Johannes Sixt
2008-02-27 18:54 ` [PATCH 06/40] Windows: Implement a wrapper of the open() function Johannes Sixt
2008-02-27 18:54 ` [PATCH 07/40] Windows: A minimal implemention of getpwuid() Johannes Sixt
2008-02-27 18:54 ` [PATCH 08/40] Windows: always chmod(, 0666) before unlink() Johannes Sixt
2008-02-28 12:09 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 09/40] Windows: Work around misbehaved rename() Johannes Sixt
2008-02-27 18:54 ` [PATCH 10/40] Windows: Treat Windows style path names Johannes Sixt
2008-02-28 12:18 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 11/40] Windows: Handle absolute paths in safe_create_leading_directories() Johannes Sixt
2008-02-27 18:54 ` [PATCH 12/40] Windows: Implement gettimeofday() Johannes Sixt
2008-02-27 18:54 ` [PATCH 13/40] Windows: Fix PRIuMAX definition Johannes Sixt
2008-02-28 12:21 ` Johannes Schindelin
2008-02-28 20:45 ` Johannes Sixt
2008-02-27 18:54 ` [PATCH 14/40] Windows: Implement setitimer() and sigaction() Johannes Sixt
2008-02-27 18:54 ` [PATCH 15/40] Windows: A work-around for a misbehaved vsnprintf Johannes Sixt
2008-02-27 18:54 ` [PATCH 16/40] Windows: Wrap execve so that shell scripts can be invoked Johannes Sixt
2008-02-27 18:54 ` [PATCH 17/40] Windows: A pipe() replacement whose ends are not inherited to children Johannes Sixt
2008-02-27 18:54 ` [PATCH 18/40] Windows: Implement start_command() Johannes Sixt
2008-02-27 18:54 ` [PATCH 19/40] Windows: Change the name of hook scripts to make them not executable Johannes Sixt
2008-02-28 15:20 ` Johannes Schindelin
2008-02-28 20:48 ` Johannes Sixt
2008-02-29 1:11 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 20/40] Windows: A rudimentary poll() emulation Johannes Sixt
2008-02-28 9:36 ` Paolo Bonzini
2008-02-28 20:49 ` Johannes Sixt
[not found] ` <5d46db230802282019o21f9ed9fo75fed8744625289e@mail.gmail.com>
[not found] ` <200802292216.25014.johannes.sixt@telecom.at>
2008-02-29 21:47 ` Govind Salinas
2008-02-29 22:16 ` Johannes Sixt
2008-02-29 23:17 ` Brian Dessent
2008-03-01 15:48 ` Robin Rosenberg
2008-03-01 19:24 ` Johannes Sixt
2008-02-27 18:54 ` [PATCH 21/40] Windows: Disambiguate DOS style paths from SSH URLs Johannes Sixt
2008-02-28 15:22 ` Johannes Schindelin
2008-02-28 20:51 ` Johannes Sixt
2008-02-27 18:54 ` [PATCH 22/40] Windows: Implement asynchronous functions as threads Johannes Sixt
2008-02-28 15:28 ` Johannes Schindelin
2008-02-28 17:48 ` Paul Franz
2008-02-29 1:27 ` Johannes Schindelin
2008-02-29 1:46 ` Paul Franz
2008-02-29 1:54 ` Johannes Schindelin
2008-02-29 3:08 ` Paul Franz
2008-02-29 7:51 ` Junio C Hamano
2008-02-29 11:45 ` Paul Franz
2008-02-29 10:26 ` Johannes Schindelin
2008-02-28 21:01 ` Johannes Sixt
2008-02-29 1:17 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 23/40] Windows: Local clone must use the drive letter in absolute paths Johannes Sixt
2008-02-28 15:31 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 24/40] Windows: Work around incompatible sort and find Johannes Sixt
2008-02-27 18:54 ` [PATCH 25/40] Windows: Implement a cpio emulation in git-clone.sh Johannes Sixt
2008-02-27 18:54 ` [PATCH 26/40] Windows: Implement wrappers for gethostbyname(), socket(), and connect() Johannes Sixt
2008-02-27 18:54 ` [PATCH 27/40] Windows: Implement a custom spawnve() Johannes Sixt
2008-02-28 15:36 ` Johannes Schindelin
2008-02-28 21:04 ` Johannes Sixt
2008-02-29 1:18 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 28/40] Windows: Add a new lstat and fstat implementation based on Win32 API Johannes Sixt
2008-02-27 18:54 ` [PATCH 29/40] Windows: Use a customized struct stat that also has the st_blocks member Johannes Sixt
2008-02-27 18:54 ` [PATCH 30/40] Turn builtin_exec_path into a function Johannes Sixt
2008-02-27 18:54 ` [PATCH 31/40] Compute the ultimate fallback for exec_path from the program invocation Johannes Sixt
2008-02-27 18:54 ` [PATCH 32/40] Windows: Use a relative default template_dir and ETC_GITCONFIG Johannes Sixt
2008-02-27 18:54 ` [PATCH 33/40] When installing, be prepared that template_dir may be relative Johannes Sixt
2008-02-28 9:49 ` Paolo Bonzini
2008-02-28 15:45 ` Johannes Schindelin
2008-02-28 15:57 ` Paolo Bonzini
2008-02-28 21:12 ` Johannes Sixt
2008-02-29 1:21 ` Johannes Schindelin
2008-02-27 18:54 ` [PATCH 34/40] Windows: Make the pager work Johannes Sixt
2008-02-27 18:54 ` [PATCH 35/40] Windows: Work around an oddity when a pipe with no reader is written to Johannes Sixt
2008-02-27 18:54 ` [PATCH 36/40] Avoid the "dup dance" in wt_status_print_verbose() when possible Johannes Sixt
2008-02-28 15:48 ` Johannes Schindelin
2008-02-27 18:55 ` [PATCH 37/40] Windows: Make 'git help -a' work Johannes Sixt
2008-02-28 9:52 ` Paolo Bonzini
2008-02-27 18:55 ` [PATCH 38/40] Windows: TMP and TEMP environment variables specify a temporary directory Johannes Sixt
2008-02-27 18:55 ` [PATCH 39/40] Windows: Fix ntohl() related warnings about printf formatting Johannes Sixt
2008-02-27 18:55 ` [PATCH 40/40] compat/pread.c: Add foward decl to fix warning Johannes Sixt
2008-02-28 15:51 ` Johannes Schindelin
2008-02-27 22:01 ` [PATCH 00/40] MinGW port Marius Storm-Olsen
2008-02-27 23:34 ` Martin Langhoff
2008-02-28 3:38 ` Nguyen Thai Ngoc Duy
2008-02-27 23:58 ` Johannes Schindelin
2008-03-02 21:20 ` Johannes Sixt
2008-03-02 22:07 ` Johannes Schindelin
2008-03-03 18:34 ` Johannes Sixt
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