From: Edgar Toernig <froese@gmx.de>
To: Pierre Habouzit <madcoder@debian.org>
Cc: Junio C Hamano <gitster@pobox.com>,
"Shawn O. Pearce" <spearce@spearce.org>,
git@vger.kernel.org
Subject: Re: [PATCH 1/5] strbuf API additions and enhancements.
Date: Wed, 19 Sep 2007 14:46:04 +0200 [thread overview]
Message-ID: <20070919144604.7deca4f7.froese@gmx.de> (raw)
In-Reply-To: <20070918224119.17650344AB3@madism.org>
Pierre Habouzit wrote:
>
> +void strbuf_addvf(struct strbuf *sb, const char *fmt, va_list ap)
> +{
> + int len;
> +
> + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> + if (len < 0) {
> + len = 0;
> + }
> + if (len > strbuf_avail(sb)) {
> + strbuf_grow(sb, len);
> + len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
> + if (len > strbuf_avail(sb)) {
> + die("this should not happen, your snprintf is broken");
> + }
> + }
> + strbuf_setlen(sb, sb->len + len);
> +}
The second vsnprintf won't work as the first one consumed all args
from va_list ap. You need to va_copy the ap. But iirc va_copy poses
compatibility issues. Unless va_copy is made available somehow,
I would suggest to let the caller know that the buffer was too small
(but isn't any more) and it has to call the function again:
int strbuf_addvf(struct strbuf *sb, const char *fmt, va_list ap)
{
int len;
len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
if (len < 0)
return 0;
if (len > strbuf_avail(sb)) {
strbuf_grow(sb, len);
return -1;
}
strbuf_setlen(sb, sb->len + len);
return 0;
}
The caller:
do {
va_start(ap, fmt);
again = strbuf_addvf(sb, fmt, ap);
va_end(ap);
} while (again);
va_copy would be nicer though...
Ciao, ET.
next prev parent reply other threads:[~2007-09-19 12:46 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-18 22:39 let's refactor quoting Pierre Habouzit
2007-09-18 17:18 ` [PATCH 1/5] strbuf API additions and enhancements Pierre Habouzit
2007-09-19 12:46 ` Edgar Toernig [this message]
2007-09-19 13:36 ` Pierre Habouzit
2007-09-19 18:46 ` Junio C Hamano
2007-09-20 6:17 ` Johannes Sixt
2007-09-20 7:20 ` Kalle Olavi Niemitalo
2007-09-20 16:10 ` Jeff King
2007-09-18 20:15 ` [PATCH 2/5] sq_quote_argv and add_to_string rework with strbuf's Pierre Habouzit
2007-09-19 8:09 ` Junio C Hamano
2007-09-19 8:23 ` Pierre Habouzit
2007-09-18 21:22 ` [PATCH 3/5] Rework unquote_c_style to work on a strbuf Pierre Habouzit
2007-09-19 0:14 ` Pierre Habouzit
2007-09-19 8:09 ` Junio C Hamano
2007-09-19 8:22 ` Pierre Habouzit
2007-09-18 21:48 ` [PATCH 5/5] Avoid duplicating memory, and use xmemdupz instead of xstrdup Pierre Habouzit
2007-09-18 22:00 ` [PATCH 4/5] Full rework of quote_c_style and write_name_quoted Pierre Habouzit
2007-09-19 0:07 ` Pierre Habouzit
2007-09-19 0:55 ` Junio C Hamano
2007-09-19 1:14 ` Pierre Habouzit
2007-09-19 6:37 ` Andreas Ericsson
2007-09-19 8:00 ` Pierre Habouzit
2007-09-19 8:08 ` Andreas Ericsson
2007-09-19 8:21 ` Pierre Habouzit
2007-09-19 8:28 ` David Kastrup
2007-09-19 8:31 ` Junio C Hamano
2007-09-19 8:38 ` David Kastrup
2007-09-19 8:28 ` Junio C Hamano
2007-09-19 8:47 ` Pierre Habouzit
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