* String allocation
@ 2011-11-13 6:01 qiang
2011-11-13 6:42 ` Eli Zaretskii
0 siblings, 1 reply; 5+ messages in thread
From: qiang @ 2011-11-13 6:01 UTC (permalink / raw)
To: emacs-devel
Thanks to all of you. Reading source code is such an experience for
me, both painful and yet enjoyable.
Since we are talking about strings, can I ask another obstacle I met. I
know when allocating string objects, emacs will retrieve one from a
string_block struct. My question is how this string_free_list works ?
where does it point to ? How it becomes a list ? Especially I'm puzzled
by this macro
#define NEXT_FREE_LISP_STRING(S) (*(struct Lisp_String **) (S))
I understand S is a pointer to a Lisp_String, how can the following code
construct a free_list ?
for (i = STRING_BLOCK_SIZE - 1; i >= 0; --i)
{
s = b->strings + i;
NEXT_FREE_LISP_STRING (s) = string_free_list;
string_free_list = s;
}
Regards
Qiang
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: String allocation
2011-11-13 6:01 String allocation qiang
@ 2011-11-13 6:42 ` Eli Zaretskii
2011-11-13 7:05 ` Qiang Guo
0 siblings, 1 reply; 5+ messages in thread
From: Eli Zaretskii @ 2011-11-13 6:42 UTC (permalink / raw)
To: qiang; +Cc: emacs-devel
> From: qiang <qguo@ualberta.ca>
> Date: Sat, 12 Nov 2011 23:01:50 -0700
>
> #define NEXT_FREE_LISP_STRING(S) (*(struct Lisp_String **) (S))
>
> I understand S is a pointer to a Lisp_String, how can the following code
> construct a free_list ?
>
> for (i = STRING_BLOCK_SIZE - 1; i >= 0; --i)
> {
> s = b->strings + i;
> NEXT_FREE_LISP_STRING (s) = string_free_list;
> string_free_list = s;
> }
After this loop is done, what will be in each element of the array
b->strings?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: String allocation
2011-11-13 6:42 ` Eli Zaretskii
@ 2011-11-13 7:05 ` Qiang Guo
2011-11-13 7:57 ` Eli Zaretskii
0 siblings, 1 reply; 5+ messages in thread
From: Qiang Guo @ 2011-11-13 7:05 UTC (permalink / raw)
To: emacs-devel
pointer to the next slot in b->strings ?
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: String allocation
2011-11-13 7:05 ` Qiang Guo
@ 2011-11-13 7:57 ` Eli Zaretskii
2011-11-13 8:32 ` Eli Zaretskii
0 siblings, 1 reply; 5+ messages in thread
From: Eli Zaretskii @ 2011-11-13 7:57 UTC (permalink / raw)
To: Qiang Guo; +Cc: emacs-devel
> From: Qiang Guo <qguo@ualberta.ca>
> Date: Sun, 13 Nov 2011 00:05:54 -0700
>
>
> pointer to the next slot in b->strings ?
Which is another way of saying "linked list".
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: String allocation
2011-11-13 7:57 ` Eli Zaretskii
@ 2011-11-13 8:32 ` Eli Zaretskii
0 siblings, 0 replies; 5+ messages in thread
From: Eli Zaretskii @ 2011-11-13 8:32 UTC (permalink / raw)
To: qguo, emacs-devel
> Date: Sun, 13 Nov 2011 02:57:28 -0500
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> Reply-To: Eli Zaretskii <eliz@gnu.org>
>
> > From: Qiang Guo <qguo@ualberta.ca>
> > Date: Sun, 13 Nov 2011 00:05:54 -0700
> >
> >
> > pointer to the next slot in b->strings ?
>
> Which is another way of saying "linked list".
And more importantly, this explains why NEXT_FREE_LISP_STRING is
called like that.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-11-13 8:32 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2011-11-13 6:01 String allocation qiang
2011-11-13 6:42 ` Eli Zaretskii
2011-11-13 7:05 ` Qiang Guo
2011-11-13 7:57 ` Eli Zaretskii
2011-11-13 8:32 ` Eli Zaretskii
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