Karthik Nayak <karthik.188@xxxxxxxxx> writes:
> So we something like this for the parsing function:
>
> int parse_ref_filter_atom(const char *atom, const char *ep)
> {
> const char *sp;
> + char *arg;
I think this and the new parameter to .parser() function should be
"const char *".
> @@ -141,6 +143,7 @@ int parse_ref_filter_atom(const char *atom, const char *ep)
> const char *formatp = strchr(sp, ':');
> if (!formatp || ep < formatp)
> formatp = ep;
> + arg = (char *)formatp;
> if (len == formatp - sp && !memcmp(valid_atom[i].name, sp, len))
> break;
And this part can just use arg without formatp. The original is a
bit sloppy and will keep looking for a colon past ep, but we already
know between sp and ep there is no NUL, so we could do this:
arg = memchr(sp, ':', ep - sp);
if ((!arg || len == arg - sp) &&
!memcmp(valid_atom[i].name, sp, len))
break;
> @@ -154,6 +157,13 @@ int parse_ref_filter_atom(const char *atom, const char *ep)
> REALLOC_ARRAY(used_atom, used_atom_cnt);
> used_atom[at].name = xmemdupz(atom, ep - atom);
> used_atom[at].type = valid_atom[i].cmp_type;
> + if (arg != ep)
> + arg = xstrndup(arg + 1, ep - arg - 1);
> + else
> + arg = NULL;
Why even copy? The original that used match_atom_name() borrowed
part of existing string via (const char **val), so you know whatever
used that &buf you grabbed out of match_atom_name() should only be
reading the values not writing into the memory, no?
That is why I think arg should be "const char *".
As the above memchr() alrady took care of "we didn't find a colon"
case, we only need to do this here, I think:
if (arg)
arg = used_atom[at].name + (arg - atom);
and without later free().
Alternatively, we could add an int field to elements of used_atom[]
array that says what byte-offset in the used_atom[].name the atom
arguments start (if any). Then .parser() does not have to take the
parameter separately [*1*].
> + if (valid_atom[i].parser)
> + valid_atom[i].parser(&used_atom[at], arg);
> + free(arg);
> if (*atom == '*')
> need_tagged = 1;
> if (!strcmp(used_atom[at].name, "symref"))
[Footnote]
*1* Thinking about it more, perhaps used_atom[].type should be
removed and instead used_atom[].atom should be a pointer into the
valid_atom[] array. Then any reference to used_atom[].type will
become used_atom[].atom->cmp_type, which is much nicer for two
reasons: (1) one less useless copy (2) one less field that has a
name "type" that is overly generic.
That does not remove the need for recording where the atom argument
is, though, in used_atom[]. We could add a bit "has_deref" to
used_atom[] and then do something like this:
arg = used_atom[i].name + used_atom[i].atom->namelen +
used_atom[i].has_deref;
but I do not think we want to go there. It would hardcode the
knowledge that used_atom[i].name is either used_atom[i].atom->name
or one asterisk prefixed to it, making future extension of the
syntax even harder.
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