On Mon, Mar 26, 2012 at 9:29 PM, Richard Gribble wrote:
> Using rcs 5.8-1:
>
> Synopsis:
> Given two mark symbols, abc (version 1.1) and abcd (version 1.2),
> executing "co -rabc <file>" will check out version 1.2, when it
> should check out version 1.1.
>
> I set the mark symbols as follows:
> rcs -nabc:1.1 -nabcd:1.2 <file>
>
>
> I dug into it, and found the following (rcsrev.c):
>
> 01: static char const *
> 02: rev_from_symbol (struct cbuf const *id)
> 03: /* Look up "id" in the list of symbolic names starting with pointer
> 04: "GROK (symbols)", and return a pointer to the corresponding
> 05: revision number. Return NULL if not present. */
> 06: {
> 07: for (struct link *ls = GROK (symbols); ls; ls = ls->next)
> 08: {
> 09: struct symdef const *d = ls->entry;
> 10:
> 11: if (!strncmp (d->meaningful, id->string, id->size))
> 12: return d->underlying;
> 13: }
> 14: return NULL;
> 15: }
>
> Note that line 11 tests the name of the requested mark symbol
> (id->string) against each element of a linked-list (ls) containing all
> the mark symbols for the file. The problem is that it will only test
> the first 'id->size' characters - so R25 (from the command line) matches
> R25a (from the list) because the first three characters match and it
> won't test any more than that (strncmp).
>
> I recommend modifying line 11 as follows:
> if ((strlen(d->meaningful) == strlen(id->size)) && !strncmp
> (d->meaningful, id->string, id->size))
I think strlen(id->size) is overkill :)
If both strings (d->meaningful and id->string) are NULL-terminated ,
then a simple call to strlen would do the job:
if (!strcmp(d->meaningful, id->string))
It would do the right thing w.r.t. different lengths.
> Of course, since you now know that the two strings are the same size,
> you could use strcmp - but that assumes that the && short-circuits, and
> I don't know if that's guaranteed.
Yes, it required by the C standard.
Csaba
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