Xapian devel - Dec 2014 - Replace atoi and atol with strtol strtoul:Need Help

Hello,
I am working on replacing atoi () and atol() functions with strtol() and
strtoul() . I came across many files which uses statement  like these
time_t secs= atoi(data_span.c_str()), here time_t Datatype is not known but
wikipedia says that it is integer so is it necessary to replace  atoi with
strtol over here ??

And is their any document which helps me what each file function does like
date.cc,cgiparams.cc,omega.cc,query.cc.

Thank You
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On Tue, Dec 16, 2014 at 02:32:31AM +0530, Priyank Bhatt
wrote:
> I am working on replacing atoi () and atol() functions with strtol() and
> strtoul() . I came across many files which uses statement  like these
> time_t secs= atoi(data_span.c_str()), here time_t Datatype is not known but
> wikipedia says that it is integer so is it necessary to replace  atoi with
> strtol over here ??
The time_t type is a standard one - ISO C only says it's a "arithmetic
type" (so it could potentially be a double) but POSIX says it's an
"integer type":

http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html

While that would allow it to be unsigned, in practice it seems to be a
signed integer, and it is 64 bit on modern systems (since a signed 32
bit integer with the Unix epoch can only represent dates up to 2038).

You missed out a relevant part of line, which in full is:

xapian-applications/omega/date.cc:      time_t secs = atoi(date_span.c_str()) *
(24 * 60 * 60);

So in this case, date_span is a number of days, so converting it via a
long is reasonable - even if long is 32 bits that can still represent a
span of 5.8 million years.  You'd want to make sure the multiplication
happens in type time_t though.

If we were actually converting a number of seconds, you'd want to use
strtoll(), at least if sizeof(long) < 8.  C++11 includes strtoll(), and
we decided to require a C++11 compiler for 1.3.x, so there's no need to
worry whether strtoll() is available.
> And is their any document which helps me what each file function does like
> date.cc,cgiparams.cc,omega.cc,query.cc.
There should be a short comment summarising the purpose of each file at
the top, for example:

| /* date.cc: date range parsing routines for omega

A few files may still lack these, but most have them.

Cheers,
    Olly

Hello ,
I came across this function *HtmlParser::decode_entities(string &s)* in
*xapian-application/omega/htmlparse.cc* which basically does is extract hex
value if any or extract number.For extracting number atoi is used and value
returned by it is stored in variable "val" , I think so replacing atoi
with
strtoul would be useful here as number can have larger value although the
variable "val" is unsigned int so i need to change the that definition
of
"val" also. Is that ok to do so ? Just need to clarify .

On 16 December 2014 at 04:34, Olly Betts <olly at survex.com>
wrote:
>
> On Tue, Dec 16, 2014 at 02:32:31AM +0530, Priyank Bhatt wrote:
> > I am working on replacing atoi () and atol() functions with strtol()
and
> > strtoul() . I came across many files which uses statement  like these
> > time_t secs= atoi(data_span.c_str()), here time_t Datatype is not
known
> but
> > wikipedia says that it is integer so is it necessary to replace  atoi
> with
> > strtol over here ??
>
> The time_t type is a standard one - ISO C only says it's a
"arithmetic
> type" (so it could potentially be a double) but POSIX says it's an
> "integer type":
>
> http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html
>
> While that would allow it to be unsigned, in practice it seems to be a
> signed integer, and it is 64 bit on modern systems (since a signed 32
> bit integer with the Unix epoch can only represent dates up to 2038).
>
> You missed out a relevant part of line, which in full is:
>
> xapian-applications/omega/date.cc:      time_t secs >
atoi(date_span.c_str()) * (24 * 60 * 60);
>
> So in this case, date_span is a number of days, so converting it via a
> long is reasonable - even if long is 32 bits that can still represent a
> span of 5.8 million years.  You'd want to make sure the multiplication
> happens in type time_t though.
>
> If we were actually converting a number of seconds, you'd want to use
> strtoll(), at least if sizeof(long) < 8.  C++11 includes strtoll(), and
> we decided to require a C++11 compiler for 1.3.x, so there's no need to
> worry whether strtoll() is available.
>
> > And is their any document which helps me what each file function does
> like
> > date.cc,cgiparams.cc,omega.cc,query.cc.
>
> There should be a short comment summarising the purpose of each file at
> the top, for example:
>
> | /* date.cc: date range parsing routines for omega
>
> A few files may still lack these, but most have them.
>
> Cheers,
>     Olly
>
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