[vlc-devel] [PATCH 1/2] include: add vlc_search.h for differences between POSIX search.h and other OS

[Steve Lhomme]

Hi

On 2019-07-12 16:35, Hugo Beauzée-Luyssen wrote:
> On Fri, Jul 12, 2019, at 3:51 PM, Steve Lhomme wrote:
>> ---
>>   include/vlc_search.h | 52 ++++++++++++++++++++++++++++++++++++++++++++
>>   src/Makefile.am      |  3 ++-
>>   2 files changed, 54 insertions(+), 1 deletion(-)
>>   create mode 100644 include/vlc_search.h
>>
>> diff --git a/include/vlc_search.h b/include/vlc_search.h
>> new file mode 100644
>> index 0000000000..6c87fa990d
>> --- /dev/null
>> +++ b/include/vlc_search.h
>> @@ -0,0 +1,52 @@
>> +/*****************************************************************************
>> + * vlc_search.h: portability fixups included from config.h
>> +
>> *****************************************************************************
>> + * Copyright © 2019 the VideoLAN project
>> + *
>> + * This program is free software; you can redistribute it and/or
>> modify it
>> + * under the terms of the GNU Lesser General Public License as
>> published by
>> + * the Free Software Foundation; either version 2.1 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU Lesser General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU Lesser General Public
>> License
>> + * along with this program; if not, write to the Free Software
>> Foundation,
>> + * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
>> +
>> *****************************************************************************/
>> +
>> +/**
>> + * \file
>> + * This file is a collection of portability fixes
>> + */
>> +
>> +#ifndef LIBVLC_SEARCH_H
>> +# define LIBVLC_SEARCH_H 1
>> +
>> +#ifdef __cplusplus
>> +extern "C" {
>> +#endif
>> +
>> +#ifdef _WIN32
>> +/* the Win32 prorotype of lfind() expects an unsigned int for 'nelp' */
> 
> Typo (proTotype)
> 
>> +static inline void *vlc_lfind(const void *key, const void *base,
>> size_t *nelp,
>> +                             size_t size, int(*cmp)(const void *,
>> const void *))
>> +{
>> +    unsigned int n;
>> +    void *res = lfind (key, base, &n, size, cmp);
>> +    *nelp = n;
>> +    return res;
> 
> I must say I don't understand what this wrapper does that wasn't already done by calling the function with an uint32_t* instead of a size_t*
> If what you want is to fix the warning on the callsite, you can probably get away with a macro that casts the 3rd pointer no?

Are "size_t" and "unsigned int" guaranteed to be the same on all Windows 
compiler ? I think on 64 bits platforms it's not the case.

So we would need a wrapper with the proper size_t variable. To do that I 
don't think you can do it as a pure macro because you also need to set 
the value of the size_t nelp to the value of the unsigned int and then 
pass that unsigned int as a pointer. (not sure the value on return needs 
to be set back on the size_t, the lfind documentation is not clear)

So if it's not a macro, it should be an inline. But to do an inline you 
need to include <search.h> so it knows about lfind(). This cannot be 
added in vlc_fixups.h

> And in any case case:
> - Does this need to be in a different file?

IMO, yes.

> - It could be enable only when _WIN64 is defined

OK but it doesn't hurt to have the same code between 32 and 64 bits Windows.

>> +}
>> +#else /* !_WIN32 */
>> +#define vlc_lfind(key, base, nelp, width, compar)  \
>> +            lfind(key, base, nelp, width, compar)
>> +#endif /* !_WIN32 */
>> +
>> +#ifdef __cplusplus
>> +} /* extern "C" */
>> +#endif
>> +
>> +#endif /* !LIBVLC_SEARCH_H */
>> diff --git a/src/Makefile.am b/src/Makefile.am
>> index 006ece5f93..25f9a4fc8b 100644
>> --- a/src/Makefile.am
>> +++ b/src/Makefile.am
>> @@ -88,6 +88,7 @@ pluginsinclude_HEADERS = \
>>   	../include/vlc_fingerprinter.h \
>>   	../include/vlc_interrupt.h \
>>   	../include/vlc_renderer_discovery.h \
>> +	../include/vlc_search.h \
>>   	../include/vlc_sort.h \
>>   	../include/vlc_sout.h \
>>   	../include/vlc_spu.h \
>> @@ -591,7 +592,7 @@ test_mrl_helpers_SOURCES = test/mrl_helpers.c
>>   test_arrays_SOURCES = test/arrays.c
>>   test_vector_SOURCES = test/vector.c
>>   test_shared_data_ptr_SOURCES = test/shared_data_ptr.cpp
>> -test_extensions_SOURCES = test/extensions.c
>> +test_extensions_SOURCES = test/extensions.c
> 
> Apparently my editor didn't remove the whitespace, sorry about that. Although this shouldn't be here :)

ok

>>   test_playlist_SOURCES = playlist/test.c \
>>   	playlist/content.c \
>>   	playlist/control.c \
> 
> Regards,
> 
> -- 
>    Hugo Beauzée-Luyssen
>    hugo at beauzee.fr
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