[vlc-devel] [PATCH 1/2] include: add vlc_search.h for differences between POSIX search.h and other OS
Steve Lhomme
robux4 at ycbcr.xyz
Mon Jul 15 12:03:20 CEST 2019
On 2019-07-15 11:53, Steve Lhomme wrote:
> On 2019-07-15 9:37, Rémi Denis-Courmont wrote:
>> Hi,
>>
>> A macro is possible, probably:
>>
>> #include<search.h>
>> #define lfind(a,b,c,d,e) \
>> lfind(a,b&(unsigned){ *(c) },d,e)
>
> That works for win32 but not for win64 where 'size_t' and 'unsigned'
> don't have the same size, as verified with this:
Or maybe I misread the patch and it doesn't do a cast, just creates a
local variable ? In that case it should work (it's missing a comma after
'b').
Still not sure we're supposed to fill a value in c after the call. But
it's not used in the code using lfind and the implementation in compat/
doesn't fill it either.
> static_assert(sizeof(size_t) == sizeof(unsigned), "cannot cast for lfind");
>
>> Le 15 juillet 2019 10:07:26 GMT+03:00, Steve Lhomme <robux4 at ycbcr.xyz>
>> a écrit :
>>> 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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>>
>> --
>> Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez
>> excuser ma brièveté.
>>
>>
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