[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 11:53:57 CEST 2019
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:
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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>
> --
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>
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