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[libcxx] Use _ftelli64/_fseeki64 on Windows #123128

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Merged
merged 5 commits into from
Jan 29, 2025
Merged

[libcxx] Use _ftelli64/_fseeki64 on Windows #123128

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2739c3c
[libcxx] Use _ftelli64/_fseeki64 on Windows
mstorsjo Jan 11, 2025
9b9f6c5
Factorize repeated fseek/ftell calls
mstorsjo Jan 28, 2025
26a0e91
Fix formatting
mstorsjo Jan 28, 2025
a7e48af
Hide the new symbols from the ABI
mstorsjo Jan 28, 2025
b4be3ef
Remove the intermediate _LIBCPP_HAS_OFF_T_FUNCTIONS define
mstorsjo Jan 29, 2025
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55 changes: 29 additions & 26 deletions libcxx/include/fstream
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Original file line number Diff line number Diff line change
Expand Up @@ -216,12 +216,6 @@ typedef basic_fstream<wchar_t> wfstream;
_LIBCPP_PUSH_MACROS
# include <__undef_macros>

# if !defined(_LIBCPP_MSVCRT) && !defined(_NEWLIB_VERSION)
# define _LIBCPP_HAS_OFF_T_FUNCTIONS 1
# else
# define _LIBCPP_HAS_OFF_T_FUNCTIONS 0
# endif

# if _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION

_LIBCPP_BEGIN_NAMESPACE_STD
Expand Down Expand Up @@ -362,6 +356,9 @@ private:
bool __read_mode();
void __write_mode();

_LIBCPP_HIDE_FROM_ABI static int __fseek(FILE* __file, pos_type __offset, int __whence);
_LIBCPP_HIDE_FROM_ABI static pos_type __ftell(FILE* __file);
Comment on lines +359 to +360
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I think we can just make these free functions. (I'd just define them at the top of the file). It would also be good to remove the !defined(_LIBCPP_MSVCRT) from the definition of _LIBCPP_HAS_OFF_T_FUNCTIONS and probably just inline _LIBCPP_HAS_OFF_T_FUNCTIONS as a whole, since at that point it's just equivalent do defind(_NEWLIB_VERSION).

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I kept the functions in the class, as they use pos_type, but I updated the PR to remove the unnecessary intermediate define _LIBCPP_HAS_OFF_T_FUNCTIONS.


_LIBCPP_EXPORTED_FROM_ABI friend FILE* __get_ostream_file(ostream&);

// There are multiple (__)open function, they use different C-API open
Expand Down Expand Up @@ -936,31 +933,42 @@ basic_filebuf<_CharT, _Traits>::seekoff(off_type __off, ios_base::seekdir __way,
default:
return pos_type(off_type(-1));
}
# if !_LIBCPP_HAS_OFF_T_FUNCTIONS
if (fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
if (__fseek(__file_, __width > 0 ? __width * __off : 0, __whence))
return pos_type(off_type(-1));
pos_type __r = ftell(__file_);
# else
if (::fseeko(__file_, __width > 0 ? __width * __off : 0, __whence))
return pos_type(off_type(-1));
pos_type __r = ftello(__file_);
# endif
pos_type __r = __ftell(__file_);
__r.state(__st_);
return __r;
}

template <class _CharT, class _Traits>
int basic_filebuf<_CharT, _Traits>::__fseek(FILE* __file, pos_type __offset, int __whence) {
# if defined(_LIBCPP_MSVCRT_LIKE)
return _fseeki64(__file, __offset, __whence);
# elif defined(_NEWLIB_VERSION)
return fseek(__file, __offset, __whence);
# else
return ::fseeko(__file, __offset, __whence);
# endif
}

template <class _CharT, class _Traits>
typename basic_filebuf<_CharT, _Traits>::pos_type basic_filebuf<_CharT, _Traits>::__ftell(FILE* __file) {
# if defined(_LIBCPP_MSVCRT_LIKE)
return _ftelli64(__file);
# elif defined(_NEWLIB_VERSION)
return ftell(__file);
# else
return ftello(__file);
# endif
}

template <class _CharT, class _Traits>
typename basic_filebuf<_CharT, _Traits>::pos_type
basic_filebuf<_CharT, _Traits>::seekpos(pos_type __sp, ios_base::openmode) {
if (__file_ == nullptr || sync())
return pos_type(off_type(-1));
# if !_LIBCPP_HAS_OFF_T_FUNCTIONS
if (fseek(__file_, __sp, SEEK_SET))
if (__fseek(__file_, __sp, SEEK_SET))
return pos_type(off_type(-1));
# else
if (::fseeko(__file_, __sp, SEEK_SET))
return pos_type(off_type(-1));
# endif
__st_ = __sp.state();
return __sp;
}
Expand Down Expand Up @@ -1007,13 +1015,8 @@ int basic_filebuf<_CharT, _Traits>::sync() {
}
}
}
# if !_LIBCPP_HAS_OFF_T_FUNCTIONS
if (fseek(__file_, -__c, SEEK_CUR))
if (__fseek(__file_, -__c, SEEK_CUR))
return -1;
# else
if (::fseeko(__file_, -__c, SEEK_CUR))
return -1;
# endif
if (__update_st)
__st_ = __state;
__extbufnext_ = __extbufend_ = __extbuf_;
Expand Down
6 changes: 0 additions & 6 deletions libcxx/test/std/input.output/file.streams/fstreams/ifstream.members/offset_range.pass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11,12 +11,6 @@
// Test that we can seek using offsets larger than 32 bit, and that we can
// retrieve file offsets larger than 32 bit.

// On MSVC targets, we only use the 32 bit fseek/ftell functions. For MinGW
// targets, we use fseeko/ftello, but the user needs to define
// _FILE_OFFSET_BITS=64 to make them 64 bit.
//
// XFAIL: target={{.*}}-windows{{.*}}

// On 32 bit Android platforms, off_t is 32 bit by default. By defining
// _FILE_OFFSET_BITS=64, one gets a 64 bit off_t, but the corresponding
// 64 bit ftello/fseeko functions are only available since Android API 24 (7.0).
Expand Down