caio/clang-p2996
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[libc++] Refactor basic_filebuf::overflow() (#144793)

Browse Source 
Refactor the function to streamline the logic so it matches the
specification in [filebuf.virtuals] more closely. In particular, avoid
modifying the put area pointers when we loop around after a partial
codecvt conversion.

Note that we're technically not up-to-spec in this implementation, since
the Standard says that we shouldn't try more than once after a partial
codecvt conversion. However, this refactoring attempts not to change any
functionality.
This commit is contained in:
Louis Dionne
2025-06-24 13:58:49 -04:00
committed by GitHub
parent 23b0564800
commit 52b27c2bd6
1 changed files with 51 additions and 32 deletions
Download Patch File Download Diff File Expand all files Collapse all files

83
libcxx/include/fstream
View File

@@ -833,40 +833,59 @@ typename basic_filebuf<_CharT, _Traits>::int_type basic_filebuf<_CharT, _Traits>
*this->pptr() = traits_type::to_char_type(__c);
this->pbump(1);
}
if (this->pptr() != this->pbase()) {
if (__always_noconv_) {
size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
if (std::fwrite(this->pbase(), sizeof(char_type), __nmemb, __file_) != __nmemb)
return traits_type::eof();
} else {
char* __extbe = __extbuf_;
codecvt_base::result __r;
do {
if (!__cv_)
std::__throw_bad_cast();
const char_type* __e;
__r = __cv_->out(__st_, this->pbase(), this->pptr(), __e, __extbuf_, __extbuf_ + __ebs_, __extbe);
if (__e == this->pbase())
return traits_type::eof();
if (__r == codecvt_base::noconv) {
size_t __nmemb = static_cast<size_t>(this->pptr() - this->pbase());
if (std::fwrite(this->pbase(), 1, __nmemb, __file_) != __nmemb)
return traits_type::eof();
} else if (__r == codecvt_base::ok || __r == codecvt_base::partial) {
size_t __nmemb = static_cast<size_t>(__extbe - __extbuf_);
if (std::fwrite(__extbuf_, 1, __nmemb, __file_) != __nmemb)
return traits_type::eof();
if (__r == codecvt_base::partial) {
this->setp(const_cast<char_type*>(__e), this->pptr());
this->__pbump(this->epptr() - this->pbase());
}
} else
return traits_type::eof();
} while (__r == codecvt_base::partial);
}
this->setp(__pb_save, __epb_save);
// There is nothing to write, early return
if (this->pptr() == this->pbase()) {
return traits_type::not_eof(__c);
}
if (__always_noconv_) {
size_t __n = static_cast<size_t>(this->pptr() - this->pbase());
if (std::fwrite(this->pbase(), sizeof(char_type), __n, __file_) != __n)
return traits_type::eof();
} else {
if (!__cv_)
std::__throw_bad_cast();
// See [filebuf.virtuals]
char_type* __b = this->pbase();
char_type* __p = this->pptr();
const char_type* __end;
char* __extbuf_end = __extbuf_;
do {
codecvt_base::result __r = __cv_->out(__st_, __b, __p, __end, __extbuf_, __extbuf_ + __ebs_, __extbuf_end);
if (__end == __b)
return traits_type::eof();
// No conversion needed: output characters directly to the file, done.
if (__r == codecvt_base::noconv) {
size_t __n = static_cast<size_t>(__p - __b);
if (std::fwrite(__b, 1, __n, __file_) != __n)
return traits_type::eof();
break;
// Conversion successful: output the converted characters to the file, done.
} else if (__r == codecvt_base::ok) {
size_t __n = static_cast<size_t>(__extbuf_end - __extbuf_);
if (std::fwrite(__extbuf_, 1, __n, __file_) != __n)
return traits_type::eof();
break;
// Conversion partially successful: output converted characters to the file and repeat with the
// remaining characters.
} else if (__r == codecvt_base::partial) {
size_t __n = static_cast<size_t>(__extbuf_end - __extbuf_);
if (std::fwrite(__extbuf_, 1, __n, __file_) != __n)
return traits_type::eof();
__b = const_cast<char_type*>(__end);
continue;
} else {
return traits_type::eof();
}
} while (true);
}
this->setp(__pb_save, __epb_save);
return traits_type::not_eof(__c);
}