Make basic_streambuf::xsputn write characters in chunks whenever possible, instead of one at a time. References PR#10193

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@229866 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow 2015-02-19 16:17:46 +00:00
parent 784fa1eeba
commit 6b5a5e52f0

View File

@ -536,12 +536,23 @@ basic_streambuf<_CharT, _Traits>::xsputn(const char_type* __s, streamsize __n)
{
streamsize __i = 0;
int_type __eof = traits_type::eof();
for (; __i < __n; ++__s, ++__i)
while( __i < __n)
{
if (__nout_ < __eout_)
*__nout_++ = *__s;
else if (overflow(traits_type::to_int_type(*__s)) == __eof)
break;
if (__nout_ >= __eout_)
{
if (overflow(traits_type::to_int_type(*__s)) == __eof)
break;
++__s;
++__i;
}
else
{
streamsize __chunk_size = _VSTD::min(__eout_ - __nout_, __n - __i);
traits_type::copy(__nout_, __s, __chunk_size);
__nout_ += __chunk_size;
__s += __chunk_size;
__i += __chunk_size;
}
}
return __i;
}