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
diff --git a/include/streambuf b/include/streambuf index 6adfc92..603c680 100644 --- a/include/streambuf +++ b/include/streambuf
@@ -536,12 +536,23 @@ { 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; } 