Page MenuHomePhabricator
Differential D51268 Diff 174864 include/istream

Changeset View

Standalone View

View Options

include/istream

Show First 20 Lines • Show All 511 Lines • ▼ Show 20 Lines
template <class _CharT, class _Traits> template <class _CharT, class _Traits>
basic_istream<_CharT, _Traits>& basic_istream<_CharT, _Traits>&
basic_istream<_CharT, _Traits>::operator>>(int& __n) basic_istream<_CharT, _Traits>::operator>>(int& __n)
{ {
return _VSTD::__input_arithmetic_with_numeric_limits<int>(*this, __n); return _VSTD::__input_arithmetic_with_numeric_limits<int>(*this, __n);
} }
template<class _CharT, class _Traits> template<class _CharT, class _Traits>
_LIBCPP_INLINE_VISIBILITY
basic_istream<_CharT, _Traits>& basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, _CharT* __s) __input_c_string(basic_istream<_CharT, _Traits>& __is, _CharT* __p, size_t __n)
{ {
#ifndef _LIBCPP_NO_EXCEPTIONS #ifndef _LIBCPP_NO_EXCEPTIONS
try try
{ {
#endif // _LIBCPP_NO_EXCEPTIONS #endif // _LIBCPP_NO_EXCEPTIONS
typename basic_istream<_CharT, _Traits>::sentry __sen(__is); typename basic_istream<_CharT, _Traits>::sentry __sen(__is);
if (__sen) if (__sen)
{ {
streamsize __n = __is.width(); auto __s = __p;
if (__n <= 0)
__n = numeric_limits<streamsize>::max() / sizeof(_CharT) - 1;
streamsize __c = 0;
const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc()); const ctype<_CharT>& __ct = use_facet<ctype<_CharT> >(__is.getloc());
ios_base::iostate __err = ios_base::goodbit; ios_base::iostate __err = ios_base::goodbit;
while (__c < __n-1) while (__s != __p + (__n-1))
{ {
typename _Traits::int_type __i = __is.rdbuf()->sgetc(); typename _Traits::int_type __i = __is.rdbuf()->sgetc();
if (_Traits::eq_int_type(__i, _Traits::eof())) if (_Traits::eq_int_type(__i, _Traits::eof()))
{ {
__err |= ios_base::eofbit; __err |= ios_base::eofbit;
break; break;
} }
_CharT __ch = _Traits::to_char_type(__i); _CharT __ch = _Traits::to_char_type(__i);
if (__ct.is(__ct.space, __ch)) if (__ct.is(__ct.space, __ch))
break; break;
*__s++ = __ch; *__s++ = __ch;
++__c;
__is.rdbuf()->sbumpc(); __is.rdbuf()->sbumpc();
} }
*__s = _CharT(); *__s = _CharT();
__is.width(0); __is.width(0);
if (__c == 0) if (__s == __p)
__err |= ios_base::failbit; __err |= ios_base::failbit;
__is.setstate(__err); __is.setstate(__err);
} }
#ifndef _LIBCPP_NO_EXCEPTIONS #ifndef _LIBCPP_NO_EXCEPTIONS
} }
catch (...) catch (...)
{ {
__is.__set_badbit_and_consider_rethrow(); __is.__set_badbit_and_consider_rethrow();
} }
#endif // _LIBCPP_NO_EXCEPTIONS #endif // _LIBCPP_NO_EXCEPTIONS
return __is; return __is;
} }
#if _LIBCPP_STD_VER > 17
template<class _CharT, class _Traits, size_t _Np>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, _CharT (&__buf)[_Np])
{
auto __n = _Np;
if (__is.width() > 0)
__n = _VSTD::min(size_t(__is.width()), _Np);
return _VSTD::__input_c_string(__is, __buf, __n);
}
template<class _Traits, size_t _Np>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<char, _Traits>&
operator>>(basic_istream<char, _Traits>& __is, unsigned char (&__buf)[_Np])
{
return __is >> (char(&)[_Np])__buf;
}
template<class _Traits, size_t _Np>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<char, _Traits>&
operator>>(basic_istream<char, _Traits>& __is, signed char (&__buf)[_Np])
{
return __is >> (char(&)[_Np])__buf;
}
#else
template<class _CharT, class _Traits>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, _CharT* __s)
{
streamsize __n = __is.width();
if (__n <= 0)
ldionneUnsubmitted
Not Done
ReplyInline Actions

Should this instead be if (__n == 0)? Can width() ever return a negative number? cppreference says this about streamsize:

Except in the constructors of std::strstreambuf, negative values of std::streamsize are never used.

I couldn't find a matching statement in the standard, however there's this footnote in 30.5.2:

streamsize is used in most places where ISO C would use size_t. Most of the uses of streamsize could use size_t, except for the strstreambuf constructors, which require negative values. It should probably be the signed type corresponding to size_t (which is what Posix.2 calls ssize_t).

This does not clearly say that negative values are never used, but it does suggest it. Maybe it's safer to still use __n <= 0.

ldionne: Should this instead be `if (__n == 0)`? Can `width()` ever return a negative number?
lichrayAuthorUnsubmitted
Not Done
ReplyInline Actions

My interpretation of 27.5.3.2 is that you can retrieve the value you set through width(streamsize). And the wording here (unmodified) says "If width() is greater than zero, [...]," so the opposite should be width() <= 0.

lichray: My interpretation of 27.5.3.2 is that you can retrieve the value you set through `width…
__n = numeric_limits<streamsize>::max() / sizeof(_CharT) - 1;
return _VSTD::__input_c_string(__is, __s, size_t(__n));
}
template<class _Traits> template<class _Traits>
inline _LIBCPP_INLINE_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
basic_istream<char, _Traits>& basic_istream<char, _Traits>&
operator>>(basic_istream<char, _Traits>& __is, unsigned char* __s) operator>>(basic_istream<char, _Traits>& __is, unsigned char* __s)
{ {
return __is >> (char*)__s; return __is >> (char*)__s;
} }
template<class _Traits> template<class _Traits>
inline _LIBCPP_INLINE_VISIBILITY inline _LIBCPP_INLINE_VISIBILITY
basic_istream<char, _Traits>& basic_istream<char, _Traits>&
operator>>(basic_istream<char, _Traits>& __is, signed char* __s) operator>>(basic_istream<char, _Traits>& __is, signed char* __s)
{ {
return __is >> (char*)__s; return __is >> (char*)__s;
} }
#endif // _LIBCPP_STD_VER > 17
template<class _CharT, class _Traits> template<class _CharT, class _Traits>
basic_istream<_CharT, _Traits>& basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>& __is, _CharT& __c) operator>>(basic_istream<_CharT, _Traits>& __is, _CharT& __c)
{ {
#ifndef _LIBCPP_NO_EXCEPTIONS #ifndef _LIBCPP_NO_EXCEPTIONS
try try
{ {
#endif // _LIBCPP_NO_EXCEPTIONS #endif // _LIBCPP_NO_EXCEPTIONS
▲ Show 20 Lines • Show All 886 Lines • Show Last 20 Lines