[Boost-bugs] [Boost C++ Libraries] #6160: support for (istream >> array < char >)

Subject: [Boost-bugs] [Boost C++ Libraries] #6160: support for (istream >> array < char >)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-11-22 00:38:37

#6160: support for (istream >> array < char >)
-----------------------------------+----------------------------------------
 Reporter:  giecrilj@…             |       Owner:  marshall
     Type:  Feature Requests       |      Status:  new     
Milestone:  To Be Determined       |   Component:  array   
  Version:  Boost 1.44.0           |    Severity:  Cosmetic
 Keywords:                         |  
-----------------------------------+----------------------------------------
 1. `array < T >` is a replacement for `T []`
 1. the standard library provides the syntax `(istream >> char [])` and
 `(ostream << char const [])`
 1. Currently, `(istream >> array < char >)` does not mean anything
 1. this functionality cannot be simulated even with `std:: copy_n <
 istreambuf_iterator >` without manual termination and much verbosity

 == My implementation ==
 {{{
 #!cpp

 #include <boost/array.hpp>      /* for ::boost:: array */
 #include <boost/version.hpp>

 #if +BOOST_VERSION <= 0313720
 #include <iomanip>      /* for ::std:: setw */
 namespace boost
 {
 /* helper classes to prevent ambiguity in matching array < char > */
 namespace detail_
 {
 /* normally, other char for every character type is char */
   template < class P_C > class other_char { public: typedef char type; };
 /* but other_char is undefined for char */
   template <> class other_char < char > {};
 /* class same_stream fails for istream */
   template
   < class P_S,
     class P_C = typename other_char < typename P_S:: char_type >:: type >
 class same_stream { public: typedef P_S stream; }; }
 /* template input */
   template < class P_C, class P_T, ::std:: size_t P_N >
   static inline ::std:: basic_istream < P_C, P_T >
 &operator >>
   (::std:: basic_istream < P_C, P_T > &p_s, ::boost:: array < P_C, P_N >
 &p_a)
   { return p_s >> ::std:: setw (p_a. static_size) >> p_a. data (); }
 /* character input, disabled for type char to avoid ambiguity */
   template < class P_C, class P_T, ::std:: size_t P_N >
   static inline typename
   detail_:: same_stream
 < ::std:: basic_istream < P_C, P_T > >:: stream
 &operator >>
   (::std:: basic_istream < P_C, P_T > &p_s,
    ::boost:: array < char, P_N > &p_a)
   { return p_s >> ::std:: setw (p_a. static_size) >> p_a. data (); }
 /* template output */
   template < class P_C, class P_T, ::std:: size_t P_N >
   static inline ::std:: basic_ostream < P_C, P_T >
   &operator <<
 (::std:: basic_ostream < P_C, P_T > &p_s,
  ::boost:: array < P_C, P_N > const &p_a) { return p_s << p_a. begin (); }
 /* character output, disabled for type char */
   template < class P_C, class P_T, ::std:: size_t P_N >
   static inline
 typename detail_:: same_stream < ::std:: basic_ostream < P_C, P_T > >::
 stream
   &operator <<
 (::std:: basic_ostream < P_C, P_T > &p_s,
  ::boost:: array < char, P_N > const &p_a)
 { return p_s << p_a. begin (); }}
 #endif  /* BOOST_VERSION */

 #include <cstdlib>      /* for EXIT_SUCCESS */
 #include <cstdio>       /* for BUFSIZ */
 #include <iostream>     /* for ::std:: cin */

 int main ()
 { // char (&x) [+BOOST_VERSION] = 0;
 #ifdef ARRAY_IN_NATIVE
 /* native code */
 char t [+BUFSIZ];
  return
    ::std:: cin >> ::std:: setw (+BUFSIZ) >> t && ::std:: cout << t <<
 '\n'?
 +EXIT_SUCCESS: +EXIT_FAILURE;
 #else /* ARRAY_IN_NATIVE */
 /* equivalent Boost code */
  ::boost:: array < char, +BUFSIZ > t;
 /* check that character input compiles for wchar_t */
  (void) sizeof (std:: wcin >> t);
  return
 ::std:: cin >> t && ::std:: cout << t << '\n'? +EXIT_SUCCESS:
 +EXIT_FAILURE;
 #endif /* ARRAY_IN_NATIVE */
 }

 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6160>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.