libcxx/test/std/input.output/iostream.format/input.streams/istream.unformatted/read.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // Requires 396145d in the built library.
  10 // XFAIL: using-built-library-before-llvm-9
  11
  12 // <istream>
  13
  14 // basic_istream<charT,traits>& read(char_type* s, streamsize n);
  15
  16 #include <istream>
  17 #include <cassert>
  18 #include <streambuf>
  19
  20 #include "test_macros.h"
  21
  22 template <class CharT>
  23 struct testbuf
  24     : public std::basic_streambuf<CharT>
  25 {
  26     typedef std::basic_string<CharT> string_type;
  27     typedef std::basic_streambuf<CharT> base;
  28 private:
  29     string_type str_;
  30 public:
  31
  32     testbuf() {}
  33     testbuf(const string_type& str)
  34         : str_(str)
  35     {
  36         base::setg(const_cast<CharT*>(str_.data()),
  37                    const_cast<CharT*>(str_.data()),
  38                    const_cast<CharT*>(str_.data()) + str_.size());
  39     }
  40
  41     CharT* eback() const {return base::eback();}
  42     CharT* gptr() const {return base::gptr();}
  43     CharT* egptr() const {return base::egptr();}
  44 };
  45
  46 int main(int, char**)
  47 {
  48     {
  49         testbuf<char> sb(" 123456789");
  50         std::istream is(&sb);
  51         char s[5];
  52         is.read(s, 5);
  53         assert(!is.eof());
  54         assert(!is.fail());
  55         assert(std::string(s, 5) == " 1234");
  56         assert(is.gcount() == 5);
  57         is.read(s, 5);
  58         assert(!is.eof());
  59         assert(!is.fail());
  60         assert(std::string(s, 5) == "56789");
  61         assert(is.gcount() == 5);
  62         is.read(s, 5);
  63         assert( is.eof());
  64         assert( is.fail());
  65         assert(is.gcount() == 0);
  66     }
  67 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  68     {
  69         testbuf<wchar_t> sb(L" 123456789");
  70         std::wistream is(&sb);
  71         wchar_t s[5];
  72         is.read(s, 5);
  73         assert(!is.eof());
  74         assert(!is.fail());
  75         assert(std::wstring(s, 5) == L" 1234");
  76         assert(is.gcount() == 5);
  77         is.read(s, 5);
  78         assert(!is.eof());
  79         assert(!is.fail());
  80         assert(std::wstring(s, 5) == L"56789");
  81         assert(is.gcount() == 5);
  82         is.read(s, 5);
  83         assert( is.eof());
  84         assert( is.fail());
  85         assert(is.gcount() == 0);
  86     }
  87 #endif
  88 #ifndef TEST_HAS_NO_EXCEPTIONS
  89     {
  90         testbuf<char> sb;
  91         std::basic_istream<char> is(&sb);
  92         is.exceptions(std::ios_base::eofbit);
  93         char s[10];
  94         bool threw = false;
  95         try {
  96             is.read(s, 5);
  97         } catch (std::ios_base::failure&) {
  98             threw = true;
  99         }
 100         assert(threw);
 101         assert(!is.bad());
 102         assert( is.eof());
 103         assert( is.fail());
 104     }
 105 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
 106     {
 107         testbuf<wchar_t> sb;
 108         std::basic_istream<wchar_t> is(&sb);
 109         is.exceptions(std::ios_base::eofbit);
 110         wchar_t s[10];
 111         bool threw = false;
 112         try {
 113             is.read(s, 5);
 114         } catch (std::ios_base::failure&) {
 115             threw = true;
 116         }
 117         assert(threw);
 118         assert(!is.bad());
 119         assert( is.eof());
 120         assert( is.fail());
 121     }
 122 #endif
 123 #endif // TEST_HAS_NO_EXCEPTIONS
 124
 125     return 0;
 126 }