1 //===----------------------------------------------------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 // <istream>
11
12 // basic_istream<charT,traits>& read(char_type* s, streamsize n);
13
14 #include <istream>
15 #include <cassert>
16
17 template <class CharT>
18 struct testbuf
19 : public std::basic_streambuf<CharT>
20 {
21 typedef std::basic_string<CharT> string_type;
22 typedef std::basic_streambuf<CharT> base;
23 private:
24 string_type str_;
25 public:
26
testbuftestbuf27 testbuf() {}
testbuftestbuf28 testbuf(const string_type& str)
29 : str_(str)
30 {
31 base::setg(const_cast<CharT*>(str_.data()),
32 const_cast<CharT*>(str_.data()),
33 const_cast<CharT*>(str_.data()) + str_.size());
34 }
35
ebacktestbuf36 CharT* eback() const {return base::eback();}
gptrtestbuf37 CharT* gptr() const {return base::gptr();}
egptrtestbuf38 CharT* egptr() const {return base::egptr();}
39 };
40
main()41 int main()
42 {
43 {
44 testbuf<char> sb(" 123456789");
45 std::istream is(&sb);
46 char s[5];
47 is.read(s, 5);
48 assert(!is.eof());
49 assert(!is.fail());
50 assert(std::string(s, 5) == " 1234");
51 assert(is.gcount() == 5);
52 is.read(s, 5);
53 assert(!is.eof());
54 assert(!is.fail());
55 assert(std::string(s, 5) == "56789");
56 assert(is.gcount() == 5);
57 is.read(s, 5);
58 assert( is.eof());
59 assert( is.fail());
60 assert(is.gcount() == 0);
61 }
62 {
63 testbuf<wchar_t> sb(L" 123456789");
64 std::wistream is(&sb);
65 wchar_t s[5];
66 is.read(s, 5);
67 assert(!is.eof());
68 assert(!is.fail());
69 assert(std::wstring(s, 5) == L" 1234");
70 assert(is.gcount() == 5);
71 is.read(s, 5);
72 assert(!is.eof());
73 assert(!is.fail());
74 assert(std::wstring(s, 5) == L"56789");
75 assert(is.gcount() == 5);
76 is.read(s, 5);
77 assert( is.eof());
78 assert( is.fail());
79 assert(is.gcount() == 0);
80 }
81 }
82