read.pass.cpp revision b64f8b07c104c6cc986570ac8ee0ed16a9f23976 
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
17template <class CharT>
18struct testbuf
19    : public std::basic_streambuf<CharT>
20{
21    typedef std::basic_string<CharT> string_type;
22    typedef std::basic_streambuf<CharT> base;
23private:
24    string_type str_;
25public:
26
27    testbuf() {}
28    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
36    CharT* eback() const {return base::eback();}
37    CharT* gptr() const {return base::gptr();}
38    CharT* egptr() const {return base::egptr();}
39};
40
41int 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