92 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// <istream>10 11// streamsize readsome(char_type* s, streamsize n);12 13#include <istream>14#include <cassert>15#include <streambuf>16 17#include "test_macros.h"18 19template <class CharT>20struct testbuf21 : public std::basic_streambuf<CharT>22{23 typedef std::basic_string<CharT> string_type;24 typedef std::basic_streambuf<CharT> base;25private:26 string_type str_;27public:28 29 testbuf() {}30 testbuf(const string_type& str)31 : str_(str)32 {33 base::setg(const_cast<CharT*>(str_.data()),34 const_cast<CharT*>(str_.data()),35 const_cast<CharT*>(str_.data()) + str_.size());36 }37 38 CharT* eback() const {return base::eback();}39 CharT* gptr() const {return base::gptr();}40 CharT* egptr() const {return base::egptr();}41};42 43int main(int, char**)44{45 {46 testbuf<char> sb(" 1234567890");47 std::istream is(&sb);48 char s[5];49 assert(is.readsome(s, 5) == 5);50 assert(!is.eof());51 assert(!is.fail());52 assert(std::string(s, 5) == " 1234");53 assert(is.gcount() == 5);54 is.readsome(s, 5);55 assert(!is.eof());56 assert(!is.fail());57 assert(std::string(s, 5) == "56789");58 assert(is.gcount() == 5);59 is.readsome(s, 5);60 assert(!is.eof());61 assert(!is.fail());62 assert(is.gcount() == 1);63 assert(std::string(s, 1) == "0");64 assert(is.readsome(s, 5) == 0);65 }66#ifndef TEST_HAS_NO_WIDE_CHARACTERS67 {68 testbuf<wchar_t> sb(L" 1234567890");69 std::wistream is(&sb);70 wchar_t s[5];71 assert(is.readsome(s, 5) == 5);72 assert(!is.eof());73 assert(!is.fail());74 assert(std::wstring(s, 5) == L" 1234");75 assert(is.gcount() == 5);76 is.readsome(s, 5);77 assert(!is.eof());78 assert(!is.fail());79 assert(std::wstring(s, 5) == L"56789");80 assert(is.gcount() == 5);81 is.readsome(s, 5);82 assert(!is.eof());83 assert(!is.fail());84 assert(is.gcount() == 1);85 assert(std::wstring(s, 1) == L"0");86 assert(is.readsome(s, 5) == 0);87 }88#endif89 90 return 0;91}92