underflow.pass.cpp
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <sstream>
// template <class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
// class basic_stringbuf
// int_type underflow();
#include <sstream>
#include <cassert>
#include "test_macros.h"
template <class CharT>
struct testbuf
: public std::basic_stringbuf<CharT>
{
typedef std::basic_stringbuf<CharT> base;
explicit testbuf(const std::basic_string<CharT>& str)
: base(str) {}
typename base::int_type underflow() {return base::underflow();}
void pbump(int n) {base::pbump(n);}
};
int main(int, char**)
{
{
testbuf<char> sb("123");
sb.pbump(3);
assert(sb.underflow() == '1');
assert(sb.underflow() == '1');
assert(sb.snextc() == '2');
assert(sb.underflow() == '2');
assert(sb.underflow() == '2');
assert(sb.snextc() == '3');
assert(sb.underflow() == '3');
assert(sb.underflow() == '3');
assert(sb.snextc() == std::char_traits<char>::eof());
assert(sb.underflow() == std::char_traits<char>::eof());
assert(sb.underflow() == std::char_traits<char>::eof());
sb.sputc('4');
assert(sb.underflow() == '4');
assert(sb.underflow() == '4');
}
{
testbuf<wchar_t> sb(L"123");
sb.pbump(3);
assert(sb.underflow() == L'1');
assert(sb.underflow() == L'1');
assert(sb.snextc() == L'2');
assert(sb.underflow() == L'2');
assert(sb.underflow() == L'2');
assert(sb.snextc() == L'3');
assert(sb.underflow() == L'3');
assert(sb.underflow() == L'3');
assert(sb.snextc() == std::char_traits<wchar_t>::eof());
assert(sb.underflow() == std::char_traits<wchar_t>::eof());
assert(sb.underflow() == std::char_traits<wchar_t>::eof());
sb.sputc(L'4');
assert(sb.underflow() == L'4');
assert(sb.underflow() == L'4');
}
return 0;
}