std::string::append (InputIterator, InputIterator) appending self incorrect

• Key: STDCXX-438
• Type: Bug
• Status: Closed
• Resolution: Fixed
• Priority: Minor
• Assignee: Farid Zaripov
• Reporter: Martin Sebor
• Component/s: 21. Strings
• Affects Version/s: 4.1.2, 4.1.3, 4.1.4, 4.2.0
• Fix Version/s: 4.2.1

Description

The 21.string.append.cpp test has been failing a number of assertions for self-referential test cases that exercise the ability to append a substring of a string into itself using the append(InputIterator, InputIterator) member template specialization for InputIterator being an actual Input Iterator. The program below reproduces the problem in a small isolated test case.

$ cat t.cpp && gmake t && ./t
#include <cassert>
#include <cstdlib>
#include <cstring>
#include <iterator>
#include <new>
#include <string>

void* operator new (std::size_t n) throw (std::bad_alloc)
{
    void* const ptr = std::malloc (n + sizeof n);
    std::memset (ptr, -1, n);
    *(std::size_t*)ptr = n;
    return (std::size_t*)ptr + 1;
}

void operator delete (void *ptr) throw ()
{
    std::memset (ptr, -1, *((std::size_t*)ptr - 1));
    std::free ((std::size_t*)ptr - 1);
    
}

struct InputIterator: std::iterator<std::input_iterator_tag, char>
{
    const char *p_;
    InputIterator (const char *p): p_ (p) { }

    char operator* () const { return *p_; }
    InputIterator& operator++ () { return ++p_, *this; }
    InputIterator operator++ (int) {
        return ++p_, InputIterator (p_ - 1);
    }

    bool operator== (const InputIterator &rhs) const { return p_ == rhs.p_; }
};


int main ()
{
    const char s[] = "abc";

    {
        std::string str (s);

        const char* p0 = s + 1;
        const char* p1 = p0 + 1;

        const InputIterator first (p0);
        const InputIterator last (p1);

        str.append (first, last);

        assert ("abcb" == str);
    }

    {
        std::string str (s);

        const char* p0 = str.data () + 1;
        const char* p1 = p0 + 1;

        const InputIterator first (p0);
        const InputIterator last (p1);

        str.append (first, last);

        assert ("abcb" == str);
    }
}

aCC -c -I/amd/devco/sebor/stdcxx/include/ansi -I/usr/include  -D_RWSTDDEBUG   -mt -D_RWSTD_USE_CONFIG -I/amd/devco/sebor/stdcxx/include -I/build/sebor/stdcxx-aCC-3.73-15D/include -I/amd/devco/sebor/stdcxx/tests/include  -Aa +nostl  -g +d  +DD64 +w +W392 +W655 +W684 +W818 +W819 +W849   t.cpp
aCC t.o -o t -L/build/sebor/stdcxx-aCC-3.73-15D/rwtest -lrwtest15D -Aa +nostl -Wl,+s -Wl,+vnocompatwarnings   -mt +DD64 -L/build/sebor/stdcxx-aCC-3.73-15D/lib  -Wl,+b/build/sebor/stdcxx-aCC-3.73-15D/lib:/build/sebor/stdcxx-aCC-3.73-15D/rwtest -lstd15D  -lm 
Assertion failed: "abcb" == str, file t.cpp, line 67
ABORT instruction (core dumped)