Function strnpbrk

Source/JSON/jsoncpp.cpp:3870–3883

https://github.com/upcaste/upcaste/blob/master/src/upcore/src/cstring/strnpbrk.cpp

// https://github.com/upcaste/upcaste/blob/master/src/upcore/src/cstring/strnpbrk.cpp
static char const* strnpbrk(char const* s, char const* accept, size_t n) {
    assert((s || !n) && accept);

    char const* const end = s + n;
    for (char const* cur = s; cur < end; ++cur) {
        int const c = *cur;
        for (char const* a = accept; *a; ++a) {
            if (*a == c) {
                return cur;
            }
        }
    }
    return NULL;
}
static std::string valueToQuotedStringN(const char* value, unsigned length) {
    if (value == NULL)
        return "";