Method try_append

include/stringzilla/stringzilla.hpp:4347–4367

template <typename char_type_, typename allocator_>
bool basic_string<char_type_, allocator_>::try_append(const_pointer str, size_type length) noexcept {
    auto result = _with_alloc([&](sz_alloc_type &alloc) {
        // Sometimes we are inserting part of this string into itself.
        // By the time `sz_string_expand` finished, the old `str` pointer may be invalidated,
        // so we need to handle that special case separately.
        auto this_span = span();
        if (str >= this_span.begin() && str < this_span.end()) {
            auto str_offset_in_this = str - data();
            sz_ptr_t start = sz_string_expand(&string_, SZ_SIZE_MAX, length, &alloc);
            if (!start) return sz_bad_alloc_k;
            sz_copy(start + this_span.size(), start + str_offset_in_this, length);
        }
        else {
            sz_ptr_t start = sz_string_expand(&string_, SZ_SIZE_MAX, length, &alloc);
            if (!start) return sz_bad_alloc_k;
            sz_copy(start + this_span.size(), str, length);
        }
        return sz_success_k;
    });
    return result == status_t::success_k;
}

template <typename char_type_, typename allocator_>
template <typename pattern_type>