Method DoNext

util/stream/str.cpp:9–14

TStringInput::~TStringInput() = default;

size_t TStringInput::DoNext(const void** ptr, size_t len) {
    len = Min(len, S_->size() - Pos_);
    *ptr = S_->data() + Pos_;
    Pos_ += len;
    return len;
}

void TStringInput::DoUndo(size_t len) {
    Y_ABORT_UNLESS(len <= Pos_);