static_queue_impl.hpp

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using namespace le;
 
template <typename T, unsigned int N>
StaticQueue<T,N>::StaticQueue():
  idx_front(0), idx_back(0), count(0)
{
}
 
template <typename T, unsigned int N>
StaticQueue<T,N>::~StaticQueue()
{
}
 
template <typename T, unsigned int N>
bool StaticQueue<T,N>::is_full() const{
  return size()==N;
}
 
template <typename T, unsigned int N>
bool StaticQueue<T,N>::is_empty() const{
  return size()==0;;
}
 
template <typename T, unsigned int N>
unsigned int StaticQueue<T,N>::size() const{
  return count;
}
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::push(const T item){
  if (is_full())
  {
    return ERR_QUEUE_FULL;
  }
 
  circle_buf[idx_back]=item;
 
  count ++;
 
  //ideally, idx_back=(idx_back+1)%N
  //but we can't assume N = 2^n in general
  idx_back ++;
  if (idx_back >= N)
  {
    idx_back = 0;
  } 
 
  return OK;
}
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::front(T &out_item) const {
  return at(0,out_item);
}
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::pop(){
  if (is_empty())
  {
    return ERR_QUEUE_EMPTY;
  }
 
  count --;
 
  //ideally, idx_back=(idx_back+1)%N
  //but we can't assume N = 2^n in general
  idx_front ++;
  if (idx_front >= N)
  {
    idx_front = 0;
  }
  return OK;
}
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::pop(T &out_item){
  auto r = front(out_item);
  if (OK!=r){
    return r;
  }
  r = pop();
  return r;
}
 
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::at(const unsigned int idx, T &out_item) const
{
 
  if (size()==0){
    return ERR_QUEUE_EMPTY;
  }
 
  if (idx>=N){
    return ERR_BAD_IDX;
  }
 
  if (idx>=size()){
    return ERR_NO_SUCH_ELEMENT;
  }
 
  unsigned int actual_idx = idx+idx_front;
  if (actual_idx > N){
    actual_idx -= N;
  }
 
  out_item = circle_buf[actual_idx];
  return OK;
 
}
 
 
template <typename T, unsigned int N>
le::Errno StaticQueue<T,N>::clear()
{
  idx_front=0;
  idx_back =0;
  count    =0;
  return OK;
}