src/libs/HeapRing.h

   1 #ifndef _HEAPRING_H
   2 #define _HEAPRING_H
   3
   4 template<class kind> class HeapRing {
   5
   6     // smoothie-specific friend classes
   7     friend class Planner;
   8     friend class Conveyor;
   9     friend class Block;
  10
  11 public:
  12     HeapRing();
  13     HeapRing(unsigned int length);
  14
  15     ~HeapRing();
  16
  17     /*
  18      * direct accessors
  19      */
  20     kind& head();
  21     kind& tail();
  22
  23     void push_front(kind&) __attribute__ ((warning("Not thread-safe if pop_back() is used in ISR context!"))); // instead, prepare(head_ref()); produce_head();
  24     kind& pop_back(void) __attribute__ ((warning("Not thread-safe if head_ref() is used to prepare new items, or push_front() is used in ISR context!"))); // instead, consume(tail_ref()); consume_tail();
  25
  26     /*
  27      * pointer accessors
  28      */
  29     kind* head_ref();
  30     kind* tail_ref();
  31
  32     void  produce_head(void);
  33     void  consume_tail(void);
  34
  35     /*
  36      * queue status
  37      */
  38     bool is_empty(void) const;
  39     bool is_full(void) const;
  40
  41     /*
  42      * resize
  43      *
  44      * returns true on success, or false if queue is not empty or not enough memory available
  45      */
  46     bool resize(unsigned int);
  47
  48     /*
  49      * provide
  50      * kind*      - new buffer pointer
  51      * int length - number of items in buffer (NOT size in bytes!)
  52      *
  53      * cause HeapRing to use a specific memory location instead of allocating its own
  54      *
  55      * returns true on success, or false if queue is not empty
  56      */
  57     bool provide(kind*, unsigned int length);
  58
  59 protected:
  60     /*
  61      * these functions are protected as they should only be used internally
  62      * or in extremely specific circumstances
  63      */
  64     kind& item(unsigned int);
  65     kind* item_ref(unsigned int);
  66
  67     unsigned int next(unsigned int) const;
  68     unsigned int prev(unsigned int) const;
  69
  70     /*
  71      * buffer variables
  72      */
  73     unsigned int length;
  74
  75     volatile unsigned int head_i;
  76     volatile unsigned int tail_i;
  77     volatile unsigned int isr_tail_i;
  78
  79 private:
  80     kind* ring;
  81 };
  82
  83 #endif /* _HEAPRING_H */