src/libs/RingBuffer.h

   1 /*
   2       This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl).
   3       Smoothie is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
   4       Smoothie is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
   5       You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>.
   6
   7       With chucks taken from http://en.wikipedia.org/wiki/Circular_buffer, see licence there also
   8 */
   9
  10 #ifndef RINGBUFFER_H
  11 #define RINGBUFFER_H
  12
  13
  14 template<class kind, int length> class RingBuffer {
  15     public:
  16         RingBuffer();
  17         int          size();
  18         int          capacity();
  19         int          next_block_index(int index);
  20         int          prev_block_index(int index);
  21         void         push_back(kind object);
  22         void         pop_front(kind &object);
  23         void         get( int index, kind &object);
  24         kind*        get_ref( int index);
  25         void         delete_first();
  26
  27         kind         buffer[length];
  28         int          head;
  29         int          tail;
  30 };
  31
  32
  33 template<class kind, int length> RingBuffer<kind, length>::RingBuffer(){
  34     this->head = this->tail = 0;
  35 }
  36
  37 template<class kind, int length>  int RingBuffer<kind, length>::capacity(){
  38     return length-1;
  39 }
  40
  41 template<class kind, int length>  int RingBuffer<kind, length>::size(){
  42 return((this->head>this->tail)?length:0)+this->tail-head;
  43 }
  44
  45 template<class kind, int length> int RingBuffer<kind, length>::next_block_index(int index){
  46     index++;
  47     if (index == length) { index = 0; }
  48     return(index);
  49 }
  50
  51 template<class kind, int length> int RingBuffer<kind, length>::prev_block_index(int index){
  52     if (index == 0) { index = length; }
  53     index--;
  54     return(index);
  55 }
  56
  57 template<class kind, int length> void RingBuffer<kind, length>::push_back(kind object){
  58     this->buffer[this->tail] = object;
  59     this->tail = (tail+1)&(length-1);
  60 }
  61
  62 template<class kind, int length> void RingBuffer<kind, length>::get(int index, kind &object){
  63     int j= 0;
  64     int k= this->head;
  65     while (k != this->tail){
  66         if (j == index) break;
  67         j++;
  68         k= (k + 1) & (length - 1);
  69     }
  70     // TODO : this checks wether we are asked a value out of range
  71     //if (k == this->tail){
  72     //    return NULL;
  73     //}
  74     object = this->buffer[k];
  75 }
  76
  77
  78 template<class kind, int length> kind* RingBuffer<kind, length>::get_ref(int index){
  79     int j= 0;
  80     int k= this->head;
  81     while (k != this->tail){
  82         if (j == index) break;
  83         j++;
  84         k= (k + 1) & (length - 1);
  85     }
  86     // TODO : this checks wether we are asked a value out of range
  87     if (k == this->tail){
  88         return NULL;
  89     }
  90     return &(this->buffer[k]);
  91 }
  92
  93 template<class kind, int length> void RingBuffer<kind, length>::pop_front(kind &object){
  94     object = this->buffer[this->head];
  95     this->head = (this->head+1)&(length-1);
  96 }
  97
  98 template<class kind, int length> void RingBuffer<kind, length>::delete_first(){
  99     //kind dummy;
 100     //this->pop_front(dummy);
 101     this->head = (this->head+1)&(length-1);
 102 }
 103
 104
 105 #endif