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         kind*        get_tail_ref();
  24         void         get( int index, kind &object);
  25         kind*        get_ref( int index);
  26         void         delete_first();
  27
  28         kind         buffer[length];
  29         int          head;
  30         int          tail;
  31 };
  32
  33
  34 template<class kind, int length> RingBuffer<kind, length>::RingBuffer(){
  35     this->head = this->tail = 0;
  36 }
  37
  38 template<class kind, int length>  int RingBuffer<kind, length>::capacity(){
  39     return length-1;
  40 }
  41
  42 template<class kind, int length>  int RingBuffer<kind, length>::size(){
  43 return((this->head>this->tail)?length:0)+this->tail-head;
  44 }
  45
  46 template<class kind, int length> int RingBuffer<kind, length>::next_block_index(int index){
  47     index++;
  48     if (index == length) { index = 0; }
  49     return(index);
  50 }
  51
  52 template<class kind, int length> int RingBuffer<kind, length>::prev_block_index(int index){
  53     if (index == 0) { index = length; }
  54     index--;
  55     return(index);
  56 }
  57
  58 template<class kind, int length> void RingBuffer<kind, length>::push_back(kind object){
  59     this->buffer[this->tail] = object;
  60     this->tail = (tail+1)&(length-1);
  61 }
  62
  63 template<class kind, int length> kind* RingBuffer<kind, length>::get_tail_ref(){
  64     return &(buffer[tail]);
  65 }
  66
  67 template<class kind, int length> void RingBuffer<kind, length>::get(int index, kind &object){
  68     int j= 0;
  69     int k= this->head;
  70     while (k != this->tail){
  71         if (j == index) break;
  72         j++;
  73         k= (k + 1) & (length - 1);
  74     }
  75     // TODO : this checks wether we are asked a value out of range
  76     //if (k == this->tail){
  77     //    return NULL;
  78     //}
  79     object = this->buffer[k];
  80 }
  81
  82
  83 template<class kind, int length> kind* RingBuffer<kind, length>::get_ref(int index){
  84     int j= 0;
  85     int k= this->head;
  86     while (k != this->tail){
  87         if (j == index) break;
  88         j++;
  89         k= (k + 1) & (length - 1);
  90     }
  91     // TODO : this checks wether we are asked a value out of range
  92     if (k == this->tail){
  93         return NULL;
  94     }
  95     return &(this->buffer[k]);
  96 }
  97
  98 template<class kind, int length> void RingBuffer<kind, length>::pop_front(kind &object){
  99     object = this->buffer[this->head];
 100     this->head = (this->head+1)&(length-1);
 101 }
 102
 103 template<class kind, int length> void RingBuffer<kind, length>::delete_first(){
 104     //kind dummy;
 105     //this->pop_front(dummy);
 106     this->head = (this->head+1)&(length-1);
 107 }
 108
 109
 110 #endif