common/ringbuffer.h

   1 #ifndef RINGBUFFER_H_
   2 #define RINGBUFFER_H_
   3
   4 #define RINGBUFFER(name, size) uint8_t name[(size)+4] = { size, 0, 0, 0 }
   5
   6 static inline uint8_t ringbuffer_fill(const uint8_t *buffer)
   7 {
   8         return buffer[1];
   9 }
  10
  11 static inline uint8_t ringbuffer_space(const uint8_t *buffer)
  12 {
  13         return buffer[0]-buffer[1];
  14 }
  15
  16 static inline void ringbuffer_push(uint8_t *buffer, uint8_t value)
  17 {
  18         const uint8_t size = buffer[0];
  19         uint8_t head = buffer[2];
  20         buffer[4+head++] = value;
  21         if(head>=size)
  22                 head -= size;
  23         buffer[2] = head;
  24         ++buffer[1];
  25 }
  26
  27 static inline void ringbuffer_blocking_push(uint8_t *buffer, uint8_t value)
  28 {
  29         const volatile uint8_t *fill = buffer+1;
  30         while(*fill>=buffer[0]) ;
  31         ringbuffer_push(buffer, value);
  32 }
  33
  34 static inline uint8_t ringbuffer_pop(uint8_t *buffer)
  35 {
  36         const uint8_t size = buffer[0];
  37         uint8_t tail = buffer[3];
  38         uint8_t value = buffer[4+tail++];
  39         if(tail>=size)
  40                 tail -= size;
  41         buffer[3] = tail;
  42         --buffer[1];
  43         return value;
  44 }
  45
  46 static inline uint8_t rinbuffer_blocking_pop(uint8_t *buffer)
  47 {
  48         const volatile uint8_t *fill = buffer+1;
  49         while(*fill==0) ;
  50         return ringbuffer_pop(buffer);
  51 }
  52
  53 #endif