board_input.c

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#include "board_input.h"
 
#include <stdint.h>

typedef enum : uint32_t {
  k_key_ring_cap = 64U, 
} board_input_cfg_t;
 
static char     s_ring[k_key_ring_cap]; 
static uint32_t s_head;                 
static uint32_t s_tail;                 
 
void board_input_push_key(char ch)
{
  const uint32_t next = (s_tail + 1U) % (uint32_t)k_key_ring_cap;
  if (next != s_head) {
    s_ring[s_tail] = ch;
    s_tail         = next;
  }
}
 
bool board_input_pop_key(char* out)
{
  if ((out == nullptr) || (s_head == s_tail)) {
    return false;
  }
  *out   = s_ring[s_head];
  s_head = (s_head + 1U) % (uint32_t)k_key_ring_cap;
  return true;
}