circbuf.c

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/** \file circbuf.c

\brief Circular buffer code


******************************************************************************/

#include "circbuf.h"

/**AutomaticStart*************************************************************/

/*---------------------------------------------------------------------------*/
/* Static function prototypes                                                */
/*---------------------------------------------------------------------------*/

/**AutomaticEnd***************************************************************/

/*---------------------------------------------------------------------------*/
/* Definition of exported functions                                          */
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/**
  * \brief  Allocate a circular buffer with entries of size entrySize
  * 
  */

Circbuf_t *
Circbuf_DoAlloc (int entrySize, int N)
{
  Circbuf_t *result = (Circbuf_t *) malloc (sizeof (Circbuf_t));
  result->N = N;
  result->numEntries = 0;
  result->entries = array_do_alloc (entrySize, N);
  result->head = 0;
  result->tail = 0;
  return result;
}


/**
  * \brief  Number of entries
  * 
  */

int
Circbuf_Num (Circbuf_t * cb)
{
  int result;
  if (cb->head <= cb->tail)
    {
      result = (cb->tail - cb->head);
    }
  else
    {
      result = cb->N - (cb->head - cb->tail);
    }
  return result;
}


/**
  * \brief  Print the queue
  * 
  */

int
Circbuf_Print (Circbuf_t * cb)
{
  printf
    ("cb->N = %d ; array_n( cb->entries ) = %d ; cb->head = %d ; cb->tail = %d\n",
     cb->N, array_n (cb->entries), cb->head, cb->tail);
  return 0;
}


/**
  * \brief  Dummy struct for testing out circbuf code
  * 
  */

struct Circbuf_test_t
{
  int a;
  char b;
};

typedef struct Circbuf_test_t Circbuf_test_t;


/**
  * \brief  Test code for circular buffer
  * 
  */

int
Circbuf_test ()
{
  Circbuf_t *aBuf;
  Circbuf_t *iBuf;

  const int N = 5;
  Circbuf_test_t A[N];

  int i;
  Circbuf_test_t datum;
  for (i = 0; i < N; i++)
    {
      A[i].a = i * i;
      A[i].b = 'a' + i;
    }

  aBuf = Circbuf_Init (Circbuf_test_t, N);
  iBuf = Circbuf_Init (int, N);

  Circbuf_Insert (int, iBuf, 0);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 1);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 2);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 3);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Delete (int, iBuf);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Delete (int, iBuf);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 0);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 1);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Delete (int, iBuf);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, 0);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
  Circbuf_Insert (int, iBuf, -1);
  printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));

  for (i = 0; i < N; i++)
    {
      printf ("Entry = %d\n", Circbuf_Delete (int, iBuf));
      printf ("Circbuf size = %d\n", Circbuf_Num (iBuf));
    }
  return 0;

  for (i = 0; i < N; i++)
    {
      printf ("Insert index %d\n", i);
      fflush (stdout);
      Circbuf_Insert (Circbuf_test_t, aBuf, A[i]);
    }
  for (i = 0; i < N; i++)
    {
      printf ("Delete index %d\n", i);
      fflush (stdout);
      datum = Circbuf_Delete (Circbuf_test_t, aBuf);
      printf ("Datum = %d %c\n", datum.a, datum.b);
    }
  for (i = 0; i < N; i++)
    {
      printf ("Insert index %d\n", i);
      fflush (stdout);
      Circbuf_Insert (Circbuf_test_t, aBuf, A[i]);
    }
  for (i = 0; i < N; i++)
    {
      printf ("Delete index %d\n", i);
      fflush (stdout);
      datum = Circbuf_Delete (Circbuf_test_t, aBuf);
      printf ("Datum = %d %c\n", datum.a, datum.b);
    }
  return 0;
}