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/*

 *

 *   Fifo for saving interrupt information, implementation

 *

 *   Lasse Lehtonen

 *

 */

#include "n2h_isr_fifo.h"

#include <sys/alt_irq.h>

#include <stdlib.h>

// Store item to last place, called only from ISR

void n2h_isr_fifo_push(N2H_isr_fifo* fifo, N2H_isr_info* item)

{

  N2H_isr_info* temp = fifo->root;

  item->next = NULL;

  while(temp != NULL && temp->next != NULL)

    {

      temp = temp->next;

    }

  if(fifo->size < 1)

    {

      fifo->root = item;

    }

  else

    {

      temp->next = item;

    }

  fifo->size++;

}

// Returns the first item, remember to free its memory!

N2H_isr_info* n2h_isr_fifo_pop (N2H_isr_fifo* fifo)

{

  N2H_isr_info* temp;

  if(fifo->size < 1)

    {

      return NULL;

    }

  // Prevent ISR from messing with fifo

  alt_irq_context cntx = alt_irq_disable_all();

  {

    temp = fifo->root;

    fifo->root = temp->next;

    fifo->size--;

  }

  alt_irq_enable_all(cntx);

  temp->next = NULL;

  return temp;

}

int n2h_isr_fifo_size(N2H_isr_fifo* fifo)

{

  return fifo->size;

}

N2H_isr_fifo* n2h_isr_fifo_create()

{

  //Allocate space for new and initialize data

  N2H_isr_fifo* fifo = (N2H_isr_fifo*) malloc(sizeof(N2H_isr_fifo));

  fifo->root = NULL;

  fifo->size = 0;

  return fifo;

}