struct fifo *init_fifo(int num)
{
struct fifo *f;
f = malloc((size_t)FIFOSZ(num));
if(f == NULL)
{
perror("Malloc error");
return NULL;
}
f->sz = 0;
f->maxsz = num;
f->head = 0;
f->tail = -1;
return(f);
}
int insert_fifo(int x, struct fifo **f)
{
struct fifo *tf;
int oldmaxsz, size;
if ((*f)->sz == (*f)->maxsz)
{
size = FIFOSZ((*f)->maxsz+INCRFIFOSZ);
tf = realloc(*f, (size_t)size);
if (tf == NULL)
{
perror("Realloc error");
return(-1);
}
*f = tf;
oldmaxsz = (*f)->maxsz;
(*f)->maxsz += INCRFIFOSZ;
if ((*f)->head)
{
size = (oldmaxsz - (*f)->head)*sizeof(int);
memmove((*f)->data+(*f)->head+INCRFIFOSZ, (*f)->data+(*f)->head, size);
(*f)->head += INCRFIFOSZ;
}
}
if ((*f)->tail == (*f)->maxsz-1)
{
(*f)->tail = 0;
}
else
{
(*f)->tail++;
}
(*f)->data[(*f)->tail] = x;
(*f)->sz++;
return(0);
}
int insert_fifo(int x, struct fifo **f)
{
struct fifo *g;
int oldmaxsz, size;
if((*f)->sz == (*f)->maxsz)
{
size = FIFOSZ((*f)->maxsz+INCRFIFOSZ);
g = realloc(*f, (size_t)size);
if( g == NULL)
{
perror("Realloc error");
return (-1);
}
*f = g;
oldmaxsz = (*f)->maxsz;
(*f)->maxsz += INCRFIFOSZ;
/* Head to maxsz of list gets moved down */
if( (*f)->head)
{
size = (oldmaxsz - (*f)->head)*sizeof(int);
memmove((*f)->data+(*f)->head+INCRFIFOSZ, (*f)->data+(*f)->head,size);
(*f)->head += INCRFIFOSZ;
}
}
if( (*f)->tail == (*f)->maxsz-1)
(*f)->tail = 0;
else
(*f)->tail++;
(*f)->data[(*f)->tail] = x;
(*f)->sz++;
return(0);
}
