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cirque_implementation.c
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cirque_implementation.c
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/*
http://www.martinbroadhurst.com/cirque-in-c.html
*/
#include <stdlib.h>
#include <D:\wamp\www\Concepts\Datastructure\cirque.h>
cirque * cirque_create(void)
{
const unsigned int size = 4;
cirque * queue = malloc(sizeof(cirque));
if (queue) {
queue->entries = malloc(size * sizeof(void *));
if (queue->entries) {
queue->size = size;
queue->head = 0;
queue->tail = 0;
queue->is_full = 0;
}
else {
free(queue);
queue = NULL;
}
}
return queue;
}
void cirque_delete(cirque * queue)
{
if (queue) {
free(queue->entries);
free(queue);
}
}
static void cirque_resize(cirque * queue)
{
void **temp = malloc(queue->size * 2 * sizeof(void *));
if (temp) {
unsigned int i = 0;
unsigned int h = queue->head;
do {
temp[i] = queue->entries[h++];
if (h == queue->size) {
h = 0;
}
i++;
} while (h != queue->tail);
free(queue->entries);
queue->entries = temp;
queue->head = 0;
queue->tail = queue->size;
queue->size *= 2;
queue->is_full = 0;
}
}
static unsigned int cirque_is_empty(const cirque * queue)
{
return (queue->head == queue->tail) && !queue->is_full;
}
unsigned int cirque_insert(cirque * queue, void * data)
{
unsigned int result;
if (queue->is_full) {
cirque_resize(queue);
if (queue->is_full) {
result = 0;
}
}
if (!queue->is_full) {
queue->entries[queue->tail++] = data;
if (queue->tail == queue->size) {
queue->tail = 0;
}
if (queue->tail == queue->head) {
queue->is_full = 1;
}
result = 1;
}
return result;
}
void * cirque_remove(cirque * queue)
{
void * data = NULL;
if (!cirque_is_empty(queue)) {
if (queue->is_full) {
queue->is_full = 0;
}
data = queue->entries[queue->head++];
if (queue->head == queue->size) {
queue->head = 0;
}
}
return data;
}
void *cirque_peek(const cirque * queue)
{
void *data = NULL;
if (!cirque_is_empty(queue)) {
data = queue->entries[queue->head];
}
return data;
}
unsigned int cirque_get_count(const cirque * queue)
{
unsigned int count;
if (cirque_is_empty(queue)) {
count = 0;
}
else if (queue->is_full) {
count = queue->size;
}
else if (queue->tail > queue->head) {
count = queue->tail - queue->head;
}
else {
count = queue->size - queue->head;
if (queue->tail > 0) {
count += queue->tail - 1;
}
}
return count;
}
void cirque_for_each(const cirque * queue, cirque_forfn fun)
{
if (!cirque_is_empty(queue)) {
unsigned int h = queue->head;
do {
fun(queue->entries[h++]);
if (h == queue->size) {
h = 0;
}
} while (h != queue->tail);
}
}