#ifndef SOCKS_QUEUE_H_
#define SOCKS_QUEUE_H_

#include <string.h>

#define QUEUE_CONTAINER(t, m, v) ((void *)((v) ? (uintptr_t)(v) - (offsetof(t, m)) : 0))

#define queue_foreach(iter_type, iter_name, queue_name, node_member) \
	for (iter_type *iter_name = QUEUE_CONTAINER(iter_type, node_member, queue_first(queue_name)); \
	     iter_name; \
	     iter_name = QUEUE_CONTAINER(iter_type, node_member, queue_next(&((iter_name)->node_member))))

#define queue_foreach_r(iter_type, iter_name, queue_name, node_member) \
	for (iter_type *iter_name = QUEUE_CONTAINER(iter_type, node_member, queue_last(queue_name)); \
	     iter_name; \
	     iter_name = QUEUE_CONTAINER(iter_type, node_member, queue_prev(&((iter_name)->node_member))))

typedef struct queue_entry {
	struct queue_entry *qe_next;
	struct queue_entry *qe_prev;
} queue_entry_t;

typedef struct queue {
	queue_entry_t *q_first;
	queue_entry_t *q_last;
	unsigned int q_length;
} queue_t;

static inline void queue_init(queue_t *q) { memset(q, 0x00, sizeof *q); }
static inline unsigned int queue_length(queue_t *q) { return q->q_length; }

static inline queue_entry_t *queue_first(queue_t *q) { return q->q_first; }
static inline queue_entry_t *queue_last(queue_t *q) { return q->q_last; }
static inline queue_entry_t *queue_next(queue_entry_t *entry) { return entry->qe_next; }
static inline queue_entry_t *queue_prev(queue_entry_t *entry) { return entry->qe_prev; }

extern void queue_insert_before(queue_t *q, queue_entry_t *entry, queue_entry_t *before);
extern void queue_insert_after(queue_t *q, queue_entry_t *entry, queue_entry_t *after);

extern void queue_push_front(queue_t *q, queue_entry_t *entry);
extern void queue_push_back(queue_t *q, queue_entry_t *entry);

extern queue_entry_t *queue_pop_front(queue_t *q);
extern queue_entry_t *queue_pop_back(queue_t *q);

extern void queue_delete(queue_t *q, queue_entry_t *entry);

#endif