sandbox: add double linked-list data structure

sandbox/queue/include/socks/queue.h

@@ -1,14 +1,48 @@
 #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 *q_next;
-	struct queue_entry *q_prev;
+	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

sandbox/queue/queue.c

@@ -0,0 +1,104 @@
+#include <socks/queue.h>
+
+void queue_insert_before(queue_t *q, queue_entry_t *entry, queue_entry_t *before)
+{
+	queue_entry_t *x = before->qe_prev;
+	if (x) {
+		x->qe_next = entry;
+	} else {
+		q->q_first = entry;
+	}
+
+	entry->qe_prev = x;
+
+	before->qe_prev = entry;
+	entry->qe_next = before;
+}
+	 
+void queue_insert_after(queue_t *q, queue_entry_t *entry, queue_entry_t *after)
+{
+	queue_entry_t *x = after->qe_next;
+	if (x) {
+		x->qe_prev = entry;
+	} else {
+		q->q_last = entry;
+	}
+
+	entry->qe_prev = x;
+
+	after->qe_next = entry;
+	entry->qe_prev = after;
+	q->q_length++;
+}
+
+void queue_push_front(queue_t *q, queue_entry_t *entry)
+{
+	if (q->q_first) {
+		q->q_first->qe_prev = entry;
+	}
+	    
+	entry->qe_next = q->q_first;
+	entry->qe_prev = NULL;
+
+	q->q_first = entry;
+
+	if (!q->q_last) {
+		q->q_last = entry;
+	}
+	
+	q->q_length++;
+}
+
+void queue_push_back(queue_t *q, queue_entry_t *entry)
+{
+	if (q->q_last) {
+		q->q_last->qe_next = entry;
+	}
+
+	entry->qe_prev = q->q_last;
+	entry->qe_next = NULL;
+
+	q->q_last = entry;
+
+	if (!q->q_first) {
+		q->q_first = entry;
+	}
+	
+	q->q_length++;
+}
+
+queue_entry_t *queue_pop_front(queue_t *q)
+{
+	queue_entry_t *x = q->q_first;
+	queue_delete(q, x);
+	return x;
+}
+
+queue_entry_t *queue_pop_back(queue_t *q)
+{
+	queue_entry_t *x = q->q_last;
+	queue_delete(q, x);
+	return x;
+}
+
+void queue_delete(queue_t *q, queue_entry_t *entry)
+{
+	if (entry == q->q_first) {
+		q->q_first = q->q_first->qe_next;
+	}
+
+	if (entry == q->q_last) {
+		q->q_last = q->q_last->qe_prev;
+	}
+
+	if (entry->qe_next) {
+		entry->qe_next->qe_prev = entry->qe_prev;
+	}
+
+	if (entry->qe_prev) {
+		entry->qe_prev->qe_next = entry->qe_next;
+	}
+
+	entry->qe_next = entry->qe_prev = NULL;
+	q->q_length--;
+}