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samba-mirror/lib/ccan/list/list.h
Rusty Russell 675593221c lib/ccan: namespacize ccan/list to avoid conflict with OpenIndiana's sys/list.h
CCAN includes a little utility called "namespacize" which prepends ccan_ to
all public methods of a module, and fixes up any dependencies it finds.  It's
a little primitive, but it works here.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-03-22 01:57:37 +01:00

470 lines
14 KiB
C

/* Licensed under LGPLv2.1+ - see LICENSE file for details */
#ifndef CCAN_LIST_H
#define CCAN_LIST_H
#include <stdbool.h>
#include <assert.h>
#include <ccan/container_of/container_of.h>
#include <ccan/check_type/check_type.h>
/**
* struct ccan_list_node - an entry in a doubly-linked list
* @next: next entry (self if empty)
* @prev: previous entry (self if empty)
*
* This is used as an entry in a linked list.
* Example:
* struct child {
* const char *name;
* // Linked list of all us children.
* struct ccan_list_node list;
* };
*/
struct ccan_list_node
{
struct ccan_list_node *next, *prev;
};
/**
* struct ccan_list_head - the head of a doubly-linked list
* @h: the ccan_list_head (containing next and prev pointers)
*
* This is used as the head of a linked list.
* Example:
* struct parent {
* const char *name;
* struct ccan_list_head children;
* unsigned int num_children;
* };
*/
struct ccan_list_head
{
struct ccan_list_node n;
};
/**
* ccan_list_check - check head of a list for consistency
* @h: the ccan_list_head
* @abortstr: the location to print on aborting, or NULL.
*
* Because list_nodes have redundant information, consistency checking between
* the back and forward links can be done. This is useful as a debugging check.
* If @abortstr is non-NULL, that will be printed in a diagnostic if the list
* is inconsistent, and the function will abort.
*
* Returns the list head if the list is consistent, NULL if not (it
* can never return NULL if @abortstr is set).
*
* See also: ccan_list_check_node()
*
* Example:
* static void dump_parent(struct parent *p)
* {
* struct child *c;
*
* printf("%s (%u children):\n", p->name, p->num_children);
* ccan_list_check(&p->children, "bad child list");
* ccan_list_for_each(&p->children, c, list)
* printf(" -> %s\n", c->name);
* }
*/
struct ccan_list_head *ccan_list_check(const struct ccan_list_head *h, const char *abortstr);
/**
* ccan_list_check_node - check node of a list for consistency
* @n: the ccan_list_node
* @abortstr: the location to print on aborting, or NULL.
*
* Check consistency of the list node is in (it must be in one).
*
* See also: ccan_list_check()
*
* Example:
* static void dump_child(const struct child *c)
* {
* ccan_list_check_node(&c->list, "bad child list");
* printf("%s\n", c->name);
* }
*/
struct ccan_list_node *ccan_list_check_node(const struct ccan_list_node *n,
const char *abortstr);
#ifdef CCAN_LIST_DEBUG
#define ccan_list_debug(h) ccan_list_check((h), __func__)
#define ccan_list_debug_node(n) ccan_list_check_node((n), __func__)
#else
#define ccan_list_debug(h) (h)
#define ccan_list_debug_node(n) (n)
#endif
/**
* CCAN_LIST_HEAD_INIT - initializer for an empty ccan_list_head
* @name: the name of the list.
*
* Explicit initializer for an empty list.
*
* See also:
* CCAN_LIST_HEAD, ccan_list_head_init()
*
* Example:
* static struct ccan_list_head my_list = CCAN_LIST_HEAD_INIT(my_list);
*/
#define CCAN_LIST_HEAD_INIT(name) { { &name.n, &name.n } }
/**
* CCAN_LIST_HEAD - define and initialize an empty ccan_list_head
* @name: the name of the list.
*
* The CCAN_LIST_HEAD macro defines a ccan_list_head and initializes it to an empty
* list. It can be prepended by "static" to define a static ccan_list_head.
*
* See also:
* CCAN_LIST_HEAD_INIT, ccan_list_head_init()
*
* Example:
* static CCAN_LIST_HEAD(my_global_list);
*/
#define CCAN_LIST_HEAD(name) \
struct ccan_list_head name = CCAN_LIST_HEAD_INIT(name)
/**
* ccan_list_head_init - initialize a ccan_list_head
* @h: the ccan_list_head to set to the empty list
*
* Example:
* ...
* struct parent *parent = malloc(sizeof(*parent));
*
* ccan_list_head_init(&parent->children);
* parent->num_children = 0;
*/
static inline void ccan_list_head_init(struct ccan_list_head *h)
{
h->n.next = h->n.prev = &h->n;
}
/**
* ccan_list_add - add an entry at the start of a linked list.
* @h: the ccan_list_head to add the node to
* @n: the ccan_list_node to add to the list.
*
* The ccan_list_node does not need to be initialized; it will be overwritten.
* Example:
* struct child *child = malloc(sizeof(*child));
*
* child->name = "marvin";
* ccan_list_add(&parent->children, &child->list);
* parent->num_children++;
*/
static inline void ccan_list_add(struct ccan_list_head *h, struct ccan_list_node *n)
{
n->next = h->n.next;
n->prev = &h->n;
h->n.next->prev = n;
h->n.next = n;
(void)ccan_list_debug(h);
}
/**
* ccan_list_add_tail - add an entry at the end of a linked list.
* @h: the ccan_list_head to add the node to
* @n: the ccan_list_node to add to the list.
*
* The ccan_list_node does not need to be initialized; it will be overwritten.
* Example:
* ccan_list_add_tail(&parent->children, &child->list);
* parent->num_children++;
*/
static inline void ccan_list_add_tail(struct ccan_list_head *h, struct ccan_list_node *n)
{
n->next = &h->n;
n->prev = h->n.prev;
h->n.prev->next = n;
h->n.prev = n;
(void)ccan_list_debug(h);
}
/**
* ccan_list_empty - is a list empty?
* @h: the ccan_list_head
*
* If the list is empty, returns true.
*
* Example:
* assert(ccan_list_empty(&parent->children) == (parent->num_children == 0));
*/
static inline bool ccan_list_empty(const struct ccan_list_head *h)
{
(void)ccan_list_debug(h);
return h->n.next == &h->n;
}
/**
* ccan_list_del - delete an entry from an (unknown) linked list.
* @n: the ccan_list_node to delete from the list.
*
* Note that this leaves @n in an undefined state; it can be added to
* another list, but not deleted again.
*
* See also:
* ccan_list_del_from()
*
* Example:
* ccan_list_del(&child->list);
* parent->num_children--;
*/
static inline void ccan_list_del(struct ccan_list_node *n)
{
(void)ccan_list_debug_node(n);
n->next->prev = n->prev;
n->prev->next = n->next;
#ifdef CCAN_LIST_DEBUG
/* Catch use-after-del. */
n->next = n->prev = NULL;
#endif
}
/**
* ccan_list_del_from - delete an entry from a known linked list.
* @h: the ccan_list_head the node is in.
* @n: the ccan_list_node to delete from the list.
*
* This explicitly indicates which list a node is expected to be in,
* which is better documentation and can catch more bugs.
*
* See also: ccan_list_del()
*
* Example:
* ccan_list_del_from(&parent->children, &child->list);
* parent->num_children--;
*/
static inline void ccan_list_del_from(struct ccan_list_head *h, struct ccan_list_node *n)
{
#ifdef CCAN_LIST_DEBUG
{
/* Thorough check: make sure it was in list! */
struct ccan_list_node *i;
for (i = h->n.next; i != n; i = i->next)
assert(i != &h->n);
}
#endif /* CCAN_LIST_DEBUG */
/* Quick test that catches a surprising number of bugs. */
assert(!ccan_list_empty(h));
ccan_list_del(n);
}
/**
* ccan_list_entry - convert a ccan_list_node back into the structure containing it.
* @n: the ccan_list_node
* @type: the type of the entry
* @member: the ccan_list_node member of the type
*
* Example:
* // First list entry is children.next; convert back to child.
* child = ccan_list_entry(parent->children.n.next, struct child, list);
*
* See Also:
* ccan_list_top(), ccan_list_for_each()
*/
#define ccan_list_entry(n, type, member) container_of(n, type, member)
/**
* ccan_list_top - get the first entry in a list
* @h: the ccan_list_head
* @type: the type of the entry
* @member: the ccan_list_node member of the type
*
* If the list is empty, returns NULL.
*
* Example:
* struct child *first;
* first = ccan_list_top(&parent->children, struct child, list);
*/
#define ccan_list_top(h, type, member) \
((type *)ccan_list_top_((h), ccan_list_off_(type, member)))
static inline const void *ccan_list_top_(const struct ccan_list_head *h, size_t off)
{
if (ccan_list_empty(h))
return NULL;
return (const char *)h->n.next - off;
}
/**
* ccan_list_tail - get the last entry in a list
* @h: the ccan_list_head
* @type: the type of the entry
* @member: the ccan_list_node member of the type
*
* If the list is empty, returns NULL.
*
* Example:
* struct child *last;
* last = ccan_list_tail(&parent->children, struct child, list);
*/
#define ccan_list_tail(h, type, member) \
((type *)ccan_list_tail_((h), ccan_list_off_(type, member)))
static inline const void *ccan_list_tail_(const struct ccan_list_head *h, size_t off)
{
if (ccan_list_empty(h))
return NULL;
return (const char *)h->n.prev - off;
}
/**
* ccan_list_for_each - iterate through a list.
* @h: the ccan_list_head (warning: evaluated multiple times!)
* @i: the structure containing the ccan_list_node
* @member: the ccan_list_node member of the structure
*
* This is a convenient wrapper to iterate @i over the entire list. It's
* a for loop, so you can break and continue as normal.
*
* Example:
* ccan_list_for_each(&parent->children, child, list)
* printf("Name: %s\n", child->name);
*/
#define ccan_list_for_each(h, i, member) \
ccan_list_for_each_off(h, i, ccan_list_off_var_(i, member))
/**
* ccan_list_for_each_rev - iterate through a list backwards.
* @h: the ccan_list_head
* @i: the structure containing the ccan_list_node
* @member: the ccan_list_node member of the structure
*
* This is a convenient wrapper to iterate @i over the entire list. It's
* a for loop, so you can break and continue as normal.
*
* Example:
* ccan_list_for_each_rev(&parent->children, child, list)
* printf("Name: %s\n", child->name);
*/
#define ccan_list_for_each_rev(h, i, member) \
for (i = container_of_var(ccan_list_debug(h)->n.prev, i, member); \
&i->member != &(h)->n; \
i = container_of_var(i->member.prev, i, member))
/**
* ccan_list_for_each_safe - iterate through a list, maybe during deletion
* @h: the ccan_list_head
* @i: the structure containing the ccan_list_node
* @nxt: the structure containing the ccan_list_node
* @member: the ccan_list_node member of the structure
*
* This is a convenient wrapper to iterate @i over the entire list. It's
* a for loop, so you can break and continue as normal. The extra variable
* @nxt is used to hold the next element, so you can delete @i from the list.
*
* Example:
* struct child *next;
* ccan_list_for_each_safe(&parent->children, child, next, list) {
* ccan_list_del(&child->list);
* parent->num_children--;
* }
*/
#define ccan_list_for_each_safe(h, i, nxt, member) \
ccan_list_for_each_safe_off(h, i, nxt, ccan_list_off_var_(i, member))
/**
* ccan_list_for_each_off - iterate through a list of memory regions.
* @h: the ccan_list_head
* @i: the pointer to a memory region wich contains list node data.
* @off: offset(relative to @i) at which list node data resides.
*
* This is a low-level wrapper to iterate @i over the entire list, used to
* implement all oher, more high-level, for-each constructs. It's a for loop,
* so you can break and continue as normal.
*
* WARNING! Being the low-level macro that it is, this wrapper doesn't know
* nor care about the type of @i. The only assumtion made is that @i points
* to a chunk of memory that at some @offset, relative to @i, contains a
* properly filled `struct node_list' which in turn contains pointers to
* memory chunks and it's turtles all the way down. Whith all that in mind
* remember that given the wrong pointer/offset couple this macro will
* happilly churn all you memory untill SEGFAULT stops it, in other words
* caveat emptor.
*
* It is worth mentioning that one of legitimate use-cases for that wrapper
* is operation on opaque types with known offset for `struct ccan_list_node'
* member(preferably 0), because it allows you not to disclose the type of
* @i.
*
* Example:
* ccan_list_for_each_off(&parent->children, child,
* offsetof(struct child, list))
* printf("Name: %s\n", child->name);
*/
#define ccan_list_for_each_off(h, i, off) \
for (i = ccan_list_node_to_off_(ccan_list_debug(h)->n.next, (off)); \
ccan_list_node_from_off_((void *)i, (off)) != &(h)->n; \
i = ccan_list_node_to_off_(ccan_list_node_from_off_((void *)i, (off))->next, \
(off)))
/**
* ccan_list_for_each_safe_off - iterate through a list of memory regions, maybe
* during deletion
* @h: the ccan_list_head
* @i: the pointer to a memory region wich contains list node data.
* @nxt: the structure containing the ccan_list_node
* @off: offset(relative to @i) at which list node data resides.
*
* For details see `ccan_list_for_each_off' and `ccan_list_for_each_safe'
* descriptions.
*
* Example:
* ccan_list_for_each_safe_off(&parent->children, child,
* next, offsetof(struct child, list))
* printf("Name: %s\n", child->name);
*/
#define ccan_list_for_each_safe_off(h, i, nxt, off) \
for (i = ccan_list_node_to_off_(ccan_list_debug(h)->n.next, (off)), \
nxt = ccan_list_node_to_off_(ccan_list_node_from_off_(i, (off))->next, \
(off)); \
ccan_list_node_from_off_(i, (off)) != &(h)->n; \
i = nxt, \
nxt = ccan_list_node_to_off_(ccan_list_node_from_off_(i, (off))->next, \
(off)))
/* Other -off variants. */
#define ccan_list_entry_off(n, type, off) \
((type *)ccan_list_node_from_off_((n), (off)))
#define ccan_list_head_off(h, type, off) \
((type *)ccan_list_head_off((h), (off)))
#define ccan_list_tail_off(h, type, off) \
((type *)ccan_list_tail_((h), (off)))
#define ccan_list_add_off(h, n, off) \
ccan_list_add((h), ccan_list_node_from_off_((n), (off)))
#define ccan_list_del_off(n, off) \
ccan_list_del(ccan_list_node_from_off_((n), (off)))
#define ccan_list_del_from_off(h, n, off) \
ccan_list_del_from(h, ccan_list_node_from_off_((n), (off)))
/* Offset helper functions so we only single-evaluate. */
static inline void *ccan_list_node_to_off_(struct ccan_list_node *node, size_t off)
{
return (void *)((char *)node - off);
}
static inline struct ccan_list_node *ccan_list_node_from_off_(void *ptr, size_t off)
{
return (struct ccan_list_node *)((char *)ptr + off);
}
/* Get the offset of the member, but make sure it's a ccan_list_node. */
#define ccan_list_off_(type, member) \
(container_off(type, member) + \
check_type(((type *)0)->member, struct ccan_list_node))
#define ccan_list_off_var_(var, member) \
(container_off_var(var, member) + \
check_type(var->member, struct ccan_list_node))
#endif /* CCAN_LIST_H */