X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Ftlist2%2Ftlist2.h;fp=ccan%2Ftlist2%2Ftlist2.h;h=82f20eca13a054f1c1400dc2294e250e701fe970;hb=7a4e71c4180eaecc8799c050eeb052b0de8cf302;hp=0000000000000000000000000000000000000000;hpb=95573b36fd8130d5925f877a83b959c22aac1dfd;p=ccan diff --git a/ccan/tlist2/tlist2.h b/ccan/tlist2/tlist2.h new file mode 100644 index 00000000..82f20eca --- /dev/null +++ b/ccan/tlist2/tlist2.h @@ -0,0 +1,242 @@ +/* Licensed under LGPL - see LICENSE file for details */ +#ifndef CCAN_TLIST2_H +#define CCAN_TLIST2_H +#include +#include + +/** + * TLIST2 - declare a typed list type (struct tlist) + * @etype: the type the list will contain + * @link: the name of the member of @etype that is the link + * + * This declares an anonymous structure to use for lists containing this type. + * The actual list can be accessed using tlist2_raw(). + * + * Example: + * #include + * #include + * struct child { + * const char *name; + * struct list_node list; + * }; + * struct parent { + * const char *name; + * TLIST2(struct child, list) children; + * unsigned int num_children; + * }; + * + */ +#define TLIST2(etype, link) \ + TCON_WRAP(struct list_head, \ + TCON_CONTAINER(canary, etype, link)) + +/** + * TLIST2_INIT - initalizer for an empty tlist + * @name: the name of the list. + * + * Explicit initializer for an empty list. + * + * See also: + * tlist2_init() + * + * Example: + * TLIST2(struct child, list) my_list = TLIST2_INIT(my_list); + */ +#define TLIST2_INIT(name) TCON_WRAP_INIT( LIST_HEAD_INIT(*tcon_unwrap(&(name))) ) + +/** + * tlist2_check - check head of a list for consistency + * @h: the tlist2 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 non-NULL if the list is consistent, NULL otherwise (it + * can never return NULL if @abortstr is set). + * + * See also: list_check() + * + * Example: + * static void dump_parent(struct parent *p) + * { + * struct child *c; + * + * printf("%s (%u children):\n", p->name, p->num_children); + * tlist2_check(&p->children, "bad child list"); + * tlist2_for_each(&p->children, c) + * printf(" -> %s\n", c->name); + * } + */ +#define tlist2_check(h, abortstr) \ + list_check(tcon_unwrap(h), (abortstr)) + +/** + * tlist2_init - initialize a tlist + * @h: the tlist to set to the empty list + * + * Example: + * ... + * struct parent *parent = malloc(sizeof(*parent)); + * + * tlist2_init(&parent->children); + * parent->num_children = 0; + */ +#define tlist2_init(h) list_head_init(tcon_unwrap(h)) + +/** + * tlist2_raw - unwrap the typed list and check the type + * @h: the tlist + * @expr: the expression to check the type against (not evaluated) + * + * This macro usually causes the compiler to emit a warning if the + * variable is of an unexpected type. It is used internally where we + * need to access the raw underlying list. + */ +#define tlist2_raw(h, expr) tcon_unwrap(tcon_container_check_ptr(h, canary, expr)) + +/** + * tlist2_unwrap - unwrap the typed list without any checks + * @h: the tlist + */ +#define tlist2_unwrap(h) tcon_unwrap(h) + +/** + * tlist2_add - add an entry at the start of a linked list. + * @h: the tlist to add the node to + * @n: the entry to add to the list. + * + * The entry's list_node does not need to be initialized; it will be + * overwritten. + * Example: + * struct child *child = malloc(sizeof(*child)); + * + * child->name = "marvin"; + * tlist2_add(&parent->children, child); + * parent->num_children++; + */ +#define tlist2_add(h, n) list_add(tlist2_raw((h), (n)), tcon_member_of(h, canary, n)) + +/** + * tlist2_add_tail - add an entry at the end of a linked list. + * @h: the tlist to add the node to + * @n: the entry to add to the list. + * + * The list_node does not need to be initialized; it will be overwritten. + * Example: + * tlist2_add_tail(&parent->children, child); + * parent->num_children++; + */ +#define tlist2_add_tail(h, n) \ + list_add_tail(tlist2_raw((h), (n)), tcon_member_of((h), canary, (n))) + +/** + * tlist2_del_from - delete an entry from a linked list. + * @h: the tlist @n is in + * @n: the entry to delete + * + * This explicitly indicates which list a node is expected to be in, + * which is better documentation and can catch more bugs. + * + * Note that this leaves @n->@member in an undefined state; it + * can be added to another list, but not deleted again. + * + * Example: + * tlist2_del_from(&parent->children, child); + * parent->num_children--; + */ +#define tlist2_del_from(h, n) \ + list_del_from(tlist2_raw((h), (n)), tcon_member_of((h), canary, (n))) + +/** + * tlist2_empty - is a list empty? + * @h: the tlist + * + * If the list is empty, returns true. + * + * Example: + * assert(tlist2_empty(&parent->children) == (parent->num_children == 0)); + */ +#define tlist2_empty(h) list_empty(tcon_unwrap(h)) + +/** + * tlist2_top - get the first entry in a list + * @h: the tlist + * + * If the list is empty, returns NULL. + * + * Example: + * struct child *first; + * first = tlist2_top(&parent->children); + * if (!first) + * printf("Empty list!\n"); + */ +#define tlist2_top(h) tcon_container_of((h), canary, list_top_(tcon_unwrap(h), 0)) + +/** + * tlist2_tail - get the last entry in a list + * @h: the tlist + * + * If the list is empty, returns NULL. + * + * Example: + * struct child *last; + * last = tlist2_tail(&parent->children); + * if (!last) + * printf("Empty list!\n"); + */ +#define tlist2_tail(h) tcon_container_of((h), canary, list_tail_(tcon_unwrap(h), 0)) + +/** + * tlist2_for_each - iterate through a list. + * @h: the tlist + * @i: an iterator of suitable type for this list. + * + * 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: + * tlist2_for_each(&parent->children, child) + * printf("Name: %s\n", child->name); + */ +#define tlist2_for_each(h, i) \ + list_for_each_off(tlist2_raw((h), (i)), (i), tcon_offset((h), canary)) + +/** + * tlist2_for_each_rev - iterate through a list backwards. + * @h: the tlist + * @i: an iterator of suitable type for this list. + * + * 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: + * tlist2_for_each_rev(&parent->children, child) + * printf("Name: %s\n", child->name); + */ +#define tlist2_for_each_rev(h, i) \ + list_for_each_rev_off(tlist2_raw((h), (i)), (i), tcon_offset((h), canary)) + +/** + * tlist2_for_each_safe - iterate through a list, maybe during deletion + * @h: the tlist + * @i: an iterator of suitable type for this list. + * @nxt: another iterator to store the next entry. + * + * 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; + * tlist2_for_each_safe(&parent->children, child, next) { + * tlist2_del_from(&parent->children, child); + * parent->num_children--; + * } + */ +#define tlist2_for_each_safe(h, i, nxt) \ + list_for_each_safe_off(tlist2_raw((h), (i)), (i), (nxt), tcon_offset((h), canary)) + +#endif /* CCAN_TLIST2_H */