X-Git-Url: https://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Flstack%2Flstack.h;h=ef910bd17f58a1e63b93a3052592c06f4de31524;hb=0fd6bb104ac424b56326bd37de8b5057eb68243f;hp=41a9f05aa8fd222c05077fd8f1f2c3be8d2b1c90;hpb=eb5cf99742db1b02cc5cac4be19226b58009a106;p=ccan diff --git a/ccan/lstack/lstack.h b/ccan/lstack/lstack.h index 41a9f05a..ef910bd1 100644 --- a/ccan/lstack/lstack.h +++ b/ccan/lstack/lstack.h @@ -6,7 +6,7 @@ #include #include -#include +#include /** * struct lstack_link - a stack link @@ -25,42 +25,113 @@ struct lstack_link { }; /** - * struct lstack - a stack + * struct lstack_ - a stack (internal type) * @b: the top of the stack (NULL if empty) */ -struct lstack { +struct lstack_ { struct lstack_link *top; }; /** - * LSTACK - define and initialize an empty stack - * @name: the name of the lstack. + * LSTACK - declare a stack + * @type: the type of elements in the stack + * @link: the field containing the lstack_link in @type * - * The LSTACK macro defines an lstack and initializes it to an empty - * stack. It can be prepended by "static" to define a static lstack. + * The LSTACK macro declares an lstack. It can be prepended by + * "static" to define a static lstack. The stack begins in undefined + * state, you must either initialize with LSTACK_INIT, or call + * lstack_init() before using it. * * See also: * lstack_init() * * Example: - * LSTACK(my_stack); + * struct element { + * int value; + * struct lstack_link link; + * }; + * LSTACK(struct element, link) my_stack; + */ +#define LSTACK(etype, link) \ + TCON_WRAP(struct lstack_, \ + TCON_CONTAINER(canary, etype, link)) + +/** + * LSTACK_INIT - initializer for an empty stack + * + * The LSTACK_INIT macro returns a suitable initializer for a stack + * defined with LSTACK. + * + * Example: + * struct element { + * int value; + * struct lstack_link link; + * }; + * LSTACK(struct element, link) my_stack = LSTACK_INIT; * * assert(lstack_empty(&my_stack)); */ -#define LSTACK(name) \ - struct lstack name = { NULL, } +#define LSTACK_INIT \ + TCON_WRAP_INIT({ NULL, }) + +/** + * lstack_entry - convert an lstack_link back into the structure containing it. + * @s: the stack + * @l: the lstack_link + * + * Example: + * struct element { + * int value; + * struct lstack_link link; + * } e; + * LSTACK(struct element, link) my_stack; + * assert(lstack_entry(&my_stack, &e.link) == &e); + */ +#define lstack_entry(s_, l_) tcon_container_of((s_), canary, (l_)) + + +/** + * lstack_init_from_top - initialize a stack with a given top element + * @s: the lstack to initialize + * @e: pointer to the top element of the new stack + * + * USE WITH CAUTION: This is for handling unusual cases where you have + * a pointer to an element in a previously constructed stack but can't + * conveniently pass around a normal struct lstack. Usually you + * should use lstack_init(). + * + * Example: + * struct element { + * int value; + * struct lstack_link link; + * } e; + * LSTACK(struct element, link) stack1 = LSTACK_INIT; + * LSTACK(struct element, link) stack2; + * + * lstack_push(&stack1, &e); + * + * lstack_init_from_top(&stack2, lstack_top(&stack1)); + */ +#define lstack_init_from_top(s_, e_) \ + (lstack_init_(tcon_unwrap(s_), tcon_member_of((s_), canary, (e_)))) /** * lstack_init - initialize a stack * @h: the lstack to set to an empty stack * * Example: - * struct lstack *sp = malloc(sizeof(*sp)); + * struct element { + * int value; + * struct lstack_link link; + * }; + * LSTACK(struct element, link) *sp = malloc(sizeof(*sp)); * lstack_init(sp); */ -static inline void lstack_init(struct lstack *s) +#define lstack_init(s_) \ + (lstack_init_(tcon_unwrap(s_), NULL)) +static inline void lstack_init_(struct lstack_ *s, struct lstack_link *top) { - s->top = NULL; + s->top = top; } /** @@ -68,47 +139,29 @@ static inline void lstack_init(struct lstack *s) * @s: the stack * * If the stack is empty, returns true. - * - * Example: - * assert(lstack_empty(sp)); */ -static inline bool lstack_empty(const struct lstack *s) +#define lstack_empty(s_) \ + lstack_empty_(tcon_unwrap(s_)) +static inline bool lstack_empty_(const struct lstack_ *s) { return (s->top == NULL); } -/** - * lstack_entry - convert an lstack_link back into the structure containing it. - * @e: the lstack_link - * @type: the type of the entry - * @member: the lstack_link member of the type - * - * Example: - * struct stacker { - * char *name; - * struct lstack_link sl; - * } st; - * assert(lstack_entry(&st.sl, struct stacker, sl) == &st); - */ -#define lstack_entry(n, type, member) container_of_or_null(n, type, member) - /** * lstack_top - get top entry in a stack * @s: the stack - * @type: the type of stack entries - * @member: the lstack_link entry * * If the stack is empty, returns NULL. * * Example: - * struct stacker *t; + * struct element *t; * - * t = lstack_top(sp, struct stacker, sl); - * assert(lstack_pop(sp, struct stacker, sl) == t); + * t = lstack_top(sp); + * assert(lstack_pop(sp) == t); */ -#define lstack_top(s, type, member) \ - lstack_entry(lstack_top_((s)), type, member) -static inline struct lstack_link *lstack_top_(const struct lstack *s) +#define lstack_top(s_) \ + lstack_entry((s_), lstack_top_(tcon_unwrap(s_))) +static inline struct lstack_link *lstack_top_(const struct lstack_ *s) { return s->top; } @@ -117,13 +170,12 @@ static inline struct lstack_link *lstack_top_(const struct lstack *s) * lstack_push - add an entry to the top of the stack * @s: the stack to add the node to * @e: the item to push - * @member: the lstack_link field of *e * * The lstack_link does not need to be initialized; it will be overwritten. */ -#define lstack_push(s, e, member) \ - lstack_push_((s), &((e)->member)) -static inline void lstack_push_(struct lstack *s, struct lstack_link *e) +#define lstack_push(s_, e_) \ + lstack_push_(tcon_unwrap(s_), tcon_member_of((s_), canary, (e_))) +static inline void lstack_push_(struct lstack_ *s, struct lstack_link *e) { e->down = lstack_top_(s); s->top = e; @@ -132,19 +184,17 @@ static inline void lstack_push_(struct lstack *s, struct lstack_link *e) /** * lstack_pop - remove and return the entry from the top of the stack * @s: the stack - * @type: the type of stack entries - * @member: the lstack_link field of @type * * Note that this leaves the returned entry's link in an undefined * state; it can be added to another stack, but not deleted again. */ -#define lstack_pop(s, type, member) \ - lstack_entry(lstack_pop_((s)), type, member) -static inline struct lstack_link *lstack_pop_(struct lstack *s) +#define lstack_pop(s_) \ + lstack_entry((s_), lstack_pop_(tcon_unwrap((s_)))) +static inline struct lstack_link *lstack_pop_(struct lstack_ *s) { struct lstack_link *top; - if (lstack_empty(s)) + if (lstack_empty_(s)) return NULL; top = lstack_top_(s);