《操作系统》的实验代码。
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#ifndef __LIBS_LIST_H__
#define __LIBS_LIST_H__
#ifndef __ASSEMBLER__
#include <defs.h>
/* *
* Simple doubly linked list implementation.
*
* Some of the internal functions ("__xxx") are useful when manipulating
* whole lists rather than single entries, as sometimes we already know
* the next/prev entries and we can generate better code by using them
* directly rather than using the generic single-entry routines.
* */
struct list_entry {
struct list_entry *prev, *next;
};
typedef struct list_entry list_entry_t;
static inline void list_init(list_entry_t *elm) __attribute__((always_inline));
static inline void list_add(list_entry_t *listelm, list_entry_t *elm) __attribute__((always_inline));
static inline void list_add_before(list_entry_t *listelm, list_entry_t *elm) __attribute__((always_inline));
static inline void list_add_after(list_entry_t *listelm, list_entry_t *elm) __attribute__((always_inline));
static inline void list_del(list_entry_t *listelm) __attribute__((always_inline));
static inline void list_del_init(list_entry_t *listelm) __attribute__((always_inline));
static inline bool list_empty(list_entry_t *list) __attribute__((always_inline));
static inline list_entry_t *list_next(list_entry_t *listelm) __attribute__((always_inline));
static inline list_entry_t *list_prev(list_entry_t *listelm) __attribute__((always_inline));
static inline void __list_add(list_entry_t *elm, list_entry_t *prev, list_entry_t *next) __attribute__((always_inline));
static inline void __list_del(list_entry_t *prev, list_entry_t *next) __attribute__((always_inline));
/* *
* list_init - initialize a new entry
* @elm: new entry to be initialized
* */
static inline void
list_init(list_entry_t *elm) {
elm->prev = elm->next = elm;
}
/* *
* list_add - add a new entry
* @listelm: list head to add after
* @elm: new entry to be added
*
* Insert the new element @elm *after* the element @listelm which
* is already in the list.
* */
static inline void
list_add(list_entry_t *listelm, list_entry_t *elm) {
list_add_after(listelm, elm);
}
/* *
* list_add_before - add a new entry
* @listelm: list head to add before
* @elm: new entry to be added
*
* Insert the new element @elm *before* the element @listelm which
* is already in the list.
* */
static inline void
list_add_before(list_entry_t *listelm, list_entry_t *elm) {
__list_add(elm, listelm->prev, listelm);
}
/* *
* list_add_after - add a new entry
* @listelm: list head to add after
* @elm: new entry to be added
*
* Insert the new element @elm *after* the element @listelm which
* is already in the list.
* */
static inline void
list_add_after(list_entry_t *listelm, list_entry_t *elm) {
__list_add(elm, listelm, listelm->next);
}
/* *
* list_del - deletes entry from list
* @listelm: the element to delete from the list
*
* Note: list_empty() on @listelm does not return true after this, the entry is
* in an undefined state.
* */
static inline void
list_del(list_entry_t *listelm) {
__list_del(listelm->prev, listelm->next);
}
/* *
* list_del_init - deletes entry from list and reinitialize it.
* @listelm: the element to delete from the list.
*
* Note: list_empty() on @listelm returns true after this.
* */
static inline void
list_del_init(list_entry_t *listelm) {
list_del(listelm);
list_init(listelm);
}
/* *
* list_empty - tests whether a list is empty
* @list: the list to test.
* */
static inline bool
list_empty(list_entry_t *list) {
return list->next == list;
}
/* *
* list_next - get the next entry
* @listelm: the list head
**/
static inline list_entry_t *
list_next(list_entry_t *listelm) {
return listelm->next;
}
/* *
* list_prev - get the previous entry
* @listelm: the list head
**/
static inline list_entry_t *
list_prev(list_entry_t *listelm) {
return listelm->prev;
}
/* *
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
* */
static inline void
__list_add(list_entry_t *elm, list_entry_t *prev, list_entry_t *next) {
prev->next = next->prev = elm;
elm->next = next;
elm->prev = prev;
}
/* *
* Delete a list entry by making the prev/next entries point to each other.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
* */
static inline void
__list_del(list_entry_t *prev, list_entry_t *next) {
prev->next = next;
next->prev = prev;
}
#endif /* !__ASSEMBLER__ */
#endif /* !__LIBS_LIST_H__ */