通用hash表

#ifndef _HASH_H
#define _HASH_H

#define ALIGN (sizeof(unsigned long) - 1)

#define HASH_SIZE 512

struct list_head         /* hash table head */
{
    struct list_head *next;
    struct list_head *prev;
};

struct word_struct        /* any data struct */
{
    struct list_head list;
    unsigned long len;
    char str[0];
};

static inline void INIT_LIST_HEAD(struct list_head *list)
{
    list->next = list;
    list->prev = list;
}

static inline void __list_add(struct list_head *new,
             struct list_head *prev,
             struct list_head *next)
{
    next->prev = new;
    new->next = next;
    new->prev = prev;
    prev->next = new;
}

static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
    __list_add(new, head->prev, head);
}

static inline void __list_del(struct list_head *prev, struct list_head *next)
{
    next->prev = prev;
    prev->next = next;
}

static inline void list_del(struct list_head *entry)
{
    __list_del(entry->prev, entry->next);
    entry->next = NULL;
    entry->prev = NULL;
}

static inline int list_empty(const struct list_head *head)
{
    return head->next == head;
}

#define container_of(ptr, type, member) ({            \
        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
        (type *)( (char *)__mptr - offsetof(type,member) );})

#define list_entry(ptr, type, member) \
    container_of(ptr, type, member)

#define list_for_each(pos, head) \
    for (pos = (head)->next; prefetch(pos->next), pos != (head); \
            pos = pos->next)