hash_table

gistfile1.txt

#include <linux/init.h>
#include <linux/modue.h>
#include <linux/list.h>

struct q_coef
{
    u8 coef;
    u8 index;
    struct hlist_node hash;
};

#define HASH_NUMBER 15

u8 coef[HASH_NUMBER] = {
    0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13,};

struct q_coef q_coef_list[HASH_NUMBER];

struct hlist_head hashtbl[HASH_NUMBER];

static inline int hash_func(u8 k)
{
    int a, b, p, m;
    a = 104;
    b = 52;
    p = 233;
    m = HASH_NUMBER;
    return ((a*k + b) % p) %m;
}

static void hash_init(void)
{
    int i, j;
    for(i = 0; i < HASH_NUMBER; i++){
        INIT_HLIST_HEAD(&hashtbl[i]);
        INIT_HLIST_NODE(&q_coef_list[i].hash);
        q_coef_list[i].coef = coef[i];
        q_coef_list[i].index = i + 1;
    }

    for(i=0; i < HASH_NUMBER;i++) {
        j = hash_func(q_coef_list[i].coef);
        hlist_add_head(&q_coef_list[i].hash, &hashtbl[j]);
    }
}

static void hash_test(void)
{
    int i,j;
    struct q_coef *q;
    struct hlist_node* hn;
    for(i = 0; i < HASH_NUMBER; i++){
        j = hash_func(coef[i]);
        hlist_for_each_entry(q, hn, &hashtbl[j],hash)
            if( q->coef == coef[i])
                printk("found:coef=0x%02x index=%d\n", q->coef, q->index);
    }
}

static int htest_init(void)
{
    hash_init();
    hash_test();
    return -1;
}

static void htest_exit(void)
{

}

module_init(htest_init);
module_exit(htest_exit);

MODULE_LICENSE("Dual BSB/GPL");