nginx hash源码

以下是Nginx的哈希源代码的简化版本：

#include <ngx_core.h>

typedef struct {
    ngx_str_t   key;
    ngx_str_t   value;
    u_short     len;
    u_char      name[1];
} ngx_hash_elt_t;

typedef struct {
    ngx_hash_elt_t  **buckets;
    ngx_uint_t        size;
} ngx_hash_t;

ngx_uint_t
ngx_hash_key(u_char *data, size_t len)
{
    ngx_uint_t  i, hash;

    hash = 0;

    for (i = 0; i < len; i++) {
        hash = ngx_hash(hash, data[i]);
    }

    return hash;
}

ngx_int_t
ngx_hash_init(ngx_hash_t *hash, ngx_hash_elt_t **buckets, ngx_uint_t size)
{
    hash->buckets = buckets;
    hash->size = size;

    return NGX_OK;
}

ngx_hash_elt_t *
ngx_hash_find(ngx_hash_t *hash, ngx_str_t *key, ngx_uint_t hash_value)
{
    ngx_hash_elt_t  *elt;

    elt = hash->buckets[hash_value % hash->size];

    while (elt) {
        if (elt->len == key->len && ngx_strncmp(elt->name, key->data, key->len) == 0) {
            return elt;
        }

        elt = elt->next;
    }

    return NULL;
}

ngx_int_t
ngx_hash_add(ngx_hash_t *hash, ngx_str_t *key, ngx_str_t *value)
{
    ngx_uint_t       hash_value;
    ngx_hash_elt_t  *elt;

    hash_value = ngx_hash_key(key->data, key->len);

    elt = ngx_hash_find(hash, key, hash_value);

    if (elt) {
        elt->value = *value;
        return NGX_OK;
    }

    elt = ngx_pcalloc(hash->pool, sizeof(ngx_hash_elt_t) + key->len);

    elt->len = (u_short) key->len;
    ngx_memcpy(elt->name, key->data, key->len);
    elt->value = *value;

    elt->next = hash->buckets[hash_value % hash->size];
    hash->buckets[hash_value % hash->size] = elt;

    return NGX_OK;
}

这是Nginx中用于哈希实现的一些简化的源代码。这些代码定义了ngx_hash_t和ngx_hash_elt_t结构体，包括哈希表的初始化、查找和添加操作。ngx_hash_key函数用于计算哈希值，ngx_hash_init函数用于初始化哈希表，ngx_hash_find函数用于在哈希表中查找元素，ngx_hash_add函数用于向哈希表中添加元素。

需要注意的是，这只是源代码的简化版本，实际的Nginx源代码包含了更多的细节和实现