学步园

链表实现文件：文件：./src/core/ngx_list.h/.c

1.基本数据结构

typedef struct ngx_list_part_s  ngx_list_part_t;

struct ngx_list_part_s {
    void             *elts;
    ngx_uint_t        nelts;
    ngx_list_part_t  *next;
};

typedef struct {
    ngx_list_part_t  *last;
    ngx_list_part_t   part;
    size_t            size;  
    ngx_uint_t        nalloc;
    ngx_pool_t       *pool;
} ngx_list_t;

2.基本操作

ngx_list_t *ngx_list_create(ngx_pool_t *pool, ngx_uint_t n, size_t size);
static ngx_inline ngx_int_t
ngx_list_init(ngx_list_t *list, ngx_pool_t *pool, ngx_uint_t n, size_t size)
void *ngx_list_push(ngx_list_t *list);

2.1创建链表

ngx_list_t *
ngx_list_create(ngx_pool_t *pool, ngx_uint_t n, size_t size)
{
    ngx_list_t  *list;

    list = ngx_palloc(pool, sizeof(ngx_list_t));
    if (list == NULL) {
        return NULL;
    }

    list->part.elts = ngx_palloc(pool, n * size);
    if (list->part.elts == NULL) {
        return NULL;
    }

    list->part.nelts = 0;
    list->part.next = NULL;
    list->last = &list->part;
    list->size = size;
    list->nalloc = n;
    list->pool = pool;

    return list;
}

2.2链表初始化

static ngx_inline ngx_int_t
ngx_list_init(ngx_list_t *list, ngx_pool_t *pool, ngx_uint_t n, size_t size)
{
    list->part.elts = ngx_palloc(pool, n * size);
    if (list->part.elts == NULL) {
        return NGX_ERROR;
    }

    list->part.nelts = 0;
    list->part.next = NULL;
    list->last = &list->part;
    list->size = size;
    list->nalloc = n;
    list->pool = pool;

    return NGX_OK;
}

void *
ngx_list_push(ngx_list_t *l)
{
    void             *elt;
    ngx_list_part_t  *last;

    last = l->last;

    if (last->nelts == l->nalloc) {

        /* the last part is full, allocate a new list part */

        last = ngx_palloc(l->pool, sizeof(ngx_list_part_t));
        if (last == NULL) {
            return NULL;
        }

        last->elts = ngx_palloc(l->pool, l->nalloc * l->size);
        if (last->elts == NULL) {
            return NULL;
        }

        last->nelts = 0;
        last->next = NULL;

        l->last->next = last;
        l->last = last;
    }

    elt = (char *) last->elts + l->size * last->nelts;
    last->nelts++;

    return elt;
}