diff options
Diffstat (limited to 'include/jemalloc/internal/ql.h')
| -rw-r--r-- | include/jemalloc/internal/ql.h | 129 |
1 files changed, 119 insertions, 10 deletions
diff --git a/include/jemalloc/internal/ql.h b/include/jemalloc/internal/ql.h index 80290407..c7f52f86 100644 --- a/include/jemalloc/internal/ql.h +++ b/include/jemalloc/internal/ql.h @@ -3,37 +3,85 @@ #include "jemalloc/internal/qr.h" +/* + * A linked-list implementation. + * + * This is built on top of the ring implementation, but that can be viewed as an + * implementation detail (i.e. trying to advance past the tail of the list + * doesn't wrap around). + * + * You define a struct like so: + * typedef strucy my_s my_t; + * struct my_s { + * int data; + * ql_elm(my_t) my_link; + * }; + * + * // We wobble between "list" and "head" for this type; we're now mostly + * // heading towards "list". + * typedef ql_head(my_t) my_list_t; + * + * You then pass a my_list_t * for a_head arguments, a my_t * for a_elm + * arguments, the token "my_link" for a_field arguments, and the token "my_t" + * for a_type arguments. + */ + /* List definitions. */ #define ql_head(a_type) \ struct { \ a_type *qlh_first; \ } +/* Static initializer for an empty list. */ #define ql_head_initializer(a_head) {NULL} +/* The field definition. */ #define ql_elm(a_type) qr(a_type) -/* List functions. */ +/* A pointer to the first element in the list, or NULL if the list is empty. */ +#define ql_first(a_head) ((a_head)->qlh_first) + +/* Dynamically initializes a list. */ #define ql_new(a_head) do { \ - (a_head)->qlh_first = NULL; \ + ql_first(a_head) = NULL; \ } while (0) -#define ql_elm_new(a_elm, a_field) qr_new((a_elm), a_field) +/* + * Sets dest to be the contents of src (overwriting any elements there), leaving + * src empty. + */ +#define ql_move(a_head_dest, a_head_src) do { \ + ql_first(a_head_dest) = ql_first(a_head_src); \ + ql_new(a_head_src); \ +} while (0) -#define ql_first(a_head) ((a_head)->qlh_first) +/* True if the list is empty, otherwise false. */ +#define ql_empty(a_head) (ql_first(a_head) == NULL) + +/* + * Initializes a ql_elm. Must be called even if the field is about to be + * overwritten. + */ +#define ql_elm_new(a_elm, a_field) qr_new((a_elm), a_field) +/* + * Obtains the last item in the list. + */ #define ql_last(a_head, a_field) \ - ((ql_first(a_head) != NULL) \ - ? qr_prev(ql_first(a_head), a_field) : NULL) + (ql_empty(a_head) ? NULL : qr_prev(ql_first(a_head), a_field)) +/* + * Gets a pointer to the next/prev element in the list. Trying to advance past + * the end or retreat before the beginning of the list returns NULL. + */ #define ql_next(a_head, a_elm, a_field) \ ((ql_last(a_head, a_field) != (a_elm)) \ ? qr_next((a_elm), a_field) : NULL) - #define ql_prev(a_head, a_elm, a_field) \ ((ql_first(a_head) != (a_elm)) ? qr_prev((a_elm), a_field) \ : NULL) +/* Inserts a_elm before a_qlelm in the list. */ #define ql_before_insert(a_head, a_qlelm, a_elm, a_field) do { \ qr_before_insert((a_qlelm), (a_elm), a_field); \ if (ql_first(a_head) == (a_qlelm)) { \ @@ -41,23 +89,41 @@ struct { \ } \ } while (0) +/* Inserts a_elm after a_qlelm in the list. */ #define ql_after_insert(a_qlelm, a_elm, a_field) \ qr_after_insert((a_qlelm), (a_elm), a_field) +/* Inserts a_elm as the first item in the list. */ #define ql_head_insert(a_head, a_elm, a_field) do { \ - if (ql_first(a_head) != NULL) { \ + if (!ql_empty(a_head)) { \ qr_before_insert(ql_first(a_head), (a_elm), a_field); \ } \ ql_first(a_head) = (a_elm); \ } while (0) +/* Inserts a_elm as the last item in the list. */ #define ql_tail_insert(a_head, a_elm, a_field) do { \ - if (ql_first(a_head) != NULL) { \ + if (!ql_empty(a_head)) { \ qr_before_insert(ql_first(a_head), (a_elm), a_field); \ } \ ql_first(a_head) = qr_next((a_elm), a_field); \ } while (0) +/* + * Given lists a = [a_1, ..., a_n] and [b_1, ..., b_n], results in: + * a = [a1, ..., a_n, b_1, ..., b_n] and b = []. + */ +#define ql_concat(a_head_a, a_head_b, a_field) do { \ + if (ql_empty(a_head_a)) { \ + ql_move(a_head_a, a_head_b); \ + } else if (!ql_empty(a_head_b)) { \ + qr_meld(ql_first(a_head_a), ql_first(a_head_b), \ + a_field); \ + ql_new(a_head_b); \ + } \ +} while (0) + +/* Removes a_elm from the list. */ #define ql_remove(a_head, a_elm, a_field) do { \ if (ql_first(a_head) == (a_elm)) { \ ql_first(a_head) = qr_next(ql_first(a_head), a_field); \ @@ -65,20 +131,63 @@ struct { \ if (ql_first(a_head) != (a_elm)) { \ qr_remove((a_elm), a_field); \ } else { \ - ql_first(a_head) = NULL; \ + ql_new(a_head); \ } \ } while (0) +/* Removes the first item in the list. */ #define ql_head_remove(a_head, a_type, a_field) do { \ a_type *t = ql_first(a_head); \ ql_remove((a_head), t, a_field); \ } while (0) +/* Removes the last item in the list. */ #define ql_tail_remove(a_head, a_type, a_field) do { \ a_type *t = ql_last(a_head, a_field); \ ql_remove((a_head), t, a_field); \ } while (0) +/* + * Given a = [a_1, a_2, ..., a_n-1, a_n, a_n+1, ...], + * ql_split(a, a_n, b, some_field) results in + * a = [a_1, a_2, ..., a_n-1] + * and replaces b's contents with: + * b = [a_n, a_n+1, ...] + */ +#define ql_split(a_head_a, a_elm, a_head_b, a_field) do { \ + if (ql_first(a_head_a) == (a_elm)) { \ + ql_move(a_head_b, a_head_a); \ + } else { \ + qr_split(ql_first(a_head_a), (a_elm), a_field); \ + ql_first(a_head_b) = (a_elm); \ + } \ +} while (0) + +/* + * An optimized version of: + * a_type *t = ql_first(a_head); + * ql_remove((a_head), t, a_field); + * ql_tail_insert((a_head), t, a_field); + */ +#define ql_rotate(a_head, a_field) do { \ + ql_first(a_head) = qr_next(ql_first(a_head), a_field); \ +} while (0) + +/* + * Helper macro to iterate over each element in a list in order, starting from + * the head (or in reverse order, starting from the tail). The usage is + * (assuming my_t and my_list_t defined as above). + * + * int sum(my_list_t *list) { + * int sum = 0; + * my_t *iter; + * ql_foreach(iter, list, link) { + * sum += iter->data; + * } + * return sum; + * } + */ + #define ql_foreach(a_var, a_head, a_field) \ qr_foreach((a_var), ql_first(a_head), a_field) |