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#ifndef JEMALLOC_INTERNAL_QL_H
#define JEMALLOC_INTERNAL_QL_H
#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)
/* 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 { \
ql_first(a_head) = NULL; \
} while (0)
/*
* 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)
/* 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_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)) { \
ql_first(a_head) = (a_elm); \
} \
} 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_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_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); \
} \
if (ql_first(a_head) != (a_elm)) { \
qr_remove((a_elm), a_field); \
} else { \
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)
#define ql_reverse_foreach(a_var, a_head, a_field) \
qr_reverse_foreach((a_var), ql_first(a_head), a_field)
#endif /* JEMALLOC_INTERNAL_QL_H */
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