rm cap, s/len/size/g in sle; comments; cmp fn type; contains api; dot fixes
This commit is contained in:
parent
7c4789e71d
commit
5481b99725
173
include/sl.h
173
include/sl.h
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@ -132,18 +132,26 @@
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*/
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/*
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* Skiplist declarations.
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* Skip List declarations.
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*/
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#ifndef SKIPLIST_MAX_HEIGHT
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#define SKIPLIST_MAX_HEIGHT 1
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#endif
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/*
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* A Skip List contains elements, a portion of which is used to manage those
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* elements while the rest is defined by the use case for this declaration. The
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* house keeping portion is the SKIPLIST_ENTRY below. It maintains the array of
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* forward pointers to nodes and has a height (a zero-based count of levels, so
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* a height of `0` means one (1) level and a height of `4` means five (5)
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* levels).
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*/
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#define SKIPLIST_ENTRY(type) \
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struct __skiplist_entry { \
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struct __skiplist_idx { \
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struct type *prev, **next; \
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size_t cap, len; \
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size_t height; \
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} sle; \
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}
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@ -152,15 +160,65 @@
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*/
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#define SKIP_FIRST(head) ((head)->slh_head)
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#define SKIP_LAST(head) ((head)->slh_tail)
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#define SKIP_NEXT(elm, field) ((elm)->field.sle.next[0])
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#define SKIP_PREV(elm, field) ((elm)->field.sle.prev)
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#define SKIP_EMPTY(head) ((head)->length == 0)
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/*
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* Skip List functions.
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* Skip List node comparison function. This macro builds a function used when
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* comparing two nodes for equality. A portion of this function, `fn_blk`, is
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* the code you supply to compare two nodes as a block (starts with `{`, your
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* code, then `}`) that should compare the node referenced by `a` to the node
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* `b` as follows:
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*
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* When:
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* *a < *b : return -1
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* *a == *b : return 0
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* *a > *b : return 1
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*
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* As stated earlier, the ordered skiplist relies on a well-behaved comparison
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* function. Specifically, given some ordering function f(a, b), it must satisfy
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* the following properties:
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*
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* 1) Be well defined: f(a, b) should always return the same value
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* 2) Be anti-symmetric: f(a, b) == Greater if and only if f(b, a) == Less, and
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* f(a, b) == Equal == f(b, a).
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* 3) Be transitive: If f(a, b) == Greater and f(b, c) == Greater then f(a, c)
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* == Greater.
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*
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* Failure to satisfy these properties can result in unexpected behavior at
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* best, and at worst will cause a segfault, null deref, or some other bad
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* behavior.
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*
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* Example for nodes with keys that are signed integeters (`int`):
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* {
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* (void)list;
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* (void)aux;
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* if (a->key < b->key)
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* return -1;
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* if (a->key > b->key)
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* return 1;
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* return 0;
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* }
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*
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* Note that the comparison function can also make use of the reference to the
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* list as well as a reference to a variable `aux` that you can point to
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* anything else required to perform your comparison. The auxiliary pointer
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* is unused for other purposes. You could even use it a pointer to a function
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* that chooses the proper comparison function for the two nodes in question.
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*
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* Example where the value of `decl` below is `ex`:
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* {
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* // Cast `aux` to a function that returns a function that properly compares
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* // `a` and `b`, for example if they were objects or different structs.
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* (skip_ex_cmp_t *(fn)(ex_node_t *, ex_node_t *)) =
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* (skip_ex_cmp_t *()(ex_node_t *, ex_node_t *))aux;
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*
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* // Use the `fn` pointed to by `aux` to get the comparison function.
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* skip_ex_cmp_t *cmp = fn(a, b);
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*
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* // Now call that function and return the proper result.
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* return cmp(list, a, b, aux);
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* }
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*/
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#define SKIP_COMPARATOR(list, type, fn) \
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#define SKIP_COMPARATOR(list, type, fn_blk) \
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int __skip_cmp_##type(struct list *head, struct type *a, struct type *b, void *aux) \
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{ \
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if (a == b) \
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@ -169,15 +227,18 @@
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return -1; \
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if (a == (head)->slh_tail || b == (head)->slh_head) \
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return 1; \
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fn \
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fn_blk \
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}
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/*
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* Skip List declarations and access methods.
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*/
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#define SKIPLIST_DECL(decl, prefix, field, free_node_blk, update_node_blk, snap_node_blk, sizeof_entry_blk) \
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\
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/* Skiplist node type */ \
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/* Skip List node type */ \
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typedef struct decl##_node decl##_node_t; \
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\
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/* Skiplist type */ \
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/* Skip List structure and type */ \
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typedef struct decl { \
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size_t level, length, max; \
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int (*cmp)(struct decl *, decl##_node_t *, decl##_node_t *, void *); \
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@ -186,27 +247,23 @@
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decl##_node_t *slh_tail; \
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} decl##_t; \
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\
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/* Snapshot of a Skiplist */ \
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/* Snapshot of a Skip List */ \
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typedef struct decl##_snap { \
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decl##_t list; \
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decl##_node_t *nodes; \
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size_t bytes; \
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} decl##_snap_t; \
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\
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/* Path taken to find an element in the Skiplist, path[0] is the match if \
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one exists */ \
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struct __##decl##_path { \
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size_t cap; \
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size_t len; \
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struct decl##_node **nodes; \
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}; \
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/* Skip List comparison function type */ \
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typedef int (*skip_##decl##_cmp_t)(decl##_t *, decl##_node_t *, decl##_node_t *, void *); \
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\
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/* Used when positioning a cursor within a Skip List. */ \
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typedef enum { SKIP_EQ = 0, SKIP_LTE = -1, SKIP_LT = -2, SKIP_GTE = 1, SKIP_GT = 2 } skip_pos_##decl_t; \
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\
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/* -- __skip_key_compare_ \
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* \
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* This function takes four arguments: \
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* - a reference to the Skiplist \
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* - a reference to the Skip List \
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* - the two nodes to compare, `a` and `b` \
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* - `aux` an additional auxiliary argument \
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* and returns: \
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@ -227,7 +284,7 @@
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\
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/* -- __skip_toss_ \
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* A "coin toss" function that is critical to the proper operation of the \
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* Skiplist. For example, when `max = 6` this function returns 0 with \
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* Skip List. For example, when `max = 6` this function returns 0 with \
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* probability 0.5, 1 with 0.25, 2 with 0.125, etc. until 6 with 0.5^7. \
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*/ \
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static int __skip_toss_##decl(size_t max) \
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@ -253,8 +310,7 @@
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n = (decl##_node_t *)calloc(1, sizeof(decl##_node_t) + sle_arr_sz); \
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if (n == NULL) \
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return ENOMEM; \
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n->field.sle.cap = slist->max; \
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n->field.sle.len = 0; \
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n->field.sle.height = 0; \
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n->field.sle.next = (decl##_node_t **)((uintptr_t)n + sizeof(decl##_node_t)); \
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*node = n; \
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return 0; \
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@ -281,12 +337,12 @@
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if (rc) \
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goto fail; \
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\
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slist->slh_head->field.sle.len = 0; \
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slist->slh_head->field.sle.height = 0; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_head->field.sle.next[i] = slist->slh_tail; \
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slist->slh_head->field.sle.prev = NULL; \
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\
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slist->slh_tail->field.sle.len = slist->max; \
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slist->slh_tail->field.sle.height = slist->max; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_tail->field.sle.next[i] = NULL; \
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slist->slh_tail->field.sle.prev = slist->slh_head; \
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@ -349,7 +405,7 @@
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return 0; \
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\
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/* Find the node that matches `node` or NULL. */ \
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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elm = elm->field.sle.next[i]; \
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@ -388,9 +444,9 @@
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return -1; \
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} \
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level = __skip_toss_##decl(slist->max - 1); \
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n->field.sle.len = level + 1; \
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n->field.sle.height = level + 1; \
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for (i = 0; i <= level; i++) { \
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if (i <= slist->slh_head->field.sle.len) { \
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if (i <= slist->slh_head->field.sle.height) { \
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n->field.sle.next[i] = path[i + 1]->field.sle.next[i]; \
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path[i + 1]->field.sle.next[i] = n; \
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} else { \
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@ -402,9 +458,9 @@
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if (n->field.sle.next[0] == slist->slh_tail) { \
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slist->slh_tail->field.sle.prev = n; \
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} \
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if (level > slist->slh_head->field.sle.len) { \
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slist->slh_head->field.sle.len = level; \
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slist->slh_tail->field.sle.len = level; \
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if (level > slist->slh_head->field.sle.height) { \
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slist->slh_head->field.sle.height = level; \
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slist->slh_tail->field.sle.height = level; \
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} \
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slist->length++; \
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\
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@ -441,7 +497,7 @@
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if (slist == NULL || n == NULL) \
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return NULL; \
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\
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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\
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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@ -471,7 +527,7 @@
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if (slist == NULL || n == NULL) \
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return NULL; \
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\
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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\
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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@ -501,7 +557,7 @@
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if (slist == NULL || n == NULL) \
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return NULL; \
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\
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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\
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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@ -531,7 +587,7 @@
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if (slist == NULL || n == NULL) \
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return NULL; \
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\
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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\
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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@ -565,7 +621,7 @@
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if (slist == NULL || n == NULL) \
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return NULL; \
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\
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i = slist->slh_head->field.sle.len; \
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i = slist->slh_head->field.sle.height; \
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\
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do { \
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while (elm && __skip_key_compare_##decl(slist, elm->field.sle.next[i], n, slist->aux) < 0) \
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@ -631,7 +687,7 @@
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return -1; \
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} \
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\
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/* -- skip_remove_ BUG: prev pointer wrong!*/ \
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/* -- skip_remove_ */ \
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int prefix##skip_remove_##decl(decl##_t *slist, decl##_node_t *n) \
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{ \
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static decl##_node_t apath[SKIPLIST_MAX_HEIGHT + 1]; \
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@ -659,8 +715,8 @@
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break; \
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path[i]->field.sle.next[i - 1] = node->field.sle.next[i - 1]; \
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if (path[i]->field.sle.next[i - 1] == slist->slh_tail) { \
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level = path[i]->field.sle.len; \
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path[i]->field.sle.len = level - 1; \
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level = path[i]->field.sle.height; \
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path[i]->field.sle.height = level - 1; \
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} \
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} \
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if (node->field.sle.next[0] == slist->slh_tail) { \
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@ -674,10 +730,10 @@
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at the tail and shrink the level. */ \
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i = 0; \
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node = slist->slh_head; \
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while (node->field.sle.next[i] != slist->slh_tail && i++ < slist->slh_head->field.sle.len) \
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while (node->field.sle.next[i] != slist->slh_tail && i++ < slist->slh_head->field.sle.height) \
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; \
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slist->slh_head->field.sle.len = i; \
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slist->slh_tail->field.sle.len = i; \
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slist->slh_head->field.sle.height = i; \
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slist->slh_tail->field.sle.height = i; \
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slist->length--; \
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} \
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return 0; \
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@ -725,7 +781,7 @@
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} \
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\
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/* -- skip_snapshot_ TODO/WIP \
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* A snapshot is a read-only view of a Skiplist at a point in \
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* A snapshot is a read-only view of a Skip List at a point in \
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* time. Once taken, a snapshot must be restored or disposed. \
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* Any number of snapshots can be created. \
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* \
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@ -786,12 +842,12 @@
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if (rc) \
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goto fail; \
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\
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slist->slh_head->field.sle.len = 0; \
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slist->slh_head->field.sle.height = 0; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_head->field.sle.next[i] = slist->slh_tail; \
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slist->slh_head->field.sle.prev = NULL; \
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\
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slist->slh_tail->field.sle.len = slist->max; \
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slist->slh_tail->field.sle.height = slist->max; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_tail->field.sle.next[i] = NULL; \
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slist->slh_tail->field.sle.prev = slist->slh_head; \
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@ -893,12 +949,12 @@
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if (rc) \
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goto fail; \
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\
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slist->slh_head->field.sle.len = 0; \
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slist->slh_head->field.sle.height = 0; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_head->field.sle.next[i] = slist->slh_tail; \
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slist->slh_head->field.sle.prev = NULL; \
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\
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slist->slh_tail->field.sle.len = slist->max; \
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slist->slh_tail->field.sle.height = slist->max; \
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for (i = 0; i < slist->max; i++) \
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slist->slh_tail->field.sle.next[i] = NULL; \
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slist->slh_tail->field.sle.prev = slist->slh_head; \
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@ -941,6 +997,17 @@
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return (vtype)0; \
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} \
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\
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int prefix##skip_contains_##decl(decl##_t *slist, ktype key) \
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{ \
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decl##_node_t *node, query; \
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\
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qblk; \
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node = prefix##skip_position_eq_##decl(slist, &query); \
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if (node) \
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return 1; \
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return 0; \
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} \
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\
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decl##_node_t *prefix##skip_pos_##decl(decl##_t *slist, skip_pos_##decl_t op, ktype key) \
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{ \
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decl##_node_t *node, query; \
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@ -1029,7 +1096,7 @@
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static void __skip_dot_node_##decl(FILE *os, decl##_t *slist, decl##_node_t *node, size_t nsg, skip_sprintf_node_##decl##_t fn) \
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{ \
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char buf[2048]; \
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size_t level, width, height = node->field.sle.len; \
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size_t level, width, height = node->field.sle.height; \
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decl##_node_t *next; \
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\
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fprintf(os, "\"node%zu %p\"", nsg, (void *)node); \
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@ -1093,7 +1160,7 @@
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\
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/* -- skip_dot_ \
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* Create a DOT file of the internal representation of the \
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* Skiplist on the provided file descriptor (default: STDOUT). \
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||||
* Skip List on the provided file descriptor (default: STDOUT). \
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||||
* \
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||||
* To view the output: \
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||||
* $ dot -Tps filename.dot -o outfile.ps \
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||||
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|
@ -1132,8 +1199,8 @@
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fprintf(os, "Empty HeadNode"); \
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else { \
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node = slist->slh_head->field.sle.next[0]; \
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||||
level = slist->slh_head->field.sle.len; \
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next = node->field.sle.next[level] == NULL ? slist->slh_tail : node->field.sle.next[level]; \
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level = slist->slh_head->field.sle.height; \
|
||||
next = node->field.sle.next[level] == NULL ? slist->slh_tail : node->field.sle.next[level]; /*TODO*/ \
|
||||
do { \
|
||||
width = __skip_dot_width_##decl(slist, node, level); \
|
||||
fprintf(os, "{ %zu | <f%zu> %p }", width, level, (void *)next); \
|
||||
|
|
@ -1147,7 +1214,7 @@
|
|||
\
|
||||
/* Edges for head node */ \
|
||||
node = slist->slh_head; \
|
||||
for (level = 0; level < slist->slh_head->field.sle.len; level++) { \
|
||||
for (level = 0; level < slist->slh_head->field.sle.height; level++) { \
|
||||
if (node->field.sle.next[level] == slist->slh_tail) \
|
||||
break; \
|
||||
fprintf(os, "\"HeadNode%zu\":f%zu -> ", nsg, level); \
|
||||
|
|
@ -1166,7 +1233,7 @@
|
|||
node = slist->slh_tail; \
|
||||
if (prefix##skip_size_##decl(slist) > 0) { \
|
||||
fprintf(os, "\"node%zu %p\" [label = \"", nsg, (void *)slist->slh_tail); \
|
||||
level = node->field.sle.len; \
|
||||
level = node->field.sle.height; \
|
||||
do { \
|
||||
fprintf(os, "<w%zu> %p", level, (void *)node); \
|
||||
if (level && node->field.sle.prev != slist->slh_head) \
|
||||
|
|
|
|||
Loading…
Reference in a new issue