diff --git a/include/sl.h b/include/sl.h index e0a7a69..bdd0173 100644 --- a/include/sl.h +++ b/include/sl.h @@ -52,15 +52,15 @@ * can grow to (`array[-2]`) and the length, or number of elements used in the * array so far (`array[-1]`). */ -#define ARRAY_ALLOC(var, type, size) \ - do { \ - (size) = (size == 0 ? 254 : size); \ - (var) = (type **)calloc(sizeof(type *), size + 2); \ - if ((var) != NULL) { \ - *(var)++ = (void *)(uintptr_t)size; \ - *(var)++ = (void *)(uintptr_t)0; \ - } \ - } while (0) +#define ARRAY_ALLOC(var, type, size) \ + do { \ + (size) = (size == 0 ? 254 : size); \ + (var) = (type **)calloc(sizeof(type *), size + 2); \ + if ((var) != NULL) { \ + *(var)++ = (void *)(uintptr_t)size; \ + *(var)++ = (void *)(uintptr_t)0; \ + } \ + } while (0) #define ARRAY_FREE(list) free((list)-2) #define ARRAY_SIZE(list) (unsigned int)(uintptr_t)(list)[-2] #define ARRAY_SET_SIZE(list, size) (list)[-2] = (void *)(uintptr_t)(size) @@ -70,20 +70,20 @@ /* * Skiplist declarations. */ -#define SKIP_HEAD(name, type) \ - struct name { \ - size_t level, length, max, fanout; \ - int (*cmp)(struct name *, struct type *, struct type *, void *); \ - void *aux; \ - struct type *slh_head; \ - struct type *slh_tail; \ - } +#define SKIP_HEAD(name, type) \ + struct name { \ + size_t level, length, max, fanout; \ + int (*cmp)(struct name *, struct type *, struct type *, void *); \ + void *aux; \ + struct type *slh_head; \ + struct type *slh_tail; \ + } -#define SKIP_ENTRY(type) \ - struct { \ - struct type **sle_next; \ - struct type *sle_prev; \ - } +#define SKIP_ENTRY(type) \ + struct { \ + struct type **sle_next; \ + struct type *sle_prev; \ + } /* * Skip List access methods. @@ -98,686 +98,664 @@ * Skip List functions. */ -#define SKIP_COMPARATOR(list, type, fn) \ - int __skip_cmp_##type(struct list *head, struct type *a, struct type *b, \ - void *aux) \ - { \ - if (a == b) \ - return 0; \ - if (a == (head)->slh_head || b == (head)->slh_tail) \ - return -1; \ - if (a == (head)->slh_tail || b == (head)->slh_head) \ - return 1; \ - fn \ - } +#define SKIP_COMPARATOR(list, type, fn) \ + int __skip_cmp_##type(struct list *head, struct type *a, struct type *b, void *aux) \ + { \ + if (a == b) \ + return 0; \ + if (a == (head)->slh_head || b == (head)->slh_tail) \ + return -1; \ + if (a == (head)->slh_tail || b == (head)->slh_head) \ + return 1; \ + fn \ + } -#define SKIPLIST_DECL(decl, prefix, field, free_node_blk, update_node_blk) \ - \ - /* Skiplist node type */ \ - typedef struct decl##_node decl##_node_t; \ - \ - /* Skiplist type */ \ - typedef struct decl { \ - size_t level, length, max, fanout; \ - int (*cmp)(struct decl *, decl##_node_t *, decl##_node_t *, void *); \ - void *aux; \ - decl##_node_t *slh_head; \ - decl##_node_t *slh_tail; \ - } decl##_t; \ - \ - /* -- __skip_key_compare_ \ - * \ - * This function takes four arguments: \ - * - a reference to the Skiplist \ - * - the two nodes to compare, `a` and `b` \ - * - `aux` an additional auxiliary argument \ - * and returns: \ - * a < b : return -1 \ - * a == b : return 0 \ - * a > b : return 1 \ - */ \ - static int __skip_key_compare_##decl(decl##_t *slist, decl##_node_t *a, \ - decl##_node_t *b, void *aux) \ - { \ - if (a == b) \ - return 0; \ - if (a == slist->slh_head || b == slist->slh_tail) \ - return -1; \ - if (a == slist->slh_tail || b == slist->slh_head) \ - return 1; \ - return slist->cmp(slist, a, b, aux); \ - } \ - \ - /* -- __skip_toss_ */ \ - static int __skip_toss_##decl(size_t max, size_t fanout) \ - { \ - size_t level = 0; \ - while (level + 1 < max) { \ - if (rand() % fanout == 0) /* NOLINT(*-msc50-cpp) */ \ - level++; \ - else \ - break; \ - } \ - return level; \ - } \ - \ - /* -- skip_alloc_node_ */ \ - int prefix##skip_alloc_node_##decl(decl##_t *slist, decl##_node_t **node) \ - { \ - decl##_node_t *n; \ - n = (decl##_node_t *)calloc(1, sizeof(decl##_node_t)); \ - ARRAY_ALLOC(n->field.sle_next, struct decl##_node, slist->max); \ - if (n && n->field.sle_next) { \ - ARRAY_SET_SIZE(n->field.sle_next, slist->max); \ - ARRAY_SET_LENGTH(n->field.sle_next, 0); \ - *node = n; \ - return 0; \ - } \ - return ENOMEM; \ - } \ - \ - /* -- skip_init_ \ - * max: 12, fanout: 4 are good defaults. \ - */ \ - int prefix##skip_init_##decl(decl##_t *slist, size_t max, size_t fanout, \ - int (*cmp)(struct decl *, decl##_node_t *, decl##_node_t *, void *)) \ - { \ - int rc = 0; \ - slist->level = 0; \ - slist->length = 0; \ - slist->max = max; \ - slist->fanout = fanout; \ - slist->cmp = cmp; \ - rc = prefix##skip_alloc_node_##decl(slist, &slist->slh_head); \ - if (rc) \ - goto fail; \ - rc = prefix##skip_alloc_node_##decl(slist, &slist->slh_tail); \ - if (rc) \ - goto fail; \ - ARRAY_SET_LENGTH(slist->slh_head->field.sle_next, max); \ - for (size_t __i = 0; __i < max; __i++) \ - slist->slh_head->field.sle_next[__i] = slist->slh_tail; \ - slist->slh_head->field.sle_prev = NULL; \ - ARRAY_SET_LENGTH(slist->slh_tail->field.sle_next, max); \ - for (size_t __i = 0; __i < max; __i++) \ - slist->slh_tail->field.sle_next[__i] = NULL; \ - slist->slh_head->field.sle_prev = slist->slh_tail; \ - fail:; \ - return rc; \ - } \ - \ - /* -- skip_free_node_ */ \ - void prefix##skip_free_node_##decl(decl##_node_t *node) \ - { \ - free_node_blk; \ - ARRAY_FREE(node->field.sle_next); \ - free(node); \ - } \ - \ - /* -- skip_size_ */ \ - int prefix##skip_size_##decl(decl##_t *slist) \ - { \ - return slist->length; \ - } \ - \ - /* -- skip_empty_ */ \ - int prefix##skip_empty_##decl(decl##_t *slist) \ - { \ - return slist->length == 0; \ - } \ - \ - /* -- skip_head_ */ \ - decl##_node_t *prefix##skip_head_##decl(decl##_t *slist) \ - { \ - return slist->slh_head->field.sle_next[0]; \ - } \ - \ - /* -- skip_tail_ */ \ - decl##_node_t *prefix##skip_tail_##decl(decl##_t *slist) \ - { \ - return slist->slh_tail->field.sle_prev; \ - } \ - \ - /* -- skip_locate_ \ - * Locates a node that matches another node returning the path to that \ - * node and the match in path[0]. \ - */ \ - decl##_node_t **prefix##skip_locate_##decl(decl##_t *slist, \ - decl##_node_t *n) \ - { \ - unsigned int i; \ - decl##_node_t **path; \ - decl##_node_t *elm = slist->slh_head; \ - \ - if (slist == NULL || n == NULL) \ - return NULL; \ - \ - i = slist->max + 1; \ - ARRAY_ALLOC(path, decl##_node_t, i); \ - ARRAY_SET_LENGTH(path, 1); \ - i = slist->level; \ - if (path == NULL) \ - return NULL; \ - \ - /* Find the node that matches `node` or NULL. */ \ - do { \ - while (elm && \ - __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, \ - slist->aux) < 0) \ - elm = elm->field.sle_next[i]; \ - path[i + 1] = elm; \ - ARRAY_SET_LENGTH(path, ARRAY_LENGTH(path) + 1); \ - } while (i--); \ - elm = elm->field.sle_next[0]; \ - if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ - path[0] = elm; \ - return path; \ - } \ - ARRAY_FREE(path); \ - return NULL; \ - } \ - \ - /* -- __skip_insert_ */ \ - static int __skip_insert_##decl(decl##_t *slist, decl##_node_t *n, \ - int flags) \ - { \ - unsigned int i; \ - decl##_node_t *prev, *elm = slist->slh_head; \ - decl##_node_t **path; \ - \ - if (n == NULL) \ - return ENOENT; \ - \ - i = slist->level; \ - ARRAY_ALLOC(path, decl##_node_t, slist->max); \ - if (path == NULL) \ - return ENOMEM; \ - \ - /* Find the position in the list where this element belongs. */ \ - do { \ - while (elm && \ - __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, \ - slist->aux) < 0) \ - elm = elm->field.sle_next[i]; \ - path[i] = elm; \ - ARRAY_SET_LENGTH(path, ARRAY_LENGTH(path) + 1); \ - } while (i--); \ - i = 0; \ - prev = elm; \ - elm = elm->field.sle_next[0]; \ - if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ - if (flags == 0) { \ - /* Don't overwrite, to do that use _REPLACE not _INSERT */ \ - ARRAY_FREE(path); \ - return -1; \ - } \ - } \ - size_t level = __skip_toss_##decl(slist->max, slist->fanout); \ - ARRAY_SET_LENGTH(n->field.sle_next, level + 1); \ - if (level > slist->level) { \ - for (i = slist->level + 1; i <= level; i++) { \ - path[i] = slist->slh_tail; \ - } \ - slist->level = level; \ - } \ - for (i = 0; i <= level; i++) { \ - n->field.sle_next[i] = path[i]->field.sle_next[i]; \ - path[i]->field.sle_next[i] = n; \ - } \ - n->field.sle_prev = prev; \ - if (n->field.sle_next[0] == slist->slh_tail) { \ - slist->slh_tail->field.sle_prev = n; \ - } \ - slist->length++; \ - ARRAY_FREE(path); \ - return 0; \ - } \ - \ - /* -- skip_insert_ */ \ - int prefix##skip_insert_##decl(decl##_t *slist, decl##_node_t *n) \ - { \ - return __skip_insert_##decl(slist, n, 0); \ - } \ - \ - /* -- skip_insert_dup_ */ \ - int prefix##skip_insert_dup_##decl(decl##_t *slist, decl##_node_t *n) \ - { \ - return __skip_insert_##decl(slist, n, 1); \ - } \ - \ - /* -- skip_find_ \ - * Find a node that matches another node. This differs from the locate() \ - * API in that it does not return the path to the node, only the match. \ - * This avoids an alloc/free for the path. \ - */ \ - decl##_node_t *prefix##skip_find_##decl(decl##_t *slist, decl##_node_t *n) \ - { \ - unsigned int i; \ - decl##_node_t *elm = slist->slh_head; \ - \ - if (slist == NULL || n == NULL) \ - return NULL; \ - \ - i = slist->level; \ - \ - do { \ - while (elm && \ - __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, \ - slist->aux) < 0) \ - elm = elm->field.sle_next[i]; \ - } while (i--); \ - elm = elm->field.sle_next[0]; \ - if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ - return elm; \ - } \ - return NULL; \ - } \ - \ - /* -- skip_find_gte \ - * Return the matching node or the next greater node after that. \ - */ \ - decl##_node_t *prefix##skip_find_gte_##decl(decl##_t *slist, \ - decl##_node_t *n) \ - { \ - int cmp; \ - unsigned int i; \ - decl##_node_t *elm = slist->slh_head; \ - \ - if (slist == NULL || n == NULL) \ - return NULL; \ - \ - i = slist->level; \ - \ - do { \ - while (elm && \ - __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, \ - slist->aux) < 0) \ - elm = elm->field.sle_next[i]; \ - } while (i--); \ - do { \ - elm = elm->field.sle_next[0]; \ - cmp = __skip_key_compare_##decl(slist, elm, n, slist->aux); \ - } while (cmp < 0); \ - return elm; \ - } \ - \ - /* -- skip_find_lte \ - * Return the matching node or the last one before it. \ - */ \ - decl##_node_t *prefix##skip_find_lte_##decl(decl##_t *slist, \ - decl##_node_t *n) \ - { \ - int cmp; \ - unsigned int i; \ - decl##_node_t *elm = slist->slh_head; \ - \ - if (slist == NULL || n == NULL) \ - return NULL; \ - \ - i = slist->level; \ - \ - do { \ - while (elm && \ - __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, \ - slist->aux) < 0) \ - elm = elm->field.sle_next[i]; \ - } while (i--); \ - elm = elm->field.sle_next[0]; \ - if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ - return elm; \ - } else { \ - do { \ - elm = elm->field.sle_prev; \ - cmp = __skip_key_compare_##decl(slist, elm, n, slist->aux); \ - } while (cmp > 0); \ - } \ - return elm; \ - } \ - \ - /* -- skip_update_ \ - * Locates a node in the list that equals the `new` node and then \ - * uses the `update_node_blk` to update the contents. \ - * WARNING: Do not update the portion of the node used for ordering \ - * (e.g. `key`) unless you really know what you're doing. \ - */ \ - int prefix##skip_update_##decl(decl##_t *slist, decl##_node_t *new) \ - { \ - decl##_node_t *node; \ - \ - if (slist == NULL || new == NULL) \ - return -1; \ - \ - node = prefix##skip_find_##decl(slist, new); \ - if (node) { \ - update_node_blk; \ - return 0; \ - } \ - return -1; \ - } \ - \ - /* -- skip_remove_ */ \ - int prefix##skip_remove_##decl(decl##_t *slist, decl##_node_t *n) \ - { \ - size_t i, s; \ - decl##_node_t **path, *node; \ - \ - if (slist == NULL || n == NULL) \ - return -1; \ - if (slist->length == 0) \ - return 0; \ - \ - path = prefix##skip_locate_##decl(slist, n); \ - s = ARRAY_LENGTH(path); \ - node = path[0]; \ - if (s > 0) { \ - node->field.sle_next[0]->field.sle_prev = node->field.sle_prev; \ - for (i = 1; i < s; i++) { \ - if (path[i]->field.sle_next[i - 1] != node) \ - break; \ - path[i]->field.sle_next[i - 1] = node->field.sle_next[i - 1]; \ - if (path[i]->field.sle_next[i - 1] == slist->slh_tail) { \ - size_t h = ARRAY_LENGTH(path[i]->field.sle_next); \ - ARRAY_SET_LENGTH(path[i]->field.sle_next, h - 1); \ - } \ - } \ - ARRAY_FREE(path); \ - free_node_blk; \ - /* Find all levels in the first element in the list that point \ - at the tail and shrink the level. */ \ - while (slist->level > 0 && \ - slist->slh_head->field.sle_next[slist->level] == slist->slh_tail) { \ - slist->level--; \ - } \ - slist->length--; \ - } \ - return 0; \ - } \ - \ - /* -- skip_next_node_ */ \ - decl##_node_t *prefix##skip_next_node_##decl(decl##_t *slist, \ - decl##_node_t *n) \ - { \ - if (slist == NULL || n == NULL) \ - return NULL; \ - if (n->field.sle_next[0] == slist->slh_tail) \ - return NULL; \ - return n->field.sle_next[0]; \ - } \ - \ - /* -- skip_prev_node_ */ \ - decl##_node_t *prefix##skip_prev_node_##decl(decl##_t *slist, \ - decl##_node_t *n) \ - { \ - if (slist == NULL || n == NULL) \ - return NULL; \ - if (n->field.sle_prev == slist->slh_head) \ - return NULL; \ - return n->field.sle_prev; \ - } \ - \ - /* -- skip_destroy_ */ \ - int prefix##skip_destroy_##decl(decl##_t *slist) \ - { \ - decl##_node_t *node, *next; \ - if (slist == NULL) \ - return 0; \ - if (prefix##skip_size_##decl(slist) == 0) \ - return 0; \ - node = prefix##skip_head_##decl(slist); \ - do { \ - next = prefix##skip_next_node_##decl(slist, node); \ - prefix##skip_free_node_##decl(node); \ - node = next; \ - } while (node != NULL); \ - \ - ARRAY_FREE(slist->slh_head->field.sle_next); \ - free(slist->slh_head); \ - ARRAY_FREE(slist->slh_tail->field.sle_next); \ - free(slist->slh_tail); \ - return 0; \ - } \ - \ - /* -- skip_snapshot_ \ - * A snapshot is a read-only view of a Skiplist at a point in \ - * time. Once taken, a snapshot must be restored or disposed. \ - * Any number of snapshots can be created. \ - */ \ - int prefix##skip_snapshot_##decl(decl##_t *slist) \ - { \ - ((void)slist); /* TODO */ \ - return 0; \ - } \ - \ - /* -- skip_restore_snapshot_ */ \ - int prefix##skip_restore_snapshot_##decl(decl##_t *slist) \ - { \ - ((void)slist); /* TODO */ \ - return 0; \ - } \ - \ - /* -- skip_dispose_snapshot_ */ \ - int prefix##skip_dispose_snapshot_##decl(decl##_t *slist) \ - { \ - ((void)slist); /* TODO */ \ - return 0; \ - } \ - \ - /* -- __skip_integrity_check_ */ \ - static int __skip_integrity_check_##decl(decl##_t *slist) \ - { \ - ((void)slist); /* TODO */ \ - return 0; \ - } +#define SKIPLIST_DECL(decl, prefix, field, free_node_blk, update_node_blk) \ + \ + /* Skiplist node type */ \ + typedef struct decl##_node decl##_node_t; \ + \ + /* Skiplist type */ \ + typedef struct decl { \ + size_t level, length, max, fanout; \ + int (*cmp)(struct decl *, decl##_node_t *, decl##_node_t *, void *); \ + void *aux; \ + decl##_node_t *slh_head; \ + decl##_node_t *slh_tail; \ + } decl##_t; \ + \ + /* -- __skip_key_compare_ \ + * \ + * This function takes four arguments: \ + * - a reference to the Skiplist \ + * - the two nodes to compare, `a` and `b` \ + * - `aux` an additional auxiliary argument \ + * and returns: \ + * a < b : return -1 \ + * a == b : return 0 \ + * a > b : return 1 \ + */ \ + static int __skip_key_compare_##decl(decl##_t *slist, decl##_node_t *a, decl##_node_t *b, void *aux) \ + { \ + if (a == b) \ + return 0; \ + if (a == slist->slh_head || b == slist->slh_tail) \ + return -1; \ + if (a == slist->slh_tail || b == slist->slh_head) \ + return 1; \ + return slist->cmp(slist, a, b, aux); \ + } \ + \ + /* -- __skip_toss_ */ \ + static int __skip_toss_##decl(size_t max, size_t fanout) \ + { \ + size_t level = 0; \ + while (level + 1 < max) { \ + if (rand() % fanout == 0) /* NOLINT(*-msc50-cpp) */ \ + level++; \ + else \ + break; \ + } \ + return level; \ + } \ + \ + /* -- skip_alloc_node_ */ \ + int prefix##skip_alloc_node_##decl(decl##_t *slist, decl##_node_t **node) \ + { \ + decl##_node_t *n; \ + n = (decl##_node_t *)calloc(1, sizeof(decl##_node_t)); \ + ARRAY_ALLOC(n->field.sle_next, struct decl##_node, slist->max); \ + if (n && n->field.sle_next) { \ + ARRAY_SET_SIZE(n->field.sle_next, slist->max); \ + ARRAY_SET_LENGTH(n->field.sle_next, 0); \ + *node = n; \ + return 0; \ + } \ + return ENOMEM; \ + } \ + \ + /* -- skip_init_ \ + * max: 12, fanout: 4 are good defaults. \ + */ \ + int prefix##skip_init_##decl(decl##_t *slist, size_t max, size_t fanout, int (*cmp)(struct decl *, decl##_node_t *, decl##_node_t *, void *)) \ + { \ + int rc = 0; \ + slist->level = 0; \ + slist->length = 0; \ + slist->max = max; \ + slist->fanout = fanout; \ + slist->cmp = cmp; \ + rc = prefix##skip_alloc_node_##decl(slist, &slist->slh_head); \ + if (rc) \ + goto fail; \ + rc = prefix##skip_alloc_node_##decl(slist, &slist->slh_tail); \ + if (rc) \ + goto fail; \ + ARRAY_SET_LENGTH(slist->slh_head->field.sle_next, max); \ + for (size_t __i = 0; __i < max; __i++) \ + slist->slh_head->field.sle_next[__i] = slist->slh_tail; \ + slist->slh_head->field.sle_prev = NULL; \ + ARRAY_SET_LENGTH(slist->slh_tail->field.sle_next, max); \ + for (size_t __i = 0; __i < max; __i++) \ + slist->slh_tail->field.sle_next[__i] = NULL; \ + slist->slh_head->field.sle_prev = slist->slh_tail; \ + fail:; \ + return rc; \ + } \ + \ + /* -- skip_free_node_ */ \ + void prefix##skip_free_node_##decl(decl##_node_t *node) \ + { \ + free_node_blk; \ + ARRAY_FREE(node->field.sle_next); \ + free(node); \ + } \ + \ + /* -- skip_size_ */ \ + int prefix##skip_size_##decl(decl##_t *slist) \ + { \ + return slist->length; \ + } \ + \ + /* -- skip_empty_ */ \ + int prefix##skip_empty_##decl(decl##_t *slist) \ + { \ + return slist->length == 0; \ + } \ + \ + /* -- skip_head_ */ \ + decl##_node_t *prefix##skip_head_##decl(decl##_t *slist) \ + { \ + return slist->slh_head->field.sle_next[0]; \ + } \ + \ + /* -- skip_tail_ */ \ + decl##_node_t *prefix##skip_tail_##decl(decl##_t *slist) \ + { \ + return slist->slh_tail->field.sle_prev; \ + } \ + \ + /* -- skip_locate_ \ + * Locates a node that matches another node returning the path to that \ + * node and the match in path[0]. \ + */ \ + decl##_node_t **prefix##skip_locate_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + unsigned int i; \ + decl##_node_t **path; \ + decl##_node_t *elm = slist->slh_head; \ + \ + if (slist == NULL || n == NULL) \ + return NULL; \ + \ + i = slist->max + 1; \ + ARRAY_ALLOC(path, decl##_node_t, i); \ + ARRAY_SET_LENGTH(path, 1); \ + i = slist->level; \ + if (path == NULL) \ + return NULL; \ + \ + /* Find the node that matches `node` or NULL. */ \ + do { \ + while (elm && __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, slist->aux) < 0) \ + elm = elm->field.sle_next[i]; \ + path[i + 1] = elm; \ + ARRAY_SET_LENGTH(path, ARRAY_LENGTH(path) + 1); \ + } while (i--); \ + elm = elm->field.sle_next[0]; \ + if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ + path[0] = elm; \ + return path; \ + } \ + ARRAY_FREE(path); \ + return NULL; \ + } \ + \ + /* -- __skip_insert_ */ \ + static int __skip_insert_##decl(decl##_t *slist, decl##_node_t *n, int flags) \ + { \ + unsigned int i; \ + decl##_node_t *prev, *elm = slist->slh_head; \ + decl##_node_t **path; \ + \ + if (n == NULL) \ + return ENOENT; \ + \ + i = slist->level; \ + ARRAY_ALLOC(path, decl##_node_t, slist->max); \ + if (path == NULL) \ + return ENOMEM; \ + \ + /* Find the position in the list where this element belongs. */ \ + do { \ + while (elm && __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, slist->aux) < 0) \ + elm = elm->field.sle_next[i]; \ + path[i] = elm; \ + ARRAY_SET_LENGTH(path, ARRAY_LENGTH(path) + 1); \ + } while (i--); \ + i = 0; \ + prev = elm; \ + elm = elm->field.sle_next[0]; \ + if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ + if (flags == 0) { \ + /* Don't overwrite, to do that use _REPLACE not _INSERT */ \ + ARRAY_FREE(path); \ + return -1; \ + } \ + } \ + size_t level = __skip_toss_##decl(slist->max, slist->fanout); \ + ARRAY_SET_LENGTH(n->field.sle_next, level + 1); \ + if (level > slist->level) { \ + for (i = slist->level + 1; i <= level; i++) { \ + path[i] = slist->slh_tail; \ + } \ + slist->level = level; \ + } \ + for (i = 0; i <= level; i++) { \ + n->field.sle_next[i] = path[i]->field.sle_next[i]; \ + path[i]->field.sle_next[i] = n; \ + } \ + n->field.sle_prev = prev; \ + if (n->field.sle_next[0] == slist->slh_tail) { \ + slist->slh_tail->field.sle_prev = n; \ + } \ + slist->length++; \ + ARRAY_FREE(path); \ + return 0; \ + } \ + \ + /* -- skip_insert_ */ \ + int prefix##skip_insert_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + return __skip_insert_##decl(slist, n, 0); \ + } \ + \ + /* -- skip_insert_dup_ */ \ + int prefix##skip_insert_dup_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + return __skip_insert_##decl(slist, n, 1); \ + } \ + \ + /* -- skip_find_ \ + * Find a node that matches another node. This differs from the locate() \ + * API in that it does not return the path to the node, only the match. \ + * This avoids an alloc/free for the path. \ + */ \ + decl##_node_t *prefix##skip_find_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + unsigned int i; \ + decl##_node_t *elm = slist->slh_head; \ + \ + if (slist == NULL || n == NULL) \ + return NULL; \ + \ + i = slist->level; \ + \ + do { \ + while (elm && __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, slist->aux) < 0) \ + elm = elm->field.sle_next[i]; \ + } while (i--); \ + elm = elm->field.sle_next[0]; \ + if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ + return elm; \ + } \ + return NULL; \ + } \ + \ + /* -- skip_find_gte \ + * Return the matching node or the next greater node after that. \ + */ \ + decl##_node_t *prefix##skip_find_gte_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + int cmp; \ + unsigned int i; \ + decl##_node_t *elm = slist->slh_head; \ + \ + if (slist == NULL || n == NULL) \ + return NULL; \ + \ + i = slist->level; \ + \ + do { \ + while (elm && __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, slist->aux) < 0) \ + elm = elm->field.sle_next[i]; \ + } while (i--); \ + do { \ + elm = elm->field.sle_next[0]; \ + cmp = __skip_key_compare_##decl(slist, elm, n, slist->aux); \ + } while (cmp < 0); \ + return elm; \ + } \ + \ + /* -- skip_find_lte \ + * Return the matching node or the last one before it. \ + */ \ + decl##_node_t *prefix##skip_find_lte_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + int cmp; \ + unsigned int i; \ + decl##_node_t *elm = slist->slh_head; \ + \ + if (slist == NULL || n == NULL) \ + return NULL; \ + \ + i = slist->level; \ + \ + do { \ + while (elm && __skip_key_compare_##decl(slist, elm->field.sle_next[i], n, slist->aux) < 0) \ + elm = elm->field.sle_next[i]; \ + } while (i--); \ + elm = elm->field.sle_next[0]; \ + if (__skip_key_compare_##decl(slist, elm, n, slist->aux) == 0) { \ + return elm; \ + } else { \ + do { \ + elm = elm->field.sle_prev; \ + cmp = __skip_key_compare_##decl(slist, elm, n, slist->aux); \ + } while (cmp > 0); \ + } \ + return elm; \ + } \ + \ + /* -- skip_update_ \ + * Locates a node in the list that equals the `new` node and then \ + * uses the `update_node_blk` to update the contents. \ + * WARNING: Do not update the portion of the node used for ordering \ + * (e.g. `key`) unless you really know what you're doing. \ + */ \ + int prefix##skip_update_##decl(decl##_t *slist, decl##_node_t *new) \ + { \ + decl##_node_t *node; \ + \ + if (slist == NULL || new == NULL) \ + return -1; \ + \ + node = prefix##skip_find_##decl(slist, new); \ + if (node) { \ + update_node_blk; \ + return 0; \ + } \ + return -1; \ + } \ + \ + /* -- skip_remove_ */ \ + int prefix##skip_remove_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + size_t i, s; \ + decl##_node_t **path, *node; \ + \ + if (slist == NULL || n == NULL) \ + return -1; \ + if (slist->length == 0) \ + return 0; \ + \ + path = prefix##skip_locate_##decl(slist, n); \ + s = ARRAY_LENGTH(path); \ + node = path[0]; \ + if (s > 0) { \ + node->field.sle_next[0]->field.sle_prev = node->field.sle_prev; \ + for (i = 1; i < s; i++) { \ + if (path[i]->field.sle_next[i - 1] != node) \ + break; \ + path[i]->field.sle_next[i - 1] = node->field.sle_next[i - 1]; \ + if (path[i]->field.sle_next[i - 1] == slist->slh_tail) { \ + size_t h = ARRAY_LENGTH(path[i]->field.sle_next); \ + ARRAY_SET_LENGTH(path[i]->field.sle_next, h - 1); \ + } \ + } \ + ARRAY_FREE(path); \ + free_node_blk; \ + /* Find all levels in the first element in the list that point \ + at the tail and shrink the level. */ \ + while (slist->level > 0 && slist->slh_head->field.sle_next[slist->level] == slist->slh_tail) { \ + slist->level--; \ + } \ + slist->length--; \ + } \ + return 0; \ + } \ + \ + /* -- skip_next_node_ */ \ + decl##_node_t *prefix##skip_next_node_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + if (slist == NULL || n == NULL) \ + return NULL; \ + if (n->field.sle_next[0] == slist->slh_tail) \ + return NULL; \ + return n->field.sle_next[0]; \ + } \ + \ + /* -- skip_prev_node_ */ \ + decl##_node_t *prefix##skip_prev_node_##decl(decl##_t *slist, decl##_node_t *n) \ + { \ + if (slist == NULL || n == NULL) \ + return NULL; \ + if (n->field.sle_prev == slist->slh_head) \ + return NULL; \ + return n->field.sle_prev; \ + } \ + \ + /* -- skip_destroy_ */ \ + int prefix##skip_destroy_##decl(decl##_t *slist) \ + { \ + decl##_node_t *node, *next; \ + if (slist == NULL) \ + return 0; \ + if (prefix##skip_size_##decl(slist) == 0) \ + return 0; \ + node = prefix##skip_head_##decl(slist); \ + do { \ + next = prefix##skip_next_node_##decl(slist, node); \ + prefix##skip_free_node_##decl(node); \ + node = next; \ + } while (node != NULL); \ + \ + ARRAY_FREE(slist->slh_head->field.sle_next); \ + free(slist->slh_head); \ + ARRAY_FREE(slist->slh_tail->field.sle_next); \ + free(slist->slh_tail); \ + return 0; \ + } \ + \ + /* -- skip_snapshot_ \ + * A snapshot is a read-only view of a Skiplist at a point in \ + * time. Once taken, a snapshot must be restored or disposed. \ + * Any number of snapshots can be created. \ + */ \ + int prefix##skip_snapshot_##decl(decl##_t *slist) \ + { \ + ((void)slist); /* TODO */ \ + return 0; \ + } \ + \ + /* -- skip_restore_snapshot_ */ \ + int prefix##skip_restore_snapshot_##decl(decl##_t *slist) \ + { \ + ((void)slist); /* TODO */ \ + return 0; \ + } \ + \ + /* -- skip_dispose_snapshot_ */ \ + int prefix##skip_dispose_snapshot_##decl(decl##_t *slist) \ + { \ + ((void)slist); /* TODO */ \ + return 0; \ + } \ + \ + /* -- __skip_integrity_check_ */ \ + static int __skip_integrity_check_##decl(decl##_t *slist) \ + { \ + ((void)slist); /* TODO */ \ + return 0; \ + } #define SKIPLIST_GETTERS(decl, prefix, ktype, vtype, qblk, rblk) \ - vtype prefix##skip_get_##decl(decl##_t *slist, ktype key) \ - { \ - decl##_node_t *node, query; \ + vtype prefix##skip_get_##decl(decl##_t *slist, ktype key) \ + { \ + decl##_node_t *node, query; \ \ - qblk; \ - node = prefix##skip_find_##decl(slist, &query); \ - if (node) { \ - rblk; \ + qblk; \ + node = prefix##skip_find_##decl(slist, &query); \ + if (node) { \ + rblk; \ + } \ + return (vtype)0; \ } \ - return (vtype)0; \ - } \ - vtype prefix##skip_gte_##decl(decl##_t *slist, ktype key) \ - { \ - decl##_node_t *node, query; \ + vtype prefix##skip_gte_##decl(decl##_t *slist, ktype key) \ + { \ + decl##_node_t *node, query; \ \ - qblk; \ - node = prefix##skip_find_gte_##decl(slist, &query); \ - if (node != slist->slh_tail) { \ - rblk; \ + qblk; \ + node = prefix##skip_find_gte_##decl(slist, &query); \ + if (node != slist->slh_tail) { \ + rblk; \ + } \ + return (vtype)0; \ } \ - return (vtype)0; \ - } \ - vtype prefix##skip_lte_##decl(decl##_t *slist, ktype key) \ - { \ - decl##_node_t *node, query; \ + vtype prefix##skip_lte_##decl(decl##_t *slist, ktype key) \ + { \ + decl##_node_t *node, query; \ \ - qblk; \ - node = prefix##skip_find_lte_##decl(slist, &query); \ - if (node != slist->slh_head) { \ - rblk; \ - } \ - return (vtype)0; \ - } + qblk; \ + node = prefix##skip_find_lte_##decl(slist, &query); \ + if (node != slist->slh_head) { \ + rblk; \ + } \ + return (vtype)0; \ + } -#define SKIPLIST_DECL_DOT(decl, prefix, field) \ - \ - /* A type for a function that writes into a char[2048] buffer \ - * a description of the value within the node. */ \ - typedef void (*skip_sprintf_node_##decl##_t)(decl##_node_t *, char *); \ - \ - /* -- __skip_dot_node_ \ - * Writes out a fragment of a DOT file representing a node. \ - */ \ - static void __skip_dot_node_##decl(FILE *os, decl##_t *slist, \ - decl##_node_t *node, size_t nsg, skip_sprintf_node_##decl##_t fn) \ - { \ - char buf[2048]; \ - size_t level, height = ARRAY_LENGTH(node->field.sle_next); \ - decl##_node_t *next; \ - \ - fprintf(os, "\"node%zu %p\"", nsg, (void *)node); \ - fprintf(os, " [label = \""); \ - level = height; \ - while (level--) { \ - fprintf(os, " { | %p } |", level, level, \ - (void *)node->field.sle_next[level]); \ - } \ - if (fn) { \ - fn(node, buf); \ - fprintf(os, " %s\"\n", buf); \ - } else { \ - fprintf(os, " ?\"\n"); \ - } \ - fprintf(os, "shape = \"record\"\n"); \ - fprintf(os, "];\n"); \ - \ - /* Now edges */ \ - level = 0; \ - for (level = 0; level < height; level++) { \ - fprintf(os, "\"node%zu %p\"", nsg, (void *)node); \ - fprintf(os, ":f%zu -> ", level); \ - fprintf(os, "\"node%zu %p\"", nsg, (void *)node->field.sle_next[level]); \ - fprintf(os, ":w%zu [];\n", level); \ - } \ - next = prefix##skip_next_node_##decl(slist, node); \ - if (next) \ - __skip_dot_node_##decl(os, slist, next, nsg, fn); \ - } \ - \ - /* -- __skip_dot_finish_ \ - * Finalize the DOT file of the internal representation. \ - */ \ - static void __skip_dot_finish_##decl(FILE *os, size_t nsg) \ - { \ - size_t i; \ - if (nsg > 0) { \ - /* Link the nodes together with an invisible node. \ - * node0 [shape=record, label = " | | | | \ - * | | | | | ", style=invis, width=0.01]; \ - */ \ - fprintf(os, "node0 [shape=record, label = \""); \ - for (i = 0; i < nsg; ++i) { \ - fprintf(os, " | ", i); \ - } \ - fprintf(os, "\", style=invis, width=0.01];\n"); \ - \ - /* Now connect nodes with invisible edges \ - * \ - * node0:f0 -> HeadNode [style=invis]; \ - * node0:f1 -> HeadNode1 [style=invis]; \ - */ \ - for (i = 0; i < nsg; ++i) { \ - fprintf(os, "node0:f%zu -> HeadNode%zu [style=invis];\n", i, i); \ - } \ - nsg = 0; \ - } \ - fprintf(os, "}\n"); \ - } \ - \ - /* -- skip_dot_start_ */ \ - static int __skip_dot_start_##decl(FILE *os, decl##_t *slist, size_t nsg, \ - skip_sprintf_node_##decl##_t fn) \ - { \ - size_t level; \ - decl##_node_t *head; \ - if (nsg == 0) { \ - fprintf(os, "digraph Skiplist {\n"); \ - fprintf(os, "label = \"Skiplist.\"\n"); \ - fprintf(os, "graph [rankdir = \"LR\"];\n"); \ - fprintf(os, "node [fontsize = \"12\" shape = \"ellipse\"];\n"); \ - fprintf(os, "edge [];\n\n"); \ - } \ - fprintf(os, "subgraph cluster%zu {\n", nsg); \ - fprintf(os, "style=dashed\n"); \ - fprintf(os, "label=\"Skip list iteration %zu\"\n\n", nsg); \ - fprintf(os, "\"HeadNode%zu\" [\n", nsg); \ - fprintf(os, "label = \""); \ - \ - /* Write out the fields */ \ - head = slist->slh_head; \ - if (SKIP_EMPTY(slist)) \ - fprintf(os, "Empty HeadNode"); \ - else { \ - level = ARRAY_LENGTH(head->field.sle_next) - 1; \ - do { \ - decl##_node_t *node = head->field.sle_next[level]; \ - fprintf(os, "{ %p }", level, (void *)node); \ - if (level) \ - fprintf(os, " | "); \ - } while (level--); \ - } \ - fprintf(os, "\"\n"); \ - fprintf(os, "shape = \"record\"\n"); \ - fprintf(os, "];\n"); \ - \ - /* Edges for head node */ \ - decl##_node_t *node = slist->slh_head; \ - for (level = 0; level < ARRAY_LENGTH(slist->slh_head->field.sle_next); \ - level++) { \ - fprintf(os, "\"HeadNode%zu\":f%zu -> ", nsg, level); \ - fprintf(os, "\"node%zu %p\"", nsg, (void *)node->field.sle_next[level]); \ - fprintf(os, ":w%zu [];\n", level); \ - } \ - fprintf(os, "\n"); \ - \ - /* Now all nodes via level 0, if non-empty */ \ - node = prefix##skip_head_##decl(slist); \ - if (node) \ - __skip_dot_node_##decl(os, slist, node, nsg, fn); \ - fprintf(os, "\n"); \ - \ - /* The tail, sentinal node */ \ - if (!SKIP_EMPTY(slist)) { \ - fprintf(os, "\"node%zu %p\" [label = \"", nsg, (void *)slist->slh_tail); \ - level = ARRAY_LENGTH(slist->slh_head->field.sle_next); \ - while (level--) { \ - fprintf(os, " %p", level, (void *)slist->slh_tail); \ - if (level) \ - fprintf(os, " | "); \ - } \ - fprintf(os, "\" shape = \"record\"];\n"); \ - } \ - \ - /* End: "subgraph cluster0 {" */ \ - fprintf(os, "}\n\n"); \ - nsg += 1; \ - \ - return nsg; \ - } \ - \ - /* -- skip_dot_ \ - * Create a DOT file of the internal representation of the \ - * Skiplist on the provided file descriptor (default: STDOUT). \ - * \ - * To view the output: \ - * $ dot -Tps filename.dot -o outfile.ps \ - * You can change the output format by varying the value after -T and \ - * choosing an appropriate filename extension after -o. \ - * See: https://graphviz.org/docs/outputs/ for the format options. \ - * \ - * https://en.wikipedia.org/wiki/DOT_(graph_description_language) \ - */ \ - int prefix##skip_dot_##decl(FILE *os, decl##_t *slist, size_t nsg, \ - skip_sprintf_node_##decl##_t fn) \ - { \ - if (__skip_integrity_check_##decl(slist) != 0) { \ - perror("Skiplist failed integrity checks, impossible to diagram."); \ - return -1; \ - } \ - if (os == NULL) \ - os = stdout; \ - if (!os) { \ - perror("Failed to open output file, unable to write DOT file."); \ - return -1; \ - } \ - __skip_dot_start_##decl(os, slist, nsg, fn); \ - __skip_dot_finish_##decl(os, nsg); \ - return 0; \ - } +#define SKIPLIST_DECL_DOT(decl, prefix, field) \ + \ + /* A type for a function that writes into a char[2048] buffer \ + * a description of the value within the node. */ \ + typedef void (*skip_sprintf_node_##decl##_t)(decl##_node_t *, char *); \ + \ + /* -- __skip_dot_node_ \ + * Writes out a fragment of a DOT file representing a node. \ + */ \ + static void __skip_dot_node_##decl(FILE *os, decl##_t *slist, decl##_node_t *node, size_t nsg, skip_sprintf_node_##decl##_t fn) \ + { \ + char buf[2048]; \ + size_t level, height = ARRAY_LENGTH(node->field.sle_next); \ + decl##_node_t *next; \ + \ + fprintf(os, "\"node%zu %p\"", nsg, (void *)node); \ + fprintf(os, " [label = \""); \ + level = height; \ + while (level--) { \ + fprintf(os, " { | %p } |", level, level, (void *)node->field.sle_next[level]); \ + } \ + if (fn) { \ + fn(node, buf); \ + fprintf(os, " %s\"\n", buf); \ + } else { \ + fprintf(os, " ?\"\n"); \ + } \ + fprintf(os, "shape = \"record\"\n"); \ + fprintf(os, "];\n"); \ + \ + /* Now edges */ \ + level = 0; \ + for (level = 0; level < height; level++) { \ + fprintf(os, "\"node%zu %p\"", nsg, (void *)node); \ + fprintf(os, ":f%zu -> ", level); \ + fprintf(os, "\"node%zu %p\"", nsg, (void *)node->field.sle_next[level]); \ + fprintf(os, ":w%zu [];\n", level); \ + } \ + next = prefix##skip_next_node_##decl(slist, node); \ + if (next) \ + __skip_dot_node_##decl(os, slist, next, nsg, fn); \ + } \ + \ + /* -- __skip_dot_finish_ \ + * Finalize the DOT file of the internal representation. \ + */ \ + static void __skip_dot_finish_##decl(FILE *os, size_t nsg) \ + { \ + size_t i; \ + if (nsg > 0) { \ + /* Link the nodes together with an invisible node. \ + * node0 [shape=record, label = " | | | | \ + * | | | | | ", style=invis, width=0.01]; \ + */ \ + fprintf(os, "node0 [shape=record, label = \""); \ + for (i = 0; i < nsg; ++i) { \ + fprintf(os, " | ", i); \ + } \ + fprintf(os, "\", style=invis, width=0.01];\n"); \ + \ + /* Now connect nodes with invisible edges \ + * \ + * node0:f0 -> HeadNode [style=invis]; \ + * node0:f1 -> HeadNode1 [style=invis]; \ + */ \ + for (i = 0; i < nsg; ++i) { \ + fprintf(os, "node0:f%zu -> HeadNode%zu [style=invis];\n", i, i); \ + } \ + nsg = 0; \ + } \ + fprintf(os, "}\n"); \ + } \ + \ + /* -- skip_dot_start_ */ \ + static int __skip_dot_start_##decl(FILE *os, decl##_t *slist, size_t nsg, skip_sprintf_node_##decl##_t fn) \ + { \ + size_t level; \ + decl##_node_t *head, *tail; \ + if (nsg == 0) { \ + fprintf(os, "digraph Skiplist {\n"); \ + fprintf(os, "label = \"Skiplist.\"\n"); \ + fprintf(os, "graph [rankdir = \"LR\"];\n"); \ + fprintf(os, "node [fontsize = \"12\" shape = \"ellipse\"];\n"); \ + fprintf(os, "edge [];\n\n"); \ + } \ + fprintf(os, "subgraph cluster%zu {\n", nsg); \ + fprintf(os, "style=dashed\n"); \ + fprintf(os, "label=\"Skip list iteration %zu\"\n\n", nsg); \ + fprintf(os, "\"HeadNode%zu\" [\n", nsg); \ + fprintf(os, "label = \""); \ + \ + /* Write out the fields */ \ + head = slist->slh_head; \ + if (SKIP_EMPTY(slist)) \ + fprintf(os, "Empty HeadNode"); \ + else { \ + level = ARRAY_LENGTH(head->field.sle_next) - 1; \ + do { \ + decl##_node_t *node = head->field.sle_next[level]; \ + fprintf(os, "{ %p }", level, (void *)node); \ + if (level && head->field.sle_next[level] != slist->slh_tail) \ + fprintf(os, " | "); \ + } while (level-- && head->field.sle_next[level] != slist->slh_tail); \ + } \ + fprintf(os, "\"\n"); \ + fprintf(os, "shape = \"record\"\n"); \ + fprintf(os, "];\n"); \ + \ + /* Edges for head node */ \ + decl##_node_t *node = slist->slh_head; \ + for (level = 0; level < ARRAY_LENGTH(slist->slh_head->field.sle_next); level++) { \ + if (node->field.sle_next[level] == slist->slh_tail) \ + break; \ + fprintf(os, "\"HeadNode%zu\":f%zu -> ", nsg, level); \ + fprintf(os, "\"node%zu %p\"", nsg, (void *)node->field.sle_next[level]); \ + fprintf(os, ":w%zu [];\n", level); \ + } \ + fprintf(os, "\n"); \ + \ + /* Now all nodes via level 0, if non-empty */ \ + node = prefix##skip_head_##decl(slist); \ + if (node) \ + __skip_dot_node_##decl(os, slist, node, nsg, fn); \ + fprintf(os, "\n"); \ + \ + /* The tail, sentinal node */ \ + tail = slist->slh_tail; \ + if (!SKIP_EMPTY(slist)) { \ + fprintf(os, "\"node%zu %p\" [label = \"", nsg, (void *)slist->slh_tail); \ + level = ARRAY_LENGTH(tail->field.sle_next) - 1; \ + do { \ + fprintf(os, " %p", level, (void *)node->field.sle_prev); \ + if (level && node->field.sle_prev != slist->slh_head) \ + fprintf(os, " | "); \ + } while (level-- && node->field.sle_prev != slist->slh_head); \ + fprintf(os, "\" shape = \"record\"];\n"); \ + } \ + \ + /* End: "subgraph cluster0 {" */ \ + fprintf(os, "}\n\n"); \ + nsg += 1; \ + \ + return nsg; \ + } \ + \ + /* -- skip_dot_ \ + * Create a DOT file of the internal representation of the \ + * Skiplist on the provided file descriptor (default: STDOUT). \ + * \ + * To view the output: \ + * $ dot -Tps filename.dot -o outfile.ps \ + * You can change the output format by varying the value after -T and \ + * choosing an appropriate filename extension after -o. \ + * See: https://graphviz.org/docs/outputs/ for the format options. \ + * \ + * https://en.wikipedia.org/wiki/DOT_(graph_description_language) \ + */ \ + int prefix##skip_dot_##decl(FILE *os, decl##_t *slist, size_t nsg, skip_sprintf_node_##decl##_t fn) \ + { \ + if (__skip_integrity_check_##decl(slist) != 0) { \ + perror("Skiplist failed integrity checks, impossible to diagram."); \ + return -1; \ + } \ + if (os == NULL) \ + os = stdout; \ + if (!os) { \ + perror("Failed to open output file, unable to write DOT file."); \ + return -1; \ + } \ + __skip_dot_start_##decl(os, slist, nsg, fn); \ + __skip_dot_finish_##decl(os, nsg); \ + return 0; \ + } #endif /* _SKIPLIST_H_ */