diff options
Diffstat (limited to 'src/btree.c')
| -rw-r--r-- | src/btree.c | 1192 |
1 files changed, 571 insertions, 621 deletions
diff --git a/src/btree.c b/src/btree.c index 63c2513..c125564 100644 --- a/src/btree.c +++ b/src/btree.c @@ -11,116 +11,111 @@ typedef unsigned char byte; struct node { - ssize_t n; /* number of items/keys/elements */ - ssize_t c; /* number of children */ - byte *items; - struct node **children; + ssize_t n; /* number of items/keys/elements */ + ssize_t c; /* number of children */ + byte* items; + struct node** children; }; struct btree { - /* Memory stuffs */ - void *(*alloc)(size_t); - void (*dealloc)(void*); + /* Memory stuffs */ + void* (*alloc)(size_t); + void (*dealloc)(void*); - /* Size stuffs */ - size_t elem_size; - ssize_t degree; + /* Size stuffs */ + size_t elem_size; + ssize_t degree; - struct node *root; + struct node* root; - /* comparison */ - int (*cmp)(const void *a, const void *b); + /* comparison */ + int (*cmp)(const void* a, const void* b); }; struct btree_iter_t { - size_t head; - struct stack { - int pos; - struct node* node; - } stack[512]; - /* This heavily relies on the assumption that a tree never grows deeper than - * 512 nodes */ + size_t head; + struct stack { + int pos; + struct node* node; + } stack[512]; + /* This heavily relies on the assumption that a tree never grows deeper than + * 512 nodes */ }; /**********************/ /* Node functionality */ /**********************/ -#define \ -node_leaf(node) (node->children == NULL) +#define node_leaf(node) (node->children == NULL) -#define \ -node_maxdegree(t) (2 * t - 1) +#define node_maxdegree(t) (2 * t - 1) -#define \ -node_mindegree(t) (t - 1) +#define node_mindegree(t) (t - 1) -#define \ -node_full(degree, t) (t->n >= 2 * degree - 1) +#define node_full(degree, t) (t->n >= 2 * degree - 1) /* Node memory */ /* `node_new` allocates a new leaf node, children should be added and allocated * when the node is no longer a leaf node */ struct node* node_new(const ssize_t degree, const size_t elem_size) { - const size_t max_items = 2 * degree; - struct node *retval = calloc(1, sizeof(struct node)); + const size_t max_items = 2 * degree; + struct node* retval = calloc(1, sizeof(struct node)); - retval->n = 0; - retval->c = 0; - retval->items = calloc(max_items, elem_size); - retval->children = NULL; + retval->n = 0; + retval->c = 0; + retval->items = calloc(max_items, elem_size); + retval->children = NULL; - return retval; + return retval; } /* `node_transition` turns a leaf node into a non-leaf. Children are not * allocated. * returnvalue: `false` if we we're unable to allocate space for the new * children. */ -bool node_transition(struct node *node, const ssize_t degree) { - const int max_children = 2 * degree + 1; - int c; +bool node_transition(struct node* node, const ssize_t degree) { + const int max_children = 2 * degree + 1; + int c; - if (!node_leaf(node)) { - perror("node_transition was called on an already non-leaf node?"); - return false; - } + if (!node_leaf(node)) { + perror("node_transition was called on an already non-leaf node?"); + return false; + } - /* Allocate pointers for children */ - node->children = calloc(max_children, sizeof(struct node*)); + /* Allocate pointers for children */ + node->children = calloc(max_children, sizeof(struct node*)); - if (node->children == NULL) { - perror("could not allocate space for children pointers"); - return false; - } + if (node->children == NULL) { + perror("could not allocate space for children pointers"); + return false; + } - /* Allocate children */ - for (c = 0; c < max_children; c++) { - node->children[c] = NULL; - } + /* Allocate children */ + for (c = 0; c < max_children; c++) { + node->children[c] = NULL; + } - return true; + return true; } -void node_free(struct node **node, size_t elem_size, void (*dealloc)(void*)) { - if (*node == NULL) return; +void node_free(struct node** node, size_t elem_size, void (*dealloc)(void*)) { + if (*node == NULL) return; - if (!node_leaf((*node))) { - ssize_t i; - for (i = 0; i < (*node)->c; i++) { - node_free(&((*node)->children[i]), elem_size, dealloc); - } - dealloc((*node)->children); - } + if (!node_leaf((*node))) { + ssize_t i; + for (i = 0; i < (*node)->c; i++) { + node_free(&((*node)->children[i]), elem_size, dealloc); + } + dealloc((*node)->children); + } - dealloc((*node)->items); - (*node)->items = NULL; + dealloc((*node)->items); + (*node)->items = NULL; - dealloc(*node); - *node = NULL; + dealloc(*node); + *node = NULL; } - /* `node_tree_split_child` splits a _full_ node (c = 2t-1 items) into two nodes * with t-1 items each. * The median key/item/element moves up to the original nodes parent, to signify @@ -131,66 +126,61 @@ void node_free(struct node **node, size_t elem_size, void (*dealloc)(void*)) { * full nodes we encounter on the way down, including the leafs themselves. * By doing this, we are assured that whenever we split a node, its parent has * room for the median key. */ -void node_tree_split_child( - const ssize_t t, - const size_t elem_size, - struct node *nonfull, - ssize_t i) { - struct node *z = node_new(t, elem_size); - struct node *y = nonfull->children[i]; - ssize_t j; +void node_tree_split_child(const ssize_t t, const size_t elem_size, + struct node* nonfull, ssize_t i) { + struct node* z = node_new(t, elem_size); + struct node* y = nonfull->children[i]; + ssize_t j; - /* `z` should be a branching node if `y` is */ - if (!node_leaf(y)) { - node_transition(z, t); - } + /* `z` should be a branching node if `y` is */ + if (!node_leaf(y)) { + node_transition(z, t); + } - z->n = t - 1; + z->n = t - 1; - /* Move last `t-1` items to new node `z` */ - /* TODO This can be done with one memcpy */ - for (j = 0; j < t-1; j++) { - const size_t offset_dst = elem_size * j; - const size_t offset_src = elem_size * (t+j); - memcpy((z->items) + offset_dst, (y->items) + offset_src, elem_size); - } - /* Set unused item-memory to zero? */ + /* Move last `t-1` items to new node `z` */ + /* TODO This can be done with one memcpy */ + for (j = 0; j < t - 1; j++) { + const size_t offset_dst = elem_size * j; + const size_t offset_src = elem_size * (t + j); + memcpy((z->items) + offset_dst, (y->items) + offset_src, elem_size); + } + /* Set unused item-memory to zero? */ - /* Move children t..2t, if applicable*/ - if (!node_leaf(y)) { - for (j = 0; j < t+1; j++) { - z->children[j] = y->children[j + t]; - } - y->c = t; - z->c = t; - } + /* Move children t..2t, if applicable*/ + if (!node_leaf(y)) { + for (j = 0; j < t + 1; j++) { + z->children[j] = y->children[j + t]; + } + y->c = t; + z->c = t; + } - y->n = t - 1; + y->n = t - 1; - /* Move children +1 */ - for (j = nonfull->n; j > i; j--) { - nonfull->children[j+1] = nonfull->children[j]; - } + /* Move children +1 */ + for (j = nonfull->n; j > i; j--) { + nonfull->children[j + 1] = nonfull->children[j]; + } - /* new child */ - nonfull->children[i+1] = z; - nonfull->c++; + /* new child */ + nonfull->children[i + 1] = z; + nonfull->c++; - /* moving keys i..n + 1*/ - /* TODO This can be done with one memcpy */ - for (j = nonfull->n; j >= i; j--) { - const size_t offset = j * elem_size; - memcpy((nonfull->items) + offset + elem_size, - (nonfull->items) + offset, - elem_size); - } + /* moving keys i..n + 1*/ + /* TODO This can be done with one memcpy */ + for (j = nonfull->n; j >= i; j--) { + const size_t offset = j * elem_size; + memcpy((nonfull->items) + offset + elem_size, (nonfull->items) + offset, + elem_size); + } - /* Lastly, copy the median element to nonfull-parent*/ - memcpy((nonfull->items) + i * elem_size, - (y->items) + (t-1) * elem_size, - elem_size); + /* Lastly, copy the median element to nonfull-parent*/ + memcpy((nonfull->items) + i * elem_size, (y->items) + (t - 1) * elem_size, + elem_size); - nonfull->n++; + nonfull->n++; } /* `node_child_merge`: Merges two children around the key at index `i` (k) @@ -202,649 +192,609 @@ void node_tree_split_child( * * WARNING: THIS FUNCTION ASSUMES THAT `i` IS A VALID INDEX */ -void node_child_merge( - struct node *x, - ssize_t i, - const size_t elem_size, void (*dealloc)(void*)) { - struct node* y = x->children[i ]; - struct node* z = x->children[i+1]; - int j = 0; +void node_child_merge(struct node* x, ssize_t i, const size_t elem_size, + void (*dealloc)(void*)) { + struct node* y = x->children[i]; + struct node* z = x->children[i + 1]; + int j = 0; - /* append k to y */ - memcpy(y->items + (elem_size * y->n++), - x->items + (elem_size * i), - elem_size); + /* append k to y */ + memcpy(y->items + (elem_size * y->n++), x->items + (elem_size * i), + elem_size); - /* append keys in z to y */ - memcpy(y->items + (elem_size * y->n), - z->items, - elem_size * z->n); - y->n += z->n; + /* append keys in z to y */ + memcpy(y->items + (elem_size * y->n), z->items, elem_size * z->n); + y->n += z->n; - /* Move children from z to y */ - for (j = 0; j < z->c; j++) { - y->children[y->c + j] = z->children[j]; - } - y->c += z->c; + /* Move children from z to y */ + for (j = 0; j < z->c; j++) { + y->children[y->c + j] = z->children[j]; + } + y->c += z->c; - /* Remove z from x */ - for (j = i+1; j < x->c; j++) { - x->children[j] = x->children[j+1]; - } - x->c--; + /* Remove z from x */ + for (j = i + 1; j < x->c; j++) { + x->children[j] = x->children[j + 1]; + } + x->c--; - /* remove k from x */ - /* TODO check if we need to use (x->n - 1 - i) instead */ - memmove(x->items + (elem_size * i), - x->items + (elem_size * (i+1)), - elem_size * (x->n - i)); - x->n--; + /* remove k from x */ + /* TODO check if we need to use (x->n - 1 - i) instead */ + memmove(x->items + (elem_size * i), x->items + (elem_size * (i + 1)), + elem_size * (x->n - i)); + x->n--; - dealloc(z); /* DO NOT USE THE RECURSIVE ONE AS CHILDREN WILL BE LOST!!! */ + dealloc(z); /* DO NOT USE THE RECURSIVE ONE AS CHILDREN WILL BE LOST!!! */ } /* ASSUME i < x->c */ -void node_shift_left( - struct node *x, - ssize_t i, - const size_t elem_size) { - struct node* y = x->children[i ]; - struct node* z = x->children[i+1]; - byte *x_k = x->items + (elem_size * i); +void node_shift_left(struct node* x, ssize_t i, const size_t elem_size) { + struct node* y = x->children[i]; + struct node* z = x->children[i + 1]; + byte* x_k = x->items + (elem_size * i); - /* Append x.k[i] to y */ - memcpy(y->items + (elem_size * y->n++), - x_k, - elem_size); + /* Append x.k[i] to y */ + memcpy(y->items + (elem_size * y->n++), x_k, elem_size); - /* Move first element of z to x.k[i] */ - memcpy(x_k, - z->items, - elem_size); + /* Move first element of z to x.k[i] */ + memcpy(x_k, z->items, elem_size); - /* Shift z's items left */ - memmove(z->items, - z->items + elem_size, - elem_size * (z->n - 1)); + /* Shift z's items left */ + memmove(z->items, z->items + elem_size, elem_size * (z->n - 1)); - if (!node_leaf(z)) { - ssize_t j; - /* append first child of z to y */ - y->children[y->c++] = z->children[0]; + if (!node_leaf(z)) { + ssize_t j; + /* append first child of z to y */ + y->children[y->c++] = z->children[0]; - /* Shift z's children left */ - for (j = 0; j < z->c; j++) { - z->children[j] = z->children[j+1]; - } - z->c--; - } + /* Shift z's children left */ + for (j = 0; j < z->c; j++) { + z->children[j] = z->children[j + 1]; + } + z->c--; + } - z->n--; + z->n--; } -void node_shift_right( - struct node *x, - ssize_t i, - const size_t elem_size) { - struct node* y = x->children[i ]; - struct node* z = x->children[i+1]; - byte *x_k = x->items + (elem_size * i); +void node_shift_right(struct node* x, ssize_t i, const size_t elem_size) { + struct node* y = x->children[i]; + struct node* z = x->children[i + 1]; + byte* x_k = x->items + (elem_size * i); - /* Shift z's items right */ - memmove(z->items + elem_size, - z->items, - elem_size * z->n); + /* Shift z's items right */ + memmove(z->items + elem_size, z->items, elem_size * z->n); - /* Prepend x.k[i] to z */ - memcpy(z->items, - x_k, - elem_size); + /* Prepend x.k[i] to z */ + memcpy(z->items, x_k, elem_size); - /* Move last element of y to x.k[i] */ - memcpy(x_k, - y->items + (elem_size * --(y->n)), - elem_size); + /* Move last element of y to x.k[i] */ + memcpy(x_k, y->items + (elem_size * --(y->n)), elem_size); - if (!node_leaf(z)) { - size_t j; - /* Shift z's children right */ - for (j = z->c; j > 0; j--) { - z->children[j] = z->children[j-1]; - } - z->c++; + if (!node_leaf(z)) { + size_t j; + /* Shift z's children right */ + for (j = z->c; j > 0; j--) { + z->children[j] = z->children[j - 1]; + } + z->c++; - /* prepend last child of y to z */ - z->children[0] = y->children[--(y->c)]; - } + /* prepend last child of y to z */ + z->children[0] = y->children[--(y->c)]; + } - z->n++; + z->n++; } /* return: Returns the new root, if a split happens */ -void node_insert_nonfull( - struct node *root, - void *elem, - const ssize_t degree, - const size_t elem_size, - int (*cmp)(const void *a, const void *b)) { +void node_insert_nonfull(struct node* root, void* elem, const ssize_t degree, + const size_t elem_size, + int (*cmp)(const void* a, const void* b)) { - /* TODO check correctness */ - ssize_t i = root->n - 1; + /* TODO check correctness */ + ssize_t i = root->n - 1; - if (node_leaf(root)) { - size_t offset = elem_size * i; - while (i >= 0 && cmp(elem, root->items + offset) < 0) { - /* TODO This can be done with one memcpy */ - memcpy(root->items + offset + elem_size, - root->items + offset, - elem_size); + if (node_leaf(root)) { + size_t offset = elem_size * i; + while (i >= 0 && cmp(elem, root->items + offset) < 0) { + /* TODO This can be done with one memcpy */ + memcpy(root->items + offset + elem_size, root->items + offset, elem_size); - i--; - offset = elem_size * i; - } - offset = elem_size * (++i); - memcpy(root->items + offset, elem, elem_size); - root->n++; + i--; + offset = elem_size * i; + } + offset = elem_size * (++i); + memcpy(root->items + offset, elem, elem_size); + root->n++; - } else { - size_t offset = elem_size * i; - struct node *nextchild = NULL; - while (i >= 0 && cmp(elem, root->items + offset) < 0) { - i--; - offset = elem_size * i; - } - i++; - nextchild = root->children[i]; - if (node_full(degree, nextchild)) { - /* TODO Check if the root has changed */ - node_tree_split_child(degree, elem_size, root, i); - if (cmp(elem, root->items + elem_size * i) > 0) { - nextchild = root->children[++i]; - } - } - node_insert_nonfull(nextchild, elem, degree, elem_size, cmp); - } + } else { + size_t offset = elem_size * i; + struct node* nextchild = NULL; + while (i >= 0 && cmp(elem, root->items + offset) < 0) { + i--; + offset = elem_size * i; + } + i++; + nextchild = root->children[i]; + if (node_full(degree, nextchild)) { + /* TODO Check if the root has changed */ + node_tree_split_child(degree, elem_size, root, i); + if (cmp(elem, root->items + elem_size * i) > 0) { + nextchild = root->children[++i]; + } + } + node_insert_nonfull(nextchild, elem, degree, elem_size, cmp); + } } /* Returns the new root, if a split occurs */ -struct node* node_insert( - struct node *root, - void *elem, - const ssize_t degree, - const size_t elem_size, - int (*cmp)(const void *a, const void *b)) { +struct node* node_insert(struct node* root, void* elem, const ssize_t degree, + const size_t elem_size, + int (*cmp)(const void* a, const void* b)) { - struct node *s = root; + struct node* s = root; - if (node_full(degree, root)) { - s = node_new(degree, elem_size); - if (s == NULL) { - fputs("BTree error: Failed to allocate new node for insertion!\n", stderr); - return NULL; - } - node_transition(s, degree); - s->children[s->c++] = root; - /* TODO Check if the root has changed */ - node_tree_split_child(degree, elem_size, s, 0); - node_insert_nonfull(s, elem, degree, elem_size, cmp); - } - else { - node_insert_nonfull(s, elem, degree, elem_size, cmp); - } - return s; + if (node_full(degree, root)) { + s = node_new(degree, elem_size); + if (s == NULL) { + fputs("BTree error: Failed to allocate new node for insertion!\n", + stderr); + return NULL; + } + node_transition(s, degree); + s->children[s->c++] = root; + /* TODO Check if the root has changed */ + node_tree_split_child(degree, elem_size, s, 0); + node_insert_nonfull(s, elem, degree, elem_size, cmp); + } else { + node_insert_nonfull(s, elem, degree, elem_size, cmp); + } + return s; } -void* node_search(struct node *x, - void *key, - int(*cmp)(const void *a, const void *b), +void* node_search(struct node* x, void* key, + int (*cmp)(const void* a, const void* b), const size_t elem_size) { - /* We set to one, since we pre-emptively do a comparison with the assumption - * that there's already one in the items */ - ssize_t i = 0; - int last_cmp_res = 0; + /* We set to one, since we pre-emptively do a comparison with the assumption + * that there's already one in the items */ + ssize_t i = 0; + int last_cmp_res = 0; - while (i < x->n - && (last_cmp_res = cmp(key, (const void*)(x->items + (i * elem_size)))) - > 0) { - i++; - } + while (i < x->n && + (last_cmp_res = cmp(key, (const void*)(x->items + (i * elem_size)))) > + 0) { + i++; + } - if ((ssize_t)i < x->n && last_cmp_res == 0) { - return (void*)(x->items + (i * elem_size)); - } else if (node_leaf(x)) { - return NULL; - } + if ((ssize_t)i < x->n && last_cmp_res == 0) { + return (void*)(x->items + (i * elem_size)); + } else if (node_leaf(x)) { + return NULL; + } - /* Assumption: ¬node_leaf(x) → x.children is allocated */ - return node_search(x->children[i], key, cmp, elem_size); + /* Assumption: ¬node_leaf(x) → x.children is allocated */ + return node_search(x->children[i], key, cmp, elem_size); } -int node_delete(struct node *x, - void *key, - int(*cmp)(const void *a, const void *b), - const ssize_t degree, - const size_t elem_size, void *(*alloc)(size_t), void (*dealloc)(void*)) { - /* Determine wether the key is in the node */ - int i = 0; /* Index of `k`, if found */ - int last_cmp_res = 0; - - while (i < x->n - && (last_cmp_res = cmp(key, (const void*)(x->items + (i * elem_size)))) - > 0) { - i++; - } +int node_delete(struct node* x, void* key, + int (*cmp)(const void* a, const void* b), const ssize_t degree, + const size_t elem_size, void* (*alloc)(size_t), + void (*dealloc)(void*)) { + /* Determine wether the key is in the node */ + int i = 0; /* Index of `k`, if found */ + int last_cmp_res = 0; - if (last_cmp_res == 0) { + while (i < x->n && + (last_cmp_res = cmp(key, (const void*)(x->items + (i * elem_size)))) > + 0) { + i++; + } - if (node_leaf(x)) { - /* 1. k ϵ x && node_leaf(x) */ - /* Delete k from x */ - int j = i; - while (j + 1 < x->n) { - const size_t offset_dst = elem_size * j; - const size_t offset_src = elem_size * (j+1); - memcpy((x->items) + offset_dst, - (x->items) + offset_src, - elem_size); - j++; - } - x->n--; - return 1; - } else { - /* 2. k ϵ x && !node_leaf(x) */ - /* let i be the index of k in x */ - /* 2a: if size(child[i]) >= t; find the largest k' in child[i] */ - /* replace k with k' */ - if (x->children[i]->n >= degree) { - struct node* y = x->children[i]; - byte *kk = alloc(elem_size); + if (last_cmp_res == 0) { - /* Find the predecessor, k' of k in y */ - { - struct node* tmp = y; - while (!node_leaf(tmp)) { - tmp = tmp->children[tmp->n-1]; - } + if (node_leaf(x)) { + /* 1. k ϵ x && node_leaf(x) */ + /* Delete k from x */ + int j = i; + while (j + 1 < x->n) { + const size_t offset_dst = elem_size * j; + const size_t offset_src = elem_size * (j + 1); + memcpy((x->items) + offset_dst, (x->items) + offset_src, elem_size); + j++; + } + x->n--; + return 1; + } else { + /* 2. k ϵ x && !node_leaf(x) */ + /* let i be the index of k in x */ + /* 2a: if size(child[i]) >= t; find the largest k' in child[i] */ + /* replace k with k' */ + if (x->children[i]->n >= degree) { + struct node* y = x->children[i]; + byte* kk = alloc(elem_size); - /* copy kk */ - memcpy(kk, tmp->items + elem_size * (tmp->n - 1), elem_size); - } + /* Find the predecessor, k' of k in y */ + { + struct node* tmp = y; + while (!node_leaf(tmp)) { + tmp = tmp->children[tmp->n - 1]; + } - /* Recursively delete kk from y */ - return node_delete(y, kk, cmp, degree, elem_size, alloc, dealloc); + /* copy kk */ + memcpy(kk, tmp->items + elem_size * (tmp->n - 1), elem_size); + } - /* replace k with kk */ - memcpy(x->items + (elem_size * i), - kk, - elem_size); + /* Recursively delete kk from y */ + return node_delete(y, kk, cmp, degree, elem_size, alloc, dealloc); - dealloc(kk); + /* replace k with kk */ + memcpy(x->items + (elem_size * i), kk, elem_size); - return 1; + dealloc(kk); - } else if (x->children[i+1]->n >= degree) { - struct node* z = x->children[i+1]; - byte *kk = alloc(elem_size); + return 1; - /* Find the successor, k' of k in z */ - { - struct node* tmp = z->children[0]; - while (!node_leaf(tmp)) { - tmp = tmp->children[0]; - } + } else if (x->children[i + 1]->n >= degree) { + struct node* z = x->children[i + 1]; + byte* kk = alloc(elem_size); - /* copy kk */ - memcpy(kk, tmp->items + elem_size * (tmp->n - 1), elem_size); - } + /* Find the successor, k' of k in z */ + { + struct node* tmp = z->children[0]; + while (!node_leaf(tmp)) { + tmp = tmp->children[0]; + } - /* Recursively delete kk from y */ - return node_delete(z, kk, cmp, degree, elem_size, alloc, dealloc); + /* copy kk */ + memcpy(kk, tmp->items + elem_size * (tmp->n - 1), elem_size); + } - /* replace k with kk */ - memcpy(x->items + (elem_size * i), - kk, - elem_size); + /* Recursively delete kk from y */ + return node_delete(z, kk, cmp, degree, elem_size, alloc, dealloc); - dealloc(kk); + /* replace k with kk */ + memcpy(x->items + (elem_size * i), kk, elem_size); - return 1; - } else { - /* Merge k and z into y */ - node_child_merge(x, i, elem_size, dealloc); + dealloc(kk); - /* recurse */ - return node_delete(x->children[i], key, cmp, degree, elem_size, alloc, dealloc); - } - } - } else if (node_leaf(x)) { - return 0; - } else { - /* 3. !(k ϵ x) */ + return 1; + } else { + /* Merge k and z into y */ + node_child_merge(x, i, elem_size, dealloc); - /* if x is a leaf, then it is not in the tree */ + /* recurse */ + return node_delete(x->children[i], key, cmp, degree, elem_size, alloc, + dealloc); + } + } + } else if (node_leaf(x)) { + return 0; + } else { + /* 3. !(k ϵ x) */ - struct node* y; - int ii; /* index of x.c[i] */ + /* if x is a leaf, then it is not in the tree */ - /* Determine x.c[i] that must contain k */ - /* if last cmp < 0, then the child must be in the left child of x.items[i]*/ - if (last_cmp_res < 0) ii = i; - /* Otherwise, it must be the very last child */ - else if (i < x->n) ii = i+1; - else ii = i; + struct node* y; + int ii; /* index of x.c[i] */ - y = x->children[ii]; + /* Determine x.c[i] that must contain k */ + /* if last cmp < 0, then the child must be in the left child of x.items[i]*/ + if (last_cmp_res < 0) ii = i; + /* Otherwise, it must be the very last child */ + else if (i < x->n) + ii = i + 1; + else + ii = i; - if (y->n < degree) { - /* we are left biased */ - if (ii > 0 && x->children[ii-1]->n >= degree) { - node_shift_right(x, ii-1, elem_size); + y = x->children[ii]; - } else if (ii < x->c - 1 && x->children[ii+1]->n >= degree) { - node_shift_left (x, ii, elem_size); + if (y->n < degree) { + /* we are left biased */ + if (ii > 0 && x->children[ii - 1]->n >= degree) { + node_shift_right(x, ii - 1, elem_size); - } else { - /* We need to determine wether we merge left or right, if possible */ - if (ii > 0) { - node_child_merge(x, ii - 1, elem_size, dealloc); - y = x->children[ii - 1]; - } - else if (ii < x->c - 1) { - node_child_merge(x, ii, elem_size, dealloc); - } - else { - perror("Cannot merge!"); - } - } + } else if (ii < x->c - 1 && x->children[ii + 1]->n >= degree) { + node_shift_left(x, ii, elem_size); - } + } else { + /* We need to determine wether we merge left or right, if possible */ + if (ii > 0) { + node_child_merge(x, ii - 1, elem_size, dealloc); + y = x->children[ii - 1]; + } else if (ii < x->c - 1) { + node_child_merge(x, ii, elem_size, dealloc); + } else { + perror("Cannot merge!"); + } + } + } - return node_delete(y, key, cmp, degree, elem_size, alloc, dealloc); - } - return 0; + return node_delete(y, key, cmp, degree, elem_size, alloc, dealloc); + } + return 0; } - /***********************/ /* Btree functionality */ /***********************/ -struct btree* btree_new(size_t elem_size, - size_t t, - int(*cmp)(const void *a, const void *b)) { - return btree_new_with_allocator(elem_size, t, cmp, malloc, free); +struct btree* btree_new(size_t elem_size, size_t t, + int (*cmp)(const void* a, const void* b)) { + return btree_new_with_allocator(elem_size, t, cmp, malloc, free); } -struct btree* btree_new_with_allocator(size_t elem_size, - size_t t, - int(*cmp)(const void *a, const void *b), - void *(*alloc)(size_t), - void (*dealloc)(void*)) { - struct btree *new_tree = alloc(sizeof(struct btree)); +struct btree* btree_new_with_allocator(size_t elem_size, size_t t, + int (*cmp)(const void* a, const void* b), + void* (*alloc)(size_t), + void (*dealloc)(void*)) { + struct btree* new_tree = alloc(sizeof(struct btree)); - new_tree->alloc = alloc; - new_tree->dealloc = dealloc; + new_tree->alloc = alloc; + new_tree->dealloc = dealloc; - new_tree->elem_size = elem_size; - new_tree->degree = t; + new_tree->elem_size = elem_size; + new_tree->degree = t; - new_tree->root = NULL; + new_tree->root = NULL; - new_tree->cmp = cmp; + new_tree->cmp = cmp; - return new_tree; + return new_tree; } -void btree_free(struct btree **btree) { - node_free(&((*btree)->root), (*btree)->elem_size, (*btree)->dealloc); - (*btree)->dealloc(*btree); - *btree = NULL; +void btree_free(struct btree** btree) { + node_free(&((*btree)->root), (*btree)->elem_size, (*btree)->dealloc); + (*btree)->dealloc(*btree); + *btree = NULL; } -void btree_insert(struct btree *btree, void *elem) { - if (btree == NULL) { - fputs("BTree error: Inserting into a NULL ptr!\n", stderr); - return; - } - if (elem == NULL) { - fputs("BTree error: Inserting NULL into a tree!\n", stderr); - return; - } - if (btree->root == NULL) { - btree->root = node_new(btree->degree, btree->elem_size); - if (btree->root == NULL) { - fputs("BTree error: Failed to create new root node!\n", stderr); - return; - } - node_insert(btree->root, - elem, - btree->degree, - btree->elem_size, - btree->cmp); - } - else { - btree->root = node_insert(btree->root, - elem, - btree->degree, - btree->elem_size, - btree->cmp); - } +void btree_insert(struct btree* btree, void* elem) { + if (btree == NULL) { + fputs("BTree error: Inserting into a NULL ptr!\n", stderr); + return; + } + if (elem == NULL) { + fputs("BTree error: Inserting NULL into a tree!\n", stderr); + return; + } + if (btree->root == NULL) { + btree->root = node_new(btree->degree, btree->elem_size); + if (btree->root == NULL) { + fputs("BTree error: Failed to create new root node!\n", stderr); + return; + } + node_insert(btree->root, elem, btree->degree, btree->elem_size, btree->cmp); + } else { + btree->root = node_insert(btree->root, elem, btree->degree, + btree->elem_size, btree->cmp); + } } -void* btree_search(struct btree *btree, void *elem) { - return node_search(btree->root, elem, btree->cmp, btree->elem_size); +void* btree_search(struct btree* btree, void* elem) { + return node_search(btree->root, elem, btree->cmp, btree->elem_size); } -int btree_delete(struct btree *btree, void *elem) { - struct node *newroot = btree->root; - int res = node_delete(btree->root, elem, btree->cmp, btree->degree, btree->elem_size, btree->alloc, btree->dealloc); - if (newroot->n == 0) { - if (node_leaf(newroot)) return res; - /* shrink the tree */ - struct node *newroot_p = newroot->children[0]; - btree->dealloc(newroot); - btree->root = newroot_p; - } - return res; +int btree_delete(struct btree* btree, void* elem) { + struct node* newroot = btree->root; + int res = node_delete(btree->root, elem, btree->cmp, btree->degree, + btree->elem_size, btree->alloc, btree->dealloc); + if (newroot->n == 0) { + if (node_leaf(newroot)) return res; + /* shrink the tree */ + struct node* newroot_p = newroot->children[0]; + btree->dealloc(newroot); + btree->root = newroot_p; + } + return res; } -void node_print(struct node *root, const size_t elem_size, const int indent, void (*print_elem)(const void*)) { - ssize_t i; - int t; +void node_print(struct node* root, const size_t elem_size, const int indent, + void (*print_elem)(const void*)) { + ssize_t i; + int t; - for (t = 0; t < indent - 1; t++) { fputs(" ┃ ", stdout); } - if (indent > 0) { fputs(" ┣┯", stdout); } - printf("printing node \x1b[33m%0lx\x1b[0m," - " c:%ld n:%ld\t\t" - "\x1b[30m%p\x1b[0m\n", - (unsigned long)((size_t)root % 0x10000), - root->c, - root->n, - (void*)root); - - if (node_leaf(root)) { - for (i = 0; i < root->n - 1; i++) { - const size_t ofst = i * elem_size; - for (t = 0; t < indent; t++) { fputs(" ┃├", stdout); } - print_elem(root->items + ofst); - } - for (t = 0; t < indent; t++) { fputs(" ┃└", stdout); } - print_elem(root->items + i * elem_size); - } else { - size_t ofst = 0; - for (i = 0; i < root->c - 1; i++) { - node_print(root->children[i], elem_size, indent + 1, print_elem); - for (t = 0; t < indent; t++) { fputs(" ┃ ", stdout); } - print_elem(root->items + ofst); - ofst += elem_size; - } - node_print(root->children[i], elem_size, indent + 1, print_elem); - } + for (t = 0; t < indent - 1; t++) { + fputs(" ┃ ", stdout); + } + if (indent > 0) { + fputs(" ┣┯", stdout); + } + printf("printing node \x1b[33m%0lx\x1b[0m," + " c:%ld n:%ld\t\t" + "\x1b[30m%p\x1b[0m\n", + (unsigned long)((size_t)root % 0x10000), root->c, root->n, + (void*)root); + if (node_leaf(root)) { + for (i = 0; i < root->n - 1; i++) { + const size_t ofst = i * elem_size; + for (t = 0; t < indent; t++) { + fputs(" ┃├", stdout); + } + print_elem(root->items + ofst); + } + for (t = 0; t < indent; t++) { + fputs(" ┃└", stdout); + } + print_elem(root->items + i * elem_size); + } else { + size_t ofst = 0; + for (i = 0; i < root->c - 1; i++) { + node_print(root->children[i], elem_size, indent + 1, print_elem); + for (t = 0; t < indent; t++) { + fputs(" ┃ ", stdout); + } + print_elem(root->items + ofst); + ofst += elem_size; + } + node_print(root->children[i], elem_size, indent + 1, print_elem); + } } -void btree_print(struct btree *btree, void (*print_elem)(const void*)) { - printf("BTRee: degree:%ld\n", btree->degree); - if (btree->root == NULL) return; - node_print(btree->root, btree->elem_size, 0, print_elem); +void btree_print(struct btree* btree, void (*print_elem)(const void*)) { + printf("BTRee: degree:%ld\n", btree->degree); + if (btree->root == NULL) return; + node_print(btree->root, btree->elem_size, 0, print_elem); } -void* btree_first(struct btree *btree) { - struct node *root; - if (btree == NULL) return NULL; - root = btree->root; +void* btree_first(struct btree* btree) { + struct node* root; + if (btree == NULL) return NULL; + root = btree->root; - if (root == NULL) return NULL; + if (root == NULL) return NULL; - while (!node_leaf(root)) root = root->children[0]; + while (!node_leaf(root)) root = root->children[0]; - if (root->n == 0) return NULL; - return root->items; /* Return first element */ + if (root->n == 0) return NULL; + return root->items; /* Return first element */ } -void* btree_last(struct btree *btree) { - struct node *root; +void* btree_last(struct btree* btree) { + struct node* root; - if (btree == NULL) return NULL; - root = btree->root; + if (btree == NULL) return NULL; + root = btree->root; - if (root == NULL) return NULL; + if (root == NULL) return NULL; - while (!node_leaf(root)) root = root->children[root->c]; + while (!node_leaf(root)) root = root->children[root->c]; - if (root->n == 0) return NULL; - return root->items + btree->elem_size * (root->n - 1); /* Return first element */ + if (root->n == 0) return NULL; + return root->items + + btree->elem_size * (root->n - 1); /* Return first element */ } -size_t btree_height(struct btree *btree) { - struct node *root; - size_t height = 0; +size_t btree_height(struct btree* btree) { + struct node* root; + size_t height = 0; - if (btree == NULL) return 0; - root = btree->root; + if (btree == NULL) return 0; + root = btree->root; - if (root == NULL) return 0; + if (root == NULL) return 0; - while (!node_leaf(root)) { - root = root->children[0]; - height++; - } + while (!node_leaf(root)) { + root = root->children[0]; + height++; + } - return height; + return height; } size_t u32_pow(size_t base, size_t exponent) { - size_t res = 1; - while (exponent > 0) { - res *= base; - exponent--; - } - return res; + size_t res = 1; + while (exponent > 0) { + res *= base; + exponent--; + } + return res; } - -size_t btree_size(struct btree *btree) { - return u32_pow(2 * btree->degree, btree_height(btree)) - 1; +size_t btree_size(struct btree* btree) { + return u32_pow(2 * btree->degree, btree_height(btree)) - 1; } +struct btree_iter_t* btree_iter_t_new(struct btree* tree) { + struct btree_iter_t* iter = NULL; -struct btree_iter_t* btree_iter_t_new(struct btree *tree) { - struct btree_iter_t *iter = NULL; + if (tree == NULL) return NULL; - if (tree == NULL) return NULL; + iter = (struct btree_iter_t*)tree->alloc(sizeof(struct btree_iter_t)); - iter = (struct btree_iter_t*)tree->alloc(sizeof(struct btree_iter_t)); + if (tree != NULL) { + iter->head = 0; + memset(iter->stack, 0, 512 * sizeof(struct node*)); - if (tree != NULL) { - iter->head = 0; - memset(iter->stack, 0, 512 * sizeof(struct node*)); - - iter->stack[iter->head].pos = 0; - iter->stack[iter->head].node = tree->root; - } else { - perror("Cannot instantiate iterator from null-pointer tree"); - } - return iter; + iter->stack[iter->head].pos = 0; + iter->stack[iter->head].node = tree->root; + } else { + perror("Cannot instantiate iterator from null-pointer tree"); + } + return iter; } +void btree_iter_t_reset(struct btree* tree, struct btree_iter_t** it) { + (*it)->head = 0; -void btree_iter_t_reset(struct btree *tree, struct btree_iter_t** it) { - (*it)->head = 0; - - (*it)->stack[0].pos = 0; - (*it)->stack[0].node = tree->root; + (*it)->stack[0].pos = 0; + (*it)->stack[0].node = tree->root; } +void* btree_iter(struct btree* tree, struct btree_iter_t* iter) { + register int pos = 0; + register ssize_t head = 0; + register ssize_t n = 0; -void* btree_iter(struct btree *tree, struct btree_iter_t *iter) { - register int pos = 0; - register ssize_t head = 0; - register ssize_t n = 0; + if (iter->stack[head].node == NULL) return NULL; - if (iter->stack[head].node == NULL) return NULL; + head = iter->head; + pos = iter->stack[head].pos; + n = iter->stack[head].node->n; - head = iter->head; - pos = iter->stack[head].pos; - n = iter->stack[head].node->n; - -#define BTREE_ITER_POP(it) { \ - iter->stack[head].pos = 0; \ - iter->stack[head].node = NULL; \ - iter->head--; head--; \ - iter->stack[head].pos++; \ - \ - pos = iter->stack[head].pos; \ - n = iter->stack[head].node->n; \ -} +#define BTREE_ITER_POP(it) \ + { \ + iter->stack[head].pos = 0; \ + iter->stack[head].node = NULL; \ + iter->head--; \ + head--; \ + iter->stack[head].pos++; \ + \ + pos = iter->stack[head].pos; \ + n = iter->stack[head].node->n; \ + } - /* Check if we have reached the end of a node. - * Take note of the difference of inequality in the if statement and - * following while */ + /* Check if we have reached the end of a node. + * Take note of the difference of inequality in the if statement and + * following while */ - /* Leafs are a special case, as, if the only node is the root node, we might - * want to exit */ - if (node_leaf(iter->stack[iter->head].node) && pos >= 2 * n) { - if (head == 0) return NULL; + /* Leafs are a special case, as, if the only node is the root node, we might + * want to exit */ + if (node_leaf(iter->stack[iter->head].node) && pos >= 2 * n) { + if (head == 0) return NULL; - /* Pop, if so */ - else BTREE_ITER_POP(iter); - } + /* Pop, if so */ + else + BTREE_ITER_POP(iter); + } - /* Otherwise, pop while we have reached the end of a node */ - while (pos > 2 * n) { - if (head == 0) return NULL; + /* Otherwise, pop while we have reached the end of a node */ + while (pos > 2 * n) { + if (head == 0) return NULL; - /* Pop, if so */ - else BTREE_ITER_POP(iter); - } + /* Pop, if so */ + else + BTREE_ITER_POP(iter); + } #undef BTREE_ITER_POP - /* On evens, we decent into children */ - if (!node_leaf(iter->stack[head].node)) { - if (pos % 2 == 0) { - /* push child node onto iter->stack */ - iter->stack[head + 1].pos = 0; - iter->stack[head + 1].node = iter->stack[head].node->children[pos / 2]; - iter->head++; head++; + /* On evens, we decent into children */ + if (!node_leaf(iter->stack[head].node)) { + if (pos % 2 == 0) { + /* push child node onto iter->stack */ + iter->stack[head + 1].pos = 0; + iter->stack[head + 1].node = iter->stack[head].node->children[pos / 2]; + iter->head++; + head++; - /* Decent all the way to the left, if pos == 0 */ - while (!node_leaf(iter->stack[iter->head].node)) { - iter->stack[head + 1].pos = 0; - iter->stack[head + 1].node = iter->stack[head].node->children[0]; - iter->head++; head++; - } - } - } + /* Decent all the way to the left, if pos == 0 */ + while (!node_leaf(iter->stack[iter->head].node)) { + iter->stack[head + 1].pos = 0; + iter->stack[head + 1].node = iter->stack[head].node->children[0]; + iter->head++; + head++; + } + } + } - /* Finally, update index and return a value */ - if (node_leaf(iter->stack[head].node)) { - iter->stack[head].pos += 2; - pos = iter->stack[head].pos; - } - else { - iter->stack[head].pos++; - pos = iter->stack[head].pos; - } + /* Finally, update index and return a value */ + if (node_leaf(iter->stack[head].node)) { + iter->stack[head].pos += 2; + pos = iter->stack[head].pos; + } else { + iter->stack[head].pos++; + pos = iter->stack[head].pos; + } - return iter->stack[head].node->items + tree->elem_size * ( (pos - 1) / 2 ); + return iter->stack[head].node->items + tree->elem_size * ((pos - 1) / 2); } |