/* Sequential list data type implemented by a binary tree. Copyright (C) 2006-2007, 2009-2024 Free Software Foundation, Inc. Written by Bruno Haible , 2006. This file is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This file is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see . */ /* Common code of gl_rbtree_list.c and gl_rbtreehash_list.c. */ /* -------------------------- gl_list_t Data Type -------------------------- */ /* Creates a subtree for count >= 1 elements. Its black-height bh is passed as argument, with 2^bh - 1 <= count <= 2^(bh+1) - 1. bh == 0 implies count == 1. Its height is h where 2^(h-1) <= count <= 2^h - 1. Return NULL upon out-of-memory. */ static gl_list_node_t create_subtree_with_contents (unsigned int bh, size_t count, const void **contents) { size_t half1 = (count - 1) / 2; size_t half2 = count / 2; /* Note: half1 + half2 = count - 1. */ gl_list_node_t node = (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl)); if (node == NULL) return NULL; if (half1 > 0) { /* half1 > 0 implies count > 1, implies bh >= 1, implies 2^(bh-1) - 1 <= half1 <= 2^bh - 1. */ node->left = create_subtree_with_contents (bh - 1, half1, contents); if (node->left == NULL) goto fail1; node->left->parent = node; } else node->left = NULL; node->value = contents[half1]; if (half2 > 0) { /* half2 > 0 implies count > 1, implies bh >= 1, implies 2^(bh-1) - 1 <= half2 <= 2^bh - 1. */ node->right = create_subtree_with_contents (bh - 1, half2, contents + half1 + 1); if (node->right == NULL) goto fail2; node->right->parent = node; } else node->right = NULL; node->color = (bh == 0 ? RED : BLACK); node->branch_size = count; return node; fail2: if (node->left != NULL) free_subtree (node->left); fail1: free (node); return NULL; } static gl_list_t gl_tree_nx_create (gl_list_implementation_t implementation, gl_listelement_equals_fn equals_fn, gl_listelement_hashcode_fn hashcode_fn, gl_listelement_dispose_fn dispose_fn, bool allow_duplicates, size_t count, const void **contents) { struct gl_list_impl *list = (struct gl_list_impl *) malloc (sizeof (struct gl_list_impl)); if (list == NULL) return NULL; list->base.vtable = implementation; list->base.equals_fn = equals_fn; list->base.hashcode_fn = hashcode_fn; list->base.dispose_fn = dispose_fn; list->base.allow_duplicates = allow_duplicates; #if WITH_HASHTABLE { size_t estimate = xsum (count, count / 2); /* 1.5 * count */ if (estimate < 10) estimate = 10; list->table_size = next_prime (estimate); if (size_overflow_p (xtimes (list->table_size, sizeof (gl_hash_entry_t)))) goto fail1; list->table = (gl_hash_entry_t *) calloc (list->table_size, sizeof (gl_hash_entry_t)); if (list->table == NULL) goto fail1; } #endif if (count > 0) { /* Assuming 2^bh - 1 <= count <= 2^(bh+1) - 2, we create a tree whose upper bh levels are black, and only the partially present lowest level is red. */ unsigned int bh; { size_t n; for (n = count + 1, bh = 0; n > 1; n = n >> 1) bh++; } list->root = create_subtree_with_contents (bh, count, contents); if (list->root == NULL) goto fail2; list->root->parent = NULL; #if WITH_HASHTABLE /* Now that the tree is built, node_position() works. Now we can add the nodes to the hash table. */ if (add_nodes_to_buckets (list) < 0) goto fail3; #endif } else list->root = NULL; return list; #if WITH_HASHTABLE fail3: free_subtree (list->root); #endif fail2: #if WITH_HASHTABLE free (list->table); fail1: #endif free (list); return NULL; } /* Rotates left a subtree. B D / \ / \ A D --> B E / \ / \ C E A C Changes the tree structure, updates the branch sizes. The caller must update the colors and register D as child of its parent. */ static gl_list_node_t rotate_left (gl_list_node_t b_node, gl_list_node_t d_node) { gl_list_node_t a_node = b_node->left; gl_list_node_t c_node = d_node->left; gl_list_node_t e_node = d_node->right; b_node->right = c_node; d_node->left = b_node; d_node->parent = b_node->parent; b_node->parent = d_node; if (c_node != NULL) c_node->parent = b_node; b_node->branch_size = (a_node != NULL ? a_node->branch_size : 0) + 1 + (c_node != NULL ? c_node->branch_size : 0); d_node->branch_size = b_node->branch_size + 1 + (e_node != NULL ? e_node->branch_size : 0); return d_node; } /* Rotates right a subtree. D B / \ / \ B E --> A D / \ / \ A C C E Changes the tree structure, updates the branch sizes. The caller must update the colors and register B as child of its parent. */ static gl_list_node_t rotate_right (gl_list_node_t b_node, gl_list_node_t d_node) { gl_list_node_t a_node = b_node->left; gl_list_node_t c_node = b_node->right; gl_list_node_t e_node = d_node->right; d_node->left = c_node; b_node->right = d_node; b_node->parent = d_node->parent; d_node->parent = b_node; if (c_node != NULL) c_node->parent = d_node; d_node->branch_size = (c_node != NULL ? c_node->branch_size : 0) + 1 + (e_node != NULL ? e_node->branch_size : 0); b_node->branch_size = (a_node != NULL ? a_node->branch_size : 0) + 1 + d_node->branch_size; return b_node; } /* Ensures the tree is balanced, after an insertion operation. Also assigns node->color. parent is the given node's parent, known to be non-NULL. */ static void rebalance_after_add (gl_list_t list, gl_list_node_t node, gl_list_node_t parent) { for (;;) { /* At this point, parent = node->parent != NULL. Think of node->color being RED (although node->color is not yet assigned.) */ gl_list_node_t grandparent; gl_list_node_t uncle; if (parent->color == BLACK) { /* A RED color for node is acceptable. */ node->color = RED; return; } grandparent = parent->parent; /* Since parent is RED, we know that grandparent is != NULL and colored BLACK. */ if (grandparent->left == parent) uncle = grandparent->right; else if (grandparent->right == parent) uncle = grandparent->left; else abort (); if (uncle != NULL && uncle->color == RED) { /* Change grandparent from BLACK to RED, and change parent and uncle from RED to BLACK. This makes it acceptable for node to be RED. */ node->color = RED; parent->color = uncle->color = BLACK; node = grandparent; } else { /* grandparent and uncle are BLACK. parent is RED. node wants to be RED too. In this case, recoloring is not sufficient. Need to perform one or two rotations. */ gl_list_node_t *grandparentp; if (grandparent->parent == NULL) grandparentp = &list->root; else if (grandparent->parent->left == grandparent) grandparentp = &grandparent->parent->left; else if (grandparent->parent->right == grandparent) grandparentp = &grandparent->parent->right; else abort (); if (grandparent->left == parent) { if (parent->right == node) { /* Rotation between node and parent. */ grandparent->left = rotate_left (parent, node); node = parent; parent = grandparent->left; } /* grandparent and uncle are BLACK. parent and node want to be RED. parent = grandparent->left. node = parent->left. grandparent parent bh+1 bh+1 / \ / \ parent uncle --> node grandparent bh bh bh bh / \ / \ node C C uncle bh bh bh bh */ *grandparentp = rotate_right (parent, grandparent); parent->color = BLACK; node->color = grandparent->color = RED; } else /* grandparent->right == parent */ { if (parent->left == node) { /* Rotation between node and parent. */ grandparent->right = rotate_right (node, parent); node = parent; parent = grandparent->right; } /* grandparent and uncle are BLACK. parent and node want to be RED. parent = grandparent->right. node = parent->right. grandparent parent bh+1 bh+1 / \ / \ uncle parent --> grandparent node bh bh bh bh / \ / \ C node uncle C bh bh bh bh */ *grandparentp = rotate_left (grandparent, parent); parent->color = BLACK; node->color = grandparent->color = RED; } return; } /* Start again with a new (node, parent) pair. */ parent = node->parent; if (parent == NULL) { /* Change node's color from RED to BLACK. This increases the tree's black-height. */ node->color = BLACK; return; } } } /* Ensures the tree is balanced, after a deletion operation. CHILD was a grandchild of PARENT and is now its child. Between them, a black node was removed. CHILD is also black, or NULL. (CHILD can also be NULL. But PARENT is non-NULL.) */ static void rebalance_after_remove (gl_list_t list, gl_list_node_t child, gl_list_node_t parent) { for (;;) { /* At this point, we reduced the black-height of the CHILD subtree by 1. To make up, either look for a possibility to turn a RED to a BLACK node, or try to reduce the black-height tree of CHILD's sibling subtree as well. */ gl_list_node_t *parentp; if (parent->parent == NULL) parentp = &list->root; else if (parent->parent->left == parent) parentp = &parent->parent->left; else if (parent->parent->right == parent) parentp = &parent->parent->right; else abort (); if (parent->left == child) { gl_list_node_t sibling = parent->right; /* sibling's black-height is >= 1. In particular, sibling != NULL. parent / \ child sibling bh bh+1 */ if (sibling->color == RED) { /* sibling is RED, hence parent is BLACK and sibling's children are non-NULL and BLACK. parent sibling bh+2 bh+2 / \ / \ child sibling --> parent SR bh bh+1 bh+1 bh+1 / \ / \ SL SR child SL bh+1 bh+1 bh bh+1 */ *parentp = rotate_left (parent, sibling); parent->color = RED; sibling->color = BLACK; /* Concentrate on the subtree of parent. The new sibling is one of the old sibling's children, and known to be BLACK. */ parentp = &sibling->left; sibling = parent->right; } /* Now we know that sibling is BLACK. parent / \ child sibling bh bh+1 */ if (sibling->right != NULL && sibling->right->color == RED) { /* parent sibling bh+1|bh+2 bh+1|bh+2 / \ / \ child sibling --> parent SR bh bh+1 bh+1 bh+1 / \ / \ SL SR child SL bh bh bh bh */ *parentp = rotate_left (parent, sibling); sibling->color = parent->color; parent->color = BLACK; sibling->right->color = BLACK; return; } else if (sibling->left != NULL && sibling->left->color == RED) { /* parent parent bh+1|bh+2 bh+1|bh+2 / \ / \ child sibling --> child SL bh bh+1 bh bh+1 / \ / \ SL SR SLL sibling bh bh bh bh / \ / \ SLL SLR SLR SR bh bh bh bh where SLL, SLR, SR are all black. */ parent->right = rotate_right (sibling->left, sibling); /* Change sibling from BLACK to RED and SL from RED to BLACK. */ sibling->color = RED; sibling = parent->right; sibling->color = BLACK; /* Now do as in the previous case. */ *parentp = rotate_left (parent, sibling); sibling->color = parent->color; parent->color = BLACK; sibling->right->color = BLACK; return; } else { if (parent->color == BLACK) { /* Change sibling from BLACK to RED. Then the entire subtree at parent has decreased its black-height. parent parent bh+2 bh+1 / \ / \ child sibling --> child sibling bh bh+1 bh bh */ sibling->color = RED; child = parent; } else { /* Change parent from RED to BLACK, but compensate by changing sibling from BLACK to RED. parent parent bh+1 bh+1 / \ / \ child sibling --> child sibling bh bh+1 bh bh */ parent->color = BLACK; sibling->color = RED; return; } } } else if (parent->right == child) { gl_list_node_t sibling = parent->left; /* sibling's black-height is >= 1. In particular, sibling != NULL. parent / \ sibling child bh+1 bh */ if (sibling->color == RED) { /* sibling is RED, hence parent is BLACK and sibling's children are non-NULL and BLACK. parent sibling bh+2 bh+2 / \ / \ sibling child --> SR parent bh+1 ch bh+1 bh+1 / \ / \ SL SR SL child bh+1 bh+1 bh+1 bh */ *parentp = rotate_right (sibling, parent); parent->color = RED; sibling->color = BLACK; /* Concentrate on the subtree of parent. The new sibling is one of the old sibling's children, and known to be BLACK. */ parentp = &sibling->right; sibling = parent->left; } /* Now we know that sibling is BLACK. parent / \ sibling child bh+1 bh */ if (sibling->left != NULL && sibling->left->color == RED) { /* parent sibling bh+1|bh+2 bh+1|bh+2 / \ / \ sibling child --> SL parent bh+1 bh bh+1 bh+1 / \ / \ SL SR SR child bh bh bh bh */ *parentp = rotate_right (sibling, parent); sibling->color = parent->color; parent->color = BLACK; sibling->left->color = BLACK; return; } else if (sibling->right != NULL && sibling->right->color == RED) { /* parent parent bh+1|bh+2 bh+1|bh+2 / \ / \ sibling child --> SR child bh+1 bh bh+1 bh / \ / \ SL SR sibling SRR bh bh bh bh / \ / \ SRL SRR SL SRL bh bh bh bh where SL, SRL, SRR are all black. */ parent->left = rotate_left (sibling, sibling->right); /* Change sibling from BLACK to RED and SL from RED to BLACK. */ sibling->color = RED; sibling = parent->left; sibling->color = BLACK; /* Now do as in the previous case. */ *parentp = rotate_right (sibling, parent); sibling->color = parent->color; parent->color = BLACK; sibling->left->color = BLACK; return; } else { if (parent->color == BLACK) { /* Change sibling from BLACK to RED. Then the entire subtree at parent has decreased its black-height. parent parent bh+2 bh+1 / \ / \ sibling child --> sibling child bh+1 bh bh bh */ sibling->color = RED; child = parent; } else { /* Change parent from RED to BLACK, but compensate by changing sibling from BLACK to RED. parent parent bh+1 bh+1 / \ / \ sibling child --> sibling child bh+1 bh bh bh */ parent->color = BLACK; sibling->color = RED; return; } } } else abort (); /* Start again with a new (child, parent) pair. */ parent = child->parent; #if 0 /* Already handled. */ if (child != NULL && child->color == RED) { child->color = BLACK; return; } #endif if (parent == NULL) return; } } static void gl_tree_remove_node_from_tree (gl_list_t list, gl_list_node_t node) { gl_list_node_t parent = node->parent; if (node->left == NULL) { /* Replace node with node->right. */ gl_list_node_t child = node->right; if (child != NULL) { child->parent = parent; /* Since node->left == NULL, child must be RED and of height 1, hence node must have been BLACK. Recolor the child. */ child->color = BLACK; } if (parent == NULL) list->root = child; else { if (parent->left == node) parent->left = child; else /* parent->right == node */ parent->right = child; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = parent; p != NULL; p = p->parent) p->branch_size--; } if (child == NULL && node->color == BLACK) rebalance_after_remove (list, child, parent); } } else if (node->right == NULL) { /* It is not absolutely necessary to treat this case. But the more general case below is more complicated, hence slower. */ /* Replace node with node->left. */ gl_list_node_t child = node->left; child->parent = parent; /* Since node->right == NULL, child must be RED and of height 1, hence node must have been BLACK. Recolor the child. */ child->color = BLACK; if (parent == NULL) list->root = child; else { if (parent->left == node) parent->left = child; else /* parent->right == node */ parent->right = child; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = parent; p != NULL; p = p->parent) p->branch_size--; } } } else { /* Replace node with the rightmost element of the node->left subtree. */ gl_list_node_t subst; gl_list_node_t subst_parent; gl_list_node_t child; color_t removed_color; for (subst = node->left; subst->right != NULL; ) subst = subst->right; subst_parent = subst->parent; child = subst->left; removed_color = subst->color; /* The case subst_parent == node is special: If we do nothing special, we get confusion about node->left, subst->left and child->parent. subst_parent == node <==> The 'for' loop above terminated immediately. <==> subst == subst_parent->left [otherwise subst == subst_parent->right] In this case, we would need to first set child->parent = node; node->left = child; and later - when we copy subst into node's position - again child->parent = subst; subst->left = child; Altogether a no-op. */ if (subst_parent != node) { if (child != NULL) child->parent = subst_parent; subst_parent->right = child; } /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = subst_parent; p != NULL; p = p->parent) p->branch_size--; } /* Copy subst into node's position. (This is safer than to copy subst's value into node, keep node in place, and free subst.) */ if (subst_parent != node) { subst->left = node->left; subst->left->parent = subst; } subst->right = node->right; subst->right->parent = subst; subst->color = node->color; subst->branch_size = node->branch_size; subst->parent = parent; if (parent == NULL) list->root = subst; else if (parent->left == node) parent->left = subst; else /* parent->right == node */ parent->right = subst; if (removed_color == BLACK) { if (child != NULL && child->color == RED) /* Recolor the child. */ child->color = BLACK; else /* Rebalancing starts at child's parent, that is subst_parent - except when subst_parent == node. In this case, we need to use its replacement, subst. */ rebalance_after_remove (list, child, subst_parent != node ? subst_parent : subst); } } } static gl_list_node_t gl_tree_nx_add_first (gl_list_t list, const void *elt) { /* Create new node. */ gl_list_node_t new_node = (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl)); if (new_node == NULL) return NULL; new_node->left = NULL; new_node->right = NULL; new_node->branch_size = 1; new_node->value = elt; #if WITH_HASHTABLE new_node->h.hashcode = (list->base.hashcode_fn != NULL ? list->base.hashcode_fn (new_node->value) : (size_t)(uintptr_t) new_node->value); #endif /* Add it to the tree. */ if (list->root == NULL) { new_node->color = BLACK; list->root = new_node; new_node->parent = NULL; } else { gl_list_node_t node; for (node = list->root; node->left != NULL; ) node = node->left; node->left = new_node; new_node->parent = node; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = node; p != NULL; p = p->parent) p->branch_size++; } /* Color and rebalance. */ rebalance_after_add (list, new_node, node); } #if WITH_HASHTABLE /* Add node to the hash table. Note that this is only possible _after_ the node has been added to the tree structure, because add_to_bucket() uses node_position(). */ if (add_to_bucket (list, new_node) < 0) { gl_tree_remove_node_from_tree (list, new_node); free (new_node); return NULL; } hash_resize_after_add (list); #endif return new_node; } static gl_list_node_t gl_tree_nx_add_last (gl_list_t list, const void *elt) { /* Create new node. */ gl_list_node_t new_node = (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl)); if (new_node == NULL) return NULL; new_node->left = NULL; new_node->right = NULL; new_node->branch_size = 1; new_node->value = elt; #if WITH_HASHTABLE new_node->h.hashcode = (list->base.hashcode_fn != NULL ? list->base.hashcode_fn (new_node->value) : (size_t)(uintptr_t) new_node->value); #endif /* Add it to the tree. */ if (list->root == NULL) { new_node->color = BLACK; list->root = new_node; new_node->parent = NULL; } else { gl_list_node_t node; for (node = list->root; node->right != NULL; ) node = node->right; node->right = new_node; new_node->parent = node; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = node; p != NULL; p = p->parent) p->branch_size++; } /* Color and rebalance. */ rebalance_after_add (list, new_node, node); } #if WITH_HASHTABLE /* Add node to the hash table. Note that this is only possible _after_ the node has been added to the tree structure, because add_to_bucket() uses node_position(). */ if (add_to_bucket (list, new_node) < 0) { gl_tree_remove_node_from_tree (list, new_node); free (new_node); return NULL; } hash_resize_after_add (list); #endif return new_node; } static gl_list_node_t gl_tree_nx_add_before (gl_list_t list, gl_list_node_t node, const void *elt) { /* Create new node. */ gl_list_node_t new_node = (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl)); if (new_node == NULL) return NULL; new_node->left = NULL; new_node->right = NULL; new_node->branch_size = 1; new_node->value = elt; #if WITH_HASHTABLE new_node->h.hashcode = (list->base.hashcode_fn != NULL ? list->base.hashcode_fn (new_node->value) : (size_t)(uintptr_t) new_node->value); #endif /* Add it to the tree. */ if (node->left == NULL) node->left = new_node; else { for (node = node->left; node->right != NULL; ) node = node->right; node->right = new_node; } new_node->parent = node; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = node; p != NULL; p = p->parent) p->branch_size++; } /* Color and rebalance. */ rebalance_after_add (list, new_node, node); #if WITH_HASHTABLE /* Add node to the hash table. Note that this is only possible _after_ the node has been added to the tree structure, because add_to_bucket() uses node_position(). */ if (add_to_bucket (list, new_node) < 0) { gl_tree_remove_node_from_tree (list, new_node); free (new_node); return NULL; } hash_resize_after_add (list); #endif return new_node; } static gl_list_node_t gl_tree_nx_add_after (gl_list_t list, gl_list_node_t node, const void *elt) { /* Create new node. */ gl_list_node_t new_node = (struct gl_list_node_impl *) malloc (sizeof (struct gl_list_node_impl)); if (new_node == NULL) return NULL; new_node->left = NULL; new_node->right = NULL; new_node->branch_size = 1; new_node->value = elt; #if WITH_HASHTABLE new_node->h.hashcode = (list->base.hashcode_fn != NULL ? list->base.hashcode_fn (new_node->value) : (size_t)(uintptr_t) new_node->value); #endif /* Add it to the tree. */ if (node->right == NULL) node->right = new_node; else { for (node = node->right; node->left != NULL; ) node = node->left; node->left = new_node; } new_node->parent = node; /* Update branch_size fields of the parent nodes. */ { gl_list_node_t p; for (p = node; p != NULL; p = p->parent) p->branch_size++; } /* Color and rebalance. */ rebalance_after_add (list, new_node, node); #if WITH_HASHTABLE /* Add node to the hash table. Note that this is only possible _after_ the node has been added to the tree structure, because add_to_bucket() uses node_position(). */ if (add_to_bucket (list, new_node) < 0) { gl_tree_remove_node_from_tree (list, new_node); free (new_node); return NULL; } hash_resize_after_add (list); #endif return new_node; }