1 files changed, 869 insertions, 0 deletions

diff --git a/extern/rangetree/intern/range_tree.c b/extern/rangetree/intern/range_tree.c
new file mode 100644
index 00000000000..766dd22234c
--- /dev/null
+++ b/extern/rangetree/intern/range_tree.c
@@ -0,0 +1,869 @@
+/*
+ * Copyright (c) 2016, Campbell Barton.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "Apache License")
+ * with the following modification; you may not use this file except in
+ * compliance with the Apache License and the following modification to it:
+ * Section 6. Trademarks. is deleted and replaced with:
+ *
+ * 6. Trademarks. This License does not grant permission to use the trade
+ *   names, trademarks, service marks, or product names of the Licensor
+ *   and its affiliates, except as required to comply with Section 4(c) of
+ *   the License and to reproduce the content of the NOTICE file.
+ *
+ * You may obtain a copy of the Apache License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the Apache License with the above modification is
+ * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the Apache License for the specific
+ * language governing permissions and limitations under the Apache License.
+ */
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include <assert.h>
+
+#include "range_tree.h"
+
+typedef unsigned int uint;
+
+/* Use binary-tree for lookups, else fallback to full search */
+#define USE_BTREE
+/* Use memory pool for nodes, else do individual allocations */
+#define USE_TPOOL
+
+/* Node representing a range in the RangeTreeUInt. */
+typedef struct Node {
+	struct Node *next, *prev;
+
+	/* range (inclusive) */
+	uint min, max;
+
+#ifdef USE_BTREE
+	/* Left leaning red-black tree, for reference implementation see:
+	 * https://gitlab.com/ideasman42/btree-mini-py */
+	struct Node *left, *right;
+	/* RED/BLACK */
+	bool color;
+#endif
+} Node;
+
+#ifdef USE_TPOOL
+/* rt_pool_* pool allocator */
+#define TPOOL_IMPL_PREFIX  rt_node
+#define TPOOL_ALLOC_TYPE   Node
+#define TPOOL_STRUCT       ElemPool_Node
+#include "generic_alloc_impl.h"
+#undef TPOOL_IMPL_PREFIX
+#undef TPOOL_ALLOC_TYPE
+#undef TPOOL_STRUCT
+#endif  /* USE_TPOOL */
+
+typedef struct LinkedList {
+	Node *first, *last;
+} LinkedList;
+
+typedef struct RangeTreeUInt {
+	uint range[2];
+	LinkedList list;
+#ifdef USE_BTREE
+	Node *root;
+#endif
+#ifdef USE_TPOOL
+	struct ElemPool_Node epool;
+#endif
+} RangeTreeUInt;
+
+/* ------------------------------------------------------------------------- */
+/* List API */
+
+static void list_push_front(LinkedList *list, Node *node)
+{
+	if (list->first != NULL) {
+		node->next = list->first;
+		node->next->prev = node;
+		node->prev = NULL;
+	}
+	else {
+		list->last = node;
+	}
+	list->first = node;
+}
+
+static void list_push_back(LinkedList *list, Node *node)
+{
+	if (list->first != NULL) {
+		node->prev = list->last;
+		node->prev->next = node;
+		node->next = NULL;
+	}
+	else {
+		list->first = node;
+	}
+	list->last = node;
+}
+
+static void list_push_after(LinkedList *list, Node *node_prev, Node *node_new)
+{
+	/* node_new before node_next */
+
+	/* empty list */
+	if (list->first == NULL) {
+		list->first = node_new;
+		list->last = node_new;
+		return;
+	}
+
+	/* insert at head of list */
+	if (node_prev == NULL) {
+		node_new->prev = NULL;
+		node_new->next = list->first;
+		node_new->next->prev = node_new;
+		list->first = node_new;
+		return;
+	}
+
+	/* at end of list */
+	if (list->last == node_prev) {
+		list->last = node_new;
+	}
+
+	node_new->next = node_prev->next;
+	node_new->prev = node_prev;
+	node_prev->next = node_new;
+	if (node_new->next) {
+		node_new->next->prev = node_new;
+	}
+}
+
+static void list_push_before(LinkedList *list, Node *node_next, Node *node_new)
+{
+	/* node_new before node_next */
+
+	/* empty list */
+	if (list->first == NULL) {
+		list->first = node_new;
+		list->last = node_new;
+		return;
+	}
+
+	/* insert at end of list */
+	if (node_next == NULL) {
+		node_new->prev = list->last;
+		node_new->next = NULL;
+		list->last->next = node_new;
+		list->last = node_new;
+		return;
+	}
+
+	/* at beginning of list */
+	if (list->first == node_next) {
+		list->first = node_new;
+	}
+
+	node_new->next = node_next;
+	node_new->prev = node_next->prev;
+	node_next->prev = node_new;
+	if (node_new->prev) {
+		node_new->prev->next = node_new;
+	}
+}
+
+static void list_remove(LinkedList *list, Node *node)
+{
+	if (node->next != NULL) {
+		node->next->prev = node->prev;
+	}
+	if (node->prev != NULL) {
+		node->prev->next = node->next;
+	}
+
+	if (list->last == node) {
+		list->last = node->prev;
+	}
+	if (list->first == node) {
+		list->first = node->next;
+	}
+}
+
+static void list_clear(LinkedList *list)
+{
+	list->first = NULL;
+	list->last = NULL;
+}
+
+/* end list API */
+
+
+/* forward declarations */
+static void rt_node_free(RangeTreeUInt *rt, Node *node);
+
+
+#ifdef USE_BTREE
+
+#ifdef DEBUG
+static bool rb_is_balanced_root(const Node *root);
+#endif
+
+/* ------------------------------------------------------------------------- */
+/* Internal BTree API
+ *
+ * Left-leaning red-black tree.
+ */
+
+/* use minimum, could use max too since nodes never overlap */
+#define KEY(n) ((n)->min)
+
+enum {
+	RED = 0,
+	BLACK = 1,
+};
+
+
+static bool is_red(const Node *node)
+{
+	return (node && (node->color == RED));
+}
+
+static int key_cmp(uint key1, uint key2)
+{
+	return (key1 == key2) ? 0 : ((key1 < key2) ? -1 : 1);
+}
+
+/* removed from the tree */
+static void rb_node_invalidate(Node *node)
+{
+#ifdef DEBUG
+	node->left = NULL;
+	node->right = NULL;
+	node->color = false;
+#else
+	(void)node;
+#endif
+}
+
+static void rb_flip_color(Node *node)
+{
+	node->color ^= 1;
+	node->left->color ^= 1;
+	node->right->color ^= 1;
+}
+
+static Node *rb_rotate_left(Node *left)
+{
+	/* Make a right-leaning 3-node lean to the left. */
+	Node *right = left->right;
+	left->right = right->left;
+	right->left = left;
+	right->color = left->color;
+	left->color = RED;
+	return right;
+}
+
+static Node *rb_rotate_right(Node *right)
+{
+	/* Make a left-leaning 3-node lean to the right. */
+	Node *left = right->left;
+	right->left = left->right;
+	left->right = right;
+	left->color = right->color;
+	right->color = RED;
+	return left;
+}
+
+/* Fixup colors when insert happened */
+static Node *rb_fixup_insert(Node *node)
+{
+	if (is_red(node->right) && !is_red(node->left)) {
+		node = rb_rotate_left(node);
+	}
+	if (is_red(node->left) && is_red(node->left->left)) {
+		node = rb_rotate_right(node);
+	}
+
+	if (is_red(node->left) && is_red(node->right)) {
+		rb_flip_color(node);
+	}
+
+	return node;
+}
+
+static Node *rb_insert_recursive(Node *node, Node *node_to_insert)
+{
+	if (node == NULL) {
+		return node_to_insert;
+	}
+
+	const int cmp = key_cmp(KEY(node_to_insert), KEY(node));
+	if (cmp == 0) {
+		/* caller ensures no collisions */
+		assert(0);
+	}
+	else if (cmp == -1) {
+		node->left = rb_insert_recursive(node->left, node_to_insert);
+	}
+	else {
+		node->right = rb_insert_recursive(node->right, node_to_insert);
+	}
+
+	return rb_fixup_insert(node);
+}
+
+static Node *rb_insert_root(Node *root, Node *node_to_insert)
+{
+	root = rb_insert_recursive(root, node_to_insert);
+	root->color = BLACK;
+	return root;
+}
+
+static Node *rb_move_red_to_left(Node *node)
+{
+	/* Assuming that h is red and both h->left and h->left->left
+	 * are black, make h->left or one of its children red.
+	 */
+	rb_flip_color(node);
+	if (node->right && is_red(node->right->left)) {
+		node->right = rb_rotate_right(node->right);
+		node = rb_rotate_left(node);
+		rb_flip_color(node);
+	}
+	return node;
+}
+
+static Node *rb_move_red_to_right(Node *node)
+{
+	/* Assuming that h is red and both h->right and h->right->left
+	 * are black, make h->right or one of its children red.
+	 */
+	rb_flip_color(node);
+	if (node->left && is_red(node->left->left)) {
+		node = rb_rotate_right(node);
+		rb_flip_color(node);
+	}
+	return node;
+}
+
+/* Fixup colors when remove happened */
+static Node *rb_fixup_remove(Node *node)
+{
+	if (is_red(node->right)) {
+		node = rb_rotate_left(node);
+	}
+	if (is_red(node->left) && is_red(node->left->left)) {
+		node = rb_rotate_right(node);
+	}
+	if (is_red(node->left) && is_red(node->right)) {
+		rb_flip_color(node);
+	}
+	return node;
+}
+
+static Node *rb_pop_min_recursive(Node *node, Node **r_node_pop)
+{
+	if (node == NULL) {
+		return NULL;
+	}
+	if (node->left == NULL) {
+		rb_node_invalidate(node);
+		*r_node_pop = node;
+		return NULL;
+	}
+	if ((!is_red(node->left)) && (!is_red(node->left->left))) {
+		node = rb_move_red_to_left(node);
+	}
+	node->left = rb_pop_min_recursive(node->left, r_node_pop);
+	return rb_fixup_remove(node);
+}
+
+static Node *rb_remove_recursive(Node *node, const Node *node_to_remove)
+{
+	if (node == NULL) {
+		return NULL;
+	}
+	if (key_cmp(KEY(node_to_remove), KEY(node)) == -1) {
+		if (node->left != NULL) {
+			if ((!is_red(node->left)) && (!is_red(node->left->left))) {
+				node = rb_move_red_to_left(node);
+			}
+		}
+		node->left = rb_remove_recursive(node->left, node_to_remove);
+	}
+	else {
+		if (is_red(node->left)) {
+			node = rb_rotate_right(node);
+		}
+		if ((node == node_to_remove) && (node->right == NULL)) {
+			rb_node_invalidate(node);
+			return NULL;
+		}
+		assert(node->right != NULL);
+		if ((!is_red(node->right)) && (!is_red(node->right->left))) {
+			node = rb_move_red_to_right(node);
+		}
+
+		if (node == node_to_remove) {
+			/* minor improvement over original method:
+			 * no need to double lookup min */
+			Node *node_free;  /* will always be set */
+			node->right = rb_pop_min_recursive(node->right, &node_free);
+
+			node_free->left = node->left;
+			node_free->right = node->right;
+			node_free->color = node->color;
+
+			rb_node_invalidate(node);
+			node = node_free;
+		}
+		else {
+			node->right = rb_remove_recursive(node->right, node_to_remove);
+		}
+	}
+	return rb_fixup_remove(node);
+}
+
+static Node *rb_btree_remove(Node *root, const Node *node_to_remove)
+{
+	root = rb_remove_recursive(root, node_to_remove);
+	if (root != NULL) {
+		root->color = BLACK;
+	}
+	return root;
+}
+
+/*
+ * Returns the node closest to and including 'key',
+ * excluding anything below.
+ */
+static Node *rb_get_or_upper_recursive(Node *n, const uint key)
+{
+	if (n == NULL) {
+		return NULL;
+	}
+	const int cmp_upper = key_cmp(KEY(n), key);
+	if (cmp_upper == 0) {
+		return n;  // exact match
+	}
+	else if (cmp_upper == 1) {
+		assert(KEY(n) >= key);
+		Node *n_test = rb_get_or_upper_recursive(n->left, key);
+		return n_test ? n_test : n;
+	}
+	else {  // cmp_upper == -1
+		return rb_get_or_upper_recursive(n->right, key);
+	}
+}
+
+/*
+ * Returns the node closest to and including 'key',
+ * excluding anything above.
+ */
+static Node *rb_get_or_lower_recursive(Node *n, const uint key)
+{
+	if (n == NULL) {
+		return NULL;
+	}
+	const int cmp_lower = key_cmp(KEY(n), key);
+	if (cmp_lower == 0) {
+		return n;  // exact match
+	}
+	else if (cmp_lower == -1) {
+		assert(KEY(n) <= key);
+		Node *n_test = rb_get_or_lower_recursive(n->right, key);
+		return n_test ? n_test : n;
+	}
+	else {  // cmp_lower == 1
+		return rb_get_or_lower_recursive(n->left, key);
+	}
+}
+
+#ifdef DEBUG
+
+static bool rb_is_balanced_recursive(const Node *node, int black)
+{
+	// Does every path from the root to a leaf have the given number
+	// of black links?
+	if (node == NULL) {
+		return black == 0;
+	}
+	if (!is_red(node)) {
+		black--;
+	}
+	return rb_is_balanced_recursive(node->left, black) &&
+	       rb_is_balanced_recursive(node->right, black);
+}
+
+static bool rb_is_balanced_root(const Node *root)
+{
+	// Do all paths from root to leaf have same number of black edges?
+	int black = 0;     // number of black links on path from root to min
+	const Node *node = root;
+	while (node != NULL) {
+		if (!is_red(node)) {
+			black++;
+		}
+		node = node->left;
+	}
+	return rb_is_balanced_recursive(root, black);
+}
+
+#endif  // DEBUG
+
+
+/* End BTree API */
+#endif  // USE_BTREE
+
+
+/* ------------------------------------------------------------------------- */
+/* Internal RangeTreeUInt API */
+
+static inline Node *rt_node_alloc(RangeTreeUInt *rt)
+{
+#ifdef USE_TPOOL
+	return rt_node_pool_elem_alloc(&rt->epool);
+#else
+	(void)rt;
+	return malloc(sizeof(Node));
+#endif
+}
+
+static Node *rt_node_new(RangeTreeUInt *rt, uint min, uint max)
+{
+	Node *node = rt_node_alloc(rt);
+
+	assert(min <= max);
+	node->prev = NULL;
+	node->next = NULL;
+	node->min = min;
+	node->max = max;
+#ifdef USE_BTREE
+	node->left = NULL;
+	node->right = NULL;
+#endif
+	return node;
+}
+
+static void rt_node_free(RangeTreeUInt *rt, Node *node)
+{
+#ifdef USE_TPOOL
+	rt_node_pool_elem_free(&rt->epool, node);
+#else
+	(void)rt;
+	free(node);
+#endif
+}
+
+#ifdef USE_BTREE
+static void rt_btree_insert(RangeTreeUInt *rt, Node *node)
+{
+	node->color = RED;
+	node->left = NULL;
+	node->right = NULL;
+	rt->root = rb_insert_root(rt->root, node);
+}
+#endif
+
+static void rt_node_add_back(RangeTreeUInt *rt, Node *node)
+{
+	list_push_back(&rt->list, node);
+#ifdef USE_BTREE
+	rt_btree_insert(rt, node);
+#endif
+}
+static void rt_node_add_front(RangeTreeUInt *rt, Node *node)
+{
+	list_push_front(&rt->list, node);
+#ifdef USE_BTREE
+	rt_btree_insert(rt, node);
+#endif
+}
+static void rt_node_add_before(RangeTreeUInt *rt, Node *node_next, Node *node)
+{
+	list_push_before(&rt->list, node_next, node);
+#ifdef USE_BTREE
+	rt_btree_insert(rt, node);
+#endif
+}
+static void rt_node_add_after(RangeTreeUInt *rt, Node *node_prev, Node *node)
+{
+	list_push_after(&rt->list, node_prev, node);
+#ifdef USE_BTREE
+	rt_btree_insert(rt, node);
+#endif
+}
+
+static void rt_node_remove(RangeTreeUInt *rt, Node *node)
+{
+	list_remove(&rt->list, node);
+#ifdef USE_BTREE
+	rt->root = rb_btree_remove(rt->root, node);
+#endif
+	rt_node_free(rt, node);
+}
+
+static Node *rt_find_node_from_value(RangeTreeUInt *rt, const uint value)
+{
+#ifdef USE_BTREE
+	Node *node = rb_get_or_lower_recursive(rt->root, value);
+	if (node != NULL) {
+		if ((value >= node->min) && (value <= node->max)) {
+			return node;
+		}
+	}
+	return NULL;
+#else
+	for (Node *node = rt->list.first; node; node = node->next) {
+		if ((value >= node->min) && (value <= node->max)) {
+			return node;
+		}
+	}
+	return NULL;
+#endif // USE_BTREE
+}
+
+static void rt_find_node_pair_around_value(RangeTreeUInt *rt, const uint value,
+                                           Node **r_node_prev, Node **r_node_next)
+{
+	if (value < rt->list.first->min) {
+		*r_node_prev = NULL;
+		*r_node_next = rt->list.first;
+		return;
+	}
+	else if (value > rt->list.last->max) {
+		*r_node_prev = rt->list.last;
+		*r_node_next = NULL;
+		return;
+	}
+	else {
+#ifdef USE_BTREE
+		Node *node_next = rb_get_or_upper_recursive(rt->root, value);
+		if (node_next != NULL) {
+			Node *node_prev = node_next->prev;
+			if ((node_prev->max < value) && (value < node_next->min)) {
+				*r_node_prev = node_prev;
+				*r_node_next = node_next;
+				return;
+			}
+		}
+#else
+		Node *node_prev = rt->list.first;
+		Node *node_next;
+		while ((node_next = node_prev->next)) {
+			if ((node_prev->max < value) && (value < node_next->min)) {
+				*r_node_prev = node_prev;
+				*r_node_next = node_next;
+				return;
+			}
+			node_prev = node_next;
+		}
+#endif // USE_BTREE
+	}
+	*r_node_prev = NULL;
+	*r_node_next = NULL;
+}
+
+
+/* ------------------------------------------------------------------------- */
+/* Public API */
+
+static RangeTreeUInt *rt_create_empty(uint min, uint max)
+{
+	RangeTreeUInt *rt = malloc(sizeof(*rt));
+	rt->range[0] = min;
+	rt->range[1] = max;
+
+	list_clear(&rt->list);
+
+#ifdef USE_BTREE
+	rt->root = NULL;
+#endif
+#ifdef USE_TPOOL
+	rt_node_pool_create(&rt->epool, 512);
+#endif
+
+	return rt;
+}
+
+RangeTreeUInt *range_tree_uint_alloc(uint min, uint max)
+{
+	RangeTreeUInt *rt = rt_create_empty(min, max);
+
+	Node *node = rt_node_new(rt, min, max);
+	rt_node_add_front(rt, node);
+	return rt;
+}
+
+void range_tree_uint_free(RangeTreeUInt *rt)
+{
+#ifdef DEBUG
+#ifdef USE_BTREE
+	assert(rb_is_balanced_root(rt->root));
+#endif
+#endif
+
+#ifdef USE_TPOOL
+
+	rt_node_pool_destroy(&rt->epool);
+#else
+	for (Node *node = rt->list.first, *node_next; node; node = node_next) {
+		node_next = node->next;
+		rt_node_free(rt, node);
+	}
+#endif
+
+	free(rt);
+}
+
+#ifdef USE_BTREE
+static Node *rt_copy_recursive(RangeTreeUInt *rt_dst, const Node *node_src)
+{
+	if (node_src == NULL) {
+		return NULL;
+	}
+
+	Node *node_dst = rt_node_alloc(rt_dst);
+
+	*node_dst = *node_src;
+	node_dst->left = rt_copy_recursive(rt_dst, node_dst->left);
+	list_push_back(&rt_dst->list, node_dst);
+	node_dst->right = rt_copy_recursive(rt_dst, node_dst->right);
+
+	return node_dst;
+}
+#endif  // USE_BTREE
+
+RangeTreeUInt *range_tree_uint_copy(const RangeTreeUInt *rt_src)
+{
+	RangeTreeUInt *rt_dst = rt_create_empty(rt_src->range[0], rt_src->range[1]);
+#ifdef USE_BTREE
+	rt_dst->root = rt_copy_recursive(rt_dst, rt_src->root);
+#else
+	for (Node *node_src = rt_src->list.first; node_src; node_src = node_src->next) {
+		Node *node_dst = rt_node_alloc(rt_dst);
+		*node_dst = *node_src;
+		list_push_back(&rt_dst->list, node_dst);
+	}
+#endif
+	return rt_dst;
+}
+
+/**
+ * Return true if the tree has the value (not taken).
+ */
+bool range_tree_uint_has(RangeTreeUInt *rt, const uint value)
+{
+	assert(value >= rt->range[0] && value <= rt->range[1]);
+	Node *node = rt_find_node_from_value(rt, value);
+	return (node != NULL);
+}
+
+static void range_tree_uint_take_impl(RangeTreeUInt *rt, const uint value, Node *node)
+{
+	assert(node == rt_find_node_from_value(rt, value));
+	if (node->min == value) {
+		if (node->max != value) {
+			node->min += 1;
+		}
+		else {
+			assert(node->min == node->max);
+			rt_node_remove(rt, node);
+		}
+	}
+	else if (node->max == value) {
+		node->max -= 1;
+	}
+	else {
+		Node *node_next = rt_node_new(rt, value + 1, node->max);
+		node->max = value - 1;
+		rt_node_add_after(rt, node, node_next);
+	}
+}
+
+void range_tree_uint_take(RangeTreeUInt *rt, const uint value)
+{
+	Node *node = rt_find_node_from_value(rt, value);
+	assert(node != NULL);
+	range_tree_uint_take_impl(rt, value, node);
+}
+
+bool range_tree_uint_retake(RangeTreeUInt *rt, const uint value)
+{
+	Node *node = rt_find_node_from_value(rt, value);
+	if (node != NULL) {
+		range_tree_uint_take_impl(rt, value, node);
+		return true;
+	}
+	else {
+		return false;
+	}
+}
+
+uint range_tree_uint_take_any(RangeTreeUInt *rt)
+{
+	Node *node = node = rt->list.first;
+	uint value = node->min;
+	if (value == node->max) {
+		rt_node_remove(rt, node);
+	}
+	else {
+		node->min += 1;
+	}
+	return value;
+}
+
+void range_tree_uint_release(RangeTreeUInt *rt, const uint value)
+{
+	bool touch_prev, touch_next;
+	Node *node_prev, *node_next;
+
+	if (rt->list.first != NULL) {
+		rt_find_node_pair_around_value(rt, value, &node_prev, &node_next);
+		/* the value must have been already taken */
+		assert(node_prev || node_next);
+
+		/* Cases:
+		 * 1) fill the gap between prev & next (two spans into one span).
+		 * 2) touching prev, (grow node_prev->max up one).
+		 * 3) touching next, (grow node_next->min down one).
+		 * 4) touching neither, add a new segment. */
+		touch_prev = (node_prev != NULL && node_prev->max + 1 == value);
+		touch_next = (node_next != NULL && node_next->min - 1 == value);
+	}
+	else {
+		// we could handle this case (4) inline,
+		// since its not a common case - use regular logic.
+		node_prev = node_next = NULL;
+		touch_prev = false;
+		touch_next = false;
+	}
+
+	if (touch_prev && touch_next) {  // 1)
+		node_prev->max = node_next->max;
+		rt_node_remove(rt, node_next);
+	}
+	else if (touch_prev) {  // 2)
+		assert(node_prev->max + 1 == value);
+		node_prev->max = value;
+	}
+	else if (touch_next) {  // 3)
+		assert(node_next->min - 1 == value);
+		node_next->min = value;
+	}
+	else {  // 4)
+		Node *node_new = rt_node_new(rt, value, value);
+		if (node_prev != NULL) {
+			rt_node_add_after(rt, node_prev, node_new);
+		}
+		else if (node_next != NULL) {
+			rt_node_add_before(rt, node_next, node_new);
+		}
+		else {
+			assert(rt->list.first == NULL);
+			rt_node_add_back(rt, node_new);
+		}
+	}
+}