Move sources to new src/ directory

1 files changed, 601 insertions, 0 deletions

diff --git a/src/avltree.c b/src/avltree.c
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+++ b/src/avltree.c
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+/*
+ * Copyright (c) 2010-2017 Richard Braun.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Upstream site with license notes :
+ * http://git.sceen.net/rbraun/librbraun.git/
+ */
+
+#include <assert.h>
+#include <stddef.h>
+#include <stdint.h>
+
+#include "macros.h"
+#include "avltree.h"
+#include "avltree_i.h"
+
+/*
+ * Convert an index of the children array (0 or 1) into a balance value
+ * (-1 or 1).
+ */
+static inline int
+avltree_i2b(int index)
+{
+    assert(avltree_check_index(index));
+    return (index - 1) | 1;
+}
+
+/*
+ * Return the index of a node in the children array of its parent.
+ *
+ * The parent parameter must not be NULL, and must be the parent of the
+ * given node.
+ */
+static inline int
+avltree_node_index(const struct avltree_node *node,
+                   const struct avltree_node *parent)
+{
+    assert(parent != NULL);
+    assert((node == NULL) || (avltree_node_parent(node) == parent));
+
+    if (parent->children[AVLTREE_LEFT] == node) {
+        return AVLTREE_LEFT;
+    }
+
+    assert(parent->children[AVLTREE_RIGHT] == node);
+
+    return AVLTREE_RIGHT;
+}
+
+/*
+ * Return the balance of a node.
+ */
+static inline int
+avltree_node_balance(const struct avltree_node *node)
+{
+    int balance;
+
+    balance = (node->parent & AVLTREE_BALANCE_MASK);
+    assert(balance != AVLTREE_BALANCE_INVALID);
+
+    return balance - 1;
+}
+
+/*
+ * Set the parent of a node, retaining its current balance.
+ */
+static inline void
+avltree_node_set_parent(struct avltree_node *node, struct avltree_node *parent)
+{
+    assert(avltree_node_check_alignment(node));
+    assert(avltree_node_check_alignment(parent));
+    node->parent = (uintptr_t)parent | (node->parent & AVLTREE_BALANCE_MASK);
+}
+
+/*
+ * Set the balance of a node, retaining its current parent.
+ */
+static inline void
+avltree_node_set_balance(struct avltree_node *node, int balance)
+{
+    assert((-1 <= balance) && (balance <= 1));
+    node->parent = (node->parent & AVLTREE_PARENT_MASK) | (balance + 1);
+}
+
+/*
+ * Return the left-most deepest child node of the given node.
+ */
+static struct avltree_node *
+avltree_node_find_deepest(struct avltree_node *node)
+{
+    struct avltree_node *parent;
+
+    assert(node != NULL);
+
+    for (;;) {
+        parent = node;
+        node = node->children[AVLTREE_LEFT];
+
+        if (node == NULL) {
+            node = parent->children[AVLTREE_RIGHT];
+
+            if (node == NULL) {
+                return parent;
+            }
+        }
+    }
+}
+
+/*
+ * Rotate an unbalanced tree.
+ *
+ * This function is called after the insertion or the removal of a node made
+ * a tree unbalanced. The node and balance parameters define the rotation root
+ * (the balance being either -2 or 2).
+ *
+ * Return true if the overall height of the subtree rooted at node has
+ * decreased, false otherwise.
+ */
+static int
+avltree_rotate(struct avltree *tree, struct avltree_node *node, int balance)
+{
+    struct avltree_node *parent, *lnode, *lrnode, *lrlnode, *lrrnode;
+    int left, right, lweight, rweight, lbalance;
+    int index = 0; /* GCC */
+
+    assert((balance == -2) || (balance == 2));
+
+    left = avltree_d2i(balance);
+    right = 1 - left;
+    lweight = balance >> 1;
+    rweight = -lweight;
+
+    parent = avltree_node_parent(node);
+
+    if (likely(parent != NULL)) {
+        index = avltree_node_index(node, parent);
+    }
+
+    lnode = node->children[left];
+    assert(lnode != NULL);
+    lbalance = avltree_node_balance(lnode);
+    lrnode = lnode->children[right];
+
+    /*
+     * Left-left case. Note that only a removal can set the left node balance
+     * to 0 when rotating.
+     */
+    if (lbalance != rweight) {
+        node->children[left] = lrnode;
+
+        if (lrnode != NULL) {
+            avltree_node_set_parent(lrnode, node);
+        }
+
+        lbalance += rweight;
+
+        lnode->children[right] = node;
+
+        avltree_node_set_parent(node, lnode);
+        avltree_node_set_balance(node, -lbalance);
+
+        avltree_node_set_parent(lnode, parent);
+        avltree_node_set_balance(lnode, lbalance);
+
+        if (unlikely(parent == NULL)) {
+            tree->root = lnode;
+        } else {
+            parent->children[index] = lnode;
+        }
+
+        /*
+         * If the adjusted balance is now 0, it means that the height of the
+         * left subtree has decreased.
+         */
+        return (lbalance == 0);
+    }
+
+    /*
+     * Left-right case.
+     */
+
+    assert(lrnode != NULL);
+    lrlnode = lrnode->children[left];
+    lrrnode = lrnode->children[right];
+
+    node->children[left] = lrrnode;
+
+    if (lrrnode != NULL) {
+        avltree_node_set_parent(lrrnode, node);
+    }
+
+    lnode->children[right] = lrlnode;
+
+    if (lrlnode != NULL) {
+        avltree_node_set_parent(lrlnode, lnode);
+    }
+
+    balance = avltree_node_balance(lrnode);
+
+    lrnode->children[left] = lnode;
+    avltree_node_set_parent(lnode, lrnode);
+    avltree_node_set_balance(lnode, ((balance == rweight) ? lweight : 0));
+
+    lrnode->children[right] = node;
+    avltree_node_set_parent(node, lrnode);
+    avltree_node_set_balance(node, ((balance == lweight) ? rweight : 0));
+
+    avltree_node_set_parent(lrnode, parent);
+    avltree_node_set_balance(lrnode, 0);
+
+    if (unlikely(parent == NULL)) {
+        tree->root = lrnode;
+    } else {
+        parent->children[index] = lrnode;
+    }
+
+    /*
+     * The balance of the new subtree root is always 0 in this case, which
+     * implies the overall subtree height has decreased.
+     */
+    return 1;
+}
+
+void
+avltree_insert_rebalance(struct avltree *tree, struct avltree_node *parent,
+                         int index, struct avltree_node *node)
+{
+    int old_balance, new_balance;
+
+    assert(avltree_node_check_alignment(parent));
+    assert(avltree_node_check_alignment(node));
+
+    node->parent = (uintptr_t)parent | AVLTREE_BALANCE_ZERO;
+    node->children[AVLTREE_LEFT] = NULL;
+    node->children[AVLTREE_RIGHT] = NULL;
+
+    /*
+     * The node is the tree root, and is the single tree entry.
+     */
+    if (parent == NULL) {
+        assert(tree->root == NULL);
+        tree->root = node;
+        return;
+    }
+
+    assert(avltree_check_index(index));
+    assert(parent->children[index] == NULL);
+    parent->children[index] = node;
+
+    for (;;) {
+        node = parent;
+
+        old_balance = avltree_node_balance(node);
+        new_balance = old_balance + avltree_i2b(index);
+
+        /*
+         * Perfect balance, stop now.
+         */
+        if (new_balance == 0) {
+            avltree_node_set_balance(node, 0);
+            return;
+        }
+
+        /*
+         * Both previous and new balances are different from 0, which means the
+         * new one has reached -2 or 2. Rebalance now.
+         */
+        if (old_balance != 0) {
+            break;
+        }
+
+        /*
+         * The new balance is either -1 or 1. Update the current node and
+         * iterate again to propagate the height change.
+         */
+        avltree_node_set_balance(node, new_balance);
+        parent = avltree_node_parent(node);
+
+        /*
+         * The tree root was reached.
+         */
+        if (parent == NULL) {
+            return;
+        }
+
+        index = avltree_node_index(node, parent);
+    }
+
+    avltree_rotate(tree, node, new_balance);
+}
+
+void *
+avltree_replace_slot(struct avltree *tree, avltree_slot_t slot,
+                     struct avltree_node *node)
+{
+    struct avltree_node *parent, *prev;
+    int index;
+
+    parent = avltree_slot_parent(slot);
+
+    if (!parent) {
+        prev = tree->root;
+        tree->root = node;
+    } else {
+        index = avltree_slot_index(slot);
+        assert(avltree_check_index(index));
+        prev = parent->children[index];
+        parent->children[index] = node;
+    }
+
+    assert(prev);
+    *node = *prev;
+
+    for (size_t i = 0; i < ARRAY_SIZE(node->children); i++) {
+        if (!node->children[i]) {
+            continue;
+        }
+
+
+        avltree_node_set_parent(node->children[i], node);
+    }
+
+    return prev;
+}
+
+void
+avltree_remove(struct avltree *tree, struct avltree_node *node)
+{
+    struct avltree_node *child, *parent;
+    int left, right, index, old_balance, new_balance;
+
+    if (node->children[AVLTREE_LEFT] == NULL) {
+        child = node->children[AVLTREE_RIGHT];
+    } else if (node->children[AVLTREE_RIGHT] == NULL) {
+        child = node->children[AVLTREE_LEFT];
+    } else {
+        struct avltree_node *successor;
+
+        /*
+         * Two-children case: replace the node with one of its successors. The
+         * choice of the successor depends on the balance of the node to remove,
+         * as swapping with a node in a heavier subtree can reduce the number of
+         * rotations needed to rebalance the tree.
+         */
+
+        old_balance = avltree_node_balance(node);
+        right = avltree_d2i(old_balance);
+        left = 1 - right;
+
+        successor = node->children[right];
+
+        while (successor->children[left] != NULL) {
+            successor = successor->children[left];
+        }
+
+        child = successor->children[right];
+        parent = avltree_node_parent(node);
+
+        if (unlikely(parent == NULL)) {
+            tree->root = successor;
+        } else {
+            parent->children[avltree_node_index(node, parent)] = successor;
+        }
+
+        parent = avltree_node_parent(successor);
+        index = avltree_node_index(successor, parent);
+
+        /*
+         * Set parent directly to keep the original balance.
+         */
+        successor->parent = node->parent;
+        successor->children[left] = node->children[left];
+        avltree_node_set_parent(successor->children[left], successor);
+
+        if (node == parent) {
+            parent = successor;
+        } else {
+            successor->children[right] = node->children[right];
+            avltree_node_set_parent(successor->children[right], successor);
+            parent->children[left] = child;
+
+            if (child != NULL) {
+                avltree_node_set_parent(child, parent);
+            }
+        }
+
+        goto update_balance;
+    }
+
+    /*
+     * Node has at most one child.
+     */
+
+    parent = avltree_node_parent(node);
+
+    if (child != NULL) {
+        avltree_node_set_parent(child, parent);
+    }
+
+    if (parent == NULL) {
+        tree->root = child;
+        return;
+    } else {
+        index = avltree_node_index(node, parent);
+        parent->children[index] = child;
+    }
+
+    /*
+     * The node has been removed, update the balance factors. At this point,
+     * the node parent and the index of the node in its parent children array
+     * must be valid.
+     */
+update_balance:
+    for (;;) {
+        node = parent;
+
+        old_balance = avltree_node_balance(node);
+        new_balance = old_balance - avltree_i2b(index);
+
+        /*
+         * The overall subtree height hasn't decreased, stop now.
+         */
+        if (old_balance == 0) {
+            avltree_node_set_balance(node, new_balance);
+            break;
+        }
+
+        parent = avltree_node_parent(node);
+
+        if (parent != NULL) {
+            index = avltree_node_index(node, parent);
+        }
+
+        /*
+         * The overall subtree height has decreased. Update the current node and
+         * iterate again to propagate the change.
+         */
+        if (new_balance == 0) {
+            avltree_node_set_balance(node, new_balance);
+        } else {
+            int decreased;
+
+            /*
+             * The new balance is either -2 or 2. Rebalance the tree and exit
+             * the loop if the rotation hasn't decreased the overall tree
+             * height.
+             */
+
+            decreased = avltree_rotate(tree, node, new_balance);
+
+            if (!decreased) {
+                break;
+            }
+        }
+
+        /*
+         * The tree root was reached.
+         */
+        if (parent == NULL) {
+            break;
+        }
+    }
+}
+
+struct avltree_node *
+avltree_nearest(struct avltree_node *parent, int index, int direction)
+{
+    assert(avltree_check_index(direction));
+
+    if (parent == NULL) {
+        return NULL;
+    }
+
+    assert(avltree_check_index(index));
+
+    if (index != direction) {
+        return parent;
+    }
+
+    return avltree_walk(parent, direction);
+}
+
+struct avltree_node *
+avltree_firstlast(const struct avltree *tree, int direction)
+{
+    struct avltree_node *prev, *cur;
+
+    assert(avltree_check_index(direction));
+
+    prev = NULL;
+
+    for (cur = tree->root; cur != NULL; cur = cur->children[direction]) {
+        prev = cur;
+    }
+
+    return prev;
+}
+
+struct avltree_node *
+avltree_walk(struct avltree_node *node, int direction)
+{
+    int left, right;
+
+    assert(avltree_check_index(direction));
+
+    left = direction;
+    right = 1 - left;
+
+    if (node == NULL) {
+        return NULL;
+    }
+
+    if (node->children[left] != NULL) {
+        node = node->children[left];
+
+        while (node->children[right] != NULL) {
+            node = node->children[right];
+        }
+    } else {
+        struct avltree_node *parent;
+        int index;
+
+        for (;;) {
+            parent = avltree_node_parent(node);
+
+            if (parent == NULL) {
+                return NULL;
+            }
+
+            index = avltree_node_index(node, parent);
+            node = parent;
+
+            if (index == right) {
+                break;
+            }
+        }
+    }
+
+    return node;
+}
+
+struct avltree_node *
+avltree_postwalk_deepest(const struct avltree *tree)
+{
+    struct avltree_node *node;
+
+    node = tree->root;
+
+    if (node == NULL) {
+        return NULL;
+    }
+
+    return avltree_node_find_deepest(node);
+}
+
+struct avltree_node *
+avltree_postwalk_unlink(struct avltree_node *node)
+{
+    struct avltree_node *parent;
+    int index;
+
+    if (node == NULL) {
+        return NULL;
+    }
+
+    assert(node->children[AVLTREE_LEFT] == NULL);
+    assert(node->children[AVLTREE_RIGHT] == NULL);
+
+    parent = avltree_node_parent(node);
+
+    if (parent == NULL) {
+        return NULL;
+    }
+
+    index = avltree_node_index(node, parent);
+    parent->children[index] = NULL;
+    node = parent->children[AVLTREE_RIGHT];
+
+    if (node == NULL) {
+        return parent;
+    }
+
+    return avltree_node_find_deepest(node);
+}