From 0e9f8d615add96ba23a86871e698f8a02f1cf010 Mon Sep 17 00:00:00 2001
From: Bruno BELANYI <bruno@belanyi.fr>
Date: Tue, 24 Nov 2020 19:42:16 +0100
Subject: [PATCH] tupperware: add intrusive AVL tree

---
 Makefile                 |   1 +
 include/tupperware/avl.h |  66 +++++++
 src/avl.c                | 418 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 485 insertions(+)
 create mode 100644 include/tupperware/avl.h
 create mode 100644 src/avl.c

diff --git a/Makefile b/Makefile
index 5e765d8..95ed1ef 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@ CPPFLAGS = -Iinclude/ -Itests/
 VPATH = src/ tests/
 
 SRC = \
+    src/avl.c \
     src/list.c \
 
 OBJS = $(SRC:.c=.o)
diff --git a/include/tupperware/avl.h b/include/tupperware/avl.h
new file mode 100644
index 0000000..6e19f1d
--- /dev/null
+++ b/include/tupperware/avl.h
@@ -0,0 +1,66 @@
+#ifndef TUPPERWARE_AVL_H
+#define TUPPERWARE_AVL_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+struct avl_node {
+    struct avl_node *left;
+    struct avl_node *right;
+    int balance;
+};
+
+typedef int (*avl_cmp_f)(const struct avl_node *lhs,
+        const struct avl_node *rhs, void *cookie);
+typedef void (*avl_map_f)(struct avl_node *n, void *cookie);
+typedef bool (*avl_filter_f)(struct avl_node *n, void *cookie);
+
+struct avl {
+    avl_cmp_f cmp;
+    void *cookie;
+    struct avl_node *root;
+};
+
+#define CONTAINER_OF(Type, Field, Ptr) \
+      ((Type*)((char*)(Ptr) - offsetof(Type, Field)))
+
+#define AVL_NODE_INIT_VAL \
+    ((struct avl_node){ \
+        .left = NULL, \
+        .right = NULL, \
+        .balance = 0, \
+    })
+
+void avl_init(struct avl *tree, avl_cmp_f cmp, void *cookie);
+void avl_clear(struct avl *tree,
+        void (*dtor)(struct avl_node *n, void *cookie), void *cookie);
+
+bool avl_insert(struct avl *tree,
+        struct avl_node *v, struct avl_node **inserted);
+struct avl_node *avl_insert_or_update(struct avl *tree, struct avl_node *v);
+void avl_insert_multi(struct avl *tree, struct avl_node *v);
+
+struct avl_node *avl_remove(struct avl *tree, struct avl_node *v);
+bool avl_remove_at(struct avl *tree, struct avl_node *v);
+
+struct avl_node *avl_find(const struct avl *tree, const struct avl_node *v);
+struct avl_node *avl_lower_bound(const struct avl *tree,
+        const struct avl_node *v);
+struct avl_node *avl_upper_bound(const struct avl *tree,
+        const struct avl_node *v);
+
+bool avl_empty(const struct avl *tree);
+size_t avl_size(const struct avl *tree);
+size_t avl_height(const struct avl *tree);
+
+void avl_merge(struct avl *tree, struct avl *more);
+void avl_update(struct avl *tree, struct avl *more);
+void avl_merge_all(struct avl *tree, struct avl *more);
+
+void avl_prefix_map(struct avl *tree, avl_map_f map, void *cookie);
+void avl_infix_map(struct avl *tree, avl_map_f map, void *cookie);
+void avl_postfix_map(struct avl *tree, avl_map_f map, void *cookie);
+void avl_map_between(const struct avl *tree,
+        struct avl_node *inter[2], avl_map_f map, void *cookie);
+
+#endif /* !TUPPERWARE_AVL_H */
diff --git a/src/avl.c b/src/avl.c
new file mode 100644
index 0000000..4f4018e
--- /dev/null
+++ b/src/avl.c
@@ -0,0 +1,418 @@
+#include "tupperware/avl.h"
+
+#include <limits.h>
+
+#define AVL_NO_CHANGE (INT_MIN)
+
+void avl_init(struct avl *tree, avl_cmp_f cmp, void *cookie) {
+    if (!tree)
+        return;
+    tree->root = NULL;
+    tree->cmp = cmp;
+    tree->cookie = cookie;
+}
+
+static void avl_clear_helper(struct avl_node *n,
+        void (*dtor)(struct avl_node *n, void *cookie), void *cookie) {
+    if (!n)
+        return;
+
+    avl_clear_helper(n->left, dtor, cookie);
+    avl_clear_helper(n->right, dtor, cookie);
+
+    n->left = NULL;
+    n->right = NULL;
+
+    dtor(n, cookie);
+}
+
+void avl_clear(struct avl *tree,
+        void (*dtor)(struct avl_node *n, void *cookie), void *cookie) {
+    if (!tree)
+        return;
+    avl_clear_helper(tree->root, dtor, cookie);
+}
+
+static void left_rotate(struct avl_node **r) {
+    struct avl_node *rhs = (*r)->right;
+    (*r)->right = rhs->left;
+    rhs->left = *r;
+    *r = rhs;
+
+    rhs->left->balance = -1 - rhs->balance;
+    rhs->balance = -rhs->left->balance;
+}
+
+static void right_rotate(struct avl_node **r) {
+    struct avl_node *lhs = (*r)->left;
+    (*r)->left = lhs->right;
+    lhs->right = *r;
+    *r = lhs;
+
+    lhs->right->balance = 1 - lhs->balance;
+    lhs->balance = -lhs->right->balance;
+}
+
+static void left_right_rotate(struct avl_node **r) {
+    struct avl_node *gc = (*r)->left->right;
+    (*r)->left->right = gc->left;
+    gc->left = (*r)->left;
+    (*r)->left = gc->right;
+    gc->right = *r;
+    *r = gc;
+
+    gc->left->balance = (gc->balance * (gc->balance - 1)) >> 1;
+    gc->right->balance = - (gc->balance * (gc->balance + 1)) >> 1;
+    gc->balance = 0;
+}
+
+static void right_left_rotate(struct avl_node **r) {
+    struct avl_node *gc = (*r)->right->left;
+    (*r)->right->left = gc->right;
+    gc->right = (*r)->right;
+    (*r)->right = gc->left;
+    gc->left = *r;
+    *r = gc;
+
+    gc->left->balance = (gc->balance * (gc->balance - 1)) >> 1;
+    gc->right->balance = - (gc->balance * (gc->balance + 1)) >> 1;
+    gc->balance = 0;
+}
+
+static int rebalance(struct avl_node **r) {
+    switch ((*r)->balance) {
+    case -2:
+        if ((*r)->right->balance == 1)
+            right_left_rotate(r);
+        else
+            left_rotate(r);
+        break;
+    case 2:
+        if ((*r)->left->balance == -1)
+            left_right_rotate(r);
+        else
+            right_rotate(r);
+        break;
+    }
+    return (*r)->balance;
+}
+
+static void avl_detach_node(struct avl_node *n) {
+    n->left = NULL;
+    n->right = NULL;
+    n->balance = 0;
+}
+
+static void avl_steal_node(struct avl_node *n1, struct avl_node *n2) {
+    n1->left = n2->left;
+    n1->right = n2->right;
+    n1->balance = n2->balance;
+    avl_detach_node(n2);
+}
+
+struct insert_parameters {
+    avl_cmp_f cmp;
+    void *cookie;
+    enum { ALLOW_MULTI, KEEP_OLD, REPLACE_OLD, } policy;
+};
+
+static int avl_insert_help(struct avl_node **r, struct avl_node *v,
+        struct avl_node **inserted, const struct insert_parameters *params) {
+    if (*r == NULL) {
+        *r = v;
+        v->balance = 0;
+        v->left = NULL;
+        v->right = NULL;
+        *inserted = v;
+        return 1;
+    }
+
+    int c = params->cmp(v, *r, params->cookie);
+    if (c == 0 && params->policy != ALLOW_MULTI) {
+        *inserted = *r;
+        if (params->policy == REPLACE_OLD) {
+            avl_steal_node(v, *r);
+            *r = v;
+        }
+        return AVL_NO_CHANGE;
+    }
+
+    struct avl_node **target = (c < 0 ? &((*r)->left) : &((*r)->right));
+    int dir = (c < 0 ? 1 : -1);
+
+    int tmp = avl_insert_help(target, v, inserted, params);
+    if (tmp == 0 || tmp == AVL_NO_CHANGE)
+        return tmp;
+
+    (*r)->balance += dir;
+
+    return rebalance(r);
+}
+
+bool avl_insert(struct avl *tree,
+        struct avl_node *v, struct avl_node **inserted) {
+    if (!tree || !v)
+        return false;
+
+    struct insert_parameters params = {
+        .cmp = tree->cmp,
+        .cookie = tree->cookie,
+        .policy = KEEP_OLD,
+    };
+    struct avl_node *inserted_int = NULL;
+    int ret = avl_insert_help(&tree->root, v, &inserted_int, &params);
+
+    if (inserted)
+        *inserted = inserted_int;
+
+    return ret != AVL_NO_CHANGE;
+}
+
+struct avl_node *avl_insert_or_update(struct avl *tree, struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    struct avl_node *previous_node = NULL;
+    struct insert_parameters params = {
+        .cmp = tree->cmp,
+        .cookie = tree->cookie,
+        .policy = REPLACE_OLD,
+    };
+
+    avl_insert_help(&tree->root, v, &previous_node, &params);
+
+    return (previous_node == v ? NULL : previous_node);
+}
+
+void avl_insert_multi(struct avl *tree, struct avl_node *v) {
+    if (!tree || !v)
+        return;
+
+    struct insert_parameters params = {
+        .cmp = tree->cmp,
+        .cookie = tree->cookie,
+        .policy = ALLOW_MULTI,
+    };
+    struct avl_node *dummy = NULL;
+    avl_insert_help(&tree->root, v, &dummy, &params);
+}
+
+static int avl_remove_min(struct avl_node **r, struct avl_node **target) {
+    if ((*r)->left == NULL) {
+        *target = *r;
+        *r = (*target)->right;
+        return 1;
+    }
+    if (avl_remove_min(&((*r)->left), target) == 0)
+        return 0;
+    (*r)->balance -= 1;
+    int bal = rebalance(r);
+    return 1 - bal * bal;
+}
+
+static int avl_remove_max(struct avl_node **r, struct avl_node **target) {
+    if ((*r)->right == NULL) {
+        *target = *r;
+        *r = (*target)->right;
+        return 1;
+    }
+    if (avl_remove_max(&((*r)->right), target) == 0)
+        return 0;
+    (*r)->balance -= 1;
+    int bal = rebalance(r);
+    return 1 - bal * bal;
+}
+
+static int avl_remove_helper_found(struct avl_node **r,
+        struct avl_node **target) {
+    *target = *r;
+
+    if ((*r)->left && (*r)->right) {
+        if ((*r)->balance < 0) {
+            int b = avl_remove_min(&((*r)->right), r);
+            avl_steal_node(*r, *target);
+            if (b == 0)
+                return 0;
+            (*r)->balance = 0;
+            return 1;
+        } else {
+            int b = avl_remove_max(&((*r)->left), r);
+            avl_steal_node(*r, *target);
+            if (b == 0)
+                return 0;
+            int bal = ((*r)->balance -= 1);
+            return 1 - (bal * bal);
+        }
+    }
+
+    if ((*r)->left != NULL)
+        *r = (*r)->left;
+    else
+        *r = (*r)->right;
+
+    avl_detach_node(*target);
+    return 1;
+}
+
+struct remove_parameters {
+    avl_cmp_f cmp;
+    void *cookie;
+    enum { REMOVE_ANY, REMOVE_EXACT, } policy;
+};
+
+static int avl_remove_helper(struct avl_node **r, struct avl_node *v,
+        struct avl_node **target, const struct remove_parameters *params) {
+    if (*r == NULL) {
+        *target = NULL;
+        return 0;
+    }
+
+    if (*r == v) // Implies equality according to `cmp`
+        return avl_remove_helper_found(r, target);
+    int c = params->cmp(v, *r, params->cookie);
+    if (c == 0 && params->policy == REMOVE_ANY)
+        return avl_remove_helper_found(r, target);
+
+    if (c < 0) {
+        if (avl_remove_helper(&((*r)->left), v, target, params) == 0)
+            return 0;
+        (*r)->balance -= 1;
+    } else {
+        if (avl_remove_helper(&((*r)->right), v, target, params) == 0)
+            return 0;
+        (*r)->balance += 1;
+    }
+    int bal = rebalance(r);
+    return 1 - bal * bal;
+}
+
+struct avl_node *avl_remove(struct avl *tree, struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    struct avl_node *target = NULL;
+    const struct remove_parameters params = {
+        .cmp = tree->cmp,
+        .cookie = tree->cookie,
+        .policy = REMOVE_ANY,
+    };
+    avl_remove_helper(&tree->root, v, &target, &params);
+    return target;
+}
+
+bool avl_remove_at(struct avl *tree, struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    struct avl_node *target = NULL;
+    const struct remove_parameters params = {
+        .cmp = tree->cmp,
+        .cookie = tree->cookie,
+        .policy = REMOVE_EXACT,
+    };
+    avl_remove_helper(&tree->root, v, &target, &params);
+    return target == v;
+}
+
+static struct avl_node *avl_find_helper(struct avl_node *r,
+        const struct avl_node *v, avl_cmp_f cmp, void *cookie) {
+    int c = 0;
+
+    while (r && (c = cmp(v, r, cookie))) {
+        if (c < 0)
+            r = r->left;
+        else
+            r = r->right;
+    }
+
+    return r;
+}
+
+struct avl_node *avl_find(const struct avl *tree, const struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    return avl_find_helper(tree->root, v, tree->cmp, tree->cookie);
+}
+
+static struct avl_node *avl_lower_bound_helper(struct avl_node *r,
+        const struct avl_node *v, avl_cmp_f cmp, void *cookie) {
+    if (!r)
+        return NULL;
+
+    int c = cmp(v, r, cookie);
+
+    if (c <= 0) {
+        struct avl_node *lhs = avl_lower_bound_helper(r->left, v, cmp, cookie);
+        return (lhs ? lhs : r);
+    }
+
+    return avl_lower_bound_helper(r->right, v, cmp, cookie);
+}
+
+struct avl_node *avl_lower_bound(const struct avl *tree,
+        const struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    return avl_lower_bound_helper(tree->root, v, tree->cmp, tree->cookie);
+}
+
+static struct avl_node *avl_upper_bound_helper(struct avl_node *r,
+        const struct avl_node *v, avl_cmp_f cmp, void *cookie) {
+    if (!r)
+        return NULL;
+
+    int c = cmp(v, r, cookie);
+
+    if (c < 0) {
+        struct avl_node *lhs = avl_upper_bound_helper(r->left, v, cmp, cookie);
+        return (lhs ? lhs : r);
+    }
+
+    return avl_upper_bound_helper(r->right, v, cmp, cookie);
+}
+
+struct avl_node *avl_upper_bound(const struct avl *tree,
+        const struct avl_node *v) {
+    if (!tree || !v)
+        return NULL;
+
+    return avl_upper_bound_helper(tree->root, v, tree->cmp, tree->cookie);
+}
+
+bool avl_empty(const struct avl *tree) {
+    if (!tree || !tree->root)
+        return true;
+    return false;
+}
+
+static size_t avl_size_helper(const struct avl_node *n) {
+    if (!n)
+        return 0;
+
+    return 1 + avl_size_helper(n->left) + avl_size_helper(n->right);
+}
+
+size_t avl_size(const struct avl *tree) {
+    if (!tree)
+        return 0;
+
+    return avl_size_helper(tree->root);
+}
+
+static size_t avl_height_helper(const struct avl_node *n) {
+    if (!n)
+        return 0;
+
+    size_t lhs = avl_height_helper(n->left);
+    size_t rhs = avl_height_helper(n->right);
+    return 1 + (lhs > rhs ? lhs : rhs);
+}
+
+size_t avl_height(const struct avl *tree) {
+    if (!tree)
+        return 0;
+
+    return avl_height_helper(tree->root);
+}