radare2/libr/util/rbtree.c

388 lines
8.6 KiB
C

/* radare - BSD 3 Clause License - Copyright 2017-2021 - MaskRay, condret */
#include <stdio.h>
#include <r_util/r_rbtree.h>
#include <r_util.h>
static inline bool red(RBNode *x) {
return x && x->red;
}
static inline RBNode *zag(RBNode *x, int dir, RBNodeSum sum) {
RBNode *y = x->child[dir];
x->child[dir] = y->child[!dir];
if (x->child[dir]) {
x->child[dir]->parent = x;
}
y->child[!dir] = x;
x->parent = y;
x->red = true;
y->red = false;
if (sum) {
sum (x);
}
return y;
}
static inline RBNode *zig_zag(RBNode *x, int dir, RBNodeSum sum) {
RBNode *y = x->child[dir], *z = y->child[!dir];
y->child[!dir] = z->child[dir];
if (y->child[!dir]) {
y->child[!dir]->parent = y;
}
z->child[dir] = y;
y->parent = z;
x->child[dir] = z->child[!dir];
if (x->child[dir]) {
x->child[dir]->parent = x;
}
z->child[!dir] = x;
x->parent = z;
x->red = y->red = true;
z->red = false;
if (sum) {
sum (x);
sum (y);
}
return z;
}
static inline RBIter bound_iter(RBNode *x, void *data, RBComparator cmp, bool upper, void *user) {
RBIter it;
it.len = 0;
memset (it.path, 0, sizeof (RBNode *) * R_RBTREE_MAX_HEIGHT);
while (x) {
const int d = cmp (data, x, user);
if (d == 0) {
it.path[it.len++] = x;
return it;
}
if (d < 0) {
if (!upper) {
it.path[it.len++] = x;
}
x = x->child[0];
} else {
if (upper) {
it.path[it.len++] = x;
}
x = x->child[1];
}
}
return it;
}
// Returns true if a node with an equal key is deleted
R_API bool r_rbtree_aug_delete(RBNode **root, void *data, RBComparator cmp, void *cmp_user, RBNodeFree freefn, void *free_user, RBNodeSum sum) {
RBNode head, *del = NULL, **del_link = NULL, *g = NULL, *p = NULL, *q = &head, *path[R_RBTREE_MAX_HEIGHT];
int direction = 1, direction2, depth = 0;
head.parent = head.child[0] = NULL;
head.child[1] = *root;
while (q->child[direction]) {
direction2 = direction;
g = p;
p = q;
if (del_link) {
direction = 1;
} else {
direction = cmp (data, q->child[direction2], cmp_user);
if (direction < 0) {
direction = 0;
} else if (direction > 0) {
direction = 1;
} else {
del_link = &q->child[direction2];
}
}
if (q != &head) {
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[depth++] = q;
}
q = q->child[direction2];
if (q->red || red (q->child[direction])) {
continue;
}
if (red (q->child[!direction])) {
if (del_link && *del_link == q) {
del_link = &q->child[!direction]->child[direction];
}
p->child[direction2] = zag (q, !direction, sum);
p->child[direction2]->parent = p->parent;
p = p->child[direction2]; //memleak here?
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[depth++] = p;
} else {
RBNode *s = p->child[!direction2];
if (!s) {
continue;
}
if (!red (s->child[0]) && !red (s->child[1])) {
p->red = false;
q->red = s->red = true;
} else {
int direction3 = g->child[0] != p;
RBNode *t;
if (red (s->child[direction2])) {
if (del_link && *del_link == p) {
del_link = &s->child[direction2]->child[direction2];
}
t = zig_zag (p, !direction2, sum);
} else {
if (del_link && *del_link == p) {
del_link = &s->child[direction2];
}
t = zag (p, !direction2, sum);
}
t->red = q->red = true;
t->child[0]->red = t->child[1]->red = false;
g->child[direction3] = t;
t->parent = g;
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[depth - 1] = t;
path[depth++] = p;
}
}
}
if (del_link && *del_link) {
del = *del_link;
if (q->child[q->child[0] == NULL]) {
q->child[q->child[0] == NULL]->parent = p;
}
p->child[q != p->child[0]] = q->child[q->child[0] == NULL];
if (del != q) {
*q = *del;
*del_link = q;
}
if (freefn) {
freefn (del, free_user);
}
}
if (sum) {
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
depth--;
}
while (depth--) {
sum (path[depth] == del ? q : path[depth]);
}
}
if ((*root = head.child[1])) {
(*root)->red = false;
(*root)->parent = NULL;
}
return del;
}
// Returns true if stuff got inserted, else false
R_API bool r_rbtree_aug_insert(RBNode **root, void *data, RBNode *node, RBComparator cmp, void *cmp_user, RBNodeSum sum) {
node->parent = node->child[0] = node->child[1] = NULL;
if (!*root) {
*root = node;
node->red = false;
if (sum) {
sum (node);
}
return true;
}
RBNode *t = NULL, *g = NULL, *p = NULL, *q = *root;
int direction = 0, depth = 0;
bool done = false;
RBNode *path[R_RBTREE_MAX_HEIGHT];
for (;;) {
if (!q) {
q = node;
q->red = true;
p->child[direction] = q;
q->parent = p;
done = true;
} else if (red (q->child[0]) && red (q->child[1])) {
q->child[0]->red = q->child[1]->red = false;
if (q != *root) {
q->red = true;
}
}
if (q->red && p && p->red) {
int direction3 = t ? t->child[0] != g : -1;
int direction2 = g->child[0] != p;
if (p->child[direction2] == q) {
g = zag (g, direction2, sum);
depth--;
path[depth - 1] = g;
} else {
g = zig_zag (g, direction2, sum);
depth -= 2;
}
if (t) {
t->child[direction3] = g;
g->parent = t;
} else {
*root = g;
g->parent = NULL;
}
}
if (done) {
break;
}
direction = cmp (data, q, cmp_user);
t = g;
g = p;
p = q;
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[depth++] = q;
if (direction < 0) {
direction = 0;
q = q->child[0];
} else {
direction = 1;
q = q->child[1];
}
}
if (sum) {
sum (q);
while (depth) {
sum (path[--depth]);
}
}
return done;
}
// returns true if the sum has been updated, false if node has not been found
R_API bool r_rbtree_aug_update_sum(RBNode *root, void *data, RBNode *node, RBComparator cmp, void *cmp_user, RBNodeSum sum) {
size_t depth = 0;
RBNode *path[R_RBTREE_MAX_HEIGHT];
RBNode *cur = root;
for (;;) {
if (!cur) {
return false;
}
if (depth >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
return false;
}
path[depth] = cur;
depth++;
if (cur == node) {
break;
}
const int direction = cmp (data, cur, cmp_user);
cur = cur->child[(direction < 0)? 0: 1];
}
for (; depth > 0; depth--) {
sum (path[depth - 1]);
}
return true;
}
R_API bool r_rbtree_delete(RBNode **root, void *data, RBComparator cmp, void *cmp_user, RBNodeFree freefn, void *free_user) {
return r_rbtree_aug_delete (root, data, cmp, cmp_user, freefn, free_user, NULL);
}
R_API RBNode *r_rbtree_find(RBNode *x, void *data, RBComparator cmp, void *user) {
// r_return_val_if_fail (x && data, NULL);
while (x) {
const int direction = cmp (data, x, user);
if (direction < 0) {
x = x->child[0];
} else if (direction > 0) {
x = x->child[1];
} else {
return x;
}
}
return NULL;
}
R_API void r_rbtree_free(RBNode *x, RBNodeFree freefn, void *user) {
if (x) {
r_rbtree_free (x->child[0], freefn, user);
r_rbtree_free (x->child[1], freefn, user);
freefn (x, user);
}
}
R_API void r_rbtree_insert(RBNode **root, void *data, RBNode *node, RBComparator cmp, void *user) {
r_rbtree_aug_insert (root, data, node, cmp, user, NULL);
}
R_API RBNode *r_rbtree_lower_bound(RBNode *x, void *data, RBComparator cmp, void *user) {
RBNode *ret = NULL;
while (x) {
int direction = cmp (data, x, user);
if (direction <= 0) {
ret = x;
x = x->child[0];
} else {
x = x->child[1];
}
}
return ret;
}
R_API RBIter r_rbtree_lower_bound_forward(RBNode *root, void *data, RBComparator cmp, void *user) {
return bound_iter (root, data, cmp, false, user);
}
R_API RBNode *r_rbtree_upper_bound(RBNode *x, void *data, RBComparator cmp, void *user) {
void *ret = NULL;
while (x) {
int direction = cmp (data, x, user);
if (direction < 0) {
x = x->child[0];
} else {
ret = x;
x = x->child[1];
}
}
return ret;
}
R_API RBIter r_rbtree_upper_bound_backward(RBNode *root, void *data, RBComparator cmp, void *user) {
return bound_iter (root, data, cmp, true, user);
}
static RBIter _first(RBNode *x, int dir) {
RBIter it;
it.len = 0;
for (; x; x = x->child[dir]) {
it.path[it.len++] = x;
}
return it;
}
R_API RBIter r_rbtree_first(RBNode *tree) {
return _first (tree, 0);
}
R_API RBIter r_rbtree_last(RBNode *tree) {
return _first (tree, 1);
}
static inline void _next(RBIter *it, int dir) {
RBNode *x = it->path[--it->len];
for (x = x->child[!dir]; x; x = x->child[dir]) {
it->path[it->len++] = x;
}
}
R_API void r_rbtree_iter_next(RBIter *it) {
_next (it, 0);
}
R_API void r_rbtree_iter_prev(RBIter *it) {
_next (it, 1);
}