radare2/libr/util/rbtree.c
2018-03-19 11:51:04 +01:00

385 lines
7.8 KiB
C

/* radare - BSD 3 Clause License - Copyright 2017 - MaskRay */
#include <stdio.h>
#include "r_util/r_rbtree.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];
y->child[!dir] = x;
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];
z->child[dir] = y;
x->child[dir] = z->child[!dir];
z->child[!dir] = x;
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, bool backward) {
RBIter it;
it.len = 0;
while (x) {
int d = cmp (data, x);
if (upper ? d < 0 : d <= 0) {
if (!backward) {
it.path[it.len++] = x;
}
x = x->child[0];
} else {
if (backward) {
it.path[it.len++] = x;
}
x = x->child[1];
}
}
return it;
}
/*
static void _check1(RBNode *x, int dep, int black, bool leftmost) {
static int black_;
if (x) {
black += !x->red;
if (x->red && ((x->child[0] && x->child[0]->red) || (x->child[1] && x->child[1]->red))) {
printf ("error: red violation\n");
}
_check1 (x->child[0], dep + 1, black, leftmost);
_check1 (x->child[1], dep + 1, black, false);
} else if (leftmost) {
black_ = black;
} else if (black_ != black) {
printf ("error: different black height\n");
}
}
static void _check(RBNode *x) {
_check1 (x, 0, 0, true);
}
*/
// Returns true if a node with an equal key is deleted
R_API bool r_rbtree_aug_delete(RBNode **root, void *data, RBComparator cmp, RBNodeFree freefn, RBNodeSum sum) {
RBNode head, *del = NULL, **del_link = NULL, *g = NULL, *p = NULL, *q = &head, *path[R_RBTREE_MAX_HEIGHT];
int d = 1, d2, dep = 0;
head.child[0] = NULL;
head.child[1] = *root;
while (q->child[d]) {
d2 = d;
g = p;
p = q;
if (del_link) {
d = 1;
} else {
d = cmp (data, q->child[d2]);
if (d < 0) {
d = 0;
} else if (d > 0) {
d = 1;
} else {
del_link = &q->child[d2];
}
}
if (q != &head) {
if (dep >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[dep++] = q;
}
q = q->child[d2];
if (q->red || red (q->child[d])) {
continue;
}
if (red (q->child[!d])) {
if (del_link && *del_link == q) {
del_link = &q->child[!d]->child[d];
}
p->child[d2] = zag (q, !d, sum);
p = p->child[d2];
if (dep >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[dep++] = p;
} else {
RBNode *s = p->child[!d2];
if (! s) {
continue;
}
if (! red (s->child[0]) && ! red (s->child[1])) {
p->red = false;
q->red = s->red = true;
} else {
int d3 = g->child[0] != p;
RBNode *t;
if (red (s->child[d2])) {
if (del_link && *del_link == p) {
del_link = &s->child[d2]->child[d2];
}
t = zig_zag (p, !d2, sum);
} else {
if (del_link && *del_link == p) {
del_link = &s->child[d2];
}
t = zag (p, !d2, sum);
}
t->red = q->red = true;
t->child[0]->red = t->child[1]->red = false;
g->child[d3] = t;
path[dep - 1] = t;
path[dep++] = p;
}
}
}
if (del_link) {
del = *del_link;
p->child[q != p->child[0]] = q->child[q->child[0] == NULL];
if (del != q) {
*q = *del;
*del_link = q;
}
if (freefn) {
freefn (del);
}
}
if (sum) {
while (dep--) {
sum (path[dep] == del ? q : path[dep]);
}
}
if ((*root = head.child[1])) {
(*root)->red = false;
}
return del;
}
// Returns 1 if `data` is inserted; 0 if an equal key already exists; -1 if allocation fails.
R_API void r_rbtree_aug_insert(RBNode **root, void *data, RBNode *node, RBComparator cmp, RBNodeSum sum) {
node->child[0] = node->child[1] = NULL;
if (!*root) {
*root = node;
node->red = false;
if (sum) {
sum (node);
}
return;
}
RBNode *t = NULL, *g = NULL, *p = NULL, *q = *root;
int d, dep = 0;
bool done = false;
RBNode *path[R_RBTREE_MAX_HEIGHT];
for (;;) {
if (!q) {
q = node;
q->red = true;
p->child[d] = q;
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 d3 = t ? t->child[0] != g : -1, d2 = g->child[0] != p;
if (p->child[d2] == q) {
g = zag (g, d2, sum);
dep--;
path[dep - 1] = g;
} else {
g = zig_zag (g, d2, sum);
dep -= 2;
}
if (t) {
t->child[d3] = g;
} else {
*root = g;
}
}
if (done) {
break;
}
d = cmp (data, q);
t = g;
g = p;
p = q;
if (dep >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
break;
}
path[dep++] = q;
if (d < 0) {
d = 0;
q = q->child[0];
} else {
d = 1;
q = q->child[1];
}
}
if (sum) {
sum (q);
while (dep) {
sum (path[--dep]);
}
}
}
// 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, RBNodeSum sum) {
int dep = 0;
RBNode *path[R_RBTREE_MAX_HEIGHT];
RBNode *cur = root;
for (;;) {
if (dep >= R_RBTREE_MAX_HEIGHT) {
eprintf ("Too deep tree\n");
return false;
}
if (!cur) {
return false;
}
path[dep] = cur;
dep++;
if (cur == node) {
break;
}
int d = cmp (data, cur);
if (d < 0) {
cur = cur->child[0];
} else {
cur = cur->child[1];
}
}
for(; dep > 0; dep--) {
sum (path[dep-1]);
}
return true;
}
R_API bool r_rbtree_delete(RBNode **root, void *data, RBComparator cmp, RBNodeFree freefn) {
return r_rbtree_aug_delete (root, data, cmp, freefn, NULL);
}
R_API RBNode *r_rbtree_find(RBNode *x, void *data, RBComparator cmp) {
while (x) {
int d = cmp (data, x);
if (d < 0) {
x = x->child[0];
} else if (d > 0) {
x = x->child[1];
} else {
return x;
}
}
return NULL;
}
R_API void r_rbtree_free(RBNode *x, RBNodeFree freefn) {
if (x) {
r_rbtree_free (x->child[0], freefn);
r_rbtree_free (x->child[1], freefn);
freefn (x);
}
}
R_API void r_rbtree_insert(RBNode **root, void *data, RBNode *node, RBComparator cmp) {
r_rbtree_aug_insert (root, data, node, cmp, NULL);
}
R_API RBNode *r_rbtree_lower_bound(RBNode *x, void *data, RBComparator cmp) {
RBNode *ret = NULL;
while (x) {
int d = cmp (data, x);
if (d <= 0) {
ret = x;
x = x->child[0];
} else {
x = x->child[1];
}
}
return ret;
}
R_API RBIter r_rbtree_lower_bound_backward(RBNode *root, void *data, RBComparator cmp) {
return bound_iter (root, data, cmp, false, true);
}
R_API RBIter r_rbtree_lower_bound_forward(RBNode *root, void *data, RBComparator cmp) {
return bound_iter (root, data, cmp, false, false);
}
R_API RBNode *r_rbtree_upper_bound(RBNode *x, void *data, RBComparator cmp) {
void *ret = NULL;
while (x) {
int d = cmp (data, x);
if (d < 0) {
ret = x;
x = x->child[0];
} else {
x = x->child[1];
}
}
return ret;
}
R_API RBIter r_rbtree_upper_bound_backward(RBNode *root, void *data, RBComparator cmp) {
return bound_iter (root, data, cmp, true, true);
}
R_API RBIter r_rbtree_upper_bound_forward(RBNode *root, void *data, RBComparator cmp) {
return bound_iter (root, data, cmp, true, false);
}
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);
}