/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrRedBlackTree_DEFINED
#define GrRedBlackTree_DEFINED
#include "GrConfig.h"
#include "SkTypes.h"
template <typename T>
class GrLess {
public:
bool operator()(const T& a, const T& b) const { return a < b; }
};
template <typename T>
class GrLess<T*> {
public:
bool operator()(const T* a, const T* b) const { return *a < *b; }
};
class GrStrLess {
public:
bool operator()(const char* a, const char* b) const { return strcmp(a,b) < 0; }
};
/**
* In debug build this will cause full traversals of the tree when the validate
* is called on insert and remove. Useful for debugging but very slow.
*/
#define DEEP_VALIDATE 0
/**
* A sorted tree that uses the red-black tree algorithm. Allows duplicate
* entries. Data is of type T and is compared using functor C. A single C object
* will be created and used for all comparisons.
*/
template <typename T, typename C = GrLess<T> >
class GrRedBlackTree : SkNoncopyable {
public:
/**
* Creates an empty tree.
*/
GrRedBlackTree();
virtual ~GrRedBlackTree();
/**
* Class used to iterater through the tree. The valid range of the tree
* is given by [begin(), end()). It is legal to dereference begin() but not
* end(). The iterator has preincrement and predecrement operators, it is
* legal to decerement end() if the tree is not empty to get the last
* element. However, a last() helper is provided.
*/
class Iter;
/**
* Add an element to the tree. Duplicates are allowed.
* @param t the item to add.
* @return an iterator to the item.
*/
Iter insert(const T& t);
/**
* Removes all items in the tree.
*/
void reset();
/**
* @return true if there are no items in the tree, false otherwise.
*/
bool empty() const {return 0 == fCount;}
/**
* @return the number of items in the tree.
*/
int count() const {return fCount;}
/**
* @return an iterator to the first item in sorted order, or end() if empty
*/
Iter begin();
/**
* Gets the last valid iterator. This is always valid, even on an empty.
* However, it can never be dereferenced. Useful as a loop terminator.
* @return an iterator that is just beyond the last item in sorted order.
*/
Iter end();
/**
* @return an iterator that to the last item in sorted order, or end() if
* empty.
*/
Iter last();
/**
* Finds an occurrence of an item.
* @param t the item to find.
* @return an iterator to a tree element equal to t or end() if none exists.
*/
Iter find(const T& t);
/**
* Finds the first of an item in iterator order.
* @param t the item to find.
* @return an iterator to the first element equal to t or end() if
* none exists.
*/
Iter findFirst(const T& t);
/**
* Finds the last of an item in iterator order.
* @param t the item to find.
* @return an iterator to the last element equal to t or end() if
* none exists.
*/
Iter findLast(const T& t);
/**
* Gets the number of items in the tree equal to t.
* @param t the item to count.
* @return number of items equal to t in the tree
*/
int countOf(const T& t) const;
/**
* Removes the item indicated by an iterator. The iterator will not be valid
* afterwards.
*
* @param iter iterator of item to remove. Must be valid (not end()).
*/
void remove(const Iter& iter) { deleteAtNode(iter.fN); }
private:
enum Color {
kRed_Color,
kBlack_Color
};
enum Child {
kLeft_Child = 0,
kRight_Child = 1
};
struct Node {
T fItem;
Color fColor;
Node* fParent;
Node* fChildren[2];
};
void rotateRight(Node* n);
void rotateLeft(Node* n);
static Node* SuccessorNode(Node* x);
static Node* PredecessorNode(Node* x);
void deleteAtNode(Node* x);
static void RecursiveDelete(Node* x);
int onCountOf(const Node* n, const T& t) const;
#ifdef SK_DEBUG
void validate() const;
int checkNode(Node* n, int* blackHeight) const;
// checks relationship between a node and its children. allowRedRed means
// node may be in an intermediate state where a red parent has a red child.
bool validateChildRelations(const Node* n, bool allowRedRed) const;
// place to stick break point if validateChildRelations is failing.
bool validateChildRelationsFailed() const { return false; }
#else
void validate() const {}
#endif
int fCount;
Node* fRoot;
Node* fFirst;
Node* fLast;
const C fComp;
};
template <typename T, typename C>
class GrRedBlackTree<T,C>::Iter {
public:
Iter() {};
Iter(const Iter& i) {fN = i.fN; fTree = i.fTree;}
Iter& operator =(const Iter& i) {
fN = i.fN;
fTree = i.fTree;
return *this;
}
// altering the sort value of the item using this method will cause
// errors.
T& operator *() const { return fN->fItem; }
bool operator ==(const Iter& i) const {
return fN == i.fN && fTree == i.fTree;
}
bool operator !=(const Iter& i) const { return !(*this == i); }
Iter& operator ++() {
SkASSERT(*this != fTree->end());
fN = SuccessorNode(fN);
return *this;
}
Iter& operator --() {
SkASSERT(*this != fTree->begin());
if (NULL != fN) {
fN = PredecessorNode(fN);
} else {
*this = fTree->last();
}
return *this;
}
private:
friend class GrRedBlackTree;
explicit Iter(Node* n, GrRedBlackTree* tree) {
fN = n;
fTree = tree;
}
Node* fN;
GrRedBlackTree* fTree;
};
template <typename T, typename C>
GrRedBlackTree<T,C>::GrRedBlackTree() : fComp() {
fRoot = NULL;
fFirst = NULL;
fLast = NULL;
fCount = 0;
validate();
}
template <typename T, typename C>
GrRedBlackTree<T,C>::~GrRedBlackTree() {
RecursiveDelete(fRoot);
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::begin() {
return Iter(fFirst, this);
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::end() {
return Iter(NULL, this);
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::last() {
return Iter(fLast, this);
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::find(const T& t) {
Node* n = fRoot;
while (NULL != n) {
if (fComp(t, n->fItem)) {
n = n->fChildren[kLeft_Child];
} else {
if (!fComp(n->fItem, t)) {
return Iter(n, this);
}
n = n->fChildren[kRight_Child];
}
}
return end();
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::findFirst(const T& t) {
Node* n = fRoot;
Node* leftMost = NULL;
while (NULL != n) {
if (fComp(t, n->fItem)) {
n = n->fChildren[kLeft_Child];
} else {
if (!fComp(n->fItem, t)) {
// found one. check if another in left subtree.
leftMost = n;
n = n->fChildren[kLeft_Child];
} else {
n = n->fChildren[kRight_Child];
}
}
}
return Iter(leftMost, this);
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::findLast(const T& t) {
Node* n = fRoot;
Node* rightMost = NULL;
while (NULL != n) {
if (fComp(t, n->fItem)) {
n = n->fChildren[kLeft_Child];
} else {
if (!fComp(n->fItem, t)) {
// found one. check if another in right subtree.
rightMost = n;
}
n = n->fChildren[kRight_Child];
}
}
return Iter(rightMost, this);
}
template <typename T, typename C>
int GrRedBlackTree<T,C>::countOf(const T& t) const {
return onCountOf(fRoot, t);
}
template <typename T, typename C>
int GrRedBlackTree<T,C>::onCountOf(const Node* n, const T& t) const {
// this is count*log(n) :(
while (NULL != n) {
if (fComp(t, n->fItem)) {
n = n->fChildren[kLeft_Child];
} else {
if (!fComp(n->fItem, t)) {
int count = 1;
count += onCountOf(n->fChildren[kLeft_Child], t);
count += onCountOf(n->fChildren[kRight_Child], t);
return count;
}
n = n->fChildren[kRight_Child];
}
}
return 0;
}
template <typename T, typename C>
void GrRedBlackTree<T,C>::reset() {
RecursiveDelete(fRoot);
fRoot = NULL;
fFirst = NULL;
fLast = NULL;
fCount = 0;
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Iter GrRedBlackTree<T,C>::insert(const T& t) {
validate();
++fCount;
Node* x = SkNEW(Node);
x->fChildren[kLeft_Child] = NULL;
x->fChildren[kRight_Child] = NULL;
x->fItem = t;
Node* returnNode = x;
Node* gp = NULL;
Node* p = NULL;
Node* n = fRoot;
Child pc = kLeft_Child; // suppress uninit warning
Child gpc = kLeft_Child;
bool first = true;
bool last = true;
while (NULL != n) {
gpc = pc;
pc = fComp(x->fItem, n->fItem) ? kLeft_Child : kRight_Child;
first = first && kLeft_Child == pc;
last = last && kRight_Child == pc;
gp = p;
p = n;
n = p->fChildren[pc];
}
if (last) {
fLast = x;
}
if (first) {
fFirst = x;
}
if (NULL == p) {
fRoot = x;
x->fColor = kBlack_Color;
x->fParent = NULL;
SkASSERT(1 == fCount);
return Iter(returnNode, this);
}
p->fChildren[pc] = x;
x->fColor = kRed_Color;
x->fParent = p;
do {
// assumptions at loop start.
SkASSERT(NULL != x);
SkASSERT(kRed_Color == x->fColor);
// can't have a grandparent but no parent.
SkASSERT(!(NULL != gp && NULL == p));
// make sure pc and gpc are correct
SkASSERT(NULL == p || p->fChildren[pc] == x);
SkASSERT(NULL == gp || gp->fChildren[gpc] == p);
// if x's parent is black then we didn't violate any of the
// red/black properties when we added x as red.
if (kBlack_Color == p->fColor) {
return Iter(returnNode, this);
}
// gp must be valid because if p was the root then it is black
SkASSERT(NULL != gp);
// gp must be black since it's child, p, is red.
SkASSERT(kBlack_Color == gp->fColor);
// x and its parent are red, violating red-black property.
Node* u = gp->fChildren[1-gpc];
// if x's uncle (p's sibling) is also red then we can flip
// p and u to black and make gp red. But then we have to recurse
// up to gp since it's parent may also be red.
if (NULL != u && kRed_Color == u->fColor) {
p->fColor = kBlack_Color;
u->fColor = kBlack_Color;
gp->fColor = kRed_Color;
x = gp;
p = x->fParent;
if (NULL == p) {
// x (prev gp) is the root, color it black and be done.
SkASSERT(fRoot == x);
x->fColor = kBlack_Color;
validate();
return Iter(returnNode, this);
}
gp = p->fParent;
pc = (p->fChildren[kLeft_Child] == x) ? kLeft_Child :
kRight_Child;
if (NULL != gp) {
gpc = (gp->fChildren[kLeft_Child] == p) ? kLeft_Child :
kRight_Child;
}
continue;
} break;
} while (true);
// Here p is red but u is black and we still have to resolve the fact
// that x and p are both red.
SkASSERT(NULL == gp->fChildren[1-gpc] || kBlack_Color == gp->fChildren[1-gpc]->fColor);
SkASSERT(kRed_Color == x->fColor);
SkASSERT(kRed_Color == p->fColor);
SkASSERT(kBlack_Color == gp->fColor);
// make x be on the same side of p as p is of gp. If it isn't already
// the case then rotate x up to p and swap their labels.
if (pc != gpc) {
if (kRight_Child == pc) {
rotateLeft(p);
Node* temp = p;
p = x;
x = temp;
pc = kLeft_Child;
} else {
rotateRight(p);
Node* temp = p;
p = x;
x = temp;
pc = kRight_Child;
}
}
// we now rotate gp down, pulling up p to be it's new parent.
// gp's child, u, that is not affected we know to be black. gp's new
// child is p's previous child (x's pre-rotation sibling) which must be
// black since p is red.
SkASSERT(NULL == p->fChildren[1-pc] ||
kBlack_Color == p->fChildren[1-pc]->fColor);
// Since gp's two children are black it can become red if p is made
// black. This leaves the black-height of both of p's new subtrees
// preserved and removes the red/red parent child relationship.
p->fColor = kBlack_Color;
gp->fColor = kRed_Color;
if (kLeft_Child == pc) {
rotateRight(gp);
} else {
rotateLeft(gp);
}
validate();
return Iter(returnNode, this);
}
template <typename T, typename C>
void GrRedBlackTree<T,C>::rotateRight(Node* n) {
/* d? d?
* / /
* n s
* / \ ---> / \
* s a? c? n
* / \ / \
* c? b? b? a?
*/
Node* d = n->fParent;
Node* s = n->fChildren[kLeft_Child];
SkASSERT(NULL != s);
Node* b = s->fChildren[kRight_Child];
if (NULL != d) {
Child c = d->fChildren[kLeft_Child] == n ? kLeft_Child :
kRight_Child;
d->fChildren[c] = s;
} else {
SkASSERT(fRoot == n);
fRoot = s;
}
s->fParent = d;
s->fChildren[kRight_Child] = n;
n->fParent = s;
n->fChildren[kLeft_Child] = b;
if (NULL != b) {
b->fParent = n;
}
GR_DEBUGASSERT(validateChildRelations(d, true));
GR_DEBUGASSERT(validateChildRelations(s, true));
GR_DEBUGASSERT(validateChildRelations(n, false));
GR_DEBUGASSERT(validateChildRelations(n->fChildren[kRight_Child], true));
GR_DEBUGASSERT(validateChildRelations(b, true));
GR_DEBUGASSERT(validateChildRelations(s->fChildren[kLeft_Child], true));
}
template <typename T, typename C>
void GrRedBlackTree<T,C>::rotateLeft(Node* n) {
Node* d = n->fParent;
Node* s = n->fChildren[kRight_Child];
SkASSERT(NULL != s);
Node* b = s->fChildren[kLeft_Child];
if (NULL != d) {
Child c = d->fChildren[kRight_Child] == n ? kRight_Child :
kLeft_Child;
d->fChildren[c] = s;
} else {
SkASSERT(fRoot == n);
fRoot = s;
}
s->fParent = d;
s->fChildren[kLeft_Child] = n;
n->fParent = s;
n->fChildren[kRight_Child] = b;
if (NULL != b) {
b->fParent = n;
}
GR_DEBUGASSERT(validateChildRelations(d, true));
GR_DEBUGASSERT(validateChildRelations(s, true));
GR_DEBUGASSERT(validateChildRelations(n, true));
GR_DEBUGASSERT(validateChildRelations(n->fChildren[kLeft_Child], true));
GR_DEBUGASSERT(validateChildRelations(b, true));
GR_DEBUGASSERT(validateChildRelations(s->fChildren[kRight_Child], true));
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Node* GrRedBlackTree<T,C>::SuccessorNode(Node* x) {
SkASSERT(NULL != x);
if (NULL != x->fChildren[kRight_Child]) {
x = x->fChildren[kRight_Child];
while (NULL != x->fChildren[kLeft_Child]) {
x = x->fChildren[kLeft_Child];
}
return x;
}
while (NULL != x->fParent && x == x->fParent->fChildren[kRight_Child]) {
x = x->fParent;
}
return x->fParent;
}
template <typename T, typename C>
typename GrRedBlackTree<T,C>::Node* GrRedBlackTree<T,C>::PredecessorNode(Node* x) {
SkASSERT(NULL != x);
if (NULL != x->fChildren[kLeft_Child]) {
x = x->fChildren[kLeft_Child];
while (NULL != x->fChildren[kRight_Child]) {
x = x->fChildren[kRight_Child];
}
return x;
}
while (NULL != x->fParent && x == x->fParent->fChildren[kLeft_Child]) {
x = x->fParent;
}
return x->fParent;
}
template <typename T, typename C>
void GrRedBlackTree<T,C>::deleteAtNode(Node* x) {
SkASSERT(NULL != x);
validate();
--fCount;
bool hasLeft = NULL != x->fChildren[kLeft_Child];
bool hasRight = NULL != x->fChildren[kRight_Child];
Child c = hasLeft ? kLeft_Child : kRight_Child;
if (hasLeft && hasRight) {
// first and last can't have two children.
SkASSERT(fFirst != x);
SkASSERT(fLast != x);
// if x is an interior node then we find it's successor
// and swap them.
Node* s = x->fChildren[kRight_Child];
while (NULL != s->fChildren[kLeft_Child]) {
s = s->fChildren[kLeft_Child];
}
SkASSERT(NULL != s);
// this might be expensive relative to swapping node ptrs around.
// depends on T.
x->fItem = s->fItem;
x = s;
c = kRight_Child;
} else if (NULL == x->fParent) {
// if x was the root we just replace it with its child and make
// the new root (if the tree is not empty) black.
SkASSERT(fRoot == x);
fRoot = x->fChildren[c];
if (NULL != fRoot) {
fRoot->fParent = NULL;
fRoot->fColor = kBlack_Color;
if (x == fLast) {
SkASSERT(c == kLeft_Child);
fLast = fRoot;
} else if (x == fFirst) {
SkASSERT(c == kRight_Child);
fFirst = fRoot;
}
} else {
SkASSERT(fFirst == fLast && x == fFirst);
fFirst = NULL;
fLast = NULL;
SkASSERT(0 == fCount);
}
delete x;
validate();
return;
}
Child pc;
Node* p = x->fParent;
pc = p->fChildren[kLeft_Child] == x ? kLeft_Child : kRight_Child;
if (NULL == x->fChildren[c]) {
if (fLast == x) {
fLast = p;
SkASSERT(p == PredecessorNode(x));
} else if (fFirst == x) {
fFirst = p;
SkASSERT(p == SuccessorNode(x));
}
// x has two implicit black children.
Color xcolor = x->fColor;
p->fChildren[pc] = NULL;
delete x;
x = NULL;
// when x is red it can be with an implicit black leaf without
// violating any of the red-black tree properties.
if (kRed_Color == xcolor) {
validate();
return;
}
// s is p's other child (x's sibling)
Node* s = p->fChildren[1-pc];
//s cannot be an implicit black node because the original
// black-height at x was >= 2 and s's black-height must equal the
// initial black height of x.
SkASSERT(NULL != s);
SkASSERT(p == s->fParent);
// assigned in loop
Node* sl;
Node* sr;
bool slRed;
bool srRed;
do {
// When we start this loop x may already be deleted it is/was
// p's child on its pc side. x's children are/were black. The
// first time through the loop they are implict children.
// On later passes we will be walking up the tree and they will
// be real nodes.
// The x side of p has a black-height that is one less than the
// s side. It must be rebalanced.
SkASSERT(NULL != s);
SkASSERT(p == s->fParent);
SkASSERT(NULL == x || x->fParent == p);
//sl and sr are s's children, which may be implicit.
sl = s->fChildren[kLeft_Child];
sr = s->fChildren[kRight_Child];
// if the s is red we will rotate s and p, swap their colors so
// that x's new sibling is black
if (kRed_Color == s->fColor) {
// if s is red then it's parent must be black.
SkASSERT(kBlack_Color == p->fColor);
// s's children must also be black since s is red. They can't
// be implicit since s is red and it's black-height is >= 2.
SkASSERT(NULL != sl && kBlack_Color == sl->fColor);
SkASSERT(NULL != sr && kBlack_Color == sr->fColor);
p->fColor = kRed_Color;
s->fColor = kBlack_Color;
if (kLeft_Child == pc) {
rotateLeft(p);
s = sl;
} else {
rotateRight(p);
s = sr;
}
sl = s->fChildren[kLeft_Child];
sr = s->fChildren[kRight_Child];
}
// x and s are now both black.
SkASSERT(kBlack_Color == s->fColor);
SkASSERT(NULL == x || kBlack_Color == x->fColor);
SkASSERT(p == s->fParent);
SkASSERT(NULL == x || p == x->fParent);
// when x is deleted its subtree will have reduced black-height.
slRed = (NULL != sl && kRed_Color == sl->fColor);
srRed = (NULL != sr && kRed_Color == sr->fColor);
if (!slRed && !srRed) {
// if s can be made red that will balance out x's removal
// to make both subtrees of p have the same black-height.
if (kBlack_Color == p->fColor) {
s->fColor = kRed_Color;
// now subtree at p has black-height of one less than
// p's parent's other child's subtree. We move x up to
// p and go through the loop again. At the top of loop
// we assumed x and x's children are black, which holds
// by above ifs.
// if p is the root there is no other subtree to balance
// against.
x = p;
p = x->fParent;
if (NULL == p) {
SkASSERT(fRoot == x);
validate();
return;
} else {
pc = p->fChildren[kLeft_Child] == x ? kLeft_Child :
kRight_Child;
}
s = p->fChildren[1-pc];
SkASSERT(NULL != s);
SkASSERT(p == s->fParent);
continue;
} else if (kRed_Color == p->fColor) {
// we can make p black and s red. This balance out p's
// two subtrees and keep the same black-height as it was
// before the delete.
s->fColor = kRed_Color;
p->fColor = kBlack_Color;
validate();
return;
}
}
break;
} while (true);
// if we made it here one or both of sl and sr is red.
// s and x are black. We make sure that a red child is on
// the same side of s as s is of p.
SkASSERT(slRed || srRed);
if (kLeft_Child == pc && !srRed) {
s->fColor = kRed_Color;
sl->fColor = kBlack_Color;
rotateRight(s);
sr = s;
s = sl;
//sl = s->fChildren[kLeft_Child]; don't need this
} else if (kRight_Child == pc && !slRed) {
s->fColor = kRed_Color;
sr->fColor = kBlack_Color;
rotateLeft(s);
sl = s;
s = sr;
//sr = s->fChildren[kRight_Child]; don't need this
}
// now p is either red or black, x and s are red and s's 1-pc
// child is red.
// We rotate p towards x, pulling s up to replace p. We make
// p be black and s takes p's old color.
// Whether p was red or black, we've increased its pc subtree
// rooted at x by 1 (balancing the imbalance at the start) and
// we've also its subtree rooted at s's black-height by 1. This
// can be balanced by making s's red child be black.
s->fColor = p->fColor;
p->fColor = kBlack_Color;
if (kLeft_Child == pc) {
SkASSERT(NULL != sr && kRed_Color == sr->fColor);
sr->fColor = kBlack_Color;
rotateLeft(p);
} else {
SkASSERT(NULL != sl && kRed_Color == sl->fColor);
sl->fColor = kBlack_Color;
rotateRight(p);
}
}
else {
// x has exactly one implicit black child. x cannot be red.
// Proof by contradiction: Assume X is red. Let c0 be x's implicit
// child and c1 be its non-implicit child. c1 must be black because
// red nodes always have two black children. Then the two subtrees
// of x rooted at c0 and c1 will have different black-heights.
SkASSERT(kBlack_Color == x->fColor);
// So we know x is black and has one implicit black child, c0. c1
// must be red, otherwise the subtree at c1 will have a different
// black-height than the subtree rooted at c0.
SkASSERT(kRed_Color == x->fChildren[c]->fColor);
// replace x with c1, making c1 black, preserves all red-black tree
// props.
Node* c1 = x->fChildren[c];
if (x == fFirst) {
SkASSERT(c == kRight_Child);
fFirst = c1;
while (NULL != fFirst->fChildren[kLeft_Child]) {
fFirst = fFirst->fChildren[kLeft_Child];
}
SkASSERT(fFirst == SuccessorNode(x));
} else if (x == fLast) {
SkASSERT(c == kLeft_Child);
fLast = c1;
while (NULL != fLast->fChildren[kRight_Child]) {
fLast = fLast->fChildren[kRight_Child];
}
SkASSERT(fLast == PredecessorNode(x));
}
c1->fParent = p;
p->fChildren[pc] = c1;
c1->fColor = kBlack_Color;
delete x;
validate();
}
validate();
}
template <typename T, typename C>
void GrRedBlackTree<T,C>::RecursiveDelete(Node* x) {
if (NULL != x) {
RecursiveDelete(x->fChildren[kLeft_Child]);
RecursiveDelete(x->fChildren[kRight_Child]);
delete x;
}
}
#ifdef SK_DEBUG
template <typename T, typename C>
void GrRedBlackTree<T,C>::validate() const {
if (fCount) {
SkASSERT(NULL == fRoot->fParent);
SkASSERT(NULL != fFirst);
SkASSERT(NULL != fLast);
SkASSERT(kBlack_Color == fRoot->fColor);
if (1 == fCount) {
SkASSERT(fFirst == fRoot);
SkASSERT(fLast == fRoot);
SkASSERT(0 == fRoot->fChildren[kLeft_Child]);
SkASSERT(0 == fRoot->fChildren[kRight_Child]);
}
} else {
SkASSERT(NULL == fRoot);
SkASSERT(NULL == fFirst);
SkASSERT(NULL == fLast);
}
#if DEEP_VALIDATE
int bh;
int count = checkNode(fRoot, &bh);
SkASSERT(count == fCount);
#endif
}
template <typename T, typename C>
int GrRedBlackTree<T,C>::checkNode(Node* n, int* bh) const {
if (NULL != n) {
SkASSERT(validateChildRelations(n, false));
if (kBlack_Color == n->fColor) {
*bh += 1;
}
SkASSERT(!fComp(n->fItem, fFirst->fItem));
SkASSERT(!fComp(fLast->fItem, n->fItem));
int leftBh = *bh;
int rightBh = *bh;
int cl = checkNode(n->fChildren[kLeft_Child], &leftBh);
int cr = checkNode(n->fChildren[kRight_Child], &rightBh);
SkASSERT(leftBh == rightBh);
*bh = leftBh;
return 1 + cl + cr;
}
return 0;
}
template <typename T, typename C>
bool GrRedBlackTree<T,C>::validateChildRelations(const Node* n,
bool allowRedRed) const {
if (NULL != n) {
if (NULL != n->fChildren[kLeft_Child] ||
NULL != n->fChildren[kRight_Child]) {
if (n->fChildren[kLeft_Child] == n->fChildren[kRight_Child]) {
return validateChildRelationsFailed();
}
if (n->fChildren[kLeft_Child] == n->fParent &&
NULL != n->fParent) {
return validateChildRelationsFailed();
}
if (n->fChildren[kRight_Child] == n->fParent &&
NULL != n->fParent) {
return validateChildRelationsFailed();
}
if (NULL != n->fChildren[kLeft_Child]) {
if (!allowRedRed &&
kRed_Color == n->fChildren[kLeft_Child]->fColor &&
kRed_Color == n->fColor) {
return validateChildRelationsFailed();
}
if (n->fChildren[kLeft_Child]->fParent != n) {
return validateChildRelationsFailed();
}
if (!(fComp(n->fChildren[kLeft_Child]->fItem, n->fItem) ||
(!fComp(n->fChildren[kLeft_Child]->fItem, n->fItem) &&
!fComp(n->fItem, n->fChildren[kLeft_Child]->fItem)))) {
return validateChildRelationsFailed();
}
}
if (NULL != n->fChildren[kRight_Child]) {
if (!allowRedRed &&
kRed_Color == n->fChildren[kRight_Child]->fColor &&
kRed_Color == n->fColor) {
return validateChildRelationsFailed();
}
if (n->fChildren[kRight_Child]->fParent != n) {
return validateChildRelationsFailed();
}
if (!(fComp(n->fItem, n->fChildren[kRight_Child]->fItem) ||
(!fComp(n->fChildren[kRight_Child]->fItem, n->fItem) &&
!fComp(n->fItem, n->fChildren[kRight_Child]->fItem)))) {
return validateChildRelationsFailed();
}
}
}
}
return true;
}
#endif
#endif