// http://www.cs.msstate.edu/~cs2314/global/BTreeAnimation/algorithm.html
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <iostream>
#include <assert.h>
#include "btree.h"
#include "ubixfs.h"
using namespace std;
#define VERIFY(x, y, z, n) if ((x) != (y)) { cout << "verify " << z << " failed" << endl; PrintWholeTree(); }
bTree::bTree(UbixFS * filesystem, fileDescriptor * myfd) {
size_t result = 0;
root = NULL;
tag = 0;
fs = filesystem;
fd = myfd;
header = new bTreeHeader;
assert(header);
memset(header, 0, sizeof(bTreeHeader));
assert(fs);
result = fs->vfs_read(fd, header, 0, sizeof(bTreeHeader));
assert(result == sizeof(bTreeHeader));
// If there are any files in this dir, load the first node of the b+tree
if (header->treeLeafCount != 0) {
assert(header->firstNodeOffset != 0);
root = new bNode;
assert(root);
result = fs->vfs_read(fd, root, header->firstNodeOffset, sizeof(bNode));
assert(result == sizeof(bNode));
} // if
} // bTree::bTree
bTree::bTree(const char * key, ubixfsInode * inode) {
/* once the FS and the bTree are interfaced, this should go away */
root = NULL;
tag = 0;
header = new bTreeHeader;
assert(header);
memset(header, 0, sizeof(bTreeHeader));
header->treeDepth = 1;
header->treeWidth = 0;
header->treeLeafCount = 0;
header->firstDeleted = -1;
header->firstNodeOffset = sizeof(bTreeHeader);
if (inode == NULL) return;
root = allocEmptyNode();
if (root == NULL) return;
root->used = 1;
root->parent.bPtr = NULL;
root->leaf = true;
root->childCount[1] = 1;
// cout << "---Creating " << inode->name << "@" << inode << endl;
strncpy(root->keys[0], key, B_MAX_NAME_LENGTH);
// insert pointer to data page to the right of the data
root->head[1].iPtr = inode;
root->tail[1].iPtr = inode;
root->present[1] = true;
if (inode != NULL) {
inode->next.bPtr = inode->prev.bPtr = NULL;
} // if
return;
} // bTree:bTree
bool
bTree::Insert(const char * key, ubixfsInode * inode) {
bNode * bnode = root;
ubixfsInode * tmpInode = NULL;
unsigned int curSlot = 0;
if (inode == NULL) return false;
// note: this code is right out of the constructor
if (root == NULL) {
if (header == NULL) header = new bTreeHeader;
assert(header);
memset(header, 0, sizeof(bTreeHeader));
header->treeDepth = 1;
header->treeWidth = 0;
header->treeLeafCount = 0;
header->firstDeleted = -1;
header->firstNodeOffset = sizeof(bTreeHeader);
root = allocEmptyNode();
assert(root);
if (root == NULL) return false;
root->used = 1;
root->parent.bPtr = NULL;
root->leaf = true;
root->childCount[1] = 1;
strncpy(root->keys[0], key, B_MAX_NAME_LENGTH);
// insert pointer to data page to the right of the data
root->head[1].iPtr = inode;
root->tail[1].iPtr = inode;
root->present[1] = true;
inode->next.iPtr = inode->prev.iPtr = NULL;
return true;
} // if
tmpInode = Find(key);
if (tmpInode != NULL) return false;
// PrintWholeTree();
// cout << "Insert(" << key << ")" << endl;
//Info(bnode);
++header->treeLeafCount;
/*
* Find the leaf node the inode goes into
*/
assert(bnode->used);
// cout << "---Inserting " << inode->name << " @ " << inode << endl;
while (bnode != NULL && !bnode->leaf) {
if (strcmp(key, bnode->keys[0]) < 0) {
bnode = bnode->head[0].bPtr;
} else {
if (strcmp(key, bnode->keys[bnode->used-1]) >= 0) {
bnode = bnode->head[bnode->used].bPtr;
} else {
for (unsigned int i = 1; i < bnode->used; i++) {
if (strcmp(key, bnode->keys[i]) < 0) {
bnode = bnode->head[i].bPtr;
break;
} // if
} // for i
} // else
}
} // while
/*
*
*/
assert(bnode);
if (bnode->leaf != true) cout << "leafnode!=true" << endl;
assert(inode);
if (strcmp(key, bnode->keys[curSlot = 0]) < 0)
tmpInode = bnode->head[curSlot].iPtr;
else
if (strcmp(key, bnode->keys[(curSlot = bnode->used)-1]) >= 0)
tmpInode = bnode->head[bnode->used].iPtr;
else {
for (curSlot = 1; curSlot < bnode->used; curSlot++) {
if (strcmp(key, bnode->keys[curSlot]) < 0) {
tmpInode = bnode->head[curSlot].iPtr;
break;
} // if
} // for curSlot
tmpInode = bnode->head[curSlot].iPtr;
} // else
if (tmpInode == NULL) {
/*
* This is the first node in this leaf
*/
bnode->head[curSlot].iPtr = bnode->tail[curSlot].iPtr = inode;
bnode->present[curSlot] = true;
if (curSlot == 0) {
if (bnode->head[1].iPtr != NULL) {
ubixfsInode * iptr = bnode->head[1].iPtr;
inode->prev.iPtr = iptr->prev.iPtr;
inode->next.iPtr = iptr;
iptr->prev.iPtr = inode;
if (inode->prev.iPtr != NULL)
inode->prev.iPtr->next.iPtr = inode;
} else {
inode->next.iPtr = inode->prev.iPtr = NULL;
} // else
} else {
++bnode->used;
} // else
} else {
/*
* Add node to leaf page. Scan through to find where it goes.
*/
if (strcmp(key, bnode->head[curSlot].iPtr->name) < 0)
{
inode->next.iPtr = bnode->head[curSlot].iPtr;
inode->prev.iPtr = inode->next.iPtr->prev.iPtr;
inode->next.iPtr->prev.iPtr = inode;
if (inode->prev.iPtr != NULL) inode->prev.iPtr->next.iPtr = inode;
bnode->head[curSlot].iPtr = inode;
} else {
if (strcmp(key, bnode->tail[curSlot].iPtr->name) > 0) {
inode->prev.iPtr = bnode->tail[curSlot].iPtr;
inode->next.iPtr = inode->prev.iPtr->next.iPtr;
inode->prev.iPtr->next.iPtr = inode;
if (inode->next.iPtr != NULL) inode->next.iPtr->prev.iPtr = inode;
bnode->tail[curSlot].iPtr = inode;
} else {
ubixfsInode * tmpInode = bnode->head[curSlot].iPtr;
for (unsigned int i = 0; i < bnode->childCount[curSlot]; i++) {
if (strcmp(key, tmpInode->name) < 0) {
inode->next.iPtr = tmpInode;
inode->prev.iPtr = tmpInode->prev.iPtr;
inode->next.iPtr->prev.iPtr = inode;
inode->prev.iPtr->next.iPtr = inode;
break;
} // if
tmpInode = tmpInode->next.iPtr;
} // for i
} // else
} // else
} // else
if (++bnode->childCount[curSlot] == B_MAX_CHILD_COUNT) {
// cout << "---- before split ----" << endl;
// Info(bnode);
if (curSlot != bnode->used) {
int shift = bnode->used - curSlot +1;
memmove(&bnode->head[curSlot+1],
&bnode->head[curSlot],
sizeof(bnode->head[0]) * shift);
memmove(&bnode->tail[curSlot+1],
&bnode->tail[curSlot],
sizeof(bnode->tail[0]) * shift);
memmove(&bnode->present[curSlot+1],
&bnode->present[curSlot],
sizeof(bnode->present[0]) * shift);
memmove(&bnode->childCount[curSlot+1],
&bnode->childCount[curSlot],
sizeof(bnode->childCount[0]) * shift);
memmove(&bnode->keys[curSlot+1],
&bnode->keys[curSlot],
sizeof(bnode->keys[0]) * (shift-1));
memset(bnode->keys[curSlot], 0, B_MAX_NAME_LENGTH);
} else {
bnode->head[curSlot+1] = bnode->head[curSlot];
bnode->tail[curSlot+1] = bnode->tail[curSlot];
bnode->childCount[curSlot+1] = bnode->childCount[curSlot];
bnode->present[curSlot+1] = bnode->present[curSlot];
} // else
ubixfsInode * tmpInode = bnode->head[curSlot].iPtr;
for (unsigned int i = 0; i < (B_MAX_CHILD_COUNT+1) >> 1; i++) {
assert(tmpInode);
tmpInode = tmpInode->next.iPtr;
} // for i
strncpy(bnode->keys[curSlot], tmpInode->name, B_MAX_NAME_LENGTH);
bnode->head[curSlot+1].iPtr = tmpInode;
bnode->tail[curSlot].iPtr = tmpInode->prev.iPtr;
bnode->childCount[curSlot] = (B_MAX_CHILD_COUNT+1) >> 1;
bnode->childCount[curSlot+1] -= bnode->childCount[curSlot];
bnode->present[curSlot] = true;
++header->treeWidth;
if (++bnode->used == B_MAX_KEYS) splitNode(bnode);
} // if leaf is full
// Info(bnode);
return true;
} // bTree::Insert
void
bTree::splitNode(bNode * oldNode) {
ubixfsInode * tmpInode = NULL;
assert(oldNode);
if (oldNode == NULL) return;
if (oldNode->used != B_MAX_KEYS) return;
bNode * newNode = allocEmptyNode();
if (newNode == NULL) return;
unsigned int shift = B_MAX_KEYS >> 1;
unsigned int splitLoc = B_MAX_KEYS - shift;
++ shift;
// cout << "oldNode before split: " << endl;
// Info(oldNode);
// cout << "splitLoc: " << splitLoc << endl;
// cout << "shift: " << shift << endl;
newNode->used = oldNode->used = B_MAX_KEYS >> 1;
newNode->parent.bPtr = oldNode->parent.bPtr;
newNode->leaf = oldNode->leaf;
// cout << "newNode->used: " << newNode->used << endl;
// cout << "oldNode->used: " << oldNode->used << endl;
memcpy(&newNode->keys[0],
&oldNode->keys[splitLoc],
sizeof(newNode->keys[0]) * (shift-1));
memset(&oldNode->keys[splitLoc], 0, sizeof(newNode->keys[0]) * (shift-1));
memcpy(&newNode->present[0],
&oldNode->present[splitLoc],
sizeof(newNode->present[0]) * shift);
memset(&oldNode->present[splitLoc], 0, sizeof(newNode->present[0]) * shift);
memcpy(&newNode->head[0],
&oldNode->head[splitLoc],
sizeof(newNode->head[0]) * shift);
memset(&oldNode->head[splitLoc], 0,
sizeof(newNode->head[0]) * shift);
memcpy(&newNode->tail[0],
&oldNode->tail[splitLoc],
sizeof(newNode->tail[0]) * shift);
memset(&oldNode->tail[splitLoc], 0,
sizeof(newNode->tail[0]) * shift);
memcpy(&newNode->childCount[0],
&oldNode->childCount[splitLoc],
sizeof(newNode->childCount[0]) * shift);
memset(&oldNode->childCount[splitLoc], 0,
sizeof(newNode->childCount[0]) * shift);
if (!newNode->leaf) {
for (unsigned int i = 0; i <= newNode->used; i++) {
newNode->head[i].bPtr->parent.bPtr = newNode;
} // for i
} // if newNode isn't a leaf
tmpInode = GetFirstNode(newNode);
assert(tmpInode);
if (oldNode == root) {
// allocate a new root node
++header->treeDepth;
root = allocEmptyNode();
oldNode->parent.bPtr = root;
newNode->parent.bPtr = root;
// strncpy(root->keys[0], newNode->keys[0], B_MAX_NAME_LENGTH);
strncpy(root->keys[0], tmpInode->name, B_MAX_NAME_LENGTH);
root->head[0].bPtr = oldNode;
root->tail[0].bPtr = root->tail[1].bPtr = NULL;
root->head[1].bPtr = newNode;
root->used = 1;
root->leaf = false;
root->present[0] = root->present[1] = true;
root->childCount[0] = root->childCount[1] = 0;
// root->childCount[0] = oldNode->used;
// root->childCount[1] = newNode->used;
// cout << "parent" << endl;
// Info(newNode->parent);
// cout << "oldNode" << endl;
// Info(oldNode);
// cout << "-----" << endl;
// cout << "newNode" << endl;
// Info(newNode);
// cout << "-----" << endl;
} else {
insertNode(newNode->parent.bPtr, tmpInode->name, newNode);
// if (oldNode->parent->used == B_MAX_KEYS) splitNode(oldNode->parent);
} // else
return;
} // bTree::splitNode
void
bTree::insertNode(bNode * node, const char * key, bNode * headPtr) {
unsigned int curSlot = 0;
if (node == NULL || key == NULL) return;
if (strcmp(key, node->keys[node->used-1]) >= 0){
curSlot = node->used;
memset(node->keys[curSlot], 0, B_MAX_NAME_LENGTH);
strncpy(node->keys[curSlot], key, B_MAX_NAME_LENGTH);
node->head[curSlot+1].bPtr = headPtr;
node->tail[curSlot+1].bPtr = NULL;
node->present[curSlot+1] = true;
node->childCount[node->used] = 0; // maybe?
} else {
for (curSlot = 0; curSlot < node->used; curSlot++) {
if (strcmp(key, node->keys[curSlot]) < 0) break;
} // for
/*
* note that there is one more item for everything but keys
* So, make the shift count +1 and just subtract it from the key shift
* later
*/
int shift = node->used - curSlot +1;
memmove(&node->head[curSlot+1],
&node->head[curSlot],
sizeof(node->head[0]) * shift);
memmove(&node->tail[curSlot+1],
&node->tail[curSlot],
sizeof(node->tail[0]) * shift);
memmove(&node->present[curSlot+1],
&node->present[curSlot],
sizeof(node->present[0]) * shift);
memmove(&node->childCount[curSlot+1],
&node->childCount[curSlot],
sizeof(node->childCount[0]) * shift);
memmove(&node->keys[curSlot+1],
&node->keys[curSlot],
sizeof(node->keys[0]) * (shift-1));
memset(node->keys[curSlot], 0, B_MAX_NAME_LENGTH);
strncpy(node->keys[curSlot], key, B_MAX_NAME_LENGTH);
node->head[curSlot+1].bPtr = headPtr;
node->tail[curSlot+1].bPtr = NULL;
node->present[curSlot+1] = true;
// node->childCount[node->used] = ?;
} // else
if (++node->used == B_MAX_KEYS) splitNode(node);
return;
} // bTree::insertNode
bNode *
bTree::allocEmptyNode(void) {
bNode * newNode = new bNode;
memset(newNode, 0, sizeof(bNode));
newNode->magic1 = B_NODE_MAGIC_1;
newNode->magic2 = B_NODE_MAGIC_2;
newNode->parent.bPtr = NULL;
newNode->tag = ++tag; // this will start at 1 (0 is the header node)
return newNode;
} // bTree::allocEmptyNode
void
bTree::Info(const bNode * node) {
ubixfsInode * inode = NULL;
if (node == NULL || root == NULL) return;
cout << node << " | " << node->parent.bPtr << endl;
for (unsigned int i = 0; i <= node->used; i++) {
inode = node->head[i].iPtr;
// cout << "(" << node->childCount[i] << ")";
for (unsigned int k = 0; k < node->childCount[i]; k++) {
cout << "[" << inode->name << "]";
inode = inode->next.iPtr;
} // for k
if (i != node->used) cout << " {" << node->keys[i] << "} ";
} // for i
cout << endl;
return;
#if 0
for (unsigned int i = 0; i < node->used; i++) {
cout << "keys[" << i << "]: " << node->keys[i] << " ";
} // for i
cout << endl;
cout << "node->used: " << node->used << endl;
cout << "leaf: " << node->leaf << endl;
for (unsigned int i = 0; i <= node->used; i++) {
inode = (ubixfsInode *)node->head[i];
cout << "node->childCount["<<i<<"]: " << node->childCount[i] << endl;
for (unsigned int j = 0; j < node->childCount[i]; j++) {
assert(inode);
cout << "[" << i << "].[" << j << "]->" << inode->name << endl;
inode = inode->next;
} // for j
} // for i
#endif
} // bTree::Info
void
bTree::Info(void) {
ubixfsInode * inode = NULL;
cout << "tree depth: " << header->treeDepth << endl;
cout << "tree width: " << header->treeWidth << endl;
cout << "tree leaf count: " << header->treeLeafCount << endl;
cout << "tag: " << tag << endl;
if (root == NULL) return;
for (unsigned int i = 0; i <= root->used; i++) {
cout << "CC[" << i << "]: " << root->childCount[i] << " ";
} // for i
cout << endl;
for (unsigned int i = 0; i <= root->used; i++) {
cout << "CH[" << i << "]: " << root->head[i].bPtr << " ";
} // for i
cout << endl;
for (unsigned int i = 0; i <=root->used; i++) {
cout << "CT[" << i << "]: " << root->tail[i].bPtr << " ";
} // for i
cout << endl;
for (unsigned int i = 0; i < root->used; i++) {
cout << "keys[" << i << "]: " << root->keys[i] << " ";
} // for i
cout << endl;
cout << "root->used: " << root->used << endl;
for (unsigned int i = 0; i <= root->used; i++) {
inode = root->head[i].iPtr;
cout << "root->childCount["<<i<<"]: " << root->childCount[i] << endl;
if (root->leaf) {
cout << "root contains leaf node" << endl;
for (unsigned int j = 0; j < root->childCount[i]; j++) {
assert(inode);
cout << "[" << i << "].[" << j << "]->" << inode->name << endl;
inode = inode->next.iPtr;
} // for j
} // if root->leaf
} // for i
} // bTree::Info
void
bTree::Print(void) {
ubixfsInode * node = GetFirstNode();
while (node != NULL) {
cout << node->name << endl;
node = node->next.iPtr;
}
} // bTree::Print
ubixfsInode *
bTree::Find(const char * key) {
/*
ubixfsInode * tmp = GetFirstNode();
while (tmp!=NULL) {
if (strcmp(tmp->name, key) == 0) return tmp;
tmp = tmp->next.iPtr;
}
return NULL;
*/
return treeSearch(root, key);
} // bTree::Find
ubixfsInode *
bTree::inodeSearch(ubixfsInode * inode, const char * key) {
if (inode == NULL || key == NULL) return NULL;
int result = strcmp(inode->name, key);
if (result == 0) return inode;
if (result < 0) {
inode = inode->next.iPtr;
while (inode != NULL && ((result = strcmp(inode->name, key)) < 0)) {
inode = inode->next.iPtr;
} // while
} else {
inode = inode->prev.iPtr;
while (inode != NULL && ((result = strcmp(inode->name, key)) > 0)) {
inode = inode->prev.iPtr;
} // while
} // else
return (result == 0 ? inode : NULL);
} // bTree::inodeSearch
ubixfsInode *
bTree::treeSearch(bNode * bnode, const char * key) {
if (bnode == NULL || key == NULL || bnode->used == 0) return NULL;
if (bnode->leaf)
return inodeSearch(GetFirstNode(bnode), key);
if (strcmp(key, bnode->keys[0]) < 0) {
return treeSearch(bnode->head[0].bPtr, key);
} // if
if (strcmp(key, bnode->keys[bnode->used-1]) >= 0) {
return treeSearch(bnode->head[bnode->used].bPtr, key);
} // if
for (unsigned int i = 1; i < bnode->used; i++) {
if (strcmp(key, bnode->keys[i]) < 0) {
return treeSearch(bnode->head[i].bPtr, key);
} // if
} // for i
return NULL;
} // bTree::treeSearch
ubixfsInode *
bTree::GetFirstNode(void) {
return GetFirstNode(root);
} // bTree::GetFirstNode
ubixfsInode *
bTree::GetFirstNode(bNode * node) {
bNode * tmpNode = node;
if (tmpNode == NULL) return NULL;
while (!tmpNode->leaf) {
for (unsigned int i = 0; i < tmpNode->used; i++) {
if (tmpNode->head[i].bPtr != NULL) {
tmpNode = tmpNode->head[i].bPtr;
break;
} // if
} // for i
} // while
for (unsigned int i = 0; i < tmpNode->used; i++) {
if (tmpNode->head[i].iPtr != NULL) return tmpNode->head[i].iPtr;
} // for i
return NULL;
} // bTree::GetFirstNode
bNode *
bTree::findLeafNode(bNode * node, const char * key) {
assert(node);
assert(key);
if (node == NULL || key == NULL) return NULL;
assert(node->used);
if (node->leaf) return node;
if (strcmp(key, node->keys[0]) < 0)
return findLeafNode(node->head[0].bPtr, key);
if (strcmp(key, node->keys[node->used-1]) >= 0)
return findLeafNode(node->head[node->used].bPtr, key);
for (unsigned int i = 1; i < node->used; i++) {
if (strcmp(key, node->keys[i]) < 0)
return findLeafNode(node->head[i].bPtr, key);
} // for i
return NULL;
} // bTree::findLeafNode
void
bTree::saveNode(FILE * fd, bNode * node, void * tmpPtr) {
bNode * ptr = (bNode *)tmpPtr;
assert(tmpPtr);
assert(fd);
assert(node);
cout << "writing tag: " << node->tag << endl;
memcpy(tmpPtr, node, sizeof(bNode));
if (node->parent.bPtr != NULL)
ptr->parent.offset = node->parent.bPtr->tag * sizeof(bNode);
else
ptr->parent.offset = 0;
for (unsigned int i = 0; i <= node->used; i++) {
bNode * bPtr = node->head[i].bPtr;
if (bPtr != NULL)
ptr->head[i].offset = bPtr->tag * sizeof(bNode);
else
ptr->head[i].offset = ~0;
ptr->present[i] = false;
} // for i
if (node->leaf) {
for (unsigned int i = 0; i <= node->used; i++) {
// ubixfsInode * inode = node->head[i].iPtr;
// mji if (inode != NULL) tmp->head[i] = inode->
} // for i
} else {
for (unsigned int i = 0; i <= node->used; i++) {
if (node->head[i].bPtr != NULL) saveNode(fd, node->head[i].bPtr, tmpPtr);
} // for i
} // else
return;
} // bTree::saveNode
bool
bTree::Save(const char * filename) {
ubixfsInode * uPtr = NULL;
if (filename == NULL) return false;
FILE * fd = NULL;
if ((fd = fopen(filename, "wb+")) == NULL) return false;
cout << "tags: " << tag << endl;
lseek(fileno(fd), tag * sizeof(bNode), SEEK_END);
header->firstNodeOffset = sizeof(bNode);
header->firstDeleted = -1;
void * tmpPtr = malloc(sizeof(bNode));
assert(tmpPtr);
uPtr = (ubixfsInode *)tmpPtr;
memset(tmpPtr, 0, sizeof(bNode));
fwrite(header, sizeof(bTreeHeader), 1, fd);
saveNode(fd, root, tmpPtr);
fclose(fd);
free(tmpPtr);
return true;
} // bTree::Save
bool
bTree::Load(const char * filename) {
if (filename == NULL) return false;
return true;
} // bTree::Load
bool
bTree::Delete(const char * key) {
if (key == NULL) return false;
return true;
} // bTree::Delete
bool
bTree::Verify(void) {
ubixfsInode * node = GetFirstNode();
if (node == NULL) return true;
while (node != NULL) {
ubixfsInode * next = node->next.iPtr;
if (next != NULL) {
// cout << node->name << "::" << node->next->name << ":::" << strcmp(node->name, node->next->name) << endl;
if (strcmp(node->name, next->name) > 0) return false;
}
node = next;
} // while
return true;
} // bTree::Verify
void
bTree::Print(bNode * node) {
if (node == NULL) return;
Info(node);
if (!node->leaf)
for (unsigned int i = 0; i <= node->used; i++) {
Print(node->head[i].bPtr);
} // for i
} // bTree::Print
void
bTree::PrintWholeTree(void) {
Print(root);
} // bTree::PrintWholeTree;
bTree::~bTree(void) {
cout << "tree depth: " << header->treeDepth << endl;
cout << "tree width: " << header->treeWidth << endl;
cout << "tree leaf count: " << header->treeLeafCount << endl;
} // bTree::~bTree