POSTINGSPTR treesearch_page_buildLL(int PageNo, char *key, struct node *root) { // ROOT, word
POSTINGSPTR result;
struct PageHdr *PagePtr = FetchPage(PageNo);
if (PagePtr != NULL) {
root = (struct node *) malloc(sizeof(struct node *));
root->value = PagePtr->PgNum;
root->next = head;
head = root;
}
if (IsLeaf(PagePtr)) { /* found leaf */
result = PageNo;
head = root;
} else if ((IsNonLeaf(PagePtr)) && (PagePtr->NumKeys == 0)) {
/* keys, if any, will be stored in Page# 2
THESE PIECE OF CODE SHOULD GO soon! **/
result = treesearch_page_buildLL(FIRSTLEAFPG, key, root);
} else if ((IsNonLeaf(PagePtr)) && (PagePtr->NumKeys > 0)) {
PAGENO ChildPage = FindPageNumOfChild(PagePtr, PagePtr->KeyListPtr, key,
PagePtr->NumKeys);
result = treesearch_page_buildLL(ChildPage, key, root);
} else {
assert(0 && "this should never happen");
}
FreePage(PagePtr);
return result;
}
PrintTreeInOrder(PAGENO pgNum, int level) {
struct PageHdr *p;
struct KeyRecord *k;
struct PageHdr *FetchPage(); // add this line to avoid seg-fault
int i;
p = (struct PageHdr * ) FetchPage(pgNum);
if(IsNonLeaf(p)) {
for(k=p->KeyListPtr; k != NULL; k = k->Next) {
PrintTreeInOrder(k->PgNum,level+1);
for(i=0; i < level*15; i++) {
printf(" ");
}
printf("%s \n",k->StoredKey);
}
PrintTreeInOrder(p->PtrToFinalRtgPg,level+1);
} else {
int count=0;
for(k=p->KeyListPtr; k != NULL; k = k->Next) {
count++;
if(k == p->KeyListPtr) {
for(i=0; i < level*15; i++) {
printf(" ");
}
printf("%s ",k->StoredKey);
} else
if(k->Next == NULL) {
printf("... %s ",k->StoredKey);
}
}
printf("(%d) \n",count);
}
}
/**
* recursive call to find the page in which the key should reside
* and return the page number (guaranteed to be a leaf page).
*/
PAGENO treesearch_page(PAGENO PageNo, char *key) { // ROOT, word
PAGENO result;
struct PageHdr *PagePtr = FetchPage(PageNo);
/*if (PagePtr != NULL) {
printf("\ntree search - pgnum:%ld", PagePtr->PgNum);
}*/
if (IsLeaf(PagePtr)) { /* found leaf */
result = PageNo;
} else if ((IsNonLeaf(PagePtr)) && (PagePtr->NumKeys == 0)) {
/* keys, if any, will be stored in Page# 2
THESE PIECE OF CODE SHOULD GO soon! **/
result = treesearch_page(FIRSTLEAFPG, key);
} else if ((IsNonLeaf(PagePtr)) && (PagePtr->NumKeys > 0)) {
PAGENO ChildPage = FindPageNumOfChild(PagePtr, PagePtr->KeyListPtr, key,
PagePtr->NumKeys);
result = treesearch_page(ChildPage, key);
} else {
assert(0 && "this should never happen");
}
FreePage(PagePtr);
return result;
}
struct PageHdr *FetchPage(PAGENO Page)
/* Page number of page to be fetched */
{
struct PageHdr *PagePtr;
struct KeyRecord *KeyNode,
*KeyListTraverser; /* To traverse the list of keys */
int i;
fetchPageCount++;
PAGENO FindNumPagesInTree(void);
/* check validity of "Page" */
if ((Page < 1) || (Page > FindNumPagesInTree())) {
printf("FetchPage: Pagenum %d out of range (%d,%d)\n", (int) Page,
(int) ROOT, (int) FindNumPagesInTree());
/* exit(-1); */
}
/* Read in the page header */
PagePtr = (struct PageHdr *) malloc(sizeof(*PagePtr));
ck_malloc(PagePtr, "PagePtr");
fseek(fpbtree, (long) Page * PAGESIZE - PAGESIZE, 0);
fread(&PagePtr->PgTypeID, sizeof(char), 1, fpbtree);
fread(&PagePtr->PgNum, sizeof(PagePtr->PgNum), 1, fpbtree);
if ((PagePtr->PgNum) != Page) {
printf("FetchPage: corrupted Page %d\n", (int) Page);
exit(-1);
}
if (IsLeaf(PagePtr))
fread(&PagePtr->PgNumOfNxtLfPg, sizeof(PagePtr->PgNumOfNxtLfPg), 1,
fpbtree);
fread(&PagePtr->NumBytes, sizeof(PagePtr->NumBytes), 1, fpbtree);
fread(&PagePtr->NumKeys, sizeof(PagePtr->NumKeys), 1, fpbtree);
PagePtr->KeyListPtr = NULL;
if (IsNonLeaf(PagePtr))
fread(&PagePtr->PtrToFinalRtgPg, sizeof(PagePtr->PtrToFinalRtgPg), 1,
fpbtree);
/* Read in the keys */
KeyListTraverser = NULL;
for (i = 0; i < PagePtr->NumKeys; i++) {
KeyNode = (struct KeyRecord *) malloc(sizeof(*KeyNode));
ck_malloc(KeyNode, "KeyNode");
if (IsNonLeaf(PagePtr))
fread(&KeyNode->PgNum, sizeof(KeyNode->PgNum), 1, fpbtree);
fread(&KeyNode->KeyLen, sizeof(KeyNode->KeyLen), 1, fpbtree);
KeyNode->StoredKey = (char *) malloc((KeyNode->KeyLen) + 1);
ck_malloc(KeyNode->StoredKey, "KeyNode->StoredKey in FetchPage()");
fread(KeyNode->StoredKey, sizeof(char), KeyNode->KeyLen, fpbtree);
(*(KeyNode->StoredKey + KeyNode->KeyLen)) =
'\0'; /* string terminator */
if (IsLeaf(PagePtr))
fread(&KeyNode->Posting, sizeof(KeyNode->Posting), 1, fpbtree);
if (KeyListTraverser == NULL) {
KeyListTraverser = KeyNode;
PagePtr->KeyListPtr = KeyNode;
} else {
KeyListTraverser->Next = KeyNode;
KeyListTraverser = KeyListTraverser->Next;
}
}
if (PagePtr->NumKeys != 0)
KeyListTraverser->Next = NULL;
return (PagePtr);
}
