public boolean insertRecord(char[] record) {
char[] key = getKey(record, 0); // Get key array
int sectorNum = getSector(convertToString(key)); // Get sector number
disk.readSector(sectorNum, buffer); // Read the sector to the buffer
boolean notDuplicate = checkNotDuplicate(buffer, key); // Check duplicate key
if (notDuplicate) // If its not a duplicate key
{
boolean availableSpace =
findAvailableAndStore(buffer, record); // find an available space in buffer
if (availableSpace) // Found available space
{
disk.writeSector(sectorNum, buffer); // Write the buffer to disk sector
return true;
} else // Need to go overflow sectors
{
if (overflowSectors == 0) // Oops i don't have a overflow sector
{
overflowStart =
this.indexStart + this.indexSectors; // Allocated the first overflow sector
disk.readSector(
overflowStart, buffer); // Read in the first empty overflow sector into buffer
findAvailableAndStore(buffer, record); // write the record into buffer
disk.writeSector(overflowStart, buffer); // Write to the disk overflow sector
overflowSectors++; // Increment number of overflow sectors in use
return true;
} else // If not the first time
{
int currOverflowSector = overflowStart;
while ((currOverflowSector < overflowStart + overflowSectors) && notDuplicate) {
disk.readSector(currOverflowSector, buffer); // Read in overflow sector
notDuplicate = checkNotDuplicate(buffer, key); // Check duplicate key
currOverflowSector++; // Move to next overflow sector
}
if (notDuplicate) // No duplicate key in overflow sector
{
currOverflowSector--; // Back to current overflow sector
availableSpace =
findAvailableAndStore(buffer, record); // Find an available space in buffer
if (!availableSpace) // If not more space in this overflow sector
{
currOverflowSector++; // Move to next overflow sector
overflowSectors++; // Increment number of overflow sectors in use
disk.readSector(
currOverflowSector, buffer); // Read next overflow sector(empty) into buffer
findAvailableAndStore(buffer, record); // write the record into empty buffer
}
disk.writeSector(currOverflowSector, buffer); // Write to the disk overflow sector
return true;
} else // Found duplicate key in overflow sector
return false;
}
}
} else // Same key is found no further action, return false
return false;
}
// <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<DELETE THIS FUNCTION WHEN
// DONE>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
public int getSectorPublic(String key) // Returns sector number indicated by key
{
boolean notFound = true; // Not found the target sector
boolean notDoneCurrSector = true; // Not done with comparing the current sector
char[] keyChar = new char[keySize];
key.getChars(0, key.length(), keyChar, 0); // Convert the key to characters
char[] currSector = new char[disk.getSectorSize()];
int address = indexRoot; // Start from root sector
int currLevel = 0; // Count current tree level
while (notFound) {
disk.readSector(address, currSector); // Read sector to buffer
int currKeyPlace = 0; // First index of the KeyOne
notDoneCurrSector = true; // Reset notDone
while (notDoneCurrSector) {
boolean lastKeyInSector = false; // is the last key in sector
int compVal = 0;
int nextKeyPlace = currKeyPlace + indexRecordSize; // Get next Key place
if (nextKeyPlace >= disk.getSectorSize()
|| currSector[nextKeyPlace] == 0) // if current key is the last key in sector
lastKeyInSector = true;
else
compVal = compareKeys(keyChar, getKey(currSector, nextKeyPlace)); // Compare with next Key
if (compVal == -1
|| lastKeyInSector) // If argument key is less than next key, or last key in sector
{
address = getSectorNumber(currSector, currKeyPlace); // Get the address of the current key
notDoneCurrSector = false;
currLevel++; // Increment leve;
} else // Else if equals or greater than next key
currKeyPlace = nextKeyPlace; // Set current key equals to next key
}
if (currLevel == indexLevels) // When we get to bottom tree level
notFound = false; // We done, we found the sector number
}
return address;
}
public boolean findRecord(char[] record) {
char[] key = getKey(record, 0); // Get key array
int sectorNum = getSector(convertToString(key)); // Get sector number
disk.readSector(sectorNum, buffer); // Read the sector to the buffer
int numKeysChecked = 0; // Count number of key we checked
int nextKeyPlace = 0; // Index of next key
int compVal = 1;
while ((numKeysChecked < recordsPerSector)
&& (buffer[nextKeyPlace] != 0)
&& compVal
!= 0) { // while not the last record in buffer && has next record && not the same Keys
char[] tempKey = getKey(buffer, nextKeyPlace); // Get keys from buffer
compVal = compareKeys(key, tempKey); // Compare key
numKeysChecked++; // Increment number of keys checked
nextKeyPlace = nextKeyPlace + recordSize; // Move to next key place
}
if (compVal == 0) // If found
{
char[] tmpRecord =
getRecord(
buffer,
nextKeyPlace - recordSize); // Back to previous key place where we found the key
copyRecord(tmpRecord, record); // Copy the entire found record into parameter record
return true;
} else if ((compVal != 0)
&& (numKeysChecked
< recordsPerSector)) // If not found and there is still space left, we know its not in
// file
return false;
else // If not found and sector is full, we need to check overflow sectors
{
int currOverflowSector = overflowStart; // First overflow sector
numKeysChecked = 0; // Count number of key we checked
nextKeyPlace = 0; // Index of next key
compVal = 1;
while ((currOverflowSector < overflowStart + overflowSectors)
&& compVal != 0) { // While has more overflow sectors and not found
disk.readSector(currOverflowSector, buffer); // Read in overflow sector to buffer
while ((numKeysChecked < recordsPerSector) && (buffer[nextKeyPlace] != 0) && compVal != 0) {
char[] tempKey = getKey(buffer, nextKeyPlace); // Get keys from buffer
compVal = compareKeys(key, tempKey); // Compare key
numKeysChecked++; // Increment number of keys checked
nextKeyPlace = nextKeyPlace + recordSize; // Move to next key place
}
currOverflowSector++; // Move to next overflow sector
}
if (compVal != 0) // Not found in overflow sector
return false;
else {
char[] tmpRecord =
getRecord(
buffer,
nextKeyPlace - recordSize); // Back to previous key place where we found the key
copyRecord(tmpRecord, record); // Copy the entire found record into parameter record
return true;
}
}
}