void BufferManager::pageIn(int index, int pageNum) {
// Read page data from disk into buffer
char buffer[4096] = {};
int blockOffset = getBlockOffset(pageNum);
fm->read(dbName, blockOffset, 8, buffer);
// Create page
pages[index] = Page(buffer);
// Set page status
pageNums[index] = pageNum;
dirtied[index] = 0;
pinned[index] = 0;
}
void LogManager::forceLSNRecord(int index) {
for (int pageNum = 0; pageNum < 4; pageNum++) {
char page[4096] = {};
fm->read(logName, pageNum * 8, 8, page);
for (int i = 0; i < 73; i++) {
char bytes[56] = {};
int start = i * 56;
for (int j = 0; j < 56; j++) { bytes[j] = page[start + j]; }
LogRecord rec = LogRecord(bytes);
if (rec.LSN == 0) {
char* recordBytes = (char*) &log[index];
for (int k = 0; k < 56; k++) { page[start + k] = recordBytes[k]; }
fm->write(logName, pageNum * 8, 8, page);
return;
}
}
}
}
void LogManager::start(char* inLogName) {
logName = inLogName;
char page[4096] = {};
for (int pageNum = 0; pageNum < 4; pageNum++) {
fm->read(logName, pageNum * 8, 8, page);
for (int i = 0; i < 73; i++) {
char bytes[56] = {};
int start = i * 56;
for (int j = 0; j < 56; j++) { bytes[j] = page[start + j]; }
LogRecord rec = LogRecord(bytes);
if (rec.LSN == 0) { return; }
else if (rec.LSN != 0) {
log[tail] = rec;
tail++;
}
}
}
}