void remove(size_t idx) {
if (idx >= count)
throw hsOutOfBoundsException(__FILE__, __LINE__);
for (size_t i=idx; i<(count-1); i++)
data[i] = data[i+1];
decSize();
}
int RecordManager::deleteRecord(const vector<char>& key, string fileName, int recordSize, int n){
//cout << "deleterecord begin{" << endl;
vector<char> nextBlock;
vector<char> nextOffset;
vector<char> delBlock;
vector<char> delOffset;
/*vector<char> delEndBlock;
vector<char> delEndOffset;*/
vector<char> headRecord;
vector<char> lastRecord;
vector<char> delRecord;
vector<char> delEndRecord;
Address head;
Address lastAddr;
Address delAddr;
int attrNum=0;
int headSize;
if (recordSize < 20)
headSize = 20;
else
headSize = recordSize;
head.setAddr(fileName, 0, 0);
headRecord = bmanager.read(head, headSize);
//找到待删记录的上一条记录
lastAddr = findLastRecord(fileName, key, recordSize,0);
if (lastAddr.isNullAddr()){//找不到此记录
//cout << "isnull!" << endl;
return 0;
}
int lastRecordSize = 0;
if (lastAddr.isHead()){//如果lastRecord为head 那么recordSize有问题
//cout << "is head!" << endl;
lastRecordSize = headSize;
lastRecord = headRecord;
}
else{
lastRecordSize = recordSize;
lastRecord = bmanager.read(lastAddr, lastRecordSize);
}
//printvc(lastRecord);
//cout << "lastrecordsize: " << lastRecordSize << endl;
//得到待删的记录
setNextAddr(lastRecord, nextBlock, nextOffset, lastRecordSize - 8);
delBlock = nextBlock;
delOffset = nextOffset;
delAddr.setAddr(fileName, char4ToInt(delBlock), char4ToInt(delOffset));
delRecord = bmanager.read(delAddr, recordSize);
//printvc(delRecord);
if (delRecord.size()>50)
attrNum = delRecord[50];//获得此表的attr数，只有在delete table时用到
delEndRecord = delRecord;
Address delEndAddr = delAddr;
for (int i = 0; i < n - 1; i++){//删除连续的n条
setNextAddr(delEndRecord, nextBlock, nextOffset, recordSize - 8);
//delEndBlock = nextBlock;
//delEndOffset = nextOffset;
delEndAddr.setAddr(fileName, char4ToInt(nextBlock), char4ToInt(nextOffset));
delEndRecord = bmanager.read(delAddr, recordSize);
}
//将del上一条记录指向delEnd的下一条记录
setNextAddr(delEndRecord, nextBlock, nextOffset, recordSize - 8);
if (lastAddr.isHead()){
updateRecordPoint(headRecord, nextBlock, nextOffset, headSize - 8);
}
else{
updateRecordPoint(lastRecord, nextBlock, nextOffset, lastRecordSize - 8);
bmanager.write(lastAddr, lastRecord);
}
//修改delete链
setNextAddr(headRecord, nextBlock, nextOffset, headSize - 16);//第一条被删记录
updateRecordPoint(delEndRecord, nextBlock, nextOffset, recordSize - 8);//将delEndRecord指向第一条被删记录
bmanager.write(delEndAddr, delEndRecord);//update过的都要写回！！
updateRecordPoint(headRecord, delBlock, delOffset, headSize - 16);//head指向delRecord
decSize(headRecord, n);
bmanager.write(head,headRecord);
//cout << "}deleterecord end 1" << endl;
return attrNum;
}
