RecordManager.cpp

#include "RecordManager.h"

bool RecordManager::Comparator(Table tableinfor, Row row, vector<Condition> conditions){
    for(int i = 0; i<conditions.size(); i++){
        int colNum = conditions[i].columnNum;
        string value1 = "";
        string value2 = conditions[i].value;
        int length1 =0;
        int length2 = value2.length();
        for(int k =0; k < row.columns[colNum].length(); k++){
            if(row.columns[colNum].c_str()[k] == EMPTY){
                length1 = k;
                break;
            }
            value1 += row.columns[colNum].c_str()[k];
        }
        float fvalue1 = atof(value1.c_str());
        float fvalue2 = atof(value2.c_str());
        switch(tableinfor.attributes[colNum].type)
        {
            case CHAR:
                switch(conditions[i].op)
                {
                    case Lt:	
                        if(value1 >= value2) return 0;
                        break;
                    case Le:
                        if(value1 > value2) return 0;
                        break;
                    case Gt:
                        if(value1 <= value2) return 0;
                        break;
                    case Ge:
                        if(value1 < value2) return 0;
                        break;
                    case Eq:
                        if(value1 != value2) return 0;
                        break;
                    case Ne:
                        if(value1  == value2) return 0;
                        break;
                }
                break;
            case INT: //整型比较，先比较长度，比如说123坑定就比99大，长度相同345与543的比较同字符串
                switch(conditions[i].op)
                {
                    case Lt:	
                        if(length1 > length2) return 0;
                        else if(length1 < length2) break;
                        else if(value1 >= value2) return 0;
                        break;
                    case Le:
                        if(length1 > length2) return 0;
                        else if(length1 < length2) break;
                        else if(value1 > value2) return 0;
                        break;
                    case Gt:
                        if(length1 < length2) return 0;
                        else if(length1 > length2) break;
                        else if(value1 <= value2) return 0;
                        break;
                    case Ge:
                        if(length1 < length2) return 0;
                        else if(length1 > length2) break;
                        else if(value1 < value2) return 0;
                        break;
                    case Eq:
                        if(length1 != length2) return 0;
                        else if(value1 != value2) return 0;
                        break;
                    case Ne:
                        if(length1 != length2) break;
                        else if(value1  == value2) return 0;
                        break;
                }
				break;
            case FLOAT:// return 0;//浮点数比较大小，不知道怎么方便 
                switch(conditions[i].op)
                {
                    case Lt:	
                        if(fvalue1 >= fvalue2) return 0;
                        break;
                    case Le:
                        if(fvalue1 > fvalue2) return 0;
                        break;
                    case Gt:
                        if(fvalue1 <= fvalue2) return 0;
                        break;
                    case Ge:
                        if(fvalue1 < fvalue2) return 0;
                        break;
                    case Eq:
                        if(fvalue1 != fvalue2) return 0;
                        break;
                    case Ne:
                        if(fvalue1  == fvalue2) return 0;
                        break;
                }
        }
    }
    return 1;
}

Data RecordManager::select(Table& tableinfor){
    string filename = tableinfor.name + ".table";
    string stringrow;
    Row splitedRow;
    Data datas;
    int length = tableinfor.totalLength + 1;//加多一位来判断这条记录是否被删除了
    const int recordNum = BLOCKSIZE / length;
	
    for(int blockOffset = 0; blockOffset < tableinfor.blockNum; blockOffset++){
        int bufferNum = buf.getIfIsInBuffer(filename, blockOffset);
        if(bufferNum == -1){
            bufferNum = buf.getEmptyBuffer();
            buf.readBlock(filename, blockOffset, bufferNum);
        }
        for(int offset = 0; offset < recordNum; offset ++){
            int position  = offset * length;
            stringrow = buf.bufferBlock[bufferNum].getvalues(position, position + length);
            if(stringrow.c_str()[0] == EMPTY) continue;//inticate that this row of record have been deleted
            stringrow.erase(stringrow.begin());//把第一位去掉
            splitedRow = splitRow(tableinfor, stringrow);
            datas.rows.push_back(splitedRow);
        }
    }
    return datas;
}
	
Data RecordManager::select(Table tableinfor, vector<Condition> conditions){
    Data datas;
    if(conditions.size() == 0){
        datas = select(tableinfor);
        return datas;
    }
    string filename = tableinfor.name + ".table";
    //buf.scanIn(tableinfor);
    string stringrow;
    Row splitedRow;
    int length = tableinfor.totalLength + 1;//加多一位来判断这条记录是否被删除了
    const int recordNum = BLOCKSIZE / length;//加多一位来判断这条记录是否被删除了
		
    for(int blockOffset = 0; blockOffset < tableinfor.blockNum; blockOffset++){
        int bufferNum = buf.getIfIsInBuffer(filename, blockOffset);
        if(bufferNum == -1){
            bufferNum = buf.getEmptyBuffer();
            buf.readBlock(filename, blockOffset, bufferNum);
        }
        for(int offset = 0; offset < recordNum; offset ++){
            int position  = offset * length;
            stringrow = buf.bufferBlock[bufferNum].getvalues(position, position + length);
            if(stringrow.c_str()[0] != EMPTY){
                stringrow.erase(stringrow.begin());//把第一位去掉
                splitedRow = splitRow(tableinfor, stringrow);
                if(Comparator(tableinfor, splitedRow, conditions)){//如果满足条件，就把结果push到datas里面去
                    datas.rows.push_back(splitedRow);
                }
            }
        }
    }
    return datas;
}
	
void RecordManager::insertValue(Table& tableinfor, Row& splitedRow){
    string stringrow = connectRow(tableinfor, splitedRow);
    insertPos iPos = buf.getInsertPosition(tableinfor);
    buf.bufferBlock[iPos.bufferNUM].values[iPos.position] = NOTEMPTY;
    for(int i = 0; i < tableinfor.totalLength; i++){
        buf.bufferBlock[iPos.bufferNUM].values[iPos.position + i + 1] = stringrow.c_str()[i];
    }
    buf.bufferBlock[iPos.bufferNUM].isWritten = 1;
}
	
int RecordManager::deleteValue(Table tableinfor){
    string filename = tableinfor.name + ".table";
    int count = 0;
    const int recordNum = BLOCKSIZE / (tableinfor.totalLength + 1);	//加多一位来判断这条记录是否被删除了
    for(int blockOffset = 0; blockOffset < tableinfor.blockNum; blockOffset++){
        int bufferNum = buf.getIfIsInBuffer(filename, blockOffset);
        if(bufferNum == -1){
            bufferNum = buf.getEmptyBuffer();
            buf.readBlock(filename, blockOffset, bufferNum);
        }
        for(int offset = 0; offset < recordNum; offset ++){
            int position  = offset * (tableinfor.totalLength + 1);
            if(buf.bufferBlock[bufferNum].values[position] != EMPTY){
                buf.bufferBlock[bufferNum].values[position] = EMPTY;
                count++;
            }
        }
    }
    return count;
}
	
int RecordManager::deleteValue(Table tableinfor, vector<Condition> conditions){
    string filename = tableinfor.name + ".table";
    string stringrow;
    Row splitedRow;
    int count = 0;
    const int recordNum = BLOCKSIZE / (tableinfor.totalLength + 1);
    for(int blockOffset = 0; blockOffset < tableinfor.blockNum; blockOffset++){
        int bufferNum = buf.getIfIsInBuffer(filename, blockOffset);
        if(bufferNum == -1){
            bufferNum = buf.getEmptyBuffer();
            buf.readBlock(filename, blockOffset, bufferNum);
        }
        for(int offset = 0; offset < recordNum; offset ++){
            int position  = offset * (tableinfor.totalLength + 1);
            stringrow = buf.bufferBlock[bufferNum].getvalues(position, position + tableinfor.totalLength + 1);
            if(stringrow.c_str()[0] != EMPTY){
                stringrow.erase(stringrow.begin());//把第一位去掉
                splitedRow = splitRow(tableinfor, stringrow);
                if(Comparator(tableinfor, splitedRow, conditions)){//如果满足条件，就把记录delete掉 
                    buf.bufferBlock[bufferNum].values[position] = DELETED;
                    count++;
                }
            }
        }
        buf.bufferBlock[bufferNum].isWritten = 1;
    }
    return count;
}
	
void RecordManager::dropTable(Table tableinfo){
    string filename = tableinfo.name + ".table";
    if( remove(filename.c_str()) != 0 )
    perror( "Error deleting file" );
    else
    buf.setInvalid(filename);//when a file is deleted, a table or an index, all the value in buffer should be set invalid
}
	
void RecordManager::createTable(Table tableinfo){
    string filename = tableinfo.name + ".table";
    fstream  fout(filename.c_str(), ios::out);
    fout.close();
}

Row RecordManager::splitRow(Table tableinfor, string row){
    Row splitedRow;
    int s_pos = 0, f_pos = 0;//start position & finish position
    for(int i= 0; i < tableinfor.attriNum; i++){
        s_pos = f_pos;
        f_pos += tableinfor.attributes[i].length;
        string col;
        for(int j = s_pos; j < f_pos; j++){
            col += row[j];
        }
        splitedRow.columns.push_back(col);
    }
    return splitedRow;
}
	
string RecordManager::connectRow(Table tableinfor, Row splitedRow){
    string tmptRow;
    string stringrow;
    for(int i = 0; i < splitedRow.columns.size(); i++){
        tmptRow = splitedRow.columns[i];
        for(;tmptRow.length() < tableinfor.attributes[i].length; tmptRow += EMPTY);//补'@'以达到要求的长度
        stringrow += tmptRow;
    }
    return stringrow;
}

void RecordManager::showDatas(const Data& datas) const{
    if(datas.rows.size() == 0){
        cout <<  "No Datas" << endl;
        return;
    }
    for(int i = 0; i< datas.rows.size(); i++){
        cout << (i+1) << " ";//序号 
        for(int j = 0; j<datas.rows[i].columns.size(); j++){
            for(int k =0; k < datas.rows[i].columns[j].length(); k++)
            if(datas.rows[i].columns[j].c_str()[k] == EMPTY) break;
            else cout << datas.rows[i].columns[j].c_str()[k];
            cout << '\t';
        }
        cout << endl;
    }
}