datatype.h

#ifndef __DATATYPE_H_
#define __DATATYPE_H_
#include <string>

const int ValueLen(4), ChildLen(3), OffsetLen(4), LeafLen(7), IntLen(5), FloatLen(10);
const int Int(0), Float(1), Char_n(2);
const int DataFile(0), IndexFile(1);
const int Greater(1), NotLess(2), Less(3), NotGreater(4);


struct blockInfo;
struct fileInfo {
    int type;                   // 0-> data file
                                // 1 -> index file
    std::string fileName;            // the name of the file
    int recordAmount;           // the number of record in the file
    int freeNum;                // the free block number which could be used for the file
    int recordLength;           // the length of the record in the file
    fileInfo *next;             // the pointer points to the next file
    blockInfo *firstBlock;      // point to the first block within the file
};
struct blockInfo {
    int blockNum;               // the block number of the block, which indicate it when it be newed
    bool dirtyBit;              // 0 -> flase
                                // 1 -> indicate dirty, write back
    blockInfo *next;            // the pointer point to next block
    fileInfo *file;             // the pointer point to the file, which the block belongs to
    int charNum;                // the number of chars in the block
    char *cBlock;               // the array space for storing the records in the block in buffer
    int iTime;                  // it indicate the age of the block in use
    int lock;                   // prevent the block from replacing
};
struct index_info {
    std::string index_name;     //the name of the index file
    int length;                 //the length of the value
    char type;                  //the type of the value
                                //0---int,1---float,2----char(n)    
    long offset;                //the record offset in the table file
    std::string value;          //the value
};


#endif