#include "stdafx.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "io.h"
const char *filename = "d:/database.txt";
const int ROWS = 10;
const int COLOUMS = 3;
class Data
{
public:
    Data() :
        m_nTotalColumns(COLOUMS),
        m_nTotalRows(ROWS),
        m_nCurCol(0),
        m_nCurRow(0),
        m_ppcData(NULL),
        m_fp(NULL)
    {
    }
 
    virtual ~Data() {}
 
 //create a dynamic 2 dimension char * array which points to a single data string
    bool Init() {
  m_ppcData = (char **)new char *[ROWS][COLOUMS];
  if(NULL == m_ppcData) {
      return false;
  }
        memset((void *)m_ppcData, NULL, ROWS * COLOUMS * sizeof(char *));
        return ReadFile();
    }
 
    //insert a record with all values of fields
    void Insert(const char *name, const char *Gender, const char *old) {
        if (NULL == name || NULL == Gender || NULL == old) {
            return;
        }
        //array is full
        if(++m_nCurRow >= m_nTotalRows) {
            return;
        }
        StrCpy(m_ppcData[m_nCurRow * m_nTotalColumns], name);
        StrCpy(m_ppcData[m_nCurRow * m_nTotalColumns + 1], Gender);
        StrCpy(m_ppcData[m_nCurRow * m_nTotalColumns + 2], old);
    }
 
    //updata a special data
    void Update(const unsigned int row, const unsigned int column, const char *data) {
        if(row > m_nCurRow || column >= m_nTotalColumns || NULL == data) {
            return;
        }
        StrCpy(m_ppcData[row * m_nTotalColumns + column], data);
    }
 
    //select a special data
    char *Select(const unsigned int row, const unsigned int column) {
        if(row > m_nCurRow || column >= m_nTotalColumns) {
            return NULL;
        }
        return m_ppcData[row * m_nTotalColumns + column];
    }
 
    //delete a row
    void DeleteRecord(const unsigned int row) {
        if(row > m_nCurRow) {
            return;
        }
        unsigned int i;
        unsigned int j;
        for(i = 0; i < m_nTotalColumns; i++) {
            delete [] m_ppcData[row * m_nTotalColumns + i];
            m_ppcData[row * m_nTotalColumns + i] = NULL;
        }
        //if the deleted row is not the last, i will fflush the data to the top
        if(row < m_nCurRow) {
            for(i = row; i < m_nCurRow; i++) {
                for(j = 0; j < m_nTotalColumns; j++) {
                    m_ppcData[i * m_nTotalColumns + j] = m_ppcData[(i + 1) * m_nTotalColumns + j];
                }
            }
        }
        memset((void *)(m_ppcData + m_nCurRow * m_nTotalColumns), NULL, COLOUMS * sizeof(char *));
        m_nCurRow--;
    }
 
    void display() {
        printf("**************\n");
        for(int i = 0; i < ROWS * COLOUMS; ++i) {
            if (NULL != m_ppcData && NULL != m_ppcData[i]) {
                printf("%s\n ", m_ppcData[i]);
            }
        }
    }
 
    void Save() {
        WriteFile();
    }
protected:
    const char* StrCpy(char *&dest, const char *src) {
        if(NULL == src) {
            return NULL;
        }
        //avoid copy self
        if(src == dest) {
            return dest;
        }
        //release original memory
        if(NULL != dest) {
            delete [ ]dest;
            dest = NULL;
        }
        int len = strlen(src);
        dest = new char[len + 1];
        if(NULL == dest) {
            return NULL;
        }
        return strcpy(dest, src);
    }
    //write data into file
    bool WriteFile() {
  m_fp = fopen(filename, "w+");
  if(NULL == m_fp) {
      return false;
  }
        for(int i = 0; i < ROWS * COLOUMS; ++i) {
            if (NULL != m_ppcData && NULL != m_ppcData[i]) {
                fputs(m_ppcData[i], m_fp);
                fputs(" ", m_fp);
            }
        }
        fclose(m_fp);
     return true;
    }
    //Read data From file
    //load all the data from the disk, do I need to do so?
    bool ReadFile() {
  m_fp = fopen(filename, "r+");
  if(NULL == m_fp) {
      return false;
  }
        long length = _filelength(_fileno(m_fp)) + 1;
        char *tmp = new char[length];
        if(NULL == tmp) {
      return false;
  }
        fgets(tmp, length, m_fp);
        int i = 0;
        char *pre = tmp;
        char *t = tmp;
        unsigned int pos;
        bool bIsEOF = false;
 
        for(i = 0, pos = 0; (i < length) && (pos < m_nTotalRows * m_nTotalColumns); ++i) {
            if(*t == '\0' || *t == ' ') {
                //if we come to the end of the data, break
                if(*t == '\0') {
                    StrCpy(m_ppcData[pos], pre);
                    break;
                }
                else {
                    *t = '\0';
                    StrCpy(m_ppcData[pos], pre);
                    //deal with multi spaces
                    while (*++t == ' ') {
                    }
                    pre = t;
                    pos++;
                }
            }
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        fclose(m_fp);
     return true;
    }
 
private:
    const unsigned int m_nTotalColumns;
    const unsigned int m_nTotalRows;
    unsigned int m_nCurCol;
    unsigned int m_nCurRow;
    FILE  *m_fp;
    char   **m_ppcData;
};
 
int main(int argc, char* argv[])
{
    Data d;
    if (d.Init()) {
        d.Update(2, 2, "100");
        d.Insert("Rock", "male", "24");
        d.display();
        char * p = d.Select(3, 2);
        printf("p = %s\n", p);
        d.DeleteRecord(1);
        d.display();
        d.Save();
    }
 return 0;
}