c++ implements merging files and splitting instance code

This paper mainly studies the relevant content of c++ implementation of merging files and splitting, and shares the implementation code as follows.

Yesterday, I saw an article about TFS, which is about the use of a distributed architecture to combine small images into large files in order to process massive images

Driven by interest, I wrote a simple file merge splitter

The merge method is simple, writing small files to large files, using base 2. In the large file header, use 1 int to record the number of small files that have been merged in. Next, write the small files block by block.

Each block is divided into three parts. The first part is the name of the file, which is recorded with 20 char. Part 2 USES an int to record the length of small files; Part 3 is the actual content of the small file

This way, when splitting, you get the number of small files by the header, and then get the name, file length, and content one by one

Attach source code

Merger:

void Merge() 
{ 
  char name[20]; 
  string str1 = "F:/ data /1.jpg"; 
  string str2 = "F:/ data /2.jpg"; 
  string strBlock = "F:/ data /BLOCK.dat"; 
 
  FILE* f1 = fopen(str1.c_str(),"rb+"); 
  FILE* f2 = fopen(str2.c_str(),"rb+"); 
  FILE* f3 = fopen(strBlock.c_str(),"rb+"); 
 
  //  Gets the length of the file  
  int iLen1 =filelength(fileno(f1)); 
  int iLen2 = filelength(fileno(f2)); 
 
  char *buf1 = new char[iLen1];  
  memset(buf1,0x0,iLen1);  
  char *buf2 = new char[iLen2];  
  memset(buf2,0x0,iLen2);  
 
  //  Get file content  
  fread(buf1,iLen1,1,f1);  
  fread(buf2,iLen2,1,f2);   
  fclose(f1);  
  fclose(f2);  
 
   
  //  Record the number of merged files in the file header  
  int iCount = 2; 
  fseek(f3,0,SEEK_SET); 
  fwrite(&iCount,sizeof(int),1,f3); 
 
  //  Write the first 1 A file  
  memset(name,0x0,20);  
  strcpy(name,str1.c_str()); 
  fwrite(name,20,1,f3);  
  fwrite(&iLen1,sizeof(int),1,f3);  
  fwrite(buf1,iLen1,1,f3);  
 
  //  Write the first 2 A file  
  memset(name,0x0,20);  
  strcpy(name,str2.c_str()); 
  fwrite(name,20,1,f3);  
  fwrite(&iLen2,sizeof(int),1,f3);  
  fwrite(buf2,iLen2,1,f3);   
 
  fclose(f3);  
    
   
    
  // Delete the requested memory     
  delete[] buf1;   
  delete[] buf2;  
} 

Resolution:

void Split() 
{ 
  char name[20]; 
  string strBlock = "F:/ data /BLOCK.dat"; 
  FILE* f3 = fopen(strBlock.c_str(),"rb+"); 
 
  //  Get number of files  
  int iCount = 0; 
  fseek(f3,0,SEEK_SET); 
  fread(&iCount,sizeof(int),1,f3); 
 
  for(int i=0;i<iCount;i++) 
  { 
    memset(name,0x0,20); 
    fread(&name,20,1,f3); 
    //  Name of the output  
    cout<<name<<endl; 
    int iLen = 0; 
    //  Read file length  
    fread(&iLen,sizeof(int),1,f3); 
    char *buff = new char[iLen]; 
    //  Read file contents  
    fread(buff,iLen,1,f3); 
    char fileLen[10]; 
    sprintf(fileLen, "%d", iLen); 
 
    //  Name by file length  
    string s = fileLen; 
    string strName = "F:/ data /"; 
    strName += s; 
    strName += string(".jpg") ; 
 
    //  new 1 A file  
    FILE* file= fopen(strName.c_str(),"wb+"); 
    fwrite(buff,iLen,1,file); 
    fclose(file); 
  } 
 
  fclose(f3); 
} 

conclusion

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