C/C ++ file path Parsing

C/C ++ file path Parsing

First, let's take a look at the path parsing and merging functions in C/C ++._splitpathAnd_makepath:

_CRT_INSECURE_DEPRECATE(_splitpath_s) _CRTIMP void   __cdecl _splitpath(_In_z_ const char * _FullPath, _Pre_maybenull_ _Post_z_ char * _Drive, _Pre_maybenull_ _Post_z_ char * _Dir, _Pre_maybenull_ _Post_z_ char * _Filename, _Pre_maybenull_ _Post_z_ char * _Ext);void  __cdecl _makepath(char* _Path, const char* _Drive, const char* _Dir, const char* _Filename, const char* _Ext);

Don't be scared by complicated function declarations. It's actually very easy.

For_splitpathPath parsing functions:

_FullPath: Full path ( input) _Drive: Drive letter ( output) _Dir: Remove the intermediate path of the drive letter and file name ( output) _Filename: File Name ( output) _Ext: Extended name ( output)

For_makepathPath synthesis function. The preceding parameters have the same meaning, but the input and output are the opposite.

A sample code is provided:

#include 
  
     #include 
   
      void main( void )  {     char full_path[_MAX_PATH];     char drive[_MAX_DRIVE];     char dir[_MAX_DIR];     char fname[_MAX_FNAME];     char ext[_MAX_EXT];     _makepath( full_path, "c", "\\sample\\file\\", "makepath", "c" );     printf( "_FullPath created with _makepath: %s\n\n", full_path);     _splitpath( full_path, drive, dir, fname, ext );     printf( "Path extracted with _splitpath:\n" );     printf( "  _Drive: %s\n", drive );     printf( "  _Dir: %s\n", dir );     printf( "  _Filename: %s\n", fname );     printf( "  _Ext: %s\n", ext );  }  // Output  _FullPath created with _makepath: c:\sample\file\makepath.cPath extracted with _splitpath:  _Drive: c:  _Dir: \sample\file\  _Filename: makepath  _Ext: .c
   
  

Some macros are defined as follows:

/* * Sizes for buffers used by the _makepath() and _splitpath() functions. * note that the sizes include space for 0-terminator */#define _MAX_PATH   260 /* max. length of full pathname */#define _MAX_DRIVE  3   /* max. length of drive component */#define _MAX_DIR    256 /* max. length of path component */#define _MAX_FNAME  256 /* max. length of file name component */#define _MAX_EXT    256 /* max. length of extension component */

Sometimes, we only need to get the file name or extension name, so using the above method is a bit cumbersome,stringType and its operation functions can be easily implemented:

string filePath = "E:\\file\\main.cpp";string extendName;int iBeginIndex  = filePath.find_last_of(".")+1;int iEndIndex    = filePath.length();extendName       = filePath.substr( iBeginIndex, iEndIndex-iBeginIndex );transform( extendName.begin(), extendName.end(), extendName.begin(), tolower ); cout << extendName << endl;// Output : cpp

Similarly, if you want to use this method to get the file name, you only needfilePath.find_last_of(".")ChangefilePath.find_last_of("\\")In addition, we usetransformFunction, where the parameterstolowerIf the character has a lower-case character, it is converted to a lower-case character.