PathResolver_page

This utility finds files or directories from a search path list.

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Principle

Assuming that a path-like environment variable is defined and filled in with the possible prioritized locations where a category of files is to be looked for, this utility will locate any file of that category from those possible locations.

The following properties are implemented:

• a directory offset can be specified. In this case, the file search will detect files either right in every search path or in the offset directory in every search path.

• the effective physical location of the file is returned, possibly with symbolic link resolution

• it is possible to locate regular files or directories

• it is possible to simply verify a search path against non existing entries

• Search paths can be specified either by giving the name of a path-like environment variable or by a text string containing the path list. In both cases the list follows the specific syntax convention of the operating system (ie ':' on Unix systems and ';' on DOS ones).

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Using the PathResolver

Accessing the PathResolver package.

One needs to add to the requirements file the following use statement:

use PathResolver PathResolver-00-* Tools

Finding a file

1. Finding a data file from the DATAPATH search list:

   #include <PathResolver/PathResolver.h>
    
   int main ()
   {
     std::string name;
    
     name = PathResolver::find_file ("a.dat", "DATAPATH");
    
     if (name == "")
       {
         std::cerr << "Cannot locate a.dat from ${DATAPATH}" << std::endl;
       }
    
     return (0);
   }

2. Finding a data file from an explicit search list:

   #include <PathResolver/PathResolver.h>
    
   int main ()
   {
     std::string name;
    
     name = PathResolver::find_file_from_list ("a.dat", "/here/data:/there/data");
    
     if (name == "")
       {
         std::cerr << "Cannot locate a.dat from either /here/data or /there/data" << std::endl;
       }
    
     return (0);
   }

Finding a directory

1. Finding a directory from the DATAPATH search list:

   #include <PathResolver/PathResolver.h>
    
   int main ()
   {
     std::string name;
    
     name = PathResolver::find_directory ("data", "DATAPATH");
    
     if (name == "")
       {
         std::cerr << "Cannot locate data directory from ${DATAPATH}" << std::endl;
       }
    
     return (0);
   }