Conversion between absolute and relative paths in Delphi

Question

Are there standard functions to perform absolute <--> relative path conversion in Delphi?

For example:

• 'Base' path is 'C:\Projects\Project1\'
• Relative path is '..\Shared\somefile.pas'
• Absolute path is 'C:\Projects\Shared\somefile.pas'

I am looking for something like this:

function AbsToRel(const AbsPath, BasePath: string): string;
// '..\Shared\somefile.pas' =
//   AbsToRel('C:\Projects\Shared\somefile.pas', 'C:\Projects\Project1\')  
function RelToAbs(const RelPath, BasePath: string): string;
// 'C:\Projects\Shared\somefile.pas' =
//   RelToAbs('..\Shared\somefile.pas', 'C:\Projects\Project1\')  

Answer 1

To convert to the absolute you have :

ExpandFileName

To have the relative path you have :

ExtractRelativePath