Question

The question is marked as ASP classic but an algorithm solution is ok.

I have the following set of files which are sequentially numbered:

1.jpg, 2.jpg, 3.jpg, 4.jpg … X.jpg

I need a function which will take as input two filenames, the fromFile and toFile parameter, and which needs to rename all needed files in such a way that the from file is moved in the sequence before the toFile and the files in between renumbered.

Examples:

Moving 1.jpg onto 4.jpg should do the following:

• rename 1.jpg to 1.jpg.temp
• rename 2.jpg to 1.jpg
• rename 3.jpg to 2.jpg
• rename 1.jpg.temp to 3.jpg
• other files are unaffected by the operation

Moving 4.jpg to 2.jpg should do the following:

• rename 4.jpg to 4.jpg.tmp
• rename 3.jpg to 4.jpg
• rename 2.jpg to 3.jpg
• rename 1.jpg to 2.jpg
• rename 4.jpg.tmp to 1.jpg
• other files are unaffected

As input i have an array of strings containing filenames and the two filenames to/from.

Can you tell me what is the best approach to the file renaming?

Answer 1

Here is a brief approach, considering all your files will be named numeric.jpg, you’re going to have to build your own functions though:

FileExists(Filename)
RenameFile(OriginalFilename,NewFilename)

<%

Input1 = Request.Form("file1")
Input2 = Request.Form("file2")

'gets digits only
Input1Digit = Left(Input1,Instr(Input1,".")) 
Input2Digit = Left(Input2,Instr(Input2,".")) 


'is file1 less than file2?             
If Input1Digit < Input2Digit Then    

    'loop through the digits frontwards 1 to 5
    For x = Input1Digit to Input2Digit    

        'if the first loop?
        If cStr(x) = cStr(Input1Digit) Then 

            'see if file exists here
            If FileExists(Input1) Then 
                FileRename(Input1, Input1 & ".temp") 'Rename the file here [From, To]
                OriginalFileExists = True
            Else
                FileRename(Input1, Input1Digit & ".jpg"
                OriginalFileExists = False
            End If

        'if not on the first loop?
        Else        

            'did the original file exist '.temp'
            If OriginalFileExists Then 
                NewFileName = cInt(x) - 1
            Else
                NewFileName = cInt(x)
            End If    

            'rename each file here
            RenameFile(x & ".jpg", NewFileName & ".jpg")

        End If    
    Next 

Else


    'loop through the digits more to less 5 to 1
    For x = Input1Digit to Input2Digit STEP -1    

        'if the first loop?
        If cStr(x) = cStr(Input1Digit) Then 

            'see if file exists here
            If FileExists(Input1) Then 
                FileRename(Input1, Input1 & ".temp") 'Rename the file here [From, To]
                OriginalFileExists = True
            Else
                FileRename(Input1, Input1Digit & ".jpg"
                OriginalFileExists = False
            End If

        'if not on the first loop?
        Else        

            'did the original file exist '.temp'
            If OriginalFileExists Then 
                NewFileName = cInt(x) + 1
            Else
                NewFileName = cInt(x)
            End If    

            'rename each file here
            RenameFile(x & ".jpg", NewFileName & ".jpg")

        End If    
    Next 



End If
%>