Mega Code Archive
Wildcard Comparing Files And String Variables !
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Title: Wildcard Comparing Files And String Variables !
Question: I Need To Know How Can I Compare Some Strings Using The Known Wildcards *,? ???
Answer:
This small parser can compare 2 strings with the use of wildcards in the second parameter. The rules of wildcards are as follows:
* Any matching string of characters.
? Any matching character.
The function is expecially usefull when implementing disk access routines where you need to sort files by wildcards. That is also why the function is called SameFile().
Unit filespec;
interface
uses
SysUtils;
type
TWildCard = class
public
Function SameFile(File1, File2 : string; isCase : boolean) : Boolean;
private
Function SameName(N1, N2 : string) : Boolean;
end;
implementation
Function TWildCard.SameName(N1,N2:string) : Boolean;
Var
P1,P2 : Byte;
Match : Boolean;
Begin
P1 := 1;
P2 := 1;
Match := True;
If (Length(N1) = 0) And (Length(N2) = 0) Then
Match := True
Else
If Length(N1) = 0 Then
If N2[1] = '*' Then
Match := True
Else
Match := False
Else
If Length(N2) = 0 Then
If N1[1] = '*' Then
Match := True
Else
Match := False;
While (Match = True) And (P1 If (N1[P1] = '?') Or (N2[P2] = '?') Then
Begin
Inc(P1);
Inc(P2);
End
Else
If N1[P1] = '*' Then
Begin
Inc(P1);
If P1 Begin
While (P2 Inc(P2);
If P2 Length(N2) Then
Match := False
Else
Begin
P1 := Succ(Length(N1));
P2 := Succ(Length(N2));
End;
End
Else
P2 := Succ(Length(N2));
End
Else
If N2[P2] = '*' Then
Begin
Inc(P2);
If P2 Begin
While (P1 Inc(P1);
If P1 Length(N1) Then
Match := False
Else
Begin
P1 := Succ(Length(N1));
P2 := Succ(Length(N2));
End;
End
Else
P1 := Succ(Length(N1));
End
Else
If N1[P1] = N2[P2] Then
Begin
Inc(P1);
Inc(P2);
End
Else
Match := False;
If P1 Length(N1) Then
Begin
While (P2 Inc(P2);
If P2 Match := FALSE;
End;
If P2 Length(N2) Then
Begin
While (P1 Inc(P1);
If P1 Match := False;
End;
SameName := Match;
End;
{ ---------------------------------------------------------------------------- }
Function TWildCard.SameFile(File1,File2 : string; isCase : boolean) : Boolean;
Begin
if not isCase then
begin
File1 := Uppercase(File1);
File2 := Uppercase(File2);
end;
SameFile := SameName(File1,File2);
End;
End.
((( Usage )))
var
Wildcard : TWildcard;
begin
Wildcard := TWildCard.Create;
// Function samefile:
// File1: String
// File2: String with wildcards to compare with
// isCase: True if case sensitive
if WildCard.SameFile( 'mystring', 'my*', FALSE ) then
;// This statement would return true
if WildCard.SameFile( 'mystring', 'str*', FALSE ) then
;// This statement would return false
if WildCard.SameFile( 'mystring', 'm?string', FALSE ) then
;// This statement would return true
if WildCard.SameFile( 'mystring', 'm?str', FALSE ) then
;// This statement would return false
end;
Regards.......
Ruslan Abu Zant.
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