(* //
Title: Search the location of the string in the stream
Description: Suitable for file search, etc.
Design: zswang
Support: wjhu111@21cn.com
Date: 2004-03-21
// *)
(* / / ================================================================================================================================================================================ ===============================
Design ideas:
Take data from the stream into the buffer
Search by one by one
============================================================================================================================================================================================================= ========================== // *)
Function ScanStream (MSTREAM: TSTREAM; MSTR: STRING): Integer;
Const
CBuffersize = $ 8000;
VAR
String;
T: string;
I: integer;
L: integer;
Begin
RESULT: = -1;
IF NOT ASSIGNED (MSTREAM).
IF mstr = ''. '.
L: = Length (MSTR);
MSTream.position: = 0;
SETLENGTH (S, CBuffersize);
T: = '';
For i: = 1 to mstream.size div cbuffersize do begin
MSTream.read (S [1], CBuffersize;
Result: = POS (MSTR, T S) - 1; // Keep the last searcher of the last search ~~
T: = Copy (S, CBuffersize - L, Maxint);
if Result> = 0 THEN Begin
Result: = Result PRED (i) * CBuffersize - Length (T);
EXIT;
END;
END;
I: = mstream.size mod cbuffersize;
SETLENGTH (S, I);
IF i> 0 THEN Begin
MSTream.read (s [1], i);
RESULT: = POS (MSTR, T S) - 1;
if Result> = 0 THEN Begin
Result: = Result MSTREAM.SIZE - I - Length (T);
EXIT;
END;
END;
End; {scanstream}
// esample
Procedure TFORM1.BUTTON1CLICK (Sender: TOBJECT);
VAR
VFileStream: tfilestream;
Begin
vFileStream: = TFileStream.create ('c: /temp/temp.exe', fmsharedenynone);
Try
Label1.caption: = INTOSTR (ScanStream (vFileStream, Edit1.Text));
Finally
VFileStream.free;
END;
END;
