Hi all,
I'm trying to write a small app that examines all files in a specified directory and gets a certain value from each file, then output the results somewhere (memo pad at the moment).
I have binary files (Oracle Forms compile .fmx files, in case you're interested) in which I want to search for the word 'Revision' and get the numbers just after the word.
I have tried ReadLn until EOF, but as it's a binary file, I suspect that there is an EOF marker somewhere in the file that stops before the code finds 'Revision'. I used ReadLn to add each line to a string variable (have tried widestring as well) to store the whole file in memory. But when the string is examined (using pos) for the word 'Revision', it does not exist, even though when I open the file in Wordpad (or Notepad) I can clearly see it.
Here's a snippet of code for the ReadLn :
var
fFileIn : TextFile;
sLine : widestring; (or string)
nPos : integer;
bFinished : boolean;
sRevision : string;
begin
.....
bFinished := False;
Repeat
ReadLn(fFileIn, sLine);
sLine := Trim(sLine);
nPos := pos('Revision', sLine);
sRevision := 'Unknown'
IF nPos <> 0 THEN
(get the revision number by looking at the next few chars)
....
bFinished := True;
end; // IF
Until EOF(fFileIn) OR bFinished;
When looking in WordPad, the word 'Revision' is completely on one line (i.e. not split over two lines).
sLine does never contain any part of 'Revision', even though it exists in the file.
I then tried using BlockRead, but that gives the same problem (as well as destroying my local loop variable and other localstring variables).
Here's the blockread snippet of code :
var
fFileIn : File;
sFile : string;
sTemp : char;
begin
.....
Repeat
blockread(fFileIn, sTemp, 1);
sFile := sFile + sTemp;
Until EOF(fFileIn);
Some of the files I am searching through do return the word 'Revision', but some don't, for each version of the code.
I thought about seeing what the value of each character is and dispensing with any below an ASCII value of 65 ('A'), but then I'll be getting rid of the EOF marker, so the code will just loop forever, unless I put some kind of counter in. I did try this with a counter of 5000 (the word appears about 4600), but even that didn't get me anywhere.
Any ideas would be gratefully recieved. (Or the names of any Windows apps that would do this for me!)
I can increase the points depending on the answer. ;)
Thanks,
Grendel.
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you could read a binary file to a string like this:
procedure TForm1.Button1Click(Sender
var
StStream: TStringStream;
FStream: TFileStream;
s: string;
begin
FStream := TFileStream.Create('d:\tes
StStream := TStringStream.Create('');
try
StStream.CopyFrom(FStream,
s := StStream.DataString;
if Pos('this', s) > 0 then
ShowMessage('Found');
finally
StStream.Free;
FStream.Free;
end;
end;
var
f : file; // untyped file
s : string; // string for reading a file
begin
// assign a file to variable
AssignFile(f, 'D:\cpuspeed.txt');
// set access mode to read-only
FileMode := fmOpenRead;
// second parameter is needed only for untyped files. it's size of block.
reset(f, 1);
// make a string long enough to read all data from file
SetLength(s, FileSize(f));
// read all the data into a string
BlockRead(f, s[1], length(s));
// close file
CloseFile(f);
// check results
ShowMessage(s);
end;
in case of fast search in huge files see
http://www.experts-exchang
meikl ;-)
You should use
BlockRead(fileVar,value,1,
to read bytes from binary file.
Declare value like Byte (var value : Byte) and after reading with BlockRead value will be
decimal number and you can find "Revision" comparing this decimal values with
coresponding ASCII codes .
Every time after reading one byte from binary file
compare value with ASCII value of letters you are looking for (for example
R=82, r=114, E=69 ...). When you find word "revision" then on the same way
read value you are looking for.
You can use this loop for searching through entire file:
repeat
BlockRead(...,numRead);
until (numRead=0);
From my ExeMod.pas unit
(you can find it here http://www.geocities.com/g
You may find other code snippets inside exemod that you can use in your program. :-)
//========================
//This code can read any file from disk and into a string
function File2String(FileName: string): string;
var
MyStream: TFileStream;
MyString: string;
begin
MyStream := TFileStream.Create(FileNam
or fmShareDenyNone);
try
MyStream.Position := 0;
SetLength(MyString, MyStream.Size);
MyStream.ReadBuffer(Pointe
finally
MyStream.Free;
end;
Result := MyString;
end;
//========================
Thanks everyone.
I mainly used the solution from Imthiyaz_ph. The problem with my code came down to a line that I didn't show you :
sLine := copy(sLine, nPos, length(sLine) - nPos);
This was giving me a blank sLine string, even though the word was at nPos. I sorted this by putting a loop around reading sLine[nLoop] and that worked. But using filestream was much better than using ReadLn as well.
I have split the points to a few of you, thanks for all your help.
Grendel.
Business Accounts
Answer for Membership
by: heretoreadPosted on 2005-02-17 at 02:47:54ID: 13333275
i thinks it's the way Pos works, it will scan until it finds the string end, which could be before you expect depending on the data.
eg STRING,0
STRING,0,13,REVISION
so you will have to make your own string function, just use a for loop and check each character.