Here is my code:
procedure TForm1.Button2Click(Sender: TObject);
var
Reader: TStreamReader;
Writer: TStreamWriter;
begin
Reader := TStreamReader.Create('D:\Downloads\cover.pdf', TEncoding.UTF8, False);
try
Writer := TStreamWriter.Create('D:\Downloads\coverb.pdf', False, TEncoding.UTF8);
try
Writer.Write(Reader.ReadToEnd());
finally
Writer.Free;
ShowMessage('Berhasil');
end;
finally
Reader.Free();
end;
end;
Using the above code, Reader.ReadToEnd(), I got no string, and coverb.pdf is empty.
I'm using Delphi XE.
PDF files are generally compressed binary files and so cannot be read as UTF8. Doing so will lead to codec errors. Remember that not all sequences of bytes are valid UTF8 sequences.
It looks like you just need to call CopyFile instead of your complex stream based code, but perhaps this is just a cut down sample.
If the file is not empty but ReadToEnd() is returning an empty string, then the TEncoding object being used to decode the file bytes into Unicode is encountering conversion errors. The RTL does not raise an exception on string conversion errors. If all you want to do is make an exact copy of the file, use CopyFile(), or use TFileStream and the TStream.CopyFrom() method.
You can use Embarcadero's ReadAllText function. Like this:
Uses IOUtils;
TFile.ReadAllText(FileName);
It will correctly detect ANSI, Unicode and binary files.
Do you need to write one new PDF file manually? In this case you need to know the struct of format to PDF files. Use the ISO 32000-2 to format version 2.0, so is possible to build with binary streams your PDF file, but with sure if you use some ready components will be more easy...
Here is one example how to do manually: https://blogs.embarcadero.com/how-to-create-a-pdf-file-with-delphi-and-add-an-image-to-it/ (this example is very simple, so don't use compress inside file)
But I sugest lybraries as GDPicture or Gnostice...
Related
Using Delphi XE2 and the native TZipFile I attempt to extract the contents of a downloaded zip file (which contains 2 zipped XML files) and it always extracts zero byte files.
The file is being compressed by C# code like this:
var zipFile = new ZipFile();
foreach (Tuple<string, string> t in filesMeta) {
zipFile.AddFile(string.Format("{0}{1}", StaticVariables.WebServerFileStorage, t.Item2), "").FileName = t.Item1 + ".xml";
}
response.Clear();
response.ContentType = "application/zip";
zipFile.Save(response.OutputStream);
response.End();
The Delphi extraction code is this:
zipFile := TZipFile.Create;
try
filename := 'C:\test\57f52480-ec87-4169-a820-0a65bc4ad952.zip';
if zipFile.IsValid(filename) then begin
zipFile.Open(filename, zmRead);
zipFile.ExtractAll('C:\test\');
end;
finally
zipFile.Free;
end;
I even tried using a TStream as the source instead of a file on disk. That's actually what I want to do since the zip file is downloaded from a web server into a TStream. I tried to extract the data using the overloaded open method of TZipFile to open the stream.
That got me zero byte files so I saved the zip file to disk and tried to open the file from disk and extract. Same zero byte files are extracted.
I even tried using the class method to extract the files from the zip file on disk:
System.Zip.TZipFile.ExtractZipFile(filename, 'C:\Test\');
Same zero byte files extracted.
The zip file is valid and the 2 zipped XML files can be extracted properly by both Windows 7 native file handling and 7-Zip.
Now here is something nutty...
In desperation I tried to see what the ExtractToFile() procedure
David Heffernan came up with in this question about extracting a zip to a stream would do so I tried using it like this:
var x : integer;
var fileCount : integer;
var fileNames : TArray<string>;
begin
zipFile := TZipFile.Create;
try
filename := 'C:\test\57f52480-ec87-4169-a820-0a65bc4ad952.zip';
if zipFile.IsValid(filename) then begin
zipFile.Open(filename, zmRead);
fileCount := zipFile.FileCount;
fileNames := copy(zipFile.FileNames, 0, MaxInt);
zipFile.Close;
for x := 0 to fileCount-1 do begin
// Use David Heffernan's stream procedure
ExtractToFile(filename, x, 'C:\test\' + fileNames[x]);
end;
end;
finally
zipFile.Free;
end;
end;
And David's procedure extracts the files to disk as expected! WTF???
I am really confused why a convoluted method of extraction would work and the simple extraction method would not work. I'll use David's example if I have to but I'd prefer to get the normal extract working if possible.
Any ideas are appreciated.
Cheers!
TJ
I had this same problem.
The source code to TZipFile shows that the TStream passed into the Read function returns the entire zip file with position set to the start of the filename you're wanting. So don't rewind. Just copyfrom or do what you want with the TStream for the uncompressed length given in the TZipHeader.
ZipStream := TStream.Create;
ZipFile.Read(MyFileName, ZipStream, ZipHeader);
//leave ZipStream pointer where it is!!!
SomethingElse.LoadFromStream(ZipStream, ZipHeader.UncompressedSize);
ZipStream.Free;
In my opinion, TZipFile should really load the ZipStream with only what is requested. The way this is implemented is not intuitive without first going through the TZipFile source code.
TL;DR: The solution to my problem was an external component. Zip Forge (or Abbrevia)
Read on for details.
Nothing I tried except for the roundabout way of saving the file and re-opening it using David's function worked. While that would have worked, it was not optimal as it required me to save the downloaded file to disk first and reopen it for extract and then delete the zip file. My goal was to just open the downloaded stream and extract the files directly to disk. One write to disk and no temporary file.
We even tried two different C# libraries to zip the files and both gave the same results on the streamed data. The Delphi TZipFile component could not handle it.
It turns out we have a license to ZipForge which I had forgotten about since I had not used it in ages it and that handles the download stream from the C# web server and extracts the files successfully.
For reference, I also tried the Abbrevia component version 5.2 and that also successfully extracted the files from the stream.
Hopefully this will help someone else.
All the suggestions by David and Uwe were appreciated.
Cheers!
TJ
Hello recently I replace TextFile with TFileStream. I never use it so I have small problem with it.
How can I add someting to my file after I assign it to variable?
How can I read someting form that file?
I need defined line form that file so I was doing something like that:
var linia_klienta:array[0..30] of string;
AssignFile(tempPlik,'klienci.txt');
Reset(tempPlik);
i:=0;
While Not Eof(tempPlik) do
begin
Readln(tempPlik,linia_klient[i]);
inc(i);
end;
CloseFile(tempPlik);
Then when line two is needed I simply
edit1.text = linia_klienta[1];
If you need to read a text file and access each line, try instead using a TStringList class with this class you can load a file, read the data (accesing each line using a index) and save the data back.
something like this
FText : TStringList;
i : integer;
begin
FText := TStringList.Create;
try
FText.LoadFromFile('C:\Foo\Foo.txt');
//read the lines
for i:=0 to FText.Count-1 do
ProcessLine(FText[i]); //do something
//Add additional lines
FText.Add('Adding a new line to the end');
FText.Add('Adding a new line to the end');
//Save the data back
FText.SaveToFile('C:\Foo\Foo.txt');
finally
FText.Free;
end;
end;
end;
I newer versions of Delphi you can use TStreamReader / TStreamWriter here is an example of using TStreamReader ... this is only for manipulating text files
var
SR : TStreamReader;
line : String;
begin
SR := TStreamReader.Create('D:\test.txt');
while not (SR.EndOfStream) do
begin
line := SR.ReadLine;
ShowMessage(line);
end;
SR.Free;
end;
TStream and its immediate descendants are mostly low-level access class. They mostly deal with generic buffers. There are some more specialized classes that descend from or use a stream to perform higher level tasks.
Since Delphi 1 TReader and TWriter could be used to read and write Delphi types directly (inlcuding strings), but they were not designed to handle "line-oriented" files (unluckily they were designed too much with component properties streaming in mind, not as a general purpose framework).
Turbo Power SysTools has a nice TStAnsiTextStream class that implements line-oriented access to text files in a way similar to that of TextFile. Since Delphi 2009 new classes (see opc0de answer) implement the same kind of access without the need of third party libraries (moreover they support different encodings thanks to Delphi 2009 extend codepage support, including Unicode).
Depending with what you want to do, its the stream class you need.
Do you want to work with text (characters with break-lines and end-of-line characters) data ?
OR, do you want to work with binary data ?
I see you are using an array of char, instead, of a string.
Do you really want to use character data as if it was binary ?
Sometimes, some applications require that case.
What is the easiest way to create and save string into .txt files?
Use TStringList.
uses
Classes, Dialogs; // Classes for TStrings, Dialogs for ShowMessage
var
Lines: TStrings;
Line: string;
FileName: string;
begin
FileName := 'test.txt';
Lines := TStringList.Create;
try
Lines.Add('First line');
Lines.Add('Second line');
Lines.SaveToFile(FileName);
Lines.LoadFromFile(FileName);
for Line in Lines do
ShowMessage(Line);
finally
Lines.Free;
end;
end;
Also SaveToFile and LoadFromFile can take an additional Encoding in Delphi 2009 and newer to set the text encoding (Ansi, UTF-8, UTF-16, UTF-16 big endian).
Actually, I prefer this:
var
Txt: TextFile;
SomeFloatNumber: Double;
SomeStringVariable: string;
Buffer: Array[1..4096] of byte;
begin
SomeStringVariable := 'Text';
AssignFile(Txt, 'Some.txt');
Rewrite(Txt);
SetTextBuf(Txt, Buffer, SizeOf(Buffer));
try
WriteLn(Txt, 'Hello, World.');
WriteLn(Txt, SomeStringVariable);
SomeFloatNumber := 3.1415;
WriteLn(Txt, SomeFloatNumber:0:2); // Will save 3.14
finally CloseFile(Txt);
end;
end;
I consider this the easiest way, since you don't need the classes or any other unit for this code. And it works for all Delphi versions including -if I'm not mistaken- all .NET versions of Delphi...
I've added a call to SetTextBuf() to this example, which is a good trick to speed up textfiles in Delphi considerably. Normally, textfiles have a buffer of only 128 bytes. I tend to increase this buffer to a multiple of 4096 bytes. In several cases, I'va also implemented my own TextFile types, allowing me to use these "console" functions to write text to memo fields or even to another, external application! At this location is some example code (ZIP) I wrote in 2000 and just modified to make sure it compiles with Delphi 2007. Not sure about newer Delphi versions, though. Then again, this code is 10 years old already.These console functions have been a standard of the Pascal language since it's beginning so I don't expect them to disappear anytime soon. The TtextRec type might be modified in the future, though, so I can't predict if this code will work in the future... Some explanations:
WA_TextCustomEdit.AssignCustomEdit allows text to be written to CustomEdit-based objects like TMemo.
WA_TextDevice.TWATextDevice is a class that can be dropped on a form, which contains events where you can do something with the data written.
WA_TextLog.AssignLog is used by me to add timestamps to every line of text.
WA_TextNull.AssignNull is basically a dummy text device. It just discards anything you write to it.
WA_TextStream.AssignStream writes text to any TStream object, including memory streams, file streams, TCP/IP streams and whatever else you have.
Code in link is hereby licensed as CC-BY
Oh, the server with the ZIP file isn't very powerful, so it tends to be down a few times every day. Sorry about that.
The IOUtils unit which was introduced in Delphi 2010 provides some very convenient functions for writing/reading text files:
//add the text 'Some text' to the file 'C:\users\documents\test.txt':
TFile.AppendAllText('C:\users\documents\text.txt', 'Some text', TEncoding.ASCII);
Or if you are using an older version of Delphi (which does not have the for line in lines method of iterating a string list):
var i : integer;
begin
...
try
Lines.Add('First line');
Lines.Add('Second line');
Lines.SaveToFile(FileName);
Lines.LoadFromFile(FileName);
for i := 0 to Lines.Count -1 do
ShowMessage(Lines[i]);
finally
Lines.Free;
end;
If you're using a Delphi version >= 2009, give a look to the TStreamWriter class.
It will also take care of text file encodings and newline characters.
procedure String2File;
var s:ansiString;
begin
s:='My String';
with TFileStream.create('c:\myfile.txt',fmCreate) do
try
writeBuffer(s[1],length(s));
finally
free;
end;
end;
Care needed when using unicode strings....
I written a program with Delphi 7 which searches *.srt files on a hard drive. This program lists the path and name of these files in a memo. Now I need convert these files from ANSI to UTF-8, but I haven't succeeded.
The Utf8Encode function takes a WideString string as parameter and returns a Utf-8 string.
Sample:
procedure ConvertANSIFileToUTF8File(AInputFileName, AOutputFileName: TFileName);
var
Strings: TStrings;
begin
Strings := TStringList.Create;
try
Strings.LoadFromFile(AInputFileName);
Strings.Text := UTF8Encode(Strings.Text);
Strings.SaveToFile(AOutputFileName);
finally
Strings.Free;
end;
end;
Take a look at GpTextStream which looks like it works with Delphi 7. It has the ability to read/write unicode files in older versions of Delphi (although does work with Delphi 2009) and should help with your conversion.
var
Latin1Encoding: TEncoding;
begin
Latin1Encoding := TEncoding.GetEncoding(28591);
try
MyTStringList.SaveToFile('some file.txt', Latin1Encoding);
finally
Latin1Encoding.Free;
end;
end;
Please read the whole answer before you start coding.
The proper answer to question - and it is not the easy one - basically consist of tree steps:
You have to determine the ANSI code page used on your computer. You can achieve this goal by using the GetACP() function from Windows API. (Important: you have to retrieve the codepage as soon as possible after the file name retrieval, because it can be changed by the user.)
You must convert your ANSI string to Unicode by calling MultiByteToWideChar() Windows API function with the correct CodePage parameter (retrieved in the previous step). After this step you have an UTF-16 string (practically a WideString) containing the file name list.
You have to convert the Unicode string to UTF-8 using UTF8Encode() or the WideCharToMultiByte() Windows API. This function will return an UTF-8 string you needed.
However this solution will return an UTF-8 string containing the input ANSI string, this probably is not the best way to solve your problems, since the file names may already be corrupted when the ANSI functions returned them, so proper file names are not guaranteed.
The proper solution to your problem is ways more complicated:
If you want to be sure that your file name list is exactly clean, you have to make sure it won't get converted to ANSI at all. You can do this by explicitly using the "W" version of the file handling API's. In this case - of course - you can not use TFileStream and other ANSI file handling objects, but the Windows API calls directly.
It is not that hard, but if you already have a complex framework built on e.g. TFileStream it could be a bit of a pain in the #ss. In this case the best solution is to create a TStream descendant that uses the appropriate API's.
I hope my answer helps you or anyone who has to deal with the same problem. (I had to not so long ago.)
I did only this:
procedure TForm1.FormCreate(Sender: TObject);
begin
Strings := TStringList.Create;
end;
procedure TForm1.Button3Click(Sender: TObject);
begin
Strings.Text := UTF8Encode(Memo1.Text);
Strings.SaveToFile('new.txt');
end;
Verified with Notepad++ UTF8 without BOM
Did you mean ASCII?
ASCII is backwards compatible with UTF-8.
http://en.wikipedia.org/wiki/UTF-8
For some reason, lately the *.UDL files on many of my client systems are no longer compatible as they were once saved as ANSI files, which is no longer compatible with the expected UNICODE file format. The end result is an error dialog which states "the file is not a valid compound file".
What is the easiest way to programatically open these files and save as a unicode file? I know I can do this by opening each one in notepad and then saving as the same file but with the "unicode" selected in the encoding section of the save as dialog, but I need to do this in the program to cut down on support calls.
This problem is very easy to duplicate, just create a *.txt file in a directory, rename it to *.UDL, then edit it using the microsoft editor. Then open it in notepad and save as the file as an ANSI encoded file. Try to open the udl from the udl editor and it will tell you its corrupt. then save it (using notepad) as a Unicode encoded file and it will open again properly.
Ok, using delphi 2009, I was able to come up with the following code which appears to work, but is it the proper way of doing this conversion?
var
sl : TStrings;
FileName : string;
begin
FileName := fServerDir+'configuration\hdconfig4.udl';
sl := TStringList.Create;
try
sl.LoadFromFile(FileName, TEncoding.Default);
sl.SaveToFile(FileName, TEncoding.Unicode);
finally
sl.Free;
end;
end;
This is very simple to do with my TGpTextFile unit. I'll put together a short sample and post it here.
It should also be very simple with the new Delphi 2009 - are you maybe using it?
EDIT: This his how you can do it using my stuff in pre-2009 Delphis.
var
strAnsi : TGpTextFile;
strUnicode: TGpTextFile;
begin
strAnsi := TGpTextFile.Create('c:\0\test.udl');
try
strAnsi.Reset; // you can also specify non-default 8-bit codepage here
strUnicode := TGpTextFile.Create('c:\0\test-out.udl');
try
strUnicode.Rewrite([cfUnicode]);
while not strAnsi.Eof do
strUnicode.Writeln(strAnsi.Readln);
finally FreeAndNil(strUnicode); end;
finally FreeAndNil(strAnsi); end;
end;
License: The code fragment above belongs to public domain. Use it anyway you like.