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Ronaldo wrote:

> 
> Hi all !! My name is Ronaldo. I4m from Brazil.
> Im having a hard time on reading a file generated by a Software
> created through Delphi, its not a regular text file, though it is a
> file that was generated by a component, which main goal is to
> compress any file using a Zlib, and then to save the bytes from that
> compressed file as binary fields. That was just a brief introduction
> so as you can have an idea of the general issue My real problem is
> reading the header and the footer generated by that component (I do
> not have any problem in reading and decompressing the data compressed
> with Zlib). At that header, there is information, such as backup
> title, size of the backup title, total bytes from the original file,
> total files in backup, the size in bytes of the path + name of the
> file that was compressed, path + name of the file compressed, date &
> time of last update on that file, and a signature EC2 or ECS,
> where the first one indicates that the content is compressed, and the
> second one indicates that is not The component writes some data with
> more frequency; if I manage to read those, I think Ill be able of
> reading the others. I created a Delphi code very simple in order to
> generate that header, and another one, to read it. I did the same in
> Java. However, what I generate in Delphi, cannot be read in Java, and
> vice versa.  Im going to leave here the source codes in Java and
> Delphi, in case someone can help me out. Probably somebody already
> passed through this issue, or at least knows both languages.
> 
> I appreciate your help in advance, and apologize for the size of this
> message.

Without going into your code in too much detail, I would guess that the
problem you're experiencing is byte order.  Delphi is Intel-based and
so writes/reads the low byte first; Java is platform-independent and
writes/reads the high byte first.

I strongly suggest that if you're trying to write code to read a ZIP
file that you start with a known good ZIP file, run it through the
Delphi and Java readers, and determine which one breaks.  Creating a
file with one language and reading it with another doesn't tell you
which one is at fault; you need the independent arbiter of a known good
ZIP file.

-- 
Kevin Dean [TeamB]
Dolphin Data Development Ltd.
http://www.datadevelopment.com/

NEW WHITEPAPERS
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Dear Kevin.
Then I have a serious possession.  
Because the application developed in Delphi uses a format proprietor to record the header, and my problem is exactly to read this header, the compacted data I am not having problem with them, it is enough to ignore the data of the header. But I need to read that header with Java to manipulate the data that were migrated of a legated system, that they are not compacted, but they were recorded with that header. A solution not very elegant it would be to write a .SO in Kylix that makes that work, but I would like to implement a solution purely Java.

I appreciate your help in advance,

Ronaldo.


"Kevin Dean [TeamB]" <NkOdSePaAnM@datadevelopment.com> wrote:
>Ronaldo wrote:
>
>> 
>> Hi all !! My name is Ronaldo. I4m from Brazil.
>> Im having a hard time on reading a file generated by a Software
>> created through Delphi, its not a regular text file, though it is a
>> file that was generated by a component, which main goal is to
>> compress any file using a Zlib, and then to save the bytes from that
>> compressed file as binary fields. That was just a brief introduction
>> so as you can have an idea of the general issue My real problem is
>> reading the header and the footer generated by that component (I do
>> not have any problem in reading and decompressing the data compressed
>> with Zlib). At that header, there is information, such as backup
>> title, size of the backup title, total bytes from the original file,
>> total files in backup, the size in bytes of the path + name of the
>> file that was compressed, path + name of the file compressed, date &
>> time of last update on that file, and a signature EC2 or ECS,
>> where the first one indicates that the content is compressed, and the
>> second one indicates that is not The component writes some data with
>> more frequency; if I manage to read those, I think Ill be able of
>> reading the others. I created a Delphi code very simple in order to
>> generate that header, and another one, to read it. I did the same in
>> Java. However, what I generate in Delphi, cannot be read in Java, and
>> vice versa.  Im going to leave here the source codes in Java and
>> Delphi, in case someone can help me out. Probably somebody already
>> passed through this issue, or at least knows both languages.
>> 
>> I appreciate your help in advance, and apologize for the size of this
>> message.
>
>Without going into your code in too much detail, I would guess that the
>problem you're experiencing is byte order.  Delphi is Intel-based and
>so writes/reads the low byte first; Java is platform-independent and
>writes/reads the high byte first.
>
>I strongly suggest that if you're trying to write code to read a ZIP
>file that you start with a known good ZIP file, run it through the
>Delphi and Java readers, and determine which one breaks.  Creating a
>file with one language and reading it with another doesn't tell you
>which one is at fault; you need the independent arbiter of a known good
>ZIP file.
>
>-- 
>Kevin Dean [TeamB]
>Dolphin Data Development Ltd.
>http://www.datadevelopment.com/
>
>NEW WHITEPAPERS
>Team Development with JBuilder and Borland Enterprise Server
>Securing Borland Enterprise Server
>http://www.datadevelopment.com/papers/index.html
>
>Please see Borland's newsgroup guidelines at
>http://info.borland.com/newsgroups/guide.html

Ronaldo wrote:

> Because the application developed in Delphi uses a format proprietor
> to record the header, and my problem is exactly to read this header,
> the compacted data I am not having problem with them, it is enough to
> ignore the data of the header. But I need to read that header with
> Java to manipulate the data that were migrated of a legated system,
> that they are not compacted, but they were recorded with that header.
> A solution not very elegant it would be to write a .SO in Kylix that
> makes that work, but I would like to implement a solution purely Java.

Reading binary files is always tricky.  The first thing you should do
is determine whether or not you are in the right place in the file.
After reading each field with Delphi, print out the current file
position.  Do the same in Java.  If the output differs, then you're
reading the wrong number of bytes.

Once you have the file positions lined up, then output the fields
themselves in Delphi and in Java.  Typically your integers will be
different, and that can be resolved in Java by reading one byte at a
time.  Assuming that the number stored is a 32-bit integer:

int result = 0;

for (int index = 0; index < 4; index++) {
  // Bytes are high-order first, so shift the result by one byte.
  result <<= 8;
  // Add (through bitwise OR) the next byte.
  result |= s.readByte();
}

-- 
Kevin Dean [TeamB]
Dolphin Data Development Ltd.
http://www.datadevelopment.com/

NEW WHITEPAPERS
Team Development with JBuilder and Borland Enterprise Server
Securing Borland Enterprise Server
http://www.datadevelopment.com/papers/index.html

Please see Borland's newsgroup guidelines at
http://info.borland.com/newsgroups/guide.html