[DUG] Reading Different Types from a Binary File

[Todd Martin]

Hi Eric

If it is easy to locate the end of the header block, just copy the data
into another (memory) stream and use a TStringList LoadFromStream() to
separate them.

Todd.
> Thanks, Ross.
>
> Yes, I am in fact using TFileStream and its Read method for the binary
> extraction.  
>
> For the Header, I was hoping to find an existing method that I could
> call to to extract the the CR LF terminated strings, however I will
> use your suggestion for the header fields rather than indexing the
> char buffer.
>
> ------------------------------------------------------------------------
> From: ross at stationplaylist.com
> To: delphi at listserver.123.net.nz
> Date: Mon, 5 Nov 2012 17:28:12 +1300
> Subject: Re: [DUG] Reading Different Types from a Binary File
>
> Personally I would use a TFileStream and FS.Read(S,1) one AnsiChar at
> a time, concatenating into an AnsiString if you want the info until
> you have ‘[End]’#13#10in the string.
>
>  
>
> This will have the file pointer at the start of the binary data where
> you can then FS.Read(MyDWORD,4) or MyByte,1 etc.
>
>  
>
> Ross.
>
>  
>
> *From:*delphi-bounces at listserver.123.net.nz
> [mailto:delphi-bounces at listserver.123.net.nz] *On Behalf Of *Eric A
> *Sent:* Monday, 5 November 2012 9:08 a.m.
> *To:* Delphi ListServer
> *Subject:* [DUG] Reading Different Types from a Binary File
>
>  
>
> This is probably a no-brainer to most of the DUG members, especially
> those used to pointers ...
>
> I need to read and extract data from a binary file which comprises:
> - a header with character type strings, each terminated by CR LF (not
> nulls)
> - binary data area with a mixture of byte types, word types and double
> word types
> - a file terminator of 0xFFFF hex
>
> The files are not huge, less than 500KB, as the structure originates
> from old memory-constrained microprocessors of the 80's.
>
> The header looks like it is based on the old INI file format and is of
> the form:
>
> [Header]
> Created=1349233072
> Title=
> Type=D
> Version=162
> [End]
>
> The binary data area follows next.  It comprises different types of
> data blocks, with sub blocks, each of which contains either bytes,
> words or double words of data in a pre-defined pattern or structure
> depending on the type of data block.
>
> I can read the file into a buffer (array of Char) but I currently have
> a chunk of somewhat ugly code to parse the header and find the start
> position of the binary data after the '[End] CR LF' string.  After
> that I need to extract data of various types depending on the
> specified datablock types, which I though I might have to use pointers
> for.
>
> What's the best approach for
> a) Extracting the header strings - is there a Delphi function to
> extract CR LF terminated character sequences as strings and maintain a
> pointer to the end of the string?
> b) Creating functions for ReadByte, ReadWord, ReadDoubleWord and
> incrementing the pointer appropriately in each case ?
>
>
> Eric
>
>
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-- 
/Fortune/ favours the *brave*
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