[DUG] Reading Different Types from a Binary File

[Ross Levis]

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#10 in 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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