Robert, If I understand Hugo correctly, he mentioned that some of the data he wants to save is "like" an Excel spreadsheet. He actually needs to save a number of different data types, most of which are binary.
The Jedi code you reference looks like it is specific to an actual Excel file. Glenn Lawler www.incodesystems.com -----Original Message----- From: Robert Alderton [SMTP:[EMAIL PROTECTED] Sent: Thursday, January 10, 2008 10:46 AM To: advanced_delphi@yahoogroups.com Subject: RE: [advanced_delphi] Structured File Format Actually the Jedi code library looks like it has pre-cooked routines http://www.koders.com/delphi/fid2AAB471E324D02F7983954B055CC906917F14DD0.aspx -----Original Message----- From: advanced_delphi@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Glenn B. Lawler Sent: Thursday, January 10, 2008 11:38 AM To: 'advanced_delphi@yahoogroups.com' Subject: RE: [advanced_delphi] Structured File Format Hugo, The easiest way to do what you are talking about is a tagged binary file. Here's how I would do it: Define a set of fixed length "tags" you want to use to define anything that could be in your file format. When you write the file do this: - Write the fixed length tag to the file - Write a 32-bit integer which is the length of the data - Write the data When you read the file do this: - Read the fixed length tag from the beginning of the file - Read the length integer - Call a routine in your program that knows how to read the data based on the tag. - Read the data from the file - Repeat until you reach the end of the file or a sentinal (a special tag that means you have reached the end of the file) The sentinal method is good because your program can easily detect when a file has been truncated. Glenn Lawler www.incodesystems.com -----Original Message----- From: Hugo Massieri [SMTP:[EMAIL PROTECTED] Sent: Thursday, January 10, 2008 10:14 AM To: advanced_delphi@yahoogroups.com Subject: Res: [advanced_delphi] Structured File Format Glenn, Thank you for your help! I believe that a file based only in a record type would not be a good idea because the data is not uniform. But I will certainly think more seriously about the memory buffer. It will need to save diferent kinds of data at once in the same file, for instance: text elements, graphic images, an array of record data... I am looking for some info on working/coding with BIFF (Binary Interchange File Format - the MSExcel ones) due to its similarities with my app needs. Have you ever heard about this format? Have some info about? Perhaps a start book. pdf, website, etc Any other ideas? Once again, thank you a lot! Hugo eof ----- Mensagem original ---- De: Glenn B. Lawler <[EMAIL PROTECTED]> Para: "advanced_delphi@yahoogroups.com" <advanced_delphi@yahoogroups.com> Enviadas: Quinta-feira, 10 de Janeiro de 2008 13:40:31 Assunto: RE: [advanced_delphi] Structured File Format Hugo, If you are clear about how to do file I/O to a binary file, the rest is straightforward. It sounds like you are trying to write a fixed record length file. There are multiple ways to do this in Pascal. The language supported method involves "File of type". Check the Delphi help for this. The basic idea is that you define a record type in Pascal and then read and write these records. That is the simplest way to deal with such a file, but it is also the least flexible. The record type must be defined in Pascal code, so your program will only be able to read and write record types you have defined in code. Another way that is indefinitely flexible, is to create a memory buffer that is the length of the record (using GetMem, or AllocMem) and then copy fields using move (see Delphi help), and SizeOf (to know how many bytes to move). You then use the binary file routines to read and write the buffer. This allows you to write a single program that can read any kind of record. To randomly access a record, you position the file pointer in multiples of the record length and then read or write to the file. On the other hand, if all you are trying to do is read and write a two dimensional grid of data, another way is to use a delimited file. Tab delimited is the easiest to deal with since a tab character (ASCII 9) is usually not allowed in the data itself. The advantage to a delimited file is that you can load it with a text editor to examine the data. The disadvantages are read and write is slower, no random access, and the files are usually larger. Hope this helps, let us know what else you need to get started. Glenn Lawler www.incodesystems. com -----Original Message----- From: Hugo Massieri [SMTP:hugomassieri@ yahoo.com. br] Sent: Thursday, January 10, 2008 8:14 AM To: advanced_delphi@ yahoogroups. com Subject: [advanced_delphi] Structured File Format Hi All! I am looking for some good information about structured file format programming, in order to save data from a Delphi application. The basics on create/open/ save binary file is ok, but unfortunately have been hard to find some useful information on the net about how to structure in order to save the data. The books i have found generally talk about graphic file format but i would like to save data as similar as an Excel spreadsheet. Any addicional information will be very appreciated, even better if accompained by some Delphi samples. Thanks in advance. Hugo Yahoo! Groups Links Yahoo! Groups Links
