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CD ROM Paradise Collection 4
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CD ROM Paradise Collection 4 1995 Nov.iso
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swagd_f.zip
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FILES.SWG
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0034_Reading GIF File Header.pas
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Pascal/Delphi Source File
|
1993-11-02
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835b
|
34 lines
{
ERIC MILLER
> How does one read/Write a header on a File in TPascal?
Easy. Write the header structure as a Type. Then open
the File as unTyped and blockread the data into a Variable
of the structure Type. Take GIFs For example:
}
Type
Gif_Header = Record { first 13 Bytes of a Gif }
Sig, Ver : Array[1..3] of Char;
Screen_X,
Screen_Y : Word;
_Packed,
Background,
Pixel_Aspect : Byte;
end;
Var
F : File; { unTyped File }
G : GIF_Header;
begin
Assign(F, 'Filename.gif');
Reset(F, 1); { blockread in Units of one Byte }
Blockread(F, G, SizeOf(G)); { read from File }
Close(F);
With G DO
begin
Writeln('Version: ', Sig, Ver);
Writeln('Res: ', Screen_X, 'x', Screen_Y, 'x', 2 SHL (_Packed and 7));
end;
end.