Re: [MacPerl] newbie question: binary file manipulation

["Paul J. Schinder" <schinder@pobox.com>]

At 12:09 AM -0300 8/12/99, Sébastien Maury wrote:

>	Hi,
>
>	I am learning perl to do file manipulation. I managed to do 
>what I want with text file but I have to convert big (about 100Mo) 
>text data file (list of points coord.) in binary file. Is it 
>possible ? For example, I would like to convert line input :
>
>x = 12.1 y = 13.4
>
>in the binary form
>XXXX YYYY (float on 4 bytes)
>
>Is there a special option in the open statement or something like that ?


No, there's nothing special that you need to do with open.  MacOS, 
like Unix, doesn't distinguish between text and binary I/O.  You use 
pack(). Pack the two floats into a buffer, and print the buffer. 
Something like this:

($x, $y) = (something that reads a pair from the text file);

$buf = pack("ff",$x,$y);
print OUTPUT_BINARY_FILE $buf;

To read the file in Perl, use unpack, and of course you'll use read() 
rather than <> to read the binary file.

>
>Thanks in advance, Sebastien
>
>_____________________________________________________________________
>Sebastien Maury                                     CENA division PII
>maury@cenatoulouse.dgac.fr             7 avenue Edouard Belin BP 4005
>http://www.cenatoulouse.cena.dgac.fr     31055 Toulouse Cedex, FRANCE
>tel : (+33) 05 62 25 96 25
>fax : (+33) 05 62 25 95 99
>_____________________________________________________________________



-----
Paul J. Schinder
schinder@pobox.com


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