in reply to Re: Hex format conversion in Perl
in thread Hex format conversion in Perl

jeroenes, did you forget the hex conversion?
(his reply is now below)
# reading (for example, a gif)
local $/ = undef;
open FILE, $file;
binmode(FILE); # needed for win32
$gif = <FILE>;
$hexgif = unpack ("H*", $gif); # convert gif to hex string

# printing
$gif = pack ("H*", $hexgif); # convert hex string back to binary data
print "Content-type: image/gif\n\n";
binmode(STDOUT);
print $gif;

[download]

Update: jeroenes is right about the size consideration. You asked for hex so that's what this code does. But a hex string is double the size of the binary data is encodes. Here are the results of some different methods for encoding binary data as text:

bytesformat% of original
5008 original jpeg 100.00%
10016 hex string 200.00%
6904 uuencoded 137.86%
6768 base64 135.14%
6706 zlib/uuencoded 133.91%
6574 zlib/base64 131.27%
4865 zlib (binary) 97.14%

Replies are listed 'Best First'.
Re:{3} Hex format conversion in Perl
by jeroenes (Priest) on Apr 19, 2001 at 19:27 UTC
    Not forgotten.
    IMHO, you don't need that conversion at all, unless there is another reason/problem. Perl has no trouble with a string like the first $gif in your code.

    Why would you want an extra conversion step? Maybe you like to dump the hex-string on a terminal, readible to the human eye? Insert it in an e-mail (base64 would be better in that case)? Does the database only accept ASCII strings (BerkeleyDB eg does accept them)?

    But if you just want to redirect the data in a perlish way, just keep with the unconverted 1-byte wide strings.

    Jeroen
    "We are not alone"(FZ)
    Update: epoptai CB'd me an alternative explanation of the posting, that makes more sense. His code will do. But, consider pack 'u*', $gif;, CGIPack or MIME::Base64 to pack your strings, as that shortens the strings somewhat.

[reply]
[d/l]

In Section Seekers of Perl Wisdom