Change 13144 by jhi@alpha on 2001/11/20 22:31:47
Give a simple example of writing PerlIO::Via handlers
in Perl.
Affected files ...
.... //depot/perl/ext/PerlIO/Via/Via.pm#5 edit
Differences ...
==== //depot/perl/ext/PerlIO/Via/Via.pm#5 (text) ====
Index: perl/ext/PerlIO/Via/Via.pm
--- perl/ext/PerlIO/Via/Via.pm.~1~ Tue Nov 20 15:45:05 2001
+++ perl/ext/PerlIO/Via/Via.pm Tue Nov 20 15:45:05 2001
@@ -119,6 +119,58 @@
=back
+=head2 Example - a Hexadecimal Handle
+
+Given the following module, Hex.pm:
+
+ package Hex;
+
+ sub PUSHED
+ {
+ my ($class,$mode) = @_;
+ # When writing we buffer the data
+ my $write = '';
+ return bless \$write,$class;
+ }
+
+ sub FILL
+ {
+ my ($obj,$fh) = @_;
+ my $line = <$fh>;
+ return (defined $line) ? pack("H*", $line) : undef;
+ return undef;
+ }
+
+ sub WRITE
+ {
+ my ($obj,$buf,$fh) = @_;
+ $$obj .= unpack("H*", $buf);
+ return length($buf);
+ }
+
+ sub FLUSH
+ {
+ my ($obj,$fh) = @_;
+ print $fh $$obj or return -1;
+ $$obj = '';
+ return 0;
+ }
+
+ 1;
+
+the following code opens up an output handle that will convert any
+output to hexadecimal dump of the output bytes: for example "A" will
+be converted to "41" (on ASCII-based machines, on EBCDIC platforms
+the "A" will become "c1")
+
+ use Hex;
+ open(my $fh, ">:Via(Hex)", "foo.hex");
+
+and the following code will read the hexdump in and convert it
+on the fly back into bytes:
+
+ open(my $fh, "<:Via(Hex)", "foo.hex");
+
=cut
End of Patch.
