mfrost@sword (Mark Frost) (12/05/90)
Thanks to all those who replied to my previous problem involving pattern
matching (yes, I did pick up the fact that I should have been using =!
instead of =~ -- oops! 8-) ).
Anyway, I've got another problem that has really been puzzling me. As part
of a larger script I am writing which deals extensively with IP addresses,
I am trying to convert decimal IP addresses to hex format. So 129.214.009.096
would give me "81D60960". I clipped the code below from my other script to
illustrate the problem. Each time I run the subroutine to convert decimal
IP address to hex ("IPTOHEX") the routine seems to drop some digits
semi-consistently.
So sometimes I might get "81600" instead of "81D6A0A0" for 129.214.160.160.
I can't see any reason for this. Being a perl novice, most of the constructs
below are quite new to me, but I don't see why they don't work. I have
included sample output below and the script itself.
Thanks
-m----------- Mark Frost (mfrost@pyramid.com)
---mmm--------- System Administrator - Hardware Engineering
-----mmmmm------- Pyramid Technology Corporation
-------mmmmmmm----- 1295 Charleston Rd, P.O. Box 7295
---------mmmmmmmmm--- Mountain View, California 94039-7295
-----------mmmmmmmmmmm- (415) 335-8163
----------------------------script--------------------------------
#!/usr/bin/perl
# Convert decimal IP address to Hex form
sub IPTOHEX
{
local(@ipaddr) = @_;
local($hexaddr,$loop);
local($digit1,$digit2) = 0;
for ($loop = 0; $loop < 4; $loop++)
{
$digit1 = (0 .. 9, 'A' .. 'F')[( $ipaddr[$loop] / 16) & 15];
$digit2 = (0 .. 9, 'A' .. 'F')[( $ipaddr[$loop] % 16) & 15];
$hexaddr = join('',$hexaddr,$digit1,$digit2);
print "ipaddr[$loop] = $ipaddr[$loop] ";
print "... digit1 = $digit1 ... digit2 = $digit2 ";
print "... hexaddr = $hexaddr\n";
} # for
$hexaddr;
} # iptohex
for ( $i = 0; $i < 5; $i++)
{
print "\nPlease enter the hostname which you want to configure (XX.XX.XX.XX)\n";
print "-> ";
$ipraw=<STDIN>;
chop($ipraw);
@ip=split(/\./,$ipraw);
$hexstring = &IPTOHEX(@ip);
print "\nHost ip entered was $ip[0].$ip[1].$ip[2].$ip[3] ($hexstring)\n";
}
------------------program output------------------------
Please enter the hostname which you want to configure (XX.XX.XX.XX)
-> 129.214.160.160
ipaddr[0] = 129 ... digit1 = 8 ... digit2 = 1 ... hexaddr = 81
ipaddr[1] = 214 ... digit1 = D ... digit2 = 6 ... hexaddr = 81D6
ipaddr[2] = 160 ... digit1 = A ... digit2 = 0 ... hexaddr = 81D6A0
ipaddr[3] = 160 ... digit1 = ... digit2 = 0 ... hexaddr = 81D6A00
Host ip entered was 129.214.160.160 (81D6A00)
Please enter the hostname which you want to configure (XX.XX.XX.XX)
-> 129.214.160.160
ipaddr[0] = 129 ... digit1 = 8 ... digit2 = 1 ... hexaddr = 81
ipaddr[1] = 214 ... digit1 = ... digit2 = 6 ... hexaddr = 816
ipaddr[2] = 160 ... digit1 = ... digit2 = 0 ... hexaddr = 8160
ipaddr[3] = 160 ... digit1 = ... digit2 = 0 ... hexaddr = 81600
Host ip entered was 129.214.160.160 (81600)
Please enter the hostname which you want to configure (XX.XX.XX.XX)
-> 129.214.160.160
ipaddr[0] = 129 ... digit1 = 8 ... digit2 = 1 ... hexaddr = 81
ipaddr[1] = 214 ... digit1 = ... digit2 = 6 ... hexaddr = 816
ipaddr[2] = 160 ... digit1 = ... digit2 = 0 ... hexaddr = 8160
ipaddr[3] = 160 ... digit1 = ... digit2 = 0 ... hexaddr = 81600
Host ip entered was 129.214.160.160 (81600)
Please enter the hostname which you want to configure (XX.XX.XX.XX)
-> 129.214.009.096
ipaddr[0] = 129 ... digit1 = 8 ... digit2 = 1 ... hexaddr = 81
ipaddr[1] = 214 ... digit1 = ... digit2 = 6 ... hexaddr = 816
ipaddr[2] = 009 ... digit1 = 0 ... digit2 = 9 ... hexaddr = 81609
ipaddr[3] = 096 ... digit1 = 6 ... digit2 = 0 ... hexaddr = 8160960
Host ip entered was 129.214.009.096 (8160960)
Please enter the hostname which you want to configure (XX.XX.XX.XX)
-> 129.214.009.096
ipaddr[0] = 129 ... digit1 = 8 ... digit2 = 1 ... hexaddr = 81
ipaddr[1] = 214 ... digit1 = ... digit2 = 6 ... hexaddr = 816
ipaddr[2] = 009 ... digit1 = 0 ... digit2 = 9 ... hexaddr = 81609
ipaddr[3] = 096 ... digit1 = 6 ... digit2 = 0 ... hexaddr = 8160960
Host ip entered was 129.214.009.096 (8160960)tchrist@convex.COM (Tom Christiansen) (12/05/90)
In article <136559@pyramid.pyramid.com> mfrost@pyramid.com (Mark Frost) writes: >Anyway, I've got another problem that has really been puzzling me. As part >of a larger script I am writing which deals extensively with IP addresses, >I am trying to convert decimal IP addresses to hex format. So 129.214.009.096 >would give me "81D60960". I didn't look too closely at your code, because it looks like you're working way, way too hard. I would just do this: sub in2hex { sprintf('%02X' x 4, split(/\./, $_[0])); } Of course, this isn't really like inet_addr(3N), as that will accept addresses in the form a.b and a.b.c as well as a.b.c.d, which is the only form this rendition works for. Accepting the other forms I leave as an exercise to the reader. :-) --tom -- Tom Christiansen tchrist@convex.com convex!tchrist "With a kernel dive, all things are possible, but it sure makes it hard to look at yourself in the mirror the next morning." -me
flee@dictionopolis.cs.psu.edu (Felix Lee) (12/05/90)
It looks like a Perl bug (tm). Consider this fragment:
for (1..3) {
for $k (0..7) {
$x = (1..4, 'a'..'d')[$k];
print $x;
}
print "\n";
}
This prints
1234abcd
1234
1234
There's a number of different workarounds, but if you just want an
&IPTOHEX subroutine, this should do:
sub IPTOHEX {
local(@ip) = @_;
sprintf('%02X' x 4, @ip);
}
--
Felix Lee flee@cs.psu.edulwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) (01/11/91)
In article <F2tmzvm3@cs.psu.edu> flee@dictionopolis.cs.psu.edu (Felix Lee) writes:
: It looks like a Perl bug (tm). Consider this fragment:
: for (1..3) {
: for $k (0..7) {
: $x = (1..4, 'a'..'d')[$k];
: print $x;
: }
: print "\n";
: }
:
: This prints
: 1234abcd
: 1234
: 1234
Fixed in 42.
Larry