Net::EMI::Common - EMI/UCP GSM SMSC Protocol Common library class

Net-EMI-Common documentation Contained in the Net-EMI-Common distribution.

Index

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NAME

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Net::EMI::Common - EMI/UCP GSM SMSC Protocol Common library class

SYNOPSIS

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use Net::EMI::Common

$emi = Net::EMI::Common->new();

DESCRIPTION

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This module implements a collection of common routines used in the Net::EMI set of classes.

The Net::EMI::Common class is primarily intended to part some functionality between the Net::EMI::Client class and any future Net::EMI::Server classes.

Even so, there is nothing to stop any application or other module to make use of the common routines found in this class.

(If someone makes use of this module to support another public module I'd like to hear about it. That way I may be able to maintain backwards compatibility for those modules.)

CONSTRUCTOR

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new()

No parameters are currently honored.

PUBLIC OBJECT METHODS

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checksum('Some string')

Calcuate packet checksum.

data_len('Some string')

Calculate data length.

encode_7bit('Some string')
ia5_decode('Some string')
ia5_encode('Some string')

SEE ALSO

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Net::EMI::Client

ACKNOWLEDGMENTS

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I'd like to thank Jochen Schneider for writing the first beta releases under the name Net::EMI and also for letting me in on the project.

In February 2003, Jochen gave me free hands to distribute this class module which is primarily built upon his work. Without Jochens initial releases, this module would probably not have seen the light.

Thanks, Rainer Thieringer, for pointing out a bug in the checksum() method.

And, as everyone else I owe so much to Larry. For having provided Perl.

AUTHOR

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Gustav Schaffter, <schaffter_cpan@hotmail.com>

COPYRIGHT

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Copyright (c) 2002 Jochen Schneider. Copyright (c) 2003 Gustav Schaffter. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

Net-EMI-Common documentation Contained in the Net-EMI-Common distribution. 
package Net::EMI::Common;
use strict;

use vars qw($VERSION);
$VERSION='1.01';

###########################################################################################################
# Since 'constants' are actually implemented as subs,
# they can be called from the outside as any other class method.
use constant STX=>chr(2);
use constant ETX=>chr(3);
use constant UCP_DELIMITER=>'/';
use constant DEF_SMSC_PORT=>3024;
use constant ACK=>'A';
use constant NACK=>'N';

###########################################################################################################
sub new {
   my$self={};
   bless($self,shift())->_init(@_);
}

###########################################################################################################
# Calculate packet checksum
sub checksum {
   shift;         # Ignore $self.
   defined($_[0])||return(0);

   my$checksum=0;
   for(split(//,shift)) {
      $checksum+=ord;
   }
   # 2003-Apr-24 Rainer Thieringer: format string corrected from %X to %02X.
   sprintf("%02X",$checksum%256);
}

###########################################################################################################
# Calculate data length
sub data_len {
	my$len=length(pop @_)+17;
	for(1..(5-length($len))) {
		$len='0'.$len;
	}
	$len;
}

###########################################################################################################
# The first 'octet' in the string returned will contain the length of the remaining user data.
sub encode_7bit {
   my($self,$msg)=@_;
   my($bit_string,$user_data)=('','');
   my($octet,$rest);

   defined($msg)&&length($msg)||return('00');   # Zero length user data.

   for(split(//,$msg)) {
      $bit_string.=unpack('b7',$_);
   }

   #print("Bitstring:$bit_string\n");

   while(defined($bit_string)&&(length($bit_string))) {
      $rest=$octet=substr($bit_string,0,8);
      $user_data.=unpack("H2",pack("b8",substr($octet.'0'x7,0,8)));
      $bit_string=(length($bit_string)>8)?substr($bit_string,8):'';
   }

   sprintf("%02X",length($rest)<5?length($user_data)-1:length($user_data)).uc($user_data);
}

###########################################################################################################
sub ia5_decode {
   my($self,$message)=@_;
   my($decoded,$i);

   defined($message)&&length($message)||return('');

	for($i=0;$i<=length($message);$i+=2) {
		$decoded.=chr(hex(substr($message,$i,2)));
	}
	$decoded;
}

###########################################################################################################
sub ia5_encode {
	join('',map{sprintf "%X",ord} split(//,pop(@_)));
}

###########################################################################################################
###########################################################################################################
#
# 'Internal' subs. Don't call these since they may, and will, change without notice.
#
###########################################################################################################
###########################################################################################################

###########################################################################################################
sub _init {
   shift;
}

###########################################################################################################
'Choppers rule';
__END__