Encode::GSM0338(3p) Perl Programmers Reference Guide Encode::GSM0338(3p) #

Encode::GSM0338(3p) Perl Programmers Reference Guide Encode::GSM0338(3p)

NNAAMMEE #

 Encode::GSM0338 -- ETSI GSM 03.38 Encoding

SSYYNNOOPPSSIISS #

   use Encode qw/encode decode/;
   $gsm0338 = encode("gsm0338", $unicode); # loads Encode::GSM0338 implicitly
   $unicode = decode("gsm0338", $gsm0338); # ditto

DDEESSCCRRIIPPTTIIOONN #

 GSM0338 is for GSM handsets. Though it shares alphanumerals with ASCII,
 control character ranges and other parts are mapped very differently,
 mainly to store Greek characters.  There are also escape sequences
 (starting with 0x1B) to cover e.g. the Euro sign.

 This was once handled by Encode::Bytes but because of all those unusual
 specifications, Encode 2.20 has relocated the support to this module.

 This module implements only _G_S_M _7 _b_i_t _D_e_f_a_u_l_t _A_l_p_h_a_b_e_t and _G_S_M _7 _b_i_t
 _d_e_f_a_u_l_t _a_l_p_h_a_b_e_t _e_x_t_e_n_s_i_o_n _t_a_b_l_e according to standard 3GPP TS 23.038
 version 16. Therefore _N_a_t_i_o_n_a_l _L_a_n_g_u_a_g_e _S_i_n_g_l_e _S_h_i_f_t and _N_a_t_i_o_n_a_l
 _L_a_n_g_u_a_g_e _L_o_c_k_i_n_g _S_h_i_f_t are not implemented nor supported.

SSeepptteettss This modules operates with octets (like any other Encode module) and not with packed septets (unlike other GSM standards). Therefore for processing binary SMS or parts of GSM TPDU payload (3GPP TS 23.040) it is needed to do conversion between octets and packed septets. For this purpose perl’s “pack” and “unpack” functions may be useful:

   $bytes = substr(pack('(b*)*', unpack '(A7)*', unpack 'b*', $septets), 0, $num_of_septets);
   $unicode = decode('GSM0338', $bytes);

   $bytes = encode('GSM0338', $unicode);
   $septets = pack 'b*', join '', map { substr $_, 0, 7 } unpack '(A8)*', unpack 'b*', $bytes;
   $num_of_septets = length $bytes;

 Please note that for correct decoding of packed septets it is required to
 know number of septets packed in binary buffer as binary buffer is always
 padded with zero bits and 7 zero bits represents character "@". Number of
 septets is also stored in TPDU payload when dealing with 3GPP TS 23.040.

BBUUGGSS #

 Encode::GSM0338 2.7 and older versions (part of Encode 3.06) incorrectly
 handled zero bytes (character "@"). This was fixed in Encode::GSM0338
 version 2.8 (part of Encode 3.07).

SSEEEE AALLSSOO #

 3GPP TS 23.038 <https://www.3gpp.org/dynareport/23038.htm>

ETSI TS 123 038 V16.0.0 (2020-07) #

 <https://www.etsi.org/deliver/etsi_ts/123000_123099/123038/16.00.00_60/ts_123038v160000p.pdf>

 Encode

perl v5.36.3 2023-02-15 Encode::GSM0338(3p)