utils.py: Add helper method to parse Service Table
This method helps in parsing Service Tables in EF.SST, EF.UST, EF.EST, EF.IST.
Takes hex string as input and output a list of available/enabled services.
Change-Id: I9b72efdb84ba7be4a40928a008a59c67f6fb71d4
diff --git a/pySim/utils.py b/pySim/utils.py
index c098384..51f2954 100644
--- a/pySim/utils.py
+++ b/pySim/utils.py
@@ -325,3 +325,25 @@
bcd = rpad(swap_nibbles(msisdn), 10 * 2) # pad to 10 octets
return ('%02x' % bcd_len) + ('%02x' % npi_ton) + bcd
+
+def parse_st(st):
+ """
+ Parses the EF S/U/IST and returns available/supported services
+ """
+ st_bytes = [st[i:i+2] for i in range(0, len(st), 2) ]
+ avail_srvc = []
+ # Get each byte and check for available services
+ for i in range(0, len(st_bytes)):
+ # Byte i contains info about Services num (8i+1) to num (8i+8)
+ byte = int(st_bytes[i], 16)
+ # Services in each byte are in order MSB to LSB
+ # MSB - Service (8i+8)
+ # LSB - Service (8i+1)
+ for j in range(1, 9):
+ if byte&0x01 == 0x01:
+ # Byte X contains info about Services num (8X-7) to num (8X)
+ # bit = 1: service available
+ # bit = 0: service not available
+ avail_srvc.append((8*i) + j)
+ byte = byte >> 1
+ return avail_srvc