From 0c4d82d84a74c2de9ef5e08119f5c3bfe8789c08 Mon Sep 17 00:00:00 2001
From: Supreeth Herle <herlesupreeth@gmail.com>
Date: Mon, 20 Apr 2020 13:28:31 +0200
Subject: [PATCH] utils.py: Add helper method to parse and print Service Table

This method helps in printing Service Tables in EF.SST, EF.UST, EF.IST.
Takes hex string of Service table, parses it and prints available service along with its description.

Change-Id: Ie1e82e07ead2e28314a5794661e6b2ced0acd72a
---
 pySim/utils.py | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/pySim/utils.py b/pySim/utils.py
index 51f29541..be670e93 100644
--- a/pySim/utils.py
+++ b/pySim/utils.py
@@ -347,3 +347,34 @@ def parse_st(st):
 				avail_srvc.append((8*i) + j)
 			byte = byte >> 1
 	return avail_srvc
+
+def dec_st(st, table="sim"):
+	"""
+	Parses the EF S/U/IST and prints the list of available services in EF S/U/IST
+	"""
+
+	if table == "usim":
+		from pySim.ts_31_102 import EF_UST_map
+		lookup_map = EF_UST_map
+	else:
+		from pySim.ts_51_011 import EF_SST_map
+		lookup_map = EF_SST_map
+
+	st_bytes = [st[i:i+2] for i in range(0, len(st), 2) ]
+
+	avail_st = ""
+	# 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 and ((8*i) + j in lookup_map):
+				# Byte X contains info about Services num (8X-7) to num (8X)
+				# bit = 1: service available
+				# bit = 0: service not available
+				avail_st += '\tService %d - %s\n' % ((8*i) + j, lookup_map[(8*i) + j])
+			byte = byte >> 1
+	return avail_st