From 0b4be10a8c587d222de7f58f17da3f25b641e72d Mon Sep 17 00:00:00 2001
From: Marianpol <marcin.musial20@gmail.com>
Date: Sun, 28 Aug 2022 12:50:22 +0200
Subject: [PATCH] Check performance level fixes

One function for all levels

Predict multiple did response length
---
 pyren/mod_elm.py | 90 +++++++++++++++++++++++++-----------------------
 1 file changed, 47 insertions(+), 43 deletions(-)

diff --git a/pyren/mod_elm.py b/pyren/mod_elm.py
index 8fcce3b..d6f349f 100644
--- a/pyren/mod_elm.py
+++ b/pyren/mod_elm.py
@@ -2154,67 +2154,71 @@ class ELM:
         performanceLevels = [3, 2]
 
         for level in performanceLevels:
-            isLevelAccepted = self.checkPerformaceLevel(level, dataids)
-            if isLevelAccepted: 
+            is_level_accepted = self.check_performance_level(level, dataids)
+            if is_level_accepted: 
                 break
 
         if self.performanceModeLevel == 3 and mod_globals.opt_obdlink:
-            for level in reversed(range(4,100)): #26 - 1 = 25  parameters per page
-                isLevelAccepted = self.checkPerformaceLevel(level, dataids)
-                if isLevelAccepted: 
+            for level in reversed(range(4, 100)): # (number_of_dids_to_get_multiframe_request, max_performance_level_to_check - 1)
+                is_level_accepted = self.check_performance_level(level, dataids)
+                if is_level_accepted:
                     return
 
-    def checkPerformaceLevel(self, level, dataids):
+    def check_performance_level(self, level, dataids):
         if len(dataids) >= level:
-            paramToSend = ''
+            predicted_response_length = 2 # length of string ReadDataByIdentifier service byte - 0x22
+            did_number = 0
+            param_to_send = ''
 
-            if level <= 3: # 3 dataids max can be send in single frame
-                frameLength = '{:02X}'.format(1 + level * 2)
-                for lvl in range(level):
-                    paramToSend += dataids.keys()[lvl]
-                
-                cmd = '22' + paramToSend
-                
-                resp = self.cmd(cmd).replace(" ", "")   #check response length first
-                if not all (c in string.hexdigits for c in resp):
-                    return False 
-                
-                if self.l1_cache.get(cmd, ""):
-                    if mod_globals.opt_caf:
-                        resp = self.send_raw(cmd + self.l1_cache.get(cmd)) # get all frames, not only first one
-                    else:                                                  # prevents from triggering false error_frame error
-                        resp = self.send_raw(frameLength + cmd + self.l1_cache.get(cmd))
-                    for s in resp.split('\n'):
-                        if s.strip().startswith("037F") or "?" in s:
-                            return False 
-            
-            else: # send multiframe command for more than 3 dataids
+            if level > 3: # Send multiframe command for more than 3 dataids
                 # Some modules can return NO DATA if multi frame command is sent after some no activity time
                 # Sending anything before main command usually helps that command to be accepted
                 self.send_cmd ("22" + dataids.keys()[0] + "1")  
 
-                for lvl in range(level):
-                    resp = self.request("22" + dataids.keys()[lvl])
-                    if any(s in resp for s in ['?', 'NR']):
-                        continue
-                    paramToSend += dataids.keys()[lvl]
-                cmd = '22' + paramToSend
-                resp = self.send_cmd(cmd)
-            if any(s in resp for s in ['?', 'NR']):
+            # while there is some dataids left and actual number of used dids 
+            # is lower than requeseted performance level
+            while did_number < len(dataids) and len(param_to_send)/4 < level:
+                # get another did
+                did = dataids.keys()[did_number]
+                did_number += 1
+
+                # exclude did_supported_in_range did
+                # sent seperatly - response provided
+                # sent in multi did request - empty response
+                # these are available only in injection module
+                if not int('0x' + did, 16) % 0x20 and self.currentaddress == '7A':
+                    continue
+
+                #check if it is supported
+                resp = self.request("22" + did)
+                if not any(s in resp for s in ['?', 'NR']):
+                    # add it to the list
+                    param_to_send += did
+                    predicted_response_length += len(did) + int(dataids[did].dataBitLength)/4
+
+            # if module does not support any did, we cannot check performance level
+            if not param_to_send:
                 return False
-        
-        self.performanceModeLevel = level
-        return True
+            
+            cmd = '22' + param_to_send
+            resp = self.send_cmd(cmd).replace(" ", "")   #check response length first
+            if any(s in resp for s in ['?', 'NR']) or len(resp) < predicted_response_length:
+                return False
+
+            self.performanceModeLevel = len(param_to_send)/4
+            return True
+        else:
+            return False
 
     def getRefreshRate(self):
-        refreshRate = 0
+        refresh_rate = 0
 
         if not self.screenRefreshTime:
-            return refreshRate
+            return refresh_rate
         
-        refreshRate = 1 / self.screenRefreshTime
+        refresh_rate = 1 / self.screenRefreshTime
         self.screenRefreshTime = 0
-        return refreshRate
+        return refresh_rate
     
     def reset_elm(self):
         self.cmd ("at z")