From: Gerhard Sittig <redacted>
Date: Wed, 22 Jul 2020 20:02:23 +0000 (+0200)
Subject: can: use common helper for bits to number conversion
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=b0edaeb30d16af16ddbe112fe12960697196b581;p=libsigrokdecode.git

can: use common helper for bits to number conversion

Eliminate repeated local string manipulation for the purpose of
number conversion from bits input. Prefer the common helper instead
(is an MSB first variant desirable to simplify call sites more?).
---

diff --git a/decoders/can/pd.py b/decoders/can/pd.py
index e38f69d..4551896 100644
--- a/decoders/can/pd.py
+++ b/decoders/can/pd.py
@@ -18,6 +18,7 @@
 ## along with this program; if not, see <http://www.gnu.org/licenses/>.
 ##
 
+from common.srdhelper import bitpack
 import sigrokdecode as srd
 
 class SamplerateError(Exception):
@@ -204,7 +205,9 @@ class Decoder(srd.Decoder):
 
             x = self.last_databit + 1
             crc_bits = self.bits[x:x + self.crc_len + 1]
-            self.crc = int(''.join(str(d) for d in crc_bits), 2)
+            bits = crc_bits
+            bits.reverse()
+            self.crc = bitpack(bits)
             self.putb([11, ['%s sequence: 0x%04x' % (crc_type, self.crc),
                             '%s: 0x%04x' % (crc_type, self.crc), '%s' % crc_type]])
             if not self.is_valid_crc(crc_bits):
@@ -294,7 +297,9 @@ class Decoder(srd.Decoder):
 
         # Bits 15-18: Data length code (DLC), in number of bytes (0-8).
         elif bitnum == self.dlc_start + 3:
-            self.dlc = int(''.join(str(d) for d in self.bits[self.dlc_start:self.dlc_start + 4]), 2)
+            bits = self.bits[self.dlc_start:self.dlc_start + 4]
+            bits.reverse()
+            self.dlc = bitpack(bits)
             self.putb([10, ['Data length code: %d' % self.dlc,
                             'DLC: %d' % self.dlc, 'DLC']])
             self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
@@ -311,7 +316,9 @@ class Decoder(srd.Decoder):
             self.ss_databytebits.append(self.samplenum) # Last databyte bit.
             for i in range(dlc2len(self.dlc)):
                 x = self.dlc_start + 4 + (8 * i)
-                b = int(''.join(str(d) for d in self.bits[x:x + 8]), 2)
+                bits = self.bits[x:x + 8]
+                bits.reverse()
+                b = bitpack(bits)
                 self.frame_bytes.append(b)
                 ss = self.ss_databytebits[i * 8]
                 es = self.ss_databytebits[((i + 1) * 8) - 1]
@@ -335,7 +342,9 @@ class Decoder(srd.Decoder):
 
         # Bits 14-31: Extended identifier (EID[17..0])
         elif bitnum == 31:
-            self.eid = int(''.join(str(d) for d in self.bits[14:]), 2)
+            bits = self.bits[14:]
+            bits.reverse()
+            self.eid = bitpack(bits)
             s = '%d (0x%x)' % (self.eid, self.eid)
             self.putb([4, ['Extended Identifier: %s' % s,
                            'Extended ID: %s' % s, 'Extended ID', 'EID']])
@@ -396,7 +405,9 @@ class Decoder(srd.Decoder):
 
         # Bits 35-38: Data length code (DLC), in number of bytes (0-8).
         elif bitnum == self.dlc_start + 3:
-            self.dlc = int(''.join(str(d) for d in self.bits[self.dlc_start:self.dlc_start + 4]), 2)
+            bits = self.bits[self.dlc_start:self.dlc_start + 4]
+            bits.reverse()
+            self.dlc = bitpack(bits)
             self.putb([10, ['Data length code: %d' % self.dlc,
                             'DLC: %d' % self.dlc, 'DLC']])
             self.last_databit = self.dlc_start + 3 + (dlc2len(self.dlc) * 8)
@@ -411,7 +422,9 @@ class Decoder(srd.Decoder):
             self.ss_databytebits.append(self.samplenum) # Last databyte bit.
             for i in range(dlc2len(self.dlc)):
                 x = self.dlc_start + 4 + (8 * i)
-                b = int(''.join(str(d) for d in self.bits[x:x + 8]), 2)
+                bits = self.bits[x:x + 8]
+                bits.reverse()
+                b = bitpack(bits)
                 self.frame_bytes.append(b)
                 ss = self.ss_databytebits[i * 8]
                 es = self.ss_databytebits[((i + 1) * 8) - 1]
@@ -459,7 +472,10 @@ class Decoder(srd.Decoder):
         # Bits 1-11: Identifier (ID[10..0])
         # The bits ID[10..4] must NOT be all recessive.
         elif bitnum == 11:
-            self.id = int(''.join(str(d) for d in self.bits[1:]), 2)
+            bits = self.bits[1:]
+            bits.reverse()
+            # BEWARE! Clobbers the decoder's .id field!
+            self.id = bitpack(bits)
             self.fullid = self.id
             s = '%d (0x%x)' % (self.id, self.id),
             self.putb([3, ['Identifier: %s' % s, 'ID: %s' % s, 'ID']])