X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=decoders%2Fi2s%2Fpd.py;h=8b45a752cbae2c750581a511cff382002734934e;hb=903e9b14c84400579e0d786b7a96e9e587b5849b;hp=989a5a5eaf9433ec653b60d3bf12c0d4f4e82468;hpb=12851357e784b893e24880efc6cd22a0cbcc64ce;p=libsigrokdecode.git

diff --git a/decoders/i2s/pd.py b/decoders/i2s/pd.py
index 989a5a5..8b45a75 100644
--- a/decoders/i2s/pd.py
+++ b/decoders/i2s/pd.py
@@ -33,6 +33,9 @@ Packet:
 <value>: integer
 '''
 
+class SamplerateError(Exception):
+    pass
+
 class Decoder(srd.Decoder):
     api_version = 2
     id = 'i2s'
@@ -90,8 +93,8 @@ class Decoder(srd.Decoder):
 
         # Calculate the sample rate.
         samplerate = '?'
-        if self.start_sample != None and \
-            self.first_sample != None and \
+        if self.start_sample is not None and \
+            self.first_sample is not None and \
             self.start_sample > self.first_sample:
             samplerate = '%d' % (self.samplesreceived *
                 self.samplerate / (self.start_sample -
@@ -128,8 +131,8 @@ class Decoder(srd.Decoder):
         return bytes([lo, hi])
 
     def decode(self, ss, es, data):
-        if self.samplerate is None:
-            raise Exception("Cannot decode without samplerate.")
+        if not self.samplerate:
+            raise SamplerateError('Cannot decode without samplerate.')
         for self.samplenum, (sck, ws, sd) in data:
 
             # Ignore sample if the bit clock hasn't changed.
@@ -148,7 +151,7 @@ class Decoder(srd.Decoder):
                 continue
 
             # Only submit the sample, if we received the beginning of it.
-            if self.start_sample != None:
+            if self.start_sample is not None:
 
                 if not self.wrote_wav_header:
                     self.put(0, 0, self.out_bin, (0, self.wav_header()))
@@ -179,8 +182,7 @@ class Decoder(srd.Decoder):
             self.start_sample = self.samplenum
 
             # Save the first sample position.
-            if self.first_sample == None:
+            if self.first_sample is None:
                 self.first_sample = self.samplenum
 
             self.oldws = ws
-