Various PDs: Throw SamplerateError instead of Exception.

Also, use the "if not self.samplerate" form, which catches both the case
where self.samplerate is None, as well as the case where it is 0.

1 files changed, 5 insertions, 2 deletions

diff --git a/decoders/usb_signalling/pd.py b/decoders/usb_signalling/pd.py
index a21fe8d..59db0d4 100644
--- a/decoders/usb_signalling/pd.py
+++ b/decoders/usb_signalling/pd.py
@@ -73,6 +73,9 @@ sym_idx = {
     'SE1': 3,
 }
 
+class SamplerateError(Exception):
+    pass
+
 class Decoder(srd.Decoder):
     api_version = 2
     id = 'usb_signalling'
@@ -217,8 +220,8 @@ class Decoder(srd.Decoder):
         self.oldsym = sym
 
     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, pins) in data:
             # State machine.
             if self.state == 'IDLE':