sdq: only use samplerate and options values after validity check

Move the calculation which involves the samplerate as well as user
provided options out of the meta packet reception and to the top of the
decode() method. Especially only use the samplerate after it was tested
for availability.

diff --git a/decoders/sdq/pd.py b/decoders/sdq/pd.py
index 1dc9c1c692bb613524406ff5a12e879c9ae60db0..d8df89ff5879f8ea4df1939bceb9c9882de29152 100644 (file)
--- a/decoders/sdq/pd.py
+++ b/decoders/sdq/pd.py
@@ -75,9 +75,6 @@ class Decoder(srd.Decoder):
     def metadata(self, key, value):
         if key == srd.SRD_CONF_SAMPLERATE:
             self.samplerate = value
-            self.bit_width = float(self.samplerate) / float(self.options['bitrate'])
-            self.half_bit_width = self.bit_width / 2.0
-            self.break_threshold = self.bit_width * 1.2 # Break if the line is low for longer than this
 
     def handle_bit(self, bit):
         self.bits.append(bit)
@@ -98,6 +95,10 @@ class Decoder(srd.Decoder):
     def decode(self):
         if not self.samplerate:
             raise SamplerateError('Cannot decode without samplerate.')
+        self.bit_width = float(self.samplerate) / float(self.options['bitrate'])
+        self.half_bit_width = self.bit_width / 2.0
+        # BREAK if the line is low for longer than this.
+        self.break_threshold = self.bit_width * 1.2
 
         while True:
             if self.state == 'INIT':