parallel: address minor style nits, no change in behaviour

Remove the redundant .itemcount variable, which exactly corresponds to
the length of the .items array.

Arrange retrieval of options and their evaluation closer to each other
for improved readability.

Use common logic to construct "words" from several multi-bit "items".
Arrange for endianess support by optionally reversing the array before
traversal.

diff --git a/decoders/parallel/pd.py b/decoders/parallel/pd.py
index 4c09d86235e45b0d332511f91826ae59c364e191..593b39b234140b2bfc5f0ff51cceed6bea47b519 100644 (file)
--- a/decoders/parallel/pd.py
+++ b/decoders/parallel/pd.py
@@ -92,7 +92,6 @@ class Decoder(srd.Decoder):
 
     def reset(self):
         self.items = []
-        self.itemcount = 0
         self.saved_item = None
         self.ss_item = self.es_item = None
         self.first = True
@@ -115,17 +114,15 @@ class Decoder(srd.Decoder):
         self.put(self.ss_word, self.es_word, self.out_ann, data)
 
     def handle_bits(self, datapins):
-        # If this is the first item in a word, save its sample number.
-        if self.itemcount == 0:
-            self.ss_word = self.samplenum
-
         # Get the bits for this item.
         item, used_pins = 0, datapins.count(1) + datapins.count(0)
         for i in range(used_pins):
             item |= datapins[i] << i
 
+        # Save the item, and its sample number if it's the first part of a word.
+        if not self.items:
+            self.ss_word = self.samplenum
         self.items.append(item)
-        self.itemcount += 1
 
         if self.first:
             # Save the start sample and item for later (no output yet).
@@ -140,26 +137,27 @@ class Decoder(srd.Decoder):
             self.ss_item = self.samplenum
             self.saved_item = item
 
-        endian, ws = self.options['endianness'], self.options['wordsize']
-
         # Get as many items as the configured wordsize says.
-        if self.itemcount < ws:
+        ws = self.options['wordsize']
+        if len(self.items) < ws:
             return
 
         # Output annotations/python for a word (a collection of items).
+        # NOTE that this feature is currently not effective. The emission
+        # of Python annotations is commented out.
+        endian = self.options['endianness']
+        if endian == 'little':
+            self.items.reverse()
         word = 0
         for i in range(ws):
-            if endian == 'little':
-                word |= self.items[i] << ((ws - 1 - i) * used_pins)
-            elif endian == 'big':
-                word |= self.items[i] << (i * used_pins)
+            word |= self.items[i] << (i * used_pins)
 
         self.es_word = self.samplenum
         # self.putpw(['WORD', word])
         # self.putw([1, ['%X' % word]])
         self.ss_word = self.samplenum
 
-        self.itemcount, self.items = 0, []
+        self.items = []
 
     def decode(self):
         for i in range(len(self.optional_channels)):