rgb_led_ws281x: refactor bit/bits handling, use more common code

Pass all .decode() routine's bit handling through a common bit handler.
Accumulate the bit values as well as their ss/es timestamps. Reduce code
duplication in the bits handler. Use common support code to get the
24/32 bit wide integer from the list of bits. Prepare to handle streams
of different per-pixel length or layout.

This commit remains backwards compatible, and keeps all warts of the
previous implementation including inconsistent annotation order. Just
eliminates unnecessary instance members and hidden coupling, to keep
timestamp handling in the .decode() method.

1 files changed, 27 insertions, 33 deletions

diff --git a/decoders/rgb_led_ws281x/pd.py b/decoders/rgb_led_ws281x/pd.py
index dbd41df..2957405 100644
--- a/decoders/rgb_led_ws281x/pd.py
+++ b/decoders/rgb_led_ws281x/pd.py
@@ -18,7 +18,7 @@
 ##
 
 import sigrokdecode as srd
-from functools import reduce
+from common.srdhelper import bitpack_msb
 
 class SamplerateError(Exception):
     pass
@@ -58,7 +58,6 @@ class Decoder(srd.Decoder):
     def reset(self):
         self.samplerate = None
         self.oldpin = None
-        self.ss_packet = None
         self.ss = None
         self.es = None
         self.bits = []
@@ -74,27 +73,35 @@ class Decoder(srd.Decoder):
     def putg(self, ss, es, cls, text):
         self.put(ss, es, self.out_ann, [cls, text])
 
-    def handle_bits(self, samplenum):
+    def handle_bits(self):
+        if len(self.bits) < self.need_bits:
+            return
+        grb = bitpack_msb(self.bits, 0)
         if self.options['type'] == 'RGB':
-            if len(self.bits) == 24:
-                grb = reduce(lambda a, b: (a << 1) | b, self.bits)
-                rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff)
-                text = ['#{:06x}'.format(rgb)]
-                self.putg(self.ss_packet, samplenum, ANN_RGB, text)
-                self.bits = []
-                self.ss_packet = None
+            rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0x0000ff)
+            text = '#{:06x}'.format(rgb)
         else:
-            if len(self.bits) == 32:
-                grb = reduce(lambda a, b: (a << 1) | b, self.bits)
-                rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0xff0000ff)
-                text = ['#{:08x}'.format(rgb)]
-                self.putg(self.ss_packet, samplenum, ANN_RGB, text)
-                self.bits = []
-                self.ss_packet = None
+            rgb = (grb & 0xff0000) >> 8 | (grb & 0x00ff00) << 8 | (grb & 0xff0000ff)
+            text = '#{:08x}'.format(rgb)
+        ss_packet, es_packet = self.bits[0][1], self.bits[-1][2]
+        self.putg(ss_packet, es_packet, ANN_RGB, [text])
+        self.bits.clear()
+
+    def handle_bit(self, ss, es, value, ann_late = False):
+        if not ann_late:
+            text = ['{:d}'.format(value)]
+            self.putg(ss, es, ANN_BIT, text)
+        item = (value, ss, es)
+        self.bits.append(item)
+        self.handle_bits()
+        if ann_late:
+            text = ['{:d}'.format(value)]
+            self.putg(ss, es, ANN_BIT, text)
 
     def decode(self):
         if not self.samplerate:
             raise SamplerateError('Cannot decode without samplerate.')
+        self.need_bits = len(self.options['type']) * 8
 
         while True:
             # TODO: Come up with more appropriate self.wait() conditions.
@@ -114,17 +121,13 @@ class Decoder(srd.Decoder):
                 tH = (self.es - self.ss) / self.samplerate
                 bit_ = True if tH >= 625e-9 else False
 
-                self.bits.append(bit_)
-                self.handle_bits(self.es)
+                self.handle_bit(self.ss, self.es, bit_, True)
 
-                text = ['{:d}'.format(bit_)]
-                self.putg(self.ss, self.es, ANN_BIT, text)
                 text = ['RESET', 'RST', 'R']
                 self.putg(self.es, self.samplenum, ANN_RESET, text)
 
                 self.inreset = True
-                self.bits = []
-                self.ss_packet = None
+                self.bits.clear()
                 self.ss = None
 
             if not self.oldpin and pin:
@@ -134,16 +137,7 @@ class Decoder(srd.Decoder):
                     duty = self.es - self.ss
                     # Ideal duty for T0H: 33%, T1H: 66%.
                     bit_ = (duty / period) > 0.5
-
-                    text = ['{:d}'.format(bit_)]
-                    self.putg(self.ss, self.samplenum, ANN_BIT, text)
-
-                    self.bits.append(bit_)
-                    self.handle_bits(self.samplenum)
-
-                if self.ss_packet is None:
-                    self.ss_packet = self.samplenum
-
+                    self.handle_bit(self.ss, self.samplenum, bit_)
                 self.ss = self.samplenum
 
             elif self.oldpin and not pin: