PERF: Speed up bitstring conversions in idex

Bitstring was allocating many new objects which added significant
overhead. We can just use Python's native int conversions and
indexing into strings to achieve the same result.

imap_processing/idex/idex_packet_parser.py

@@ -821,11 +821,15 @@ def _parse_high_sample_waveform(self, waveform_raw: str):
 
         The very last 4 numbers are bad usually, so remove those
         """
-        w = bitstring.ConstBitStream(bin=waveform_raw)
         ints = []
-        while w.pos < len(w):
-            w.read("pad:2")  # skip 2
-            ints += w.readlist(["uint:10"] * 3)
+        for i in range(0, len(waveform_raw), 32):
+            # 32 bit chunks, divided up into 2, 10, 10, 10
+            # skip first two bits
+            ints += [
+                int(waveform_raw[i + 2 : i + 12], 2),
+                int(waveform_raw[i + 12 : i + 22], 2),
+                int(waveform_raw[i + 22 : i + 32], 2),
+            ]
         return ints[:-4]  # Remove last 4 numbers
 
     def _parse_low_sample_waveform(self, waveform_raw: str):
@@ -836,11 +840,12 @@ def _parse_low_sample_waveform(self, waveform_raw: str):
             * 8 bits of padding
             * 2x12 bits of integer data.
         """
-        w = bitstring.ConstBitStream(bin=waveform_raw)
         ints = []
-        while w.pos < len(w):
-            w.read("pad:8")  # skip 8
-            ints += w.readlist(["uint:12"] * 2)
+        for i in range(0, len(waveform_raw), 32):
+            ints += [
+                int(waveform_raw[i + 8 : i + 20], 2),
+                int(waveform_raw[i + 20 : i + 32], 2),
+            ]
         return ints
 
     def _calc_low_sample_resolution(self, num_samples: int):