L2SS-192: Improved naming & comments of extract_bits.

devices/SDP_statistics.py

@@ -4,19 +4,19 @@ import numpy
 
 __all__ = ["StatisticsPacket"]
 
-def extract_bits(value: bytes, first: int, last:int=None) -> int:
-    """ Return bits [first:last] from value, and return their integer value. Bit 0 = LSB.
+def get_bit_value(value: bytes, first_bit: int, last_bit:int=None) -> int:
+    """ Return bits [first_bit:last_bit] from value, and return their integer value. Bit 0 = LSB.
 
         For example, extracting bits 2-3 from b'01100' returns 11 binary = 3 decimal:
-            extract_bits(b'01100', 2, 3) == 3
+            get_bit_value(b'01100', 2, 3) == 3
     
-        If last is not given, just the value of bit 'first' is returned. """
+        If 'last_bit' is not given, just the value of bit 'first_bit' is returned. """
 
-    # default last to first
-    if last is None:
-        last = first
+    # default last_bit to first_bit
+    if last_bit is None:
+        last_bit = first_bit
 
-    return value >> first & ((1 << (last - first + 1)) - 1)
+    return value >> first_bit & ((1 << (last_bit - first_bit + 1)) - 1)
 
 class StatisticsPacket(object):
     """
@@ -71,15 +71,15 @@ class StatisticsPacket(object):
 
         return {
           "_raw": bits,
-          "antenna_band_index": extract_bits(bits, 15),
-          "nyquist_zone_index": extract_bits(bits, 13, 14),
-          "t_adc": extract_bits(bits, 12),
-          "fsub_type": extract_bits(bits, 11),
-          "payload_error": extract_bits(bits, 10),
-          "beam_repositioning_flag": extract_bits(bits, 9),
-          "subband_calibrated_flag": extract_bits(bits, 8),
-          "reserved": extract_bits(bits, 5, 7),
-          "gn_index": extract_bits(bits, 0, 4),
+          "antenna_band_index": get_bit_value(bits, 15),
+          "nyquist_zone_index": get_bit_value(bits, 13, 14),
+          "t_adc": get_bit_value(bits, 12),
+          "fsub_type": get_bit_value(bits, 11),
+          "payload_error": get_bit_value(bits, 10),
+          "beam_repositioning_flag": get_bit_value(bits, 9),
+          "subband_calibrated_flag": get_bit_value(bits, 8),
+          "reserved": get_bit_value(bits, 5, 7),
+          "gn_index": get_bit_value(bits, 0, 4),
         }
 
     @property