Read log files generated by users

Let the program reads file generated by rt2ms, logpeek, or itself.

#94 (closed)

sohstationviewer/model/reftek_data/reftek_reader/log_file_reader.py

 from pathlib import Path
 from typing import List, Literal, Optional, Dict, Callable, Tuple
 
+import numpy as np
+from obspy import UTCDateTime
+
 LogFileFormat = Literal['rt2ms', 'logpeek', 'sohstationviewer']
 # These packets can be found in section 4 of the RT130 record documentation.
 RT130_PACKETS = ['SH', 'SC', 'OM', 'DS', 'AD', 'CD', 'FD', 'EH', 'ET']
@@ -256,3 +259,31 @@ class LogFileReader:
             # separate the SOH lines blocks during processing.
             self.soh_lines.append('\n')
             self.masspos_lines.extend(masspos_lines)
+
+
+def process_mass_poss_line(masspos_lines: List[str]
+                           ) -> List[Tuple[np.ndarray, np.ndarray]]:
+    """
+    Process a list of mass-position lines into a list of mass-position data,
+    sorted by the channel suffix
+    :param masspos_lines: a list of mass-position log lines
+    :return: a list of mass-position data, sorted by the channel suffix
+    """
+    # There can be 6 mass-position channels.
+    mass_pos_data = []
+    for masspos_num in range(6):
+        current_lines = [line.split()
+                         for line
+                         in masspos_lines
+                         if int(line.split()[2]) == masspos_num]
+        data = np.asarray([line[3] for line in current_lines], dtype=float)
+        time_format = '%Y:%j:%H:%M:%S.%f'
+        times = np.array(
+            # strptime requires the microsecond component to have 6 digits, but
+            # a mass-position log lines only have 3 digits for microsecond. So,
+            # we have to pad the time with 0s.
+            [UTCDateTime.strptime(line[1] + '000', time_format).timestamp
+             for line in current_lines]
+        )
+        mass_pos_data.append((times, data))
+    return mass_pos_data