Add single register binary file reader

Author: glopesdev

harp/io.py

@@ -0,0 +1,47 @@
+import numpy as np
+import pandas as pd
+
+_SECONDS_PER_TICK = 32e6
+payloadtypes = {
+    1 : np.dtype(np.uint8),
+    2 : np.dtype(np.uint16),
+    4 : np.dtype(np.uint32),
+    8 : np.dtype(np.uint64),
+    129 : np.dtype(np.int8),
+    130 : np.dtype(np.int16),
+    132 : np.dtype(np.int32),
+    136 : np.dtype(np.int64),
+    68 : np.dtype(np.float32)
+}
+
+def read(file: str, columns=None):
+    '''
+    Read single-register Harp data from the specified file.
+    
+    :param str file: The path to a Harp binary file containing data from a single device register.
+    :param str or array-like names: The optional column labels to use for the data values.
+    :return: A pandas data frame containing harp event data, sorted by time.
+    '''
+    data = np.fromfile(file, dtype=np.uint8)
+    if len(data) == 0:
+        return pd.DataFrame(
+            columns=columns,
+            index=pd.Index([], dtype=np.float64, name='time'))
+
+    stride = data[1] + 2
+    length = len(data) // stride
+    payloadsize = stride - 12
+    payloadtype = payloadtypes[data[4] & ~0x10]
+    elementsize = payloadtype.itemsize
+    payloadshape = (length, payloadsize // elementsize)
+    seconds = np.ndarray(length, dtype=np.uint32, buffer=data, offset=5, strides=stride)
+    micros = np.ndarray(length, dtype=np.uint16, buffer=data, offset=9, strides=stride)
+    seconds = micros * _SECONDS_PER_TICK + seconds
+    payload = np.ndarray(
+        payloadshape,
+        dtype=payloadtype,
+        buffer=data, offset=11,
+        strides=(stride, elementsize))
+    time = pd.Series(seconds)
+    time.name = 'time'
+    return pd.DataFrame(payload, index=time, columns=columns)