initial commit

mne/io/bti/read.py

@@ -0,0 +1,98 @@
+# Authors: The MNE-Python contributors.
+# License: BSD-3-Clause
+# Copyright the MNE-Python contributors.
+
+import numpy as np
+
+from ..._fiff.utils import read_str
+
+
+def _unpack_matrix(fid, rows, cols, dtype, out_dtype):
+    """Unpack matrix."""
+    dtype = np.dtype(dtype)
+
+    string = fid.read(int(dtype.itemsize * rows * cols))
+    out = np.frombuffer(string, dtype=dtype).reshape(rows, cols).astype(out_dtype)
+    return out
+
+
+def _unpack_simple(fid, dtype, out_dtype):
+    """Unpack a NumPy type."""
+    dtype = np.dtype(dtype)
+    string = fid.read(dtype.itemsize)
+    out = np.frombuffer(string, dtype=dtype).astype(out_dtype)
+
+    if len(out) > 0:
+        out = out[0]
+    return out
+
+
+def read_char(fid, count=1):
+    """Read character from bti file."""
+    return _unpack_simple(fid, f">S{count}", "S")
+
+
+def read_uint16(fid):
+    """Read unsigned 16bit integer from bti file."""
+    return _unpack_simple(fid, ">u2", np.uint32)
+
+
+def read_int16(fid):
+    """Read 16bit integer from bti file."""
+    return _unpack_simple(fid, ">i2", np.int32)
+
+
+def read_uint32(fid):
+    """Read unsigned 32bit integer from bti file."""
+    return _unpack_simple(fid, ">u4", np.uint32)
+
+
+def read_int32(fid):
+    """Read 32bit integer from bti file."""
+    return _unpack_simple(fid, ">i4", np.int32)
+
+
+def read_int64(fid):
+    """Read 64bit integer from bti file."""
+    return _unpack_simple(fid, ">u8", np.int64)
+
+
+def read_float(fid):
+    """Read 32bit float from bti file."""
+    return _unpack_simple(fid, ">f4", np.float32)
+
+
+def read_double(fid):
+    """Read 64bit float from bti file."""
+    return _unpack_simple(fid, ">f8", np.float64)
+
+
+def read_int16_matrix(fid, rows, cols):
+    """Read 16bit integer matrix from bti file."""
+    return _unpack_matrix(
+        fid,
+        rows,
+        cols,
+        dtype=">i2",
+        out_dtype=np.int32,
+    )
+
+
+def read_float_matrix(fid, rows, cols):
+    """Read 32bit float matrix from bti file."""
+    return _unpack_matrix(fid, rows, cols, dtype=">f4", out_dtype=np.float32)
+
+
+def read_double_matrix(fid, rows, cols):
+    """Read 64bit float matrix from bti file."""
+    return _unpack_matrix(fid, rows, cols, dtype=">f8", out_dtype=np.float64)
+
+
+def read_transform(fid):
+    """Read 64bit float matrix transform from bti file."""
+    return read_double_matrix(fid, rows=4, cols=4)
+
+
+def read_dev_header(x):
+    """Create a dev header."""
+    return dict(size=read_int32(x), checksum=read_int32(x), reserved=read_str(x, 32))