Start splitting some functionality out into different files

nptdms/__init__.py

@@ -7,5 +7,6 @@
 from .version import __version_info__, __version__
 
 # Export public objects
-from .tdms import TdmsFile, TdmsObject
+from .tdms import TdmsFile
+from .tdms_segment import TdmsObject
 from .writer import TdmsWriter, RootObject, GroupObject, ChannelObject

nptdms/common.py

@@ -1,12 +1,14 @@
-from collections import namedtuple
-import numpy as np
-
-
+import itertools
 try:
     long
 except NameError:
     # Python 3
     long = int
+try:
+    zip_longest = itertools.izip_longest
+except AttributeError:
+    # Python 3
+    zip_longest = itertools.zip_longest
 
 
 toc_properties = {
@@ -17,3 +19,39 @@
     'kTocBigEndian': (long(1) << 6),
     'kTocNewObjList': (long(1) << 2)
 }
+
+
+def path_components(path):
+    """Convert a path into group and channel name components"""
+
+    def yield_components(path):
+        # Iterate over each character and the next character
+        chars = zip_longest(path, path[1:])
+        try:
+            # Iterate over components
+            while True:
+                char, next_char = next(chars)
+                if char != '/':
+                    raise ValueError("Invalid path, expected \"/\"")
+                elif (next_char is not None and next_char != "'"):
+                    raise ValueError("Invalid path, expected \"'\"")
+                else:
+                    # Consume "'" or raise StopIteration if at the end
+                    next(chars)
+                component = []
+                # Iterate over characters in component name
+                while True:
+                    char, next_char = next(chars)
+                    if char == "'" and next_char == "'":
+                        component += "'"
+                        # Consume second "'"
+                        next(chars)
+                    elif char == "'":
+                        yield "".join(component)
+                        break
+                    else:
+                        component += char
+        except StopIteration:
+            return
+
+    return list(yield_components(path))

nptdms/daqmx.py

@@ -0,0 +1,76 @@
+import numpy as np
+
+from nptdms import types
+from nptdms.log import log_manager
+
+
+log = log_manager.get_logger(__name__)
+
+
+class DaqMxMetadata(object):
+    """ Describes DAQmx data
+    """
+
+    __slots__ = [
+        'chunk_size',
+        'data_type',
+        'dimension',
+        'raw_data_widths',
+        'scale_id',
+        'scaler_data_type',
+        'scaler_data_type_code',
+        'scaler_raw_buffer_index',
+        'scaler_raw_buffer_index',
+        'scaler_raw_byte_offset',
+        'scaler_sample_format_bitmap',
+        'scaler_vector_length',
+        ]
+
+    def __init__(self, f, endianness):
+        """
+        Read the metadata for a DAQmx raw segment.  This is the raw
+        DAQmx-specific portion of the raw data index.
+        """
+        self.data_type = types.tds_data_types[0xFFFFFFFF]
+        self.dimension = types.Uint32.read(f, endianness)
+        # In TDMS format version 2.0, 1 is the only valid value for dimension
+        if self.dimension != 1:
+            log.warning("Data dimension is not 1")
+        self.chunk_size = types.Uint64.read(f, endianness)
+        # size of vector of format changing scalers
+        self.scaler_vector_length = types.Uint32.read(f, endianness)
+        # Size of the vector
+        log.debug("mxDAQ format scaler vector size '%d'",
+                  self.scaler_vector_length)
+        if self.scaler_vector_length > 1:
+            log.error("mxDAQ multiple format changing scalers not implemented")
+
+        for _ in range(self.scaler_vector_length):
+            # WARNING: This code overwrites previous values with new
+            # values.  At this time NI provides no documentation on
+            # how to use these scalers and sample TDMS files do not
+            # include more than one of these scalers.
+            self.scaler_data_type_code = types.Uint32.read(f, endianness)
+            self.scaler_data_type = (
+                types.tds_data_types[self.scaler_data_type_code])
+
+            # more info for format changing scaler
+            self.scaler_raw_buffer_index = types.Uint32.read(f, endianness)
+            self.scaler_raw_byte_offset = types.Uint32.read(f, endianness)
+            self.scaler_sample_format_bitmap = types.Uint32.read(f, endianness)
+            self.scale_id = types.Uint32.read(f, endianness)
+
+        raw_data_widths_length = types.Uint32.read(f, endianness)
+        self.raw_data_widths = np.zeros(raw_data_widths_length, dtype=np.int32)
+        for cnt in range(raw_data_widths_length):
+            self.raw_data_widths[cnt] = types.Uint32.read(f, endianness)
+
+    def __str__(self):
+        """ Return string representation of DAQmx metadata
+        """
+        properties = (
+            "%s: %s" % (name, getattr(self, name))
+            for name in self.__slots__)
+
+        properties_list = ", ".join(properties)
+        return "%s: ('%s')" % (self.__class__.__name__, properties_list)

nptdms/log.py

@@ -0,0 +1,38 @@
+import logging
+
+
+class LogManager(object):
+    """ Manages multiple loggers from different modules
+    """
+
+    def __init__(self):
+        self.log_level = logging.WARNING
+
+        self.console_handler = logging.StreamHandler()
+        self.console_handler.setLevel(self.log_level)
+
+        self.formatter = logging.Formatter(
+            '[%(name)s %(levelname)s] %(message)s')
+        self.console_handler.setFormatter(self.formatter)
+
+        self.loggers = {}
+
+    def get_logger(self, module_name):
+        """ Return a logger for a module
+        """
+        log = logging.getLogger(module_name)
+        log.setLevel(self.log_level)
+        log.addHandler(self.console_handler)
+        self.loggers[module_name] = log
+        return log
+
+    def set_level(self, level):
+        """ Set the log level for all loggers that have been created
+        """
+        self.log_level = level
+        self.console_handler.setLevel(level)
+        for log in self.loggers.values():
+            log.setLevel(level)
+
+
+log_manager = LogManager()

nptdms/scaling.py

@@ -1,10 +1,11 @@
-import logging
 import numpy as np
 import re
 
+from nptdms.utils import OrderedDict
+from nptdms.log import log_manager
 
-log = logging.getLogger(__name__)
-log.setLevel(logging.WARNING)
+
+log = log_manager.get_logger(__name__)
 
 
 class LinearScaling(object):