Source code for nidaqmx.system._collections.persisted_scale_collection

import ctypes
import six
from import Sequence

from nidaqmx._lib import lib_importer, ctypes_byte_str
from nidaqmx.errors import (
    check_for_error, is_string_buffer_too_small, DaqError)
from nidaqmx.error_codes import DAQmxErrors
from import PersistedScale
from nidaqmx.utils import unflatten_channel_string

[docs]class PersistedScaleCollection(Sequence): """ Contains the collection of custom scales on a DAQmx system. This class defines methods that implements a container object. """ def __contains__(self, item): scale_names = self.scale_names if isinstance(item, six.string_types): items = unflatten_channel_string(item) return all([i in scale_names for i in items]) elif isinstance(item, PersistedScale): return item._name in scale_names def __eq__(self, other): if isinstance(other, self.__class__): return True return False def __getitem__(self, index): """ Indexes a subset of custom scales on this collection. Args: index: The value of the index. The following index types are supported: - str: Name of the custom scale. You also can specify a string that contains a list or range of names to this input. If you have a list of names, use the DAQmx Flatten Channel String function to convert the list to a string. - int: Index/position of the custom scale in the collection. - slice: Range of the indexes/positions of custom scales in the collection. Returns: List[]: Indicates the subset of custom scales indexed. """ if isinstance(index, six.integer_types): return PersistedScale(self.scale_names[index]) elif isinstance(index, slice): return [PersistedScale(name) for name in self.scale_names[index]] elif isinstance(index, six.string_types): names = unflatten_channel_string(index) if len(names) == 1: return PersistedScale(names[0]) return [PersistedScale(name) for name in names] else: raise DaqError( 'Invalid index type "{0}" used to access collection.' .format(type(index)), DAQmxErrors.UNKNOWN) def __iter__(self): for scale_name in self.scale_names: yield PersistedScale(scale_name) def __len__(self): return len(self.scale_names) def __ne__(self, other): return not self.__eq__(other) def __reversed__(self): scale_names = self.scale_names scale_names.reverse() for scale_name in scale_names: yield PersistedScale(scale_name) @property def scale_names(self): """ List[str]: Indicates the names of all the custom scales on this collection. """ cfunc = lib_importer.windll.DAQmxGetSysScales if cfunc.argtypes is None: with cfunc.arglock: if cfunc.argtypes is None: cfunc.argtypes = [ ctypes.c_char_p, ctypes.c_uint] temp_size = 0 while True: val = ctypes.create_string_buffer(temp_size) size_or_code = cfunc( val, temp_size) if is_string_buffer_too_small(size_or_code): # Buffer size must have changed between calls; check again. temp_size = 0 elif size_or_code > 0 and temp_size == 0: # Buffer size obtained, use to retrieve data. temp_size = size_or_code else: break check_for_error(size_or_code) return unflatten_channel_string(val.value.decode('ascii'))