/usr/lib/python2.7/dist-packages/pyvisa/util.py is in python-pyvisa 1.8-2.
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"""
pyvisa.util
~~~~~~~~~~~
General utility functions.
This file is part of PyVISA.
:copyright: 2014 by PyVISA Authors, see AUTHORS for more details.
:license: MIT, see LICENSE for more details.
"""
from __future__ import division, unicode_literals, print_function, absolute_import
import functools
import io
import os
import platform
import sys
import subprocess
import warnings
from .compat import check_output, string_types, OrderedDict, struct
from . import __version__, logger
def read_user_library_path():
"""Return the library path stored in one of the following configuration files:
<sys prefix>/share/pyvisa/.pyvisarc
~/.pyvisarc
<sys prefix> is the site-specific directory prefix where the platform
independent Python files are installed.
Example configuration file:
[Paths]
visa library=/my/path/visa.so
Return `None` if configuration files or keys are not present.
"""
try:
from ConfigParser import SafeConfigParser as ConfigParser, NoSectionError
except ImportError:
from configparser import ConfigParser, NoSectionError
config_parser = ConfigParser()
files = config_parser.read([os.path.join(sys.prefix, "share", "pyvisa", ".pyvisarc"),
os.path.join(os.path.expanduser("~"), ".pyvisarc")])
if not files:
logger.debug('No user defined library files')
return None
logger.debug('User defined library files: %s' % files)
try:
return config_parser.get("Paths", "visa library")
except (KeyError, NoSectionError):
logger.debug('KeyError or NoSectionError while reading config file')
return None
class LibraryPath(str):
#: Architectural information (32, ) or (64, ) or (32, 64)
_arch = None
def __new__(cls, path, found_by='auto'):
obj = super(LibraryPath, cls).__new__(cls, path)
obj.path = path
obj.found_by = found_by
return obj
@property
def arch(self):
if self._arch is None:
try:
self._arch = get_arch(self.path)
except:
self._arch = tuple()
return self._arch
@property
def is_32bit(self):
if not self.arch:
return 'n/a'
return 32 in self.arch
@property
def is_64bit(self):
if not self.arch:
return 'n/a'
return 64 in self.arch
@property
def bitness(self):
if not self.arch:
return 'n/a'
return ', '.join(str(a) for a in self.arch)
def warn_for_invalid_kwargs(keyw, allowed_keys):
for key in keyw.keys():
if key not in allowed_keys:
warnings.warn('Keyword argument "%s" unknown' % key, stacklevel=3)
def filter_kwargs(keyw, selected_keys):
result = {}
for key, value in keyw.items():
if key in selected_keys:
result[key] = value
return result
def split_kwargs(keyw, self_keys, parent_keys, warn=True):
self_kwargs = dict()
parent_kwargs = dict()
self_keys = set(self_keys)
parent_keys = set(parent_keys)
all_keys = self_keys | parent_keys
for key, value in keyw.items():
if warn and key not in all_keys:
warnings.warn('Keyword argument "%s" unknown' % key, stacklevel=3)
if key in self_keys:
self_kwargs[key] = value
if key in parent_keys:
parent_kwargs[key] = value
return self_kwargs, parent_kwargs
_converters = {
's': str,
'b': functools.partial(int, base=2),
'c': chr,
'd': int,
'o': functools.partial(int, base=8),
'x': functools.partial(int, base=16),
'X': functools.partial(int, base=16),
'e': float,
'E': float,
'f': float,
'F': float,
'g': float,
'G': float,
}
def from_ascii_block(ascii_data, converter='f', separator=',', container=list):
"""Parse ascii data and return an iterable of numbers.
:param ascii_data: data to be parsed.
:type ascii_data: str
:param converter: function used to convert each value.
Defaults to float
:type converter: callable
:param separator: a callable that split the str into individual elements.
If a str is given, data.split(separator) is used.
:type: separator: (str) -> collections.Iterable[T] | str
:param container: container type to use for the output data.
"""
if isinstance(converter, string_types):
try:
converter = _converters[converter]
except KeyError:
raise ValueError('Invalid code for converter: %s not in %s' % (converter, str(tuple(_converters.keys()))))
if isinstance(separator, string_types):
data = ascii_data.split(separator)
else:
data = separator(ascii_data)
return container([converter(raw_value) for raw_value in data])
def to_ascii_block(iterable, converter='f', separator=','):
"""Parse ascii data and return an iterable of numbers.
:param iterable: data to be parsed.
:type iterable: collections.Iterable[T]
:param converter: function used to convert each value.
String formatting codes are also accepted.
Defaults to str.
:type converter: callable | str
:param separator: a callable that split the str into individual elements.
If a str is given, data.split(separator) is used.
:type: separator: (collections.Iterable[T]) -> str | str
"""
if isinstance(separator, string_types):
separator = separator.join
if isinstance(converter, string_types):
converter = '%' + converter
return separator(converter % val for val in iterable)
else:
return separator(converter(val) for val in iterable)
def parse_binary(bytes_data, is_big_endian=False, is_single=False):
"""Parse ascii data and return an iterable of numbers.
To be deprecated in 1.7
:param bytes_data: data to be parsed.
:param is_big_endian: boolean indicating the endianness.
:param is_single: boolean indicating the type (if not is double)
:return:
"""
data = bytes_data
hash_sign_position = bytes_data.find(b"#")
if hash_sign_position == -1:
raise ValueError('Could not find valid hash position')
if hash_sign_position > 0:
data = data[hash_sign_position:]
data_1 = data[1:2].decode('ascii')
if data_1.isdigit() and int(data_1) > 0:
number_of_digits = int(data_1)
# I store data and data_length in two separate variables in case
# that data is too short. FixMe: Maybe I should raise an error if
# it's too long and the trailing part is not just CR/LF.
data_length = int(data[2:2 + number_of_digits])
data = data[2 + number_of_digits:2 + number_of_digits + data_length]
else:
data = data[2:]
if data[-1:].decode('ascii') == "\n":
data = data[:-1]
data_length = len(data)
if is_big_endian:
endianess = ">"
else:
endianess = "<"
try:
if is_single:
fmt = endianess + str(data_length // 4) + 'f'
else:
fmt = endianess + str(data_length // 8) + 'd'
result = list(struct.unpack(fmt, data))
except struct.error:
raise ValueError("Binary data itself was malformed")
return result
def parse_ieee_block_header(block):
"""Parse the header of a IEEE block.
Definite Length Arbitrary Block:
#<header_length><data_length><data>
The header_length specifies the size of the data_length field.
And the data_length field specifies the size of the data.
Indefinite Length Arbitrary Block:
#0<data>
:param block: IEEE block.
:type block: bytes
:return: (offset, data_length)
:rtype: (int, int)
"""
begin = block.find(b'#')
if begin < 0:
raise ValueError("Could not find hash sign (#) indicating the start of the block.")
try:
# int(block[begin+1]) != int(block[begin+1:begin+2]) in Python 3
header_length = int(block[begin+1:begin+2])
except ValueError:
header_length = 0
offset = begin + 2 + header_length
if header_length > 0:
# #3100DATA
# 012345
data_length = int(block[begin+2:offset])
else:
# #0DATA
# 012
data_length = len(block) - offset - 1
return offset, data_length
def from_ieee_block(block, datatype='f', is_big_endian=False, container=list):
"""Convert a block in the IEEE format into an iterable of numbers.
Definite Length Arbitrary Block:
#<header_length><data_length><data>
The header_length specifies the size of the data_length field.
And the data_length field specifies the size of the data.
Indefinite Length Arbitrary Block:
#0<data>
:param block: IEEE block.
:type block: bytes
:param datatype: the format string for a single element. See struct module.
:param is_big_endian: boolean indicating endianess.
:param container: container type to use for the output data.
:return: items
:rtype: type(container)
"""
offset, data_length = parse_ieee_block_header(block)
if len(block) < offset + data_length:
raise ValueError("Binary data is incomplete. The header states %d data bytes, "
"but %d where received." % (data_length, len(block) - offset))
return from_binary_block(block, offset, data_length, datatype, is_big_endian, container)
def from_binary_block(block, offset=0, data_length=None, datatype='f', is_big_endian=False, container=list):
"""Convert a binary block into an iterable of numbers.
:param block: binary block.
:type block: bytes
:param offset: offset at which the data block starts (default=0)
:param data_length: size in bytes of the data block (default=len(block) - offset)
:param datatype: the format string for a single element. See struct module.
:param is_big_endian: boolean indicating endianess.
:param container: container type to use for the output data.
:return: items
:rtype: type(container)
"""
if data_length is None:
data_length = len(block) - offset
element_length = struct.calcsize(datatype)
array_length = int(data_length / element_length)
endianess = '>' if is_big_endian else '<'
fullfmt = '%s%d%s' % (endianess, array_length, datatype)
try:
return container(struct.unpack_from(fullfmt, block, offset))
except struct.error:
raise ValueError("Binary data was malformed")
def to_ieee_block(iterable, datatype='f', is_big_endian=False):
"""Convert an iterable of numbers into a block of data in the IEEE format.
:param iterable: an iterable of numbers.
:param datatype: the format string for a single element. See struct module.
:param is_big_endian: boolean indicating endianess.
:return: IEEE block.
:rtype: bytes
"""
array_length = len(iterable)
element_length = struct.calcsize(datatype)
data_length = array_length * element_length
header = '%d' % data_length
header = '#%d%s'%(len(header),header)
endianess = '>' if is_big_endian else '<'
fullfmt = '%s%d%s' % (endianess, array_length, datatype)
if sys.version >= '3':
return bytes(header, 'ascii') + struct.pack(fullfmt, *iterable)
else:
return str(header) + struct.pack(fullfmt, *iterable)
def get_system_details(backends=True):
"""Return a dictionary with information about the system
"""
buildno, builddate = platform.python_build()
if sys.maxunicode == 65535:
# UCS2 build (standard)
unitype = 'UCS2'
else:
# UCS4 build (most recent Linux distros)
unitype = 'UCS4'
bits, linkage = platform.architecture()
d = {
'platform': platform.platform(),
'processor': platform.processor(),
'executable': sys.executable,
'implementation': getattr(platform, 'python_implementation',
lambda: 'n/a')(),
'python': platform.python_version(),
'compiler': platform.python_compiler(),
'buildno': buildno,
'builddate': builddate,
'unicode': unitype,
'bits': bits,
'pyvisa': __version__,
'backends': OrderedDict()
}
if backends:
from . import highlevel
for backend in highlevel.list_backends():
if backend.startswith('pyvisa-'):
backend = backend[7:]
try:
cls = highlevel.get_wrapper_class(backend)
except Exception as e:
d['backends'][backend] = ['Could not instantiate backend',
'-> %s' % str(e)]
continue
try:
d['backends'][backend] = cls.get_debug_info()
except Exception as e:
d['backends'][backend] = ['Could not obtain debug info',
'-> %s' % str(e)]
return d
def system_details_to_str(d, indent=''):
"""Return a str with the system details.
"""
l = ['Machine Details:',
' Platform ID: %s' % d.get('platform', 'n/a'),
' Processor: %s' % d.get('processor', 'n/a'),
'',
'Python:',
' Implementation: %s' % d.get('implementation', 'n/a'),
' Executable: %s' % d.get('executable', 'n/a'),
' Version: %s' % d.get('python', 'n/a'),
' Compiler: %s' % d.get('compiler', 'n/a'),
' Bits: %s' % d.get('bits', 'n/a'),
' Build: %s (#%s)' % (d.get('builddate', 'n/a'),
d.get('buildno', 'n/a')),
' Unicode: %s' % d.get('unicode', 'n/a'),
'',
'PyVISA Version: %s' % d.get('pyvisa', 'n/a'),
'',
]
def _to_list(key, value, indent_level=0):
sp = ' ' * indent_level * 3
if isinstance(value, string_types):
if key:
return ['%s%s: %s' % (sp, key, value)]
else:
return ['%s%s' % (sp, value)]
elif isinstance(value, dict):
if key:
al = ['%s%s:' % (sp, key)]
else:
al = []
for k, v in value.items():
al.extend(_to_list(k, v, indent_level+1))
return al
elif isinstance(value, (tuple, list)):
if key:
al = ['%s%s:' % (sp, key)]
else:
al = []
for v in value:
al.extend(_to_list(None, v, indent_level+1))
return al
l.extend(_to_list('Backends', d['backends']))
joiner = '\n' + indent
return indent + joiner.join(l) + '\n'
def get_debug_info(to_screen=True):
out = system_details_to_str(get_system_details())
if not to_screen:
return out
print(out)
def pip_install(package):
try:
# noinspection PyPackageRequirements,PyUnresolvedReferences
import pip
return pip.main(['install', package])
except ImportError:
print(system_details_to_str(get_system_details()))
raise RuntimeError('Please install pip to continue.')
machine_types = {
0: 'UNKNOWN',
0x014c: 'I386',
0x0162: 'R3000',
0x0166: 'R4000',
0x0168: 'R10000',
0x0169: 'WCEMIPSV2',
0x0184: 'ALPHA',
0x01a2: 'SH3',
0x01a3: 'SH3DSP',
0x01a4: 'SH3E',
0x01a6: 'SH4',
0x01a8: 'SH5',
0x01c0: 'ARM',
0x01c2: 'THUMB',
0x01c4: 'ARMNT',
0x01d3: 'AM33',
0x01f0: 'POWERPC',
0x01f1: 'POWERPCFP',
0x0200: 'IA64',
0x0266: 'MIPS16',
0x0284: 'ALPHA64',
#0x0284: 'AXP64', # same
0x0366: 'MIPSFPU',
0x0466: 'MIPSFPU16',
0x0520: 'TRICORE',
0x0cef: 'CEF',
0x0ebc: 'EBC',
0x8664: 'AMD64',
0x9041: 'M32R',
0xc0ee: 'CEE',
}
def get_shared_library_arch(filename):
with io.open(filename, 'rb') as fp:
dos_headers = fp.read(64)
_ = fp.read(4)
magic, skip, offset = struct.unpack(str('2s58sl'), dos_headers)
if magic != b'MZ':
raise Exception('Not an executable')
fp.seek(offset, io.SEEK_SET)
pe_header = fp.read(6)
sig, skip, machine = struct.unpack(str('2s2sH'), pe_header)
if sig != b'PE':
raise Exception('Not a PE executable')
return machine_types.get(machine, 'UNKNOWN')
def get_arch(filename):
this_platform = sys.platform
if this_platform.startswith('win'):
machine_type = get_shared_library_arch(filename)
if machine_type == 'I386':
return 32,
elif machine_type in ('IA64', 'AMD64'):
return 64,
else:
return ()
elif not this_platform in ('linux2', 'linux3', 'linux', 'darwin'):
raise OSError('')
out = check_output(["file", filename], stderr=subprocess.STDOUT)
out = out.decode('ascii')
ret = []
if this_platform.startswith('linux'):
if '32-bit' in out:
ret.append(32)
if '64-bit' in out:
ret.append(64)
elif this_platform == 'darwin':
if '(for architecture i386)' in out:
ret.append(32)
if '(for architecture x86_64)' in out:
ret.append(64)
return tuple(ret)
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