/usr/lib/python2.7/dist-packages/dicom/valuerep.py is in python-dicom 0.9.7-1.1ubuntu1.
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"""Special classes for DICOM value representations (VR)"""
# Copyright (c) 2008-2012 Darcy Mason
# This file is part of pydicom, released under a modified MIT license.
# See the file license.txt included with this distribution, also
# available at http://pydicom.googlecode.com
from decimal import Decimal
import dicom.config
from dicom.multival import MultiValue
from sys import version_info
if version_info[0] < 3:
namebase = object
bytestring = str
strbase = str
else:
namebase = bytestring
strbase = basestring
def is_stringlike(name):
"""Return True if name is string-like."""
try:
name + ""
except TypeError:
return False
else:
return True
def clean_escseq(element, encodings):
"""Remove escape sequences that Python does not remove from
Korean encoding ISO 2022 IR 149 due to the G1 code element.
"""
if 'euc_kr' in encodings:
return element.replace(
"\x1b\x24\x29\x43", "").replace("\x1b\x28\x42", "")
else:
return element
class DS(Decimal):
"""Store values for DICOM VR of DS (Decimal String).
Note: if constructed by an empty string, returns the empty string,
not an instance of this class.
"""
def __new__(cls, val):
"""Create an instance of DS object, or return a blank string if one is
passed in, e.g. from a type 2 DICOM blank value.
"""
# DICOM allows spaces around the string, but python doesn't, so clean it
if isinstance(val, strbase):
val=val.strip()
if val == '':
return val
if isinstance(val, float) and not dicom.config.allow_DS_float:
msg = ("DS cannot be instantiated with a float value, unless "
"config.allow_DS_float is set to True. It is recommended to "
"convert to a string instead, with the desired number of digits, "
"or use Decimal.quantize and pass a Decimal instance.")
raise TypeError, msg
if not isinstance(val, Decimal):
val = super(DS, cls).__new__(cls, val)
if len(str(val)) > 16 and dicom.config.enforce_valid_values:
msg = ("DS value representation must be <= 16 characters by DICOM "
"standard. Initialize with a smaller string, or set config.enforce_valid_values "
"to False to override, "
"or use Decimal.quantize() and initialize with a Decimal instance.")
raise OverflowError, msg
return val
def __init__(self, val):
"""Store the original string if one given, for exact write-out of same
value later. E.g. if set '1.23e2', Decimal would write '123', but DS
will use the original
"""
# ... also if user changes a data element value, then will get
# a different Decimal, as Decimal is immutable.
if isinstance(val, strbase):
self.original_string = val
def __repr__(self):
if hasattr(self, 'original_string'):
return "'" + self.original_string + "'"
else:
return "'" + super(DS,self).__str__() + "'"
class IS(int):
"""Derived class of int. Stores original integer string for exact rewriting
of the string originally read or stored.
Don't use this directly; call the IS() factory function instead.
"""
# Unlikely that str(int) will not be the same as the original, but could happen
# with leading zeros.
def __new__(cls, val):
"""Create instance if new integer string"""
if isinstance(val, strbase) and val.strip() == '':
return ''
newval = super(IS, cls).__new__(cls, val)
# check if a float or Decimal passed in, then could have lost info,
# and will raise error. E.g. IS(Decimal('1')) is ok, but not IS(1.23)
if isinstance(val, (float, Decimal)) and newval != val:
raise TypeError, "Could not convert value to integer without loss"
# Checks in case underlying int is >32 bits, DICOM does not allow this
if (newval < -2**31 or newval >= 2**31) and dicom.config.enforce_valid_values:
message = "Value exceeds DICOM limits of -2**31 to (2**31 - 1) for IS"
raise OverflowError, message
return newval
def __init__(self, val):
# If a string passed, then store it
if isinstance(val, basestring):
self.original_string = val
def __repr__(self):
if hasattr(self, 'original_string'):
return "'" + self.original_string + "'"
else:
return "'" + int.__str__(self) + "'"
def MultiString(val, valtype=str):
"""Split a string by delimiters if there are any
val -- DICOM string to split up
valtype -- default str, but can be e.g. UID to overwrite to a specific type
"""
# Remove trailing blank used to pad to even length
# 2005.05.25: also check for trailing 0, error made in PET files we are converting
if val and (val.endswith(' ') or val.endswith('\x00')):
val = val[:-1]
# XXX --> simpler version python > 2.4 splitup = [valtype(x) if x else x for x in val.split("\\")]
splitup = []
for subval in val.split("\\"):
if subval:
splitup.append(valtype(subval))
else:
splitup.append(subval)
if len(splitup) == 1:
return splitup[0]
else:
return MultiValue(valtype, splitup)
class PersonNameBase(namebase):
"""Base class for Person Name classes"""
def __init__(self, val):
"""Initialize the PN properties"""
# Note normally use __new__ on subclassing an immutable, but here we just want
# to do some pre-processing for properties
# PS 3.5-2008 section 6.2 (p.28) and 6.2.1 describes PN. Briefly:
# single-byte-characters=ideographic characters=phonetic-characters
# (each with?):
# family-name-complex^Given-name-complex^Middle-name^name-prefix^name-suffix
self.parse()
def formatted(self, format_str):
"""Return a formatted string according to the format pattern
Use "...%(property)...%(property)..." where property is one of
family_name, given_name, middle_name, name_prefix, name_suffix
"""
return format_str % self.__dict__
def parse(self):
"""Break down the components and name parts"""
self.components = self.split("=")
nComponents = len(self.components)
self.single_byte = self.components[0]
self.ideographic = ''
self.phonetic = ''
if nComponents > 1:
self.ideographic = self.components[1]
if nComponents > 2:
self.phonetic = self.components[2]
if self.single_byte:
name_string = self.single_byte+"^^^^" # in case missing trailing items are left out
parts = name_string.split("^")[:5]
(self.family_name, self.given_name, self.middle_name,
self.name_prefix, self.name_suffix) = parts
else:
(self.family_name, self.given_name, self.middle_name,
self.name_prefix, self.name_suffix) = ('', '', '', '', '')
class PersonName(PersonNameBase, str):
"""Human-friendly class to hold VR of Person Name (PN)
Name is parsed into the following properties:
single-byte, ideographic, and phonetic components (PS3.5-2008 6.2.1)
family_name,
given_name,
middle_name,
name_prefix,
name_suffix
"""
def __new__(cls, val):
"""Return instance of the new class"""
# Check if trying to convert a string that has already been converted
if isinstance(val, PersonName):
return val
return super(PersonName, cls).__new__(cls, val)
def family_comma_given(self):
"""Return name as 'Family-name, Given-name'"""
return self.formatted("%(family_name)s, %(given_name)s")
# def __str__(self):
# return str(self.byte_string)
# XXX need to process the ideographic or phonetic components?
# def __len__(self):
# return len(self.byte_string)
class PersonNameUnicode(PersonNameBase, unicode):
"""Unicode version of Person Name"""
def __new__(cls, val, encodings):
"""Return unicode string after conversion of each part
val -- the PN value to store
encodings -- a list of python encodings, generally found
from dicom.charset.python_encodings mapping
of values in DICOM data element (0008,0005).
"""
# Make the possible three character encodings explicit:
if not isinstance(encodings, list):
encodings = [encodings]*3
if len(encodings) == 2:
encodings.append(encodings[1])
components = val.split("=")
# Remove the first encoding if only one component is present
if (len(components) == 1):
del encodings[0]
unicomponents = [clean_escseq(
unicode(components[i],encodings[i]), encodings)
for i, component in enumerate(components)]
new_val = u"=".join(unicomponents)
return unicode.__new__(cls, new_val)
def __init__(self, val, encodings):
self.encodings = encodings
PersonNameBase.__init__(self, val)
def family_comma_given(self):
"""Return name as 'Family-name, Given-name'"""
return self.formatted("%(family_name)u, %(given_name)u")
class OtherByte(bytestring):
pass
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