From a5b4b5b40222dd9bf7256438fe390937fec10c6e Mon Sep 17 00:00:00 2001
From: Paul McCarthy <pauld.mccarthy@gmail.com>
Date: Thu, 18 May 2017 18:38:53 +0100
Subject: [PATCH] New method on Nifti class, to retrieve strings from nifti
headers (moved here from fsleyes OverlayInfoPanel)
---
fsl/data/image.py | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/fsl/data/image.py b/fsl/data/image.py
index e88aba1b1..0b191d95c 100644
--- a/fsl/data/image.py
+++ b/fsl/data/image.py
@@ -34,6 +34,7 @@ and file names:
import os
import os.path as op
+import string
import logging
import six
@@ -290,6 +291,33 @@ class Nifti(notifier.Notifier):
return origShape, shape, pixdims
+ def strval(self, key):
+ """Returns the specified NIFTI header field, converted to a python
+ string, correctly null-terminated, and with non-printable characters
+ removed.
+
+ This method is used to sanitise some NIFTI header fields. The default
+ Python behaviour for converting a sequence of bytes to a string is to
+ strip all termination characters (bytes with value of ``0x00``) from
+ the end of the sequence.
+
+ This default behaviour does not handle the case where a sequence of
+ bytes which did contain a long string is subsequently overwritten with
+ a shorter string - the short string will be terminated, but that
+ termination character will be followed by the remainder of the
+ original string.
+ """
+
+ val = self.header[key]
+
+ try: val = bytes(val).partition(b'\0')[0]
+ except: val = bytes(val)
+
+ val = val.decode('ascii')
+
+ return ''.join([c for c in val if c in string.printable])
+
+
@property
def niftiVersion(self):
"""Returns the NIFTI file version:
--
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