Moved version number utility functions from FSLeyes into fslpy. And removed

hotfixes - the patch number will be used for maintenance releases.

fsl/version.py

@@ -4,13 +4,76 @@
 #
 # Author: Paul McCarthy <pauldmccarthy@gmail.com>
 #
-"""The sole purpose of this module is as a container for the ``fslpy``
-version number and information.
+"""The primary purpose of this module is as a container for the ``fslpy``
+version number. A couple of conveniense functions for comparing version
+numbers are also defined here.
 
 .. autosummary::
+   :nosignatures:
 
    __version__
+   parseVersionString
+   compareVersions
+
+
+The ``fslpy`` version number consists of three numbers, separated by a period,
+which roughly obeys the Semantic Versioning conventions (http://semver.org/):
+
+ 1. The major release number. This gets updated for major/external releases.
+
+ 2. The minor release number. This gets updated for minor/internal releases,
+    which involve new features, bug-fixes, and other updates.
+
+ 3. The point release number. This gets updated for minor/internal releases,
+    which primarily involve bug-fixes and minor changes.
 """
 
 __version__ = '1.0.0'
 """Current version number, as a string. """
+
+
+def parseVersionString(versionString):
+    """Parses the given version string, and returns a tuple containing
+    the individual components of the version number (see the description
+    of the :attr:`__version__` attribute).
+
+    An error is raised if the ``versionString`` is invalid.
+    """
+
+    components = versionString.split('.')
+
+    # Major, minor, and point
+    # version are always numeric
+    major, minor, point = [int(c) for c in components]
+
+    return major, minor, point
+
+
+def compareVersions(v1, v2, ignorePoint=False):
+    """Compares the given ``fslpy`` version numbers.
+
+    :arg v1:          Version number to compare
+    :arg v2:          Version number to compare
+    :arg ignorePoint: Defaults to ``False``. If ``True``, the point release
+                      numbers are ignored in the comparison.
+
+    :returns: One of the following:
+
+                - -1 if ``v1`` < ``v2`` (i.e. ``v1`` is older than ``v2``)
+                -  0 if ``v1`` == ``v2``
+                -  0 if ``v1`` > ``v2``
+    """
+
+    v1 = parseVersionString(v1)
+    v2 = parseVersionString(v2)
+
+    if ignorePoint:
+        v1 = v1[:2]
+        v2 = v2[:2]
+
+    for p1, p2 in zip(v1, v2):
+
+        if p1 > p2: return  1
+        if p1 < p2: return -1
+
+    return 0