abstracted similar digit range classes in POSIXUsers/GroupPatterns into Bcfg2.Utils

1 files changed, 67 insertions, 0 deletions

diff --git a/src/lib/Bcfg2/Utils.py b/src/lib/Bcfg2/Utils.py
new file mode 100644
index 000000000..ba17e1a63
--- /dev/null
+++ b/src/lib/Bcfg2/Utils.py
@@ -0,0 +1,67 @@
+""" Miscellaneous useful utility functions, classes, etc., that are
+used by both client and server.  Stuff that doesn't fit anywhere
+else. """
+
+from Bcfg2.Compat import any  # pylint: disable=W0622
+
+
+class PackedDigitRange(object):
+    """ Representation of a set of integer ranges. A range is
+    described by a comma-delimited string of integers and ranges,
+    e.g.::
+
+        1,10-12,15-20
+
+    Ranges are inclusive on both bounds, and may include 0.  Negative
+    numbers are not supported."""
+
+    def __init__(self, *ranges):
+        """ May be instantiated in one of two ways::
+
+            PackedDigitRange(<comma-delimited list of ranges>)
+
+        Or::
+
+            PackedDigitRange(<int_or_range>[, <int_or_range>[, ...]])
+
+        E.g., both of the following are valid::
+
+            PackedDigitRange("1-5,7, 10-12")
+            PackedDigitRange("1-5", 7, "10-12")
+        """
+        self.ranges = []
+        self.ints = []
+        self.str = ",".join(str(r) for r in ranges)
+        if len(ranges) == 1 and "," in ranges[0]:
+            ranges = ranges[0].split(",")
+        for item in ranges:
+            item = str(item).strip()
+            if item.endswith("-"):
+                self.ranges.append((int(item[:-1]), None))
+            elif '-' in str(item):
+                self.ranges.append(tuple(int(x) for x in item.split('-')))
+            else:
+                self.ints.append(int(item))
+
+    def includes(self, other):
+        """ Return True if ``other`` is included in this range.
+        Functionally equivalent to ``other in range``, which should be
+        used instead. """
+        return other in self
+
+    def __contains__(self, other):
+        other = int(other)
+        if other in self.ints:
+            return True
+        return any((end is None and other >= start) or
+                   (end is not None and other >= start and other <= end)
+                   for start, end in self.ranges)
+
+    def __repr__(self):
+        return "%s:%s" % (self.__class__.__name__, str(self))
+
+    def __str__(self):
+        return "[%s]" % self.str
+
+    def __len__(self):
+        return sum(r[1] - r[0] + 1 for r in self.ranges) + len(self.ints)