def test_constructor(self): """Tests that fromAtom can create empty intervals.""" a = Interval.fromAtom(0, 0) b = Interval.fromAtom(10, 0) self.assertEqual(a, b) self.assertEqual(a, Interval()) self.assertEqual(a, Interval.fromAtoms([(0, 0), (5, 0)]))
def test_len(self):
"""Specifically test len. This is also being tested in the object invariant
throughout the entire test suite so we just do a quick one here."""
a = Interval.fromAtom(3, 3)
b = Interval.fromAtom(9, 5)
self.assertEqual(len(a) + len(b), len(a.union(b)))
self.assertEqual(len(a), 3)
self.assertEqual(len(b), 5)
self.assertEqual(len(Interval()), 0)
def test_union_overlap_compound(self):
"""Test some compound cases of union with overlap."""
a = Interval.fromAtoms([(5, 10), (20, 10), (50, 50)])
b = Interval.fromAtoms([(0, 8), (10, 15), (28, 82)])
self.assertEqual(a.union(b, True), b.union(a, True))
self.assertEqual(a.union(b, True), Interval.fromAtom(0, 110))
b = Interval.fromAtoms([(0, 8), (28, 82)])
self.assertEqual(a.union(b, True), Interval.fromAtoms([(0, 15), (20, 90)]))
def test_union_empty(self): """Test that empty intervals are well behaved.""" a = Interval() b = Interval() c = a.union(b) d = b.union(a) self.assertEqual(a, b) self.assertEqual(b, c) self.assertEqual(c, d)
def test_union_merge_start_nonzero(self):
"""Tests merges for several coumpound intervals, all starting after 0
(regression test against special-case bug)"""
a = Interval.fromAtoms([(1, 2), (5, 2), (9, 2)])
b = Interval.fromAtoms([(3, 2), (7, 1)])
a_b = a.union(b)
self.assertEqual(a_b, Interval.fromAtoms([(1, 7), (9, 2)]))
a_b_c = Interval.fromAtom(8, 1).union(a_b)
self.assertEqual(a_b_c, Interval.fromAtom(1, 10))
self.assertEqual(len(a_b_c), 10)
def test_union_sym_comm(self):
"""Test that union is symmetric and commutative."""
ivals = [Interval(), Interval.fromAtom(4, 2), Interval.fromAtom(6, 3), \
Interval.fromAtom(11, 2), Interval.fromAtom(13, 15)]
# If this were much larger we could use a prefix generator but I prefer
# simplicity to speed in tests.
correct = _union_multi(ivals)
for iv in itertools.permutations(ivals):
self.assertEqual(correct, _union_multi(iv))
def test_min_max(self):
"""Test the min and max of the interval."""
atoms = [(0, 2), (8, 2), (4, 2)]
ival = Interval.fromAtoms(atoms)
self.assertEquals(ival.min(), 0)
self.assertEquals(ival.max(), 9)
ival = Interval.fromAtom(5, 1)
self.assertEquals(ival.min(), 5)
self.assertEquals(ival.max(), 5)
ival = Interval()
self.assertIsNone(ival.min())
self.assertIsNone(ival.max())
def test_union_overlap_symmetry(self):
"""Test that the order does not matter."""
for (a, b) in [(Interval.fromAtom(5, 10), Interval.fromAtom(10, 10)),
(Interval.fromAtom(5, 5), Interval.fromAtom(5, 15)),
(Interval.fromAtom(5, 20), Interval.fromAtom(10, 15)),
(Interval.fromAtom(10, 5), Interval.fromAtom(5, 15))]:
self.assertEqual(a.union(b, allow_overlap=True),
b.union(a, allow_overlap=True))
def test_union_merge_start_zero(self):
"""Tests merges for several coumpound intervals, all start at 0."""
# Simple case with an extra hole in the original spec.
a = Interval.fromAtoms([(0, 2), (4, 2), (6, 2)])
b = Interval.fromAtoms([(2, 2)])
self.assertEqual(a.union(b), Interval.fromAtom(0, 8))
# Holes filled partially
a = Interval.fromAtoms([(0, 2), (4, 2), (8, 2), (20, 3)])
b = Interval.fromAtoms([(2, 1), (6, 1), (10, 5), (16, 4)])
a_b = a.union(b)
self.assertEqual(Interval.fromAtoms([(0, 3), (4, 3), (8, 7), (16, 7)]), a_b)
a_b_c = a_b.union(Interval.fromAtoms([(3, 1), (7, 1)]))
self.assertEqual(Interval.fromAtoms([(0, 15), (16, 7)]), a_b_c)
a_b_c_d = a_b_c.union(Interval.fromAtom(15, 1))
self.assertEqual(Interval.fromAtom(0, 23), a_b_c_d)
self.assertEqual(len(a_b_c_d), 23)
def test_eq_neq(self):
"""Makes sure equality and inequality work, since all other tests depend on
them. I test many values because Python's default eq/neq behavion can
be weird and miss edge cases."""
# The other tests thoroughly test eq == true, so I focus on eq == false and
# both values of ne.
a = Interval.fromAtoms([(0, 2), (4, 2), (8, 2)])
empty = Interval()
self.assertFalse(a == Interval.fromAtoms([(0, 2)]))
self.assertTrue(a != Interval.fromAtoms([(0, 2)]))
self.assertTrue(a == a)
self.assertFalse(a != a)
self.assertFalse(a == empty)
self.assertTrue(a != empty)
self.assertTrue(empty == Interval())
self.assertFalse(empty != Interval())
self.assertTrue(empty == empty)
self.assertFalse(empty != empty)
b = Interval.fromAtoms([(0, 2), (4, 2), (6, 2)])
c = Interval.fromAtoms([(0, 2), (4, 4)])
self.assertTrue(b == c)
self.assertFalse(b != c)
self.assertFalse(b != b)
self.assertTrue(b == b)
self.assertFalse(c != c)
self.assertTrue(c == Interval.fromAtoms([(0, 2), (4, 4)]))
def __init__(self, filename, size, subdir):
# Total size of the file
self.size = size
# Number of bytes in the file that have been used already.
self.used = 0
# Relative name of the file.
self.filename = filename
# Regions of the file in use.
self._extents = Interval()
# Subdir the file is currently in.
self.subdir = subdir
def getAllocation(self, requested):
"""Requests an allocation from the file of the given size. Raises OutOfPad
if the file is out of space."""
if requested > self.free:
raise OutOfPad("File %s has %i bytes but you requested %i." % \
(self.filename, self.free, requested))
alloc = Allocation()
for (start, length) in self._extents.iterExterior(self.size):
interval = Interval.fromAtom(start, min(requested - len(alloc), length))
seg = Allocation(self, interval)
alloc.unionUpdate(seg)
if len(alloc) >= requested:
assert len(alloc) == requested
break
assert len(alloc) == requested
return alloc
def test_iterExterior(self):
"""Tests the iterExterior method."""
atoms = [(0, 2), (4, 2), (8, 2)]
ival = Interval.fromAtoms(atoms)
self.assertEquals(list(ival.iterExterior()), [(2, 2), (6, 2)])
self.assertEquals(list(ival.iterExterior(10)), [(2, 2), (6, 2)])
self.assertRaises(AssertionError, lambda: list(ival.iterExterior(9)))
self.assertEquals(list(ival.iterExterior(11)), [(2, 2), (6, 2), (10, 1)])
self.assertEquals(list(ival.iterExterior(3000)), [(2, 2), (6, 2), (10, 2990)])
# Length identities
cmpl = Interval.fromAtoms(ival.iterExterior(50))
self.assertEquals(len(cmpl) + len(ival), 50)
self.assertEquals(cmpl.union(ival), Interval.fromAtom(0, 50))
empty = Interval()
for length in (0, 1, 2, 5):
self.assertEquals(len(Interval.fromAtoms(empty.iterExterior(length))), \
length)
ival = Interval.fromAtom(0, 1)
for length in (1, 2, 5):
self.assertEquals(len(Interval.fromAtoms(ival.iterExterior(length))), \
length - 1)
class File(object):
"""Holds data on what parts of a file have already been used."""
__metaclass__ = invariant.EnforceInvariant
def __init__(self, filename, size, subdir):
# Total size of the file
self.size = size
# Number of bytes in the file that have been used already.
self.used = 0
# Relative name of the file.
self.filename = filename
# Regions of the file in use.
self._extents = Interval()
# Subdir the file is currently in.
self.subdir = subdir
def _checkInvariant(self):
assert self.size >= self.used
assert len(self._extents) == self.used
@property
def free(self):
return self.size - self.used
@property
def path(self):
"""Returns the path of the padfile relative to the paddir."""
return (self.subdir, self.filename)
def getAllocation(self, requested):
"""Requests an allocation from the file of the given size. Raises OutOfPad
if the file is out of space."""
if requested > self.free:
raise OutOfPad("File %s has %i bytes but you requested %i." % \
(self.filename, self.free, requested))
alloc = Allocation()
for (start, length) in self._extents.iterExterior(self.size):
interval = Interval.fromAtom(start, min(requested - len(alloc), length))
seg = Allocation(self, interval)
alloc.unionUpdate(seg)
if len(alloc) >= requested:
assert len(alloc) == requested
break
assert len(alloc) == requested
return alloc
def commitAllocation(self, ival):
"""Mark the specified interval as used. Error if overlaps with currently
used area."""
self._extents = self._extents.union(ival)
self.used += len(ival)
def consumeEntireFile(self):
"""Mark the entire file as consumed. Used to prevent its use for encryption
while keeping it around for decryption."""
self.used = self.size
self._extents = Interval.fromAtom(0, self.size)
def fromSerializationState(klass, state):
"""See Allocation.toSerializationState"""
self = klass()
for (filename, atoms) in state:
self.unionUpdate(Allocation(filename, Interval.fromAtoms(atoms)))
return self
def test_constructor_equiv(self):
"""Make sure the from* constructors are equivalent. (Default is tested
with union)."""
a = Interval.fromAtom(3, 4).union(Interval.fromAtom(12, 10))
b = Interval.fromAtoms([(3, 4), (12, 10)])
self.assertEqual(a, b)
c = Interval.fromAtom(3, 4).union(Interval.fromAtom(7, 10))
d = Interval.fromAtoms([(7, 10), (3, 4)])
e = Interval.fromAtom(3, 14)
self.assertEqual(c, d)
self.assertEqual(d, e)
# fromAtoms must tolerate 0-length intervals.
f = Interval.fromAtoms([(0, 2), (2, 0), (2, 2)])
self.assertEqual(f, Interval.fromAtom(0, 4))
# and must not tolerate overlap.
with self.assertRaises(AssertionError):
Interval.fromAtoms([(0, 5), (4, 5)])
# and should be able to create empty intervals (regression test)
self.assertEqual(Interval.fromAtoms([]), Interval())
self.assertEqual(Interval.fromAtoms([(5, 0)]), Interval())
def test_union_overlap(self):
"""Test that union works correctly when overlap is enabled."""
a = Interval.fromAtom(5, 10)
b = Interval.fromAtom(10, 10)
self.assertEqual(a.union(b, allow_overlap=True), Interval.fromAtom(5, 15))
a = Interval.fromAtom(5, 5)
b = Interval.fromAtom(5, 15)
self.assertEqual(a.union(b, allow_overlap=True), Interval.fromAtom(5, 15))
a = Interval.fromAtom(5, 20)
b = Interval.fromAtom(10, 15)
self.assertEqual(a.union(b, allow_overlap=True), Interval.fromAtom(5, 20))
a = Interval.fromAtom(10, 5)
b = Interval.fromAtom(5, 15)
self.assertEqual(a.union(b, allow_overlap=True), Interval.fromAtom(5, 15))
def test_iterInterior(self): """Tests the iterInterior method.""" atoms = [(0, 2), (4, 2), (8, 2)] self.assertEqual(atoms, list(Interval.fromAtoms(atoms).iterInterior())) self.assertEqual([], list(Interval().iterInterior()))
def consumeEntireFile(self):
"""Mark the entire file as consumed. Used to prevent its use for encryption
while keeping it around for decryption."""
self.used = self.size
self._extents = Interval.fromAtom(0, self.size)
def test_union_overlap(self):
"""It is part of the design spec that intervals to union must be disjoint,
since otherwise would likely indicate an error in the main program."""
# Off by one
with self.assertRaises(AssertionError):
Interval.fromAtom(0, 5).union(Interval.fromAtom(4, 5))
a = Interval.fromAtom(0, 5).union(Interval.fromAtom(5, 5))
self.assertEqual(a, Interval.fromAtom(0, 10))
# Containment
with self.assertRaises(AssertionError):
Interval.fromAtom(0, 5).union(Interval.fromAtom(2, 1))
with self.assertRaises(AssertionError):
Interval.fromAtom(2, 1).union(Interval.fromAtom(0, 5))
# Overlap by 1 (regression test)
with self.assertRaises(AssertionError):
Interval.fromAtom(0, 5).union(Interval.fromAtom(4, 1))
# Multiple intervals
b = Interval.fromAtoms([(2, 3), (10, 3), (20, 10000)])
with self.assertRaises(AssertionError):
Interval.fromAtom(0, 5).union(b)
with self.assertRaises(AssertionError):
Interval.fromAtom(2, 19).union(b)
with self.assertRaises(AssertionError):
Interval.fromAtom(900, 2).union(b)
# With self
with self.assertRaises(AssertionError):
a.union(a)
with self.assertRaises(AssertionError):
b.union(b)
