def __init__(self, content, lowest=1, highest=1):
self.content = content
self.content_length = content.__len__()
self.length = fastdivmod.powersum(self.content_length, lowest, highest)
self.lowest = lowest
self.highest = highest
def arbitrary_entry(i):
return (fastdivmod.powersum(self.content_length, lowest, i+lowest-1), i+lowest)
def entry_from_prev(i, prev):
return (prev[0] + (self.content_length ** prev[1]), prev[1] + 1)
self.offsets = cachingseq.CachingFuncSequence(
arbitrary_entry, highest - lowest+1, entry_from_prev)
# This needs to be a constant in order to reuse caclulations in future
# calls to bisect (a moving target will produce more misses).
if self.offsets[-1][0] > sys.maxsize:
i = 0
while i + 2 < len(self.offsets):
if self.offsets[i+1][0] > sys.maxsize:
self.index_of_offset = i
self.offset_break = self.offsets[i][0]
break
i += 1
else:
self.index_of_offset = len(self.offsets)
self.offset_break = sys.maxsize
def __init__(self, content, lowest=1, highest=1):
self.content = content
self.content_length = content.__len__()
self.length = fastdivmod.powersum(self.content_length, lowest, highest)
self.lowest = lowest
self.highest = highest
def arbitrary_entry(i):
return (fastdivmod.powersum(self.content_length, lowest,
i + lowest - 1), i + lowest)
def entry_from_prev(i, prev):
return (prev[0] + (self.content_length**prev[1]), prev[1] + 1)
self.offsets = cachingseq.CachingFuncSequence(arbitrary_entry,
highest - lowest + 1,
entry_from_prev)
# This needs to be a constant in order to reuse caclulations in future
# calls to bisect (a moving target will produce more misses).
if self.offsets[-1][0] > sys.maxint:
i = 0
while i + 2 < len(self.offsets):
if self.offsets[i + 1][0] > sys.maxint:
self.index_of_offset = i
self.offset_break = self.offsets[i][0]
break
i += 1
else:
self.index_of_offset = len(self.offsets)
self.offset_break = sys.maxint
def __init__(self, content, lowest=1, highest=1):
self.content = content
self.content_length = content.__len__()
self.length = fastdivmod.powersum(self.content_length, lowest, highest)
self.lowest = lowest
self.highest = highest
def arbitrary_entry(i):
return (
fastdivmod.powersum(self.content_length, lowest,
i + lowest - 1),
i + lowest,
)
def entry_from_prev(i, prev):
return (prev[0] + (self.content_length**prev[1]), prev[1] + 1)
self.offsets = cachingseq.CachingFuncSequence(arbitrary_entry,
highest - lowest + 1,
entry_from_prev)
# `offset_break` is an optimization around bisect, which would normally
# choose the "middle" value to bisect on, which does a lot of work
# that's unnecessary at the bottom of the range (say, the first 256
# entries).
#
# A good choice of OFFSET_BREAK_THRESHOLD minimizes the wasted work up
# front (we have to calculate all the offsets now up to it), and is
# still larger than most performant lookups will need. Anything above
# that will result in a big penalty as we get into arbitrary-precision
# integers and use the standard bisect logic.
if self.offsets[-1][0] > OFFSET_BREAK_THRESHOLD:
for i in range(len(self.offsets) - 1):
if self.offsets[i + 1][0] > OFFSET_BREAK_THRESHOLD:
self.index_of_offset = i
self.offset_break = self.offsets[i][0]
return
self.index_of_offset = len(self.offsets)
self.offset_break = self.offsets[-1][0] + 1
def arbitrary_entry(i):
return (fastdivmod.powersum(self.content_length, lowest,
i + lowest - 1), i + lowest)
def powersum_runner(base, low, high):
expected = sum([base ** i for i in range(low, high+1)])
actual = powersum(base, low, high)
assert expected == actual
def arbitrary_entry(i):
return (fastdivmod.powersum(self.content_length, lowest, i+lowest-1), i+lowest)
def powersum_runner(base, low, high):
expected = sum([base**i for i in range(low, high + 1)])
actual = powersum(base, low, high)
assert expected == actual
def test_powersum(self, base, low, high):
expected = sum([base**i for i in range(low, high + 1)])
actual = powersum(base, low, high)
self.assertEqual(expected, actual)
