def __init__(self,
rref,
server,
data_size,
block_size,
num_segments,
num_share_hashes,
uri_extension_size_max,
pipeline_size=50000):
self._rref = rref
self._server = server
self._data_size = data_size
self._block_size = block_size
self._num_segments = num_segments
effective_segments = mathutil.next_power_of_k(num_segments, 2)
self._segment_hash_size = (2 * effective_segments - 1) * HASH_SIZE
# how many share hashes are included in each share? This will be
# about ln2(num_shares).
self._share_hashtree_size = num_share_hashes * (2 + HASH_SIZE)
# we commit to not sending a uri extension larger than this
self._uri_extension_size_max = uri_extension_size_max
self._create_offsets(block_size, data_size)
# k=3, max_segment_size=128KiB gives us a typical segment of 43691
# bytes. Setting the default pipeline_size to 50KB lets us get two
# segments onto the wire but not a third, which would keep the pipe
# filled.
self._pipeline = pipeline.Pipeline(pipeline_size)
def which_bucket(self, size):
# return (min,max) such that min <= size <= max
# values are from the set (0,0), (1,3), (4,10), (11,31), (32,100),
# (101,316), (317, 1000), etc: two per decade
assert size >= 0
i = 0
while True:
if i >= len(self.buckets):
# extend the list
new_lower = self.buckets[i-1][1]+1
new_upper = int(mathutil.next_power_of_k(new_lower, self.root))
self.buckets.append( (new_lower, new_upper) )
maybe = self.buckets[i]
if maybe[0] <= size <= maybe[1]:
return maybe
i += 1
def which_bucket(self, size):
# return (min,max) such that min <= size <= max
# values are from the set (0,0), (1,3), (4,10), (11,31), (32,100),
# (101,316), (317, 1000), etc: two per decade
assert size >= 0
i = 0
while True:
if i >= len(self.buckets):
# extend the list
new_lower = self.buckets[i - 1][1] + 1
new_upper = int(mathutil.next_power_of_k(new_lower, self.root))
self.buckets.append((new_lower, new_upper))
maybe = self.buckets[i]
if maybe[0] <= size <= maybe[1]:
return maybe
i += 1
def __init__(self, rref, server, data_size, block_size, num_segments,
num_share_hashes, uri_extension_size_max, pipeline_size=50000):
self._rref = rref
self._server = server
self._data_size = data_size
self._block_size = block_size
self._num_segments = num_segments
effective_segments = mathutil.next_power_of_k(num_segments,2)
self._segment_hash_size = (2*effective_segments - 1) * HASH_SIZE
# how many share hashes are included in each share? This will be
# about ln2(num_shares).
self._share_hashtree_size = num_share_hashes * (2+HASH_SIZE)
# we commit to not sending a uri extension larger than this
self._uri_extension_size_max = uri_extension_size_max
self._create_offsets(block_size, data_size)
# k=3, max_segment_size=128KiB gives us a typical segment of 43691
# bytes. Setting the default pipeline_size to 50KB lets us get two
# segments onto the wire but not a third, which would keep the pipe
# filled.
self._pipeline = pipeline.Pipeline(pipeline_size)
def calc(filesize, params=(3,7,10), segsize=DEFAULT_MAX_SEGMENT_SIZE):
num_shares = params[2]
if filesize <= upload.Uploader.URI_LIT_SIZE_THRESHOLD:
urisize = len(uri.LiteralFileURI("A"*filesize).to_string())
sharesize = 0
sharespace = 0
else:
u = upload.FileUploader(None) # XXX changed
u.set_params(params)
# unfortunately, Encoder doesn't currently lend itself to answering
# this question without measuring a filesize, so we have to give it a
# fake one
data = BigFakeString(filesize)
u.set_filehandle(data)
u.set_encryption_key("a"*16)
sharesize, blocksize = u.setup_encoder()
# how much overhead?
# 0x20 bytes of offsets
# 0x04 bytes of extension length
# 0x1ad bytes of extension (=429)
# total is 465 bytes
num_segments = mathutil.div_ceil(filesize, segsize)
num_share_hashes = int(math.log(mathutil.next_power_of_k(num_shares, 2),
2)) + 1
sharesize = storage.allocated_size(sharesize, num_segments,
num_share_hashes,
429)
sharespace = num_shares * roundup(sharesize)
urisize = len(uri.pack_uri(storage_index="a"*32,
key="a"*16,
uri_extension_hash="a"*32,
needed_shares=params[0],
total_shares=params[2],
size=filesize))
return urisize, sharesize, sharespace
def calc(filesize, params=(3, 7, 10), segsize=DEFAULT_MAX_SEGMENT_SIZE):
num_shares = params[2]
if filesize <= upload.Uploader.URI_LIT_SIZE_THRESHOLD:
urisize = len(uri.LiteralFileURI("A" * filesize).to_string())
sharesize = 0
sharespace = 0
else:
u = upload.FileUploader(None) # XXX changed
u.set_params(params)
# unfortunately, Encoder doesn't currently lend itself to answering
# this question without measuring a filesize, so we have to give it a
# fake one
data = BigFakeString(filesize)
u.set_filehandle(data)
u.set_encryption_key("a" * 16)
sharesize, blocksize = u.setup_encoder()
# how much overhead?
# 0x20 bytes of offsets
# 0x04 bytes of extension length
# 0x1ad bytes of extension (=429)
# total is 465 bytes
num_segments = mathutil.div_ceil(filesize, segsize)
num_share_hashes = int(
math.log(mathutil.next_power_of_k(num_shares, 2), 2)) + 1
sharesize = storage.allocated_size(sharesize, num_segments,
num_share_hashes, 429)
sharespace = num_shares * roundup(sharesize)
urisize = len(
uri.pack_uri(storage_index="a" * 32,
key="a" * 16,
uri_extension_hash="a" * 32,
needed_shares=params[0],
total_shares=params[2],
size=filesize))
return urisize, sharesize, sharespace
