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mutable.py: fix padding/shape-of-input-data to zfec

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Zooko O'Whielacronx 2007-11-09 18:06:25 -07:00
parent f34b8b251a
commit f6451deb74
1 changed files with 10 additions and 13 deletions
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23
src/allmydata/mutable.py
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@ -892,27 +892,24 @@ class Publish:
# now apply FEC
self.MAX_SEGMENT_SIZE = 1024*1024
data_length = len(crypttext)
if len(crypttext) < 10:
# TODO: FEC doesn't handle short (or empty) strings very well, so
# give it something longer and we'll trim the results later. For
# some reason I suspect the lower limit is k**2
crypttext = crypttext + "\x00"*(10-len(crypttext))
segment_size = min(self.MAX_SEGMENT_SIZE, len(crypttext))
# this must be a multiple of self.required_shares
segment_size = mathutil.next_multiple(segment_size, required_shares)
self.num_segments = mathutil.div_ceil(len(crypttext), segment_size)
assert self.num_segments == 1 # SDMF restrictions
if segment_size:
self.num_segments = mathutil.div_ceil(len(crypttext), segment_size)
else:
self.num_segments = 0
assert self.num_segments in [0, 1,] # SDMF restrictions
fec = codec.CRSEncoder()
fec.set_params(segment_size, required_shares, total_shares)
piece_size = fec.get_block_size()
crypttext_pieces = []
for offset in range(0, len(crypttext), piece_size):
crypttext_pieces = [None] * required_shares
for i in range(len(crypttext_pieces)):
offset = i * piece_size
piece = crypttext[offset:offset+piece_size]
if len(piece) < piece_size:
pad_size = piece_size - len(piece)
piece = piece + "\x00"*pad_size
crypttext_pieces.append(piece)
piece = piece + "\x00"*(piece_size - len(piece)) # padding
crypttext_pieces[i] = piece
assert len(piece) == piece_size
d = fec.encode(crypttext_pieces)