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make encode_new use py_ecc for real live erasure coding

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(This patch is not tested -- I'm working on a Mac which doesn't have gcc
installed...  (gcc is necessary for the crypto module.)  I will now attempt to
connect to a better development computer over my mom's staticy, failure-prone,
14.4 K modem...)
This commit is contained in:
Zooko O'Whielacronx 2006-12-29 13:50:53 -07:00
parent f3f91105bd
commit b0315fc549
1 changed files with 20 additions and 5 deletions
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25
src/allmydata/encode_new.py
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@ -5,6 +5,8 @@ from twisted.internet import defer
from allmydata.chunk import HashTree, roundup_pow2 from allmydata.chunk import HashTree, roundup_pow2
from Crypto.Cipher import AES from Crypto.Cipher import AES
import sha import sha
from allmydata.util import mathutil
from allmydata.util.assertutil import _assert, precondition
def hash(data): def hash(data):
return sha.new(data).digest() return sha.new(data).digest()
@ -67,14 +69,19 @@ class Encoder(object):
infile.seek(0, 2) infile.seek(0, 2)
self.file_size = infile.tell() self.file_size = infile.tell()
infile.seek(0, 0) infile.seek(0, 0)
fsize = 1.0 * self.file_size
self.segment_size = 1024
self.num_segments = int(math.ceil(fsize / self.segment_size))
self.num_shares = 100 self.num_shares = 100
self.required_shares = 25 self.required_shares = 25
# The segment size needs to be an even multiple of required_shares.
# (See encode_segment().)
self.segment_size = mathutil.next_multiple(1024, self.required_shares)
self.num_segments = mathutil.div_ceil(self.file_size, self.segment_size)
self.share_size = self.file_size / self.required_shares self.share_size = self.file_size / self.required_shares
self.fecer = rs_code.RSCode(self.num_shares, self.required_shares)
def get_reservation_size(self): def get_reservation_size(self):
self.num_shares = 100 self.num_shares = 100
self.share_size = self.file_size / self.required_shares self.share_size = self.file_size / self.required_shares
@ -104,8 +111,16 @@ class Encoder(object):
return d return d
def encode_segment(self, crypttext): def encode_segment(self, crypttext):
shares = [crypttext] * self.num_shares precondition((len(crypttext) % self.required_shares) == 0, len(crypttext), self.required_shares, len(crypttext) % self.required_shares)
return shares subshares = [[] for x in range(self.num_shares)]
# Note string slices aren't an efficient way to use memory, so when we
# upgrade from the unusably slow py_ecc prototype to a fast ECC we
# should also fix up this memory usage (by using the array module).
for i in range(0, len(crypttext), self.required_shares):
words = self.fecer.Encode(crypttext[i:i+self.required_shares])
for (subshare, word,) in zip(subshares, words):
subshare.append(word)
return [ ''.join(subshare) for subshare in subshares ]
def do_segment(self, segnum): def do_segment(self, segnum):
segment_plaintext = self.infile.read(self.segment_size) segment_plaintext = self.infile.read(self.segment_size)