def getStrongMDSPropertyDegree(repairNodeno, nativeBlockNum, parityBlockNum, checkNum, enc_matrix):
'''Get strong MDS property degree.'''
currentStrongMDSPropertyDegree = 0
survivalcoeffvectorset = []
flag = 0
for i in range(parityBlockNum):
#get coeff vectors of survival parity blocks
if int(i/2)!= repairNodeno:
survivalcoeffvectorset.append(CoeffVector(nativeBlockNum))
for j in range(nativeBlockNum):
survivalcoeffvectorset[i - flag*2].coeff_[j] = enc_matrix[i][j]
survivalcoeffvectorset[i - flag*2].first()
else:
flag =1
s = 0
for i in range(parityBlockNum-2):
for j in range(parityBlockNum-2):
if i<j:
checkmatrix = CoeffMatrix(nativeBlockNum)
for k in range (parityBlockNum-2):
if k!=i and k!=j:
checkmatrix.addcoeffvector(survivalcoeffvectorset[k].copy())
if checkmatrix.rank_ == nativeBlockNum:
currentStrongMDSPropertyDegree += 1
s += 1
return currentStrongMDSPropertyDegree
def getStrongMDSPropertyDegree(repairNodeno, nativeBlockNum, parityBlockNum,
checkNum, enc_matrix):
'''Get strong MDS property degree.'''
currentStrongMDSPropertyDegree = 0
survivalcoeffvectorset = []
flag = 0
for i in range(parityBlockNum):
#get coeff vectors of survival parity blocks
if int(i / 2) != repairNodeno:
survivalcoeffvectorset.append(CoeffVector(nativeBlockNum))
for j in range(nativeBlockNum):
survivalcoeffvectorset[i -
flag * 2].coeff_[j] = enc_matrix[i][j]
survivalcoeffvectorset[i - flag * 2].first()
else:
flag = 1
s = 0
for i in range(parityBlockNum - 2):
for j in range(parityBlockNum - 2):
if i < j:
checkmatrix = CoeffMatrix(nativeBlockNum)
for k in range(parityBlockNum - 2):
if k != i and k != j:
checkmatrix.addcoeffvector(
survivalcoeffvectorset[k].copy())
if checkmatrix.rank_ == nativeBlockNum:
currentStrongMDSPropertyDegree += 1
s += 1
return currentStrongMDSPropertyDegree
def checkMDS(MSR_n, MSR_k, enc_matrix):
'''Check MDS property, for fmsr(k=n-2) only.'''
'''Return a MDS property value.'''
nativeBlockNum = getNativeBlockNum(MSR_n, MSR_k)
parityBlockNum = getParityBlockNum(MSR_n, MSR_k)
MDSpropery = True
allcoeffvectors = []
for i in range(parityBlockNum):
allcoeffvectors.append(CoeffVector(nativeBlockNum))
for j in range(nativeBlockNum):
allcoeffvectors[i].coeff_[j] = enc_matrix[i][j]
allcoeffvectors[i].first()
permutation = int(MSR_n * (MSR_n - 1) / 2)
#permutation of selecting n-2 nodes from n nodes
checkmatrix = [CoeffMatrix(nativeBlockNum) for col in range(permutation)]
s = 0
for i in range(MSR_n):
for j in range(MSR_n):
if i < j:
for b in range(MSR_n):
if b != i and b != j:
checkmatrix[s].addcoeffvector(
allcoeffvectors[b * 2].copy())
checkmatrix[s].addcoeffvector(
allcoeffvectors[b * 2 + 1].copy())
if checkmatrix[s].rank_ != nativeBlockNum:
MDSpropery = False
s += 1
return MDSpropery
def decode(n, k, src, blocknums, parityCoeff, dest, filesize, setting):
'''Decode chunk files to dest file.'''
## special handling for 0B files
if filesize <= 0:
open(dest,'wb').close()
return
cv_temp=[]
nativeBlockNum = getNativeBlockNum(n, k)
parityBlockNum = getParityBlockNum(n, k)
enc_matrix = [[GF256int(0) for col in range(nativeBlockNum)] for row in range(parityBlockNum)]
dec_matrix = [[GF256int(0) for col in range(nativeBlockNum)] for row in range(nativeBlockNum)]
rev_matrix = [[GF256int(0) for col in range(nativeBlockNum)] for row in range(nativeBlockNum)]
gj_matrix = [[GF256int(0) for col in range(nativeBlockNum*2)] for row in range(nativeBlockNum)]
## generate the encoding matrix
counter = 0
for i in range(parityBlockNum):
for j in range(nativeBlockNum):
enc_matrix[i][j] = GF256int(parityCoeff[counter])
counter += 1
cm1 = CoeffMatrix(nativeBlockNum)
for i in range(parityBlockNum):
cv_temp.append(CoeffVector(nativeBlockNum))
for j in range(nativeBlockNum):
cv_temp[i].coeff_[j] = enc_matrix[i][j]
cv_temp[i].first()
cm1.addcoeffvector(cv_temp[i])
## generate the decoding matrix
i=0
for selectChunkNo in blocknums:
for j in range(nativeBlockNum):
dec_matrix[i][j]=enc_matrix[selectChunkNo][j]
i += 1
## initialize the reverse matrix
for i in range(nativeBlockNum):
for j in range(nativeBlockNum):
if j==i:
rev_matrix[i][j]= GF256int(1)
## initialize the Gauss-Jordan matrix = [decoding,reverse]
for i in range(nativeBlockNum):
for j in range(nativeBlockNum*2):
if j<nativeBlockNum:
gj_matrix[i][j]= dec_matrix[i][j]
else:
gj_matrix[i][j]= rev_matrix[i][j-nativeBlockNum]
reversematrix(n, k, gj_matrix)
for i in range(nativeBlockNum):
for j in range(nativeBlockNum):
dec_matrix[i][j] = gj_matrix[i][j+nativeBlockNum]
##generate decode data chunks
selectchunk=[]
for filename in src:
infile = open(filename,'rb')
selectchunk.append(infile.read())
infile.close()
chunksize = os.path.getsize(src[0])
indatalist = ''.join(selectchunk)
##rebuild the original chunks
parityCoeff_temp = ''.join([chr(dec_matrix[i][j]) \
for i in range(nativeBlockNum) \
for j in range(nativeBlockNum)])
outdatalist = codings.clibfmsr.clibfmsr.decodeComputation(indatalist, \
parityCoeff_temp, nativeBlockNum, chunksize)
outfile = open(dest,'wb')
writelen = 1048576
writenext = 0
for i in range(0,filesize-writelen,writelen):
writenext = i+writelen
outfile.write(outdatalist[i:writenext])
outfile.write(outdatalist[writenext:filesize])
outfile.close()
def decode(n, k, src, blocknums, parityCoeff, dest, filesize, setting):
'''Decode chunk files to dest file.'''
## special handling for 0B files
if filesize <= 0:
open(dest, 'wb').close()
return
cv_temp = []
nativeBlockNum = getNativeBlockNum(n, k)
parityBlockNum = getParityBlockNum(n, k)
enc_matrix = [[GF256int(0) for col in range(nativeBlockNum)]
for row in range(parityBlockNum)]
dec_matrix = [[GF256int(0) for col in range(nativeBlockNum)]
for row in range(nativeBlockNum)]
rev_matrix = [[GF256int(0) for col in range(nativeBlockNum)]
for row in range(nativeBlockNum)]
gj_matrix = [[GF256int(0) for col in range(nativeBlockNum * 2)]
for row in range(nativeBlockNum)]
## generate the encoding matrix
counter = 0
for i in range(parityBlockNum):
for j in range(nativeBlockNum):
enc_matrix[i][j] = GF256int(parityCoeff[counter])
counter += 1
cm1 = CoeffMatrix(nativeBlockNum)
for i in range(parityBlockNum):
cv_temp.append(CoeffVector(nativeBlockNum))
for j in range(nativeBlockNum):
cv_temp[i].coeff_[j] = enc_matrix[i][j]
cv_temp[i].first()
cm1.addcoeffvector(cv_temp[i])
## generate the decoding matrix
i = 0
for selectChunkNo in blocknums:
for j in range(nativeBlockNum):
dec_matrix[i][j] = enc_matrix[selectChunkNo][j]
i += 1
## initialize the reverse matrix
for i in range(nativeBlockNum):
for j in range(nativeBlockNum):
if j == i:
rev_matrix[i][j] = GF256int(1)
## initialize the Gauss-Jordan matrix = [decoding,reverse]
for i in range(nativeBlockNum):
for j in range(nativeBlockNum * 2):
if j < nativeBlockNum:
gj_matrix[i][j] = dec_matrix[i][j]
else:
gj_matrix[i][j] = rev_matrix[i][j - nativeBlockNum]
reversematrix(n, k, gj_matrix)
for i in range(nativeBlockNum):
for j in range(nativeBlockNum):
dec_matrix[i][j] = gj_matrix[i][j + nativeBlockNum]
##generate decode data chunks
selectchunk = []
for filename in src:
infile = open(filename, 'rb')
selectchunk.append(infile.read())
infile.close()
chunksize = os.path.getsize(src[0])
indatalist = ''.join(selectchunk)
##rebuild the original chunks
parityCoeff_temp = ''.join([chr(dec_matrix[i][j]) \
for i in range(nativeBlockNum) \
for j in range(nativeBlockNum)])
outdatalist = codings.clibfmsr.clibfmsr.decodeComputation(indatalist, \
parityCoeff_temp, nativeBlockNum, chunksize)
outfile = open(dest, 'wb')
writelen = 1048576
writenext = 0
for i in range(0, filesize - writelen, writelen):
writenext = i + writelen
outfile.write(outdatalist[i:writenext])
outfile.write(outdatalist[writenext:filesize])
outfile.close()
