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deal with files < 64k in oshash

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j 2009-06-14 21:22:47 +02:00
parent c3c9c49788
commit a2bf2a77d1
1 changed files with 32 additions and 31 deletions
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63
oxlib/file.py
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@ -5,7 +5,7 @@ from __future__ import division
import os
import hashlib
import sys
import struct
import struct
def sha1sum(filename):
@ -20,37 +20,38 @@ def sha1sum(filename):
'''
os hash - http://trac.opensubtitles.org/projects/opensubtitles/wiki/HashSourceCodes
plus modification for files < 64k, buffer is filled with file data and padded with 0
'''
def oshash(filename):
try:
longlongformat = 'q' # long long
bytesize = struct.calcsize(longlongformat)
f = open(filename, "rb")
filesize = os.path.getsize(filename)
hash = filesize
if filesize < 65536:
return "SizeError"
for x in range(int(65536/bytesize)):
buffer = f.read(bytesize)
(l_value,)= struct.unpack(longlongformat, buffer)
hash += l_value
hash = hash & 0xFFFFFFFFFFFFFFFF #to remain as 64bit number
def oshash(filename):
try:
longlongformat = 'q' # long long
bytesize = struct.calcsize(longlongformat)
f.seek(max(0,filesize-65536),0)
for x in range(int(65536/bytesize)):
buffer = f.read(bytesize)
(l_value,)= struct.unpack(longlongformat, buffer)
hash += l_value
hash = hash & 0xFFFFFFFFFFFFFFFF
f.close()
returnedhash = "%016x" % hash
return returnedhash
except(IOError):
f = open(filename, "rb")
filesize = os.path.getsize(filename)
hash = filesize
if filesize < 65536:
for x in range(int(filesize/bytesize)):
buffer = f.read(bytesize)
(l_value,)= struct.unpack(longlongformat, buffer)
hash += l_value
hash = hash & 0xFFFFFFFFFFFFFFFF #to remain as 64bit number
else:
for x in range(int(65536/bytesize)):
buffer = f.read(bytesize)
(l_value,)= struct.unpack(longlongformat, buffer)
hash += l_value
hash = hash & 0xFFFFFFFFFFFFFFFF #to remain as 64bit number
f.seek(max(0,filesize-65536),0)
for x in range(int(65536/bytesize)):
buffer = f.read(bytesize)
(l_value,)= struct.unpack(longlongformat, buffer)
hash += l_value
hash = hash & 0xFFFFFFFFFFFFFFFF
f.close()
returnedhash = "%016x" % hash
return returnedhash
except(IOError):
return "IOError"