python-oxlib/oxlib/file.py

# -*- coding: utf-8 -*-
# vi:si:et:sw=4:sts=4:ts=4
# GPL 2008
from __future__ import division
import os
import hashlib
import sys
import struct
import subprocess

import simplejson

__all__ = ['sha1sum', 'oshash', 'avinfo']

def sha1sum(filename):
    sha1 = hashlib.sha1()
    file=open(filename)
    buffer=file.read(4096)
    while buffer:
        sha1.update(buffer)
        buffer=file.read(4096)
    file.close()
    return sha1.hexdigest()

'''
    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:
            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"

def avinfo(filename):
    if os.path.getsize(filename):
        p = subprocess.Popen(['ffmpeg2theora', '--info', filename], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        info, error = p.communicate()
        return simplejson.loads(info)
    return {'path': filename, 'size': 0}