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import sys, os, string
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#write now write only GIF/JPEG
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#image types
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imgtypes=['JPG', 'GIF','GIF']
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#signature at beginning of file
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imgsigs=['JFIF', 'GIF87a', 'GIF89a']
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#offset of signatures from
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#file beginning
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imgsigoffs=[6, 0, 0]
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#our marker array
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imgmarker=[]
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def main():
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if len(sys.argv) < 2:
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print 'Usage: picdumper <file>\n'
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sys.exit(1)
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filename = os.path.abspath(sys.argv[1])
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if not os.path.isfile(filename):
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print 'Error: No such file ', filename
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sys.exit(2)
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#open file in binary mode
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try:
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infile = open(filename, 'rb')
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#dont bother about specific exceptions
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except:
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print 'Could not open file to read !', filename
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sys.exit(3)
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if infile is None:
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print 'Error opening file ', filename
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sys.exit(3)
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c = infile.read(1)
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lastmatch=""
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while c != '':
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#look for image sig
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for x in range(0, len(imgsigs)):
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#find if c is first character of imgsig
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sig=imgsigs[x]
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if c == sig[0]:
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#find if the rest of imgsig match
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lentoread=len(sig) - 1
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chunk=c + infile.read(lentoread)
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#print chunk
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#matches
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if chunk==sig:
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fpos=int(infile.tell())
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#now we are at end of sig, for getting image
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#pos we need to subtract length of sig and offset
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sigpos=fpos - len(sig)
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imgpos=sigpos - imgsigoffs[x]
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#write position and image type to marker
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imgmarker.append((imgpos, imgtypes[x]))
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lastmatch=imgtypes[x]
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else:
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#bug, we need to reset file position
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#to match other sigs correctly if this
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#one does not.
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currpos=int(infile.tell())
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prevpos=currpos-lentoread
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#seek to previous position
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infile.seek(prevpos)
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#read next char
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c=infile.read(1)
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posn=int(infile.tell())
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imgmarker.append((posn, lastmatch))
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print imgmarker
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#write images
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#rewind file
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infile.seek(0)
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imgcount=0
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#most collections store image in reverse
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#order that was appended
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x=len(imgmarker)-1
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while x>=1:
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imgcount += 1
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imginfo=imgmarker[x]
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imgposn=imginfo[0]
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imgtype=imginfo[1]
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#this is the tricky part, to get the correct image
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#we need the file posn before previous one!, that
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#is we need to jump a position. Otherwise all images
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#will be junk or of small resolution.
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imginfoprev=imgmarker[x-2]
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imgposnprev=imginfoprev[0]
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#get length in chars
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imglen= imgposn - imgposnprev
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#seek to file position
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infile.seek(imgposnprev)
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#read so many chars
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data=infile.read(imglen)
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#create file name
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imgname="image" + str(imgcount) + '.' + string.lower(imgtype)
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try:
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ofile=open(imgname, 'wb')
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except:
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print 'Could not open file ', imgname, ' for writing...\n'
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continue
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if ofile is None:
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print 'Error while trying to create file ', imgname, '!\n'
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continue
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else:
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print 'Dumping image file ', imgname, '...\n'
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ofile.write(data)
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ofile.close()
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#previous marker
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x-=1
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print 'Dumped ', imgcount, ' images\n'
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if __name__=="__main__":
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main()
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