59 lines
1.2 KiB
Ruby
59 lines
1.2 KiB
Ruby
# -*- coding: binary -*-
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require 'rex/image_source/image_source'
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require 'rex/struct2'
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module Rex
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module ImageSource
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class Disk < ImageSource
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attr_accessor :file, :file_offset, :size
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WINDOW_SIZE = 4096
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WINDOW_OVERLAP = 64
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def initialize(_file, _offset = 0, _len = nil)
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_len = _file.stat.size if !_len
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self.file = _file
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self.file_offset = _offset
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self.size = _len
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end
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def read(offset, len)
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if offset < 0 || offset+len > size
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raise RangeError, "Offset #{offset} outside of image source", caller
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end
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file.seek(file_offset + offset)
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file.read(len)
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end
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def index(search, offset = 0)
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# do a sliding window search across the disk
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while offset < size
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# get a full window size if we can, we
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# don't want to read past our boundaries
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wsize = size - offset
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wsize = WINDOW_SIZE if wsize > WINDOW_SIZE
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window = self.read(offset, wsize)
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res = window.index(search)
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return res + offset if res
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offset += WINDOW_SIZE - WINDOW_OVERLAP
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end
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end
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def subsource(offset, len)
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self.class.new(file, file_offset+offset, len)
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end
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def close
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file.close
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end
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end
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end
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end
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