39 lines
1.0 KiB
Ruby
39 lines
1.0 KiB
Ruby
# This is an "interface" that should be implemented by any digest class
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# passed into FileChecksum. Note that this isn't strictly enforced at
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# the moment, and this class isn't directly used. It is merely here for
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# documentation of structure of the class.
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class DigestClass
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def update(string); end
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def hexdigest; end
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end
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class FileChecksum
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BUFFER_SIZE = 16328
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# Initializes an object to calculate the checksum of a file. The given
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# ``digest_klass`` should implement the ``DigestClass`` interface. Note
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# that the built-in Ruby digest classes duck type this properly:
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# Digest::MD5, Digest::SHA1, etc.
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def initialize(path, digest_klass)
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@digest_klass = digest_klass
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@path = path
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end
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# This calculates the checksum of the file and returns it as a
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# string.
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#
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# @return [String]
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def checksum
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digest = @digest_klass.new
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File.open(@path, "r") do |f|
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while !f.eof
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buf = f.readpartial(BUFFER_SIZE)
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digest.update(buf)
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end
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end
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return digest.hexdigest
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end
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end
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