Created
April 28, 2016 11:40
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defmodule JavaClassVersion do | |
def read_class_file(file) do | |
file | |
|> File.read!() | |
|> java_major_minor() | |
|> java_version() | |
|> IO.inspect() | |
end | |
def java_major_minor(<<0xCA, 0xFE, 0xBA, 0xBE, # magic word | |
minor_version :: bytes-size(2), | |
major_version :: bytes-size(2), | |
rest :: binary >>) do | |
{major_version, minor_version} | |
end | |
def java_version({<<0x00, 0x34>>, _minor_version}), do: 8 | |
def java_version({<<0x00, 0x33>>, _minor_version}), do: 7 | |
def java_version({<<0x00, 0x32>>, _minor_version}), do: 6 | |
def java_version({<<0x00, 0x31>>, _minor_version}), do: 5 | |
def java_version({<<0x00, 0x30>>, _minor_version}), do: 1.4 | |
def java_version({<<0x00, 0x2F>>, _minor_version}), do: 1.3 | |
def java_version({<<0x00, 0x2E>>, _minor_version}), do: 1.2 | |
def java_version({<<0x00, 0x2D>>, _minor_version}), do: 1.1 | |
end |
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