49 lines
1.3 KiB
Ruby
49 lines
1.3 KiB
Ruby
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class BitStruct
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# Class for fixed length binary strings of characters.
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# Declared with BitStruct.char.
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class CharField < Field
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#def self.default
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# don't define this, since it must specify N nulls and we don't know N
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#end
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# Used in describe.
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def self.class_name
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@class_name ||= "char"
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end
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def add_accessors_to(cl, attr = name) # :nodoc:
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unless offset % 8 == 0
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raise ArgumentError,
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"Bad offset, #{offset}, for #{self.class} #{name}." +
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" Must be multiple of 8."
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end
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unless length % 8 == 0
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raise ArgumentError,
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"Bad length, #{length}, for #{self.class} #{name}." +
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" Must be multiple of 8."
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end
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offset_byte = offset / 8
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length_byte = length / 8
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last_byte = offset_byte + length_byte - 1
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byte_range = offset_byte..last_byte
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val_byte_range = 0..length_byte-1
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cl.class_eval do
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define_method attr do ||
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self[byte_range].to_s
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end
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define_method "#{attr}=" do |val|
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val = val.to_s
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if val.length < length_byte
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val += "\0" * (length_byte - val.length)
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end
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self[byte_range] = val[val_byte_range]
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end
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end
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end
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end
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end
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