Class: VariableByteCode

Inherits:
Object
  • Object
show all
Defined in:
lib/ls4/lib/vbcode.rb

Overview

VariableByteCode

Copyright © 2010 FURUHASHI Sadayuki. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Class Method Summary collapse

Class Method Details

.decode(raw) ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 55

def self.decode(raw)
	i = 0
	value = 0
	while raw.length > i
		v = raw[i].unpack('C')[0]
		if v & 0b10000000 != 0
			v &= 0b01111111
			v <<= (i*7)
			value |= v
		else
			v <<= (i*7)
			value |= v
			return value
		end
		i += 1
	end
	return value
end

.decode_index(raw, from = 0) ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 96

def self.decode_index(raw, from=0)
	i = from
	value = 0
	while raw.length > i
		v = raw[i].unpack('C')[0]
		if v & 0b10000000 != 0
			v &= 0b01111111
			v <<= ((i-from)*7)
			value |= v
		else
			v <<= ((i-from)*7)
			value |= v
			return value, i+1
		end
		i += 1
	end
	return value, i
end

.decode_n(raw, from = 0, length = raw.length-from) ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 187

def self.decode_n(raw, from=0, length=raw.length-from)
	upto = from + length
	upto = raw.length if upto > raw.length
	values = []
	while upto > from
		value, from = decode_index(raw, from)
		values << value
	end
	values
end

.decode_stream(io) ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 137

def self.decode_stream(io)
	i = 0
	value = 0
	b = " "
	while b = io.read(1, b)
		v = b.unpack('C')[0]
		if v & 0b10000000 != 0
			v &= 0b01111111
			v <<= (i*7)
			value |= v
		else
			v <<= (i*7)
			value |= v
			return value
		end
		i += 1
	end
	return value
end

.encode(value, raw = "") ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 32

def self.encode(value, raw="")
	begin
		v = value & 0b01111111 | 0b10000000
		value >>= 7
		raw << [v].pack('C')
	end while value > 0
	raw[raw.length-1] = [raw[raw.length-1].unpack('C')[0] & 0b01111111].pack('C')
	raw
end

.encode_n(array, out = "") ⇒ Object 



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# File 'lib/ls4/lib/vbcode.rb', line 179

def self.encode_n(array, out="")
	array.each {|value|
		encode(value, out)
	}
	out
end