module ZBase32

# File lib/zbase32.rb, line 14
def decode(bytes)
  from_5bit(bytes.split('').map { |chr| MNET32.index(chr) }).pack('c*')
end

# File lib/zbase32.rb, line 10
def encode(bytes)
  to_5bit(bytes).map { |value| MNET32[value] }.join('')
end

# File lib/zbase32.rb, line 47
def from_5bit(ab)
  chunks = ab.reverse

  bit_count = 0
  bytes = []
  current_byte = 0
  chunks.each do |chunk|
    5.times do |j|
      current_byte = (current_byte >> 1) | (get_bit(chunk, j) << 7)
      bit_count += 1
      next unless bit_count > 7

      bit_count = 0
      bytes.push(current_byte)
      current_byte = 0
    end
  end

  bytes.reverse
end

# File lib/zbase32.rb, line 20
def get_bit(byte, offset)
  (byte >> offset) & 0x01
end

# File lib/zbase32.rb, line 24
def to_5bit(ab)
  bytes = ab.bytes.to_a.reverse

  bit_count = 0
  chunks = []
  current_chunk = 0
  bytes.each do |b|
    8.times do |j|
      current_chunk = (current_chunk >> 1) | (get_bit(b, j) << 4)
      bit_count += 1
      next unless bit_count > 4

      bit_count = 0
      chunks.push(current_chunk)
      current_chunk = 0
    end
  end

  chunks.push(current_chunk >> (5 - bit_count)) if bit_count > 0

  chunks.reverse
end