Class: RQRCodeCore::QRUtil

Inherits:
Object
  • Object
show all
Defined in:
lib/rqrcode_core/qrcode/qr_util.rb

Constant Summary collapse

PATTERN_POSITION_TABLE = 
[
  [],
  [6, 18],
  [6, 22],
  [6, 26],
  [6, 30],
  [6, 34],
  [6, 22, 38],
  [6, 24, 42],
  [6, 26, 46],
  [6, 28, 50],
  [6, 30, 54],
  [6, 32, 58],
  [6, 34, 62],
  [6, 26, 46, 66],
  [6, 26, 48, 70],
  [6, 26, 50, 74],
  [6, 30, 54, 78],
  [6, 30, 56, 82],
  [6, 30, 58, 86],
  [6, 34, 62, 90],
  [6, 28, 50, 72, 94],
  [6, 26, 50, 74, 98],
  [6, 30, 54, 78, 102],
  [6, 28, 54, 80, 106],
  [6, 32, 58, 84, 110],
  [6, 30, 58, 86, 114],
  [6, 34, 62, 90, 118],
  [6, 26, 50, 74, 98, 122],
  [6, 30, 54, 78, 102, 126],
  [6, 26, 52, 78, 104, 130],
  [6, 30, 56, 82, 108, 134],
  [6, 34, 60, 86, 112, 138],
  [6, 30, 58, 86, 114, 142],
  [6, 34, 62, 90, 118, 146],
  [6, 30, 54, 78, 102, 126, 150],
  [6, 24, 50, 76, 102, 128, 154],
  [6, 28, 54, 80, 106, 132, 158],
  [6, 32, 58, 84, 110, 136, 162],
  [6, 26, 54, 82, 110, 138, 166],
  [6, 30, 58, 86, 114, 142, 170]
].freeze
G15 = 
1 << 10 | 1 << 8 | 1 << 5 | 1 << 4 | 1 << 2 | 1 << 1 | 1 << 0
G18 = 
1 << 12 | 1 << 11 | 1 << 10 | 1 << 9 | 1 << 8 | 1 << 5 | 1 << 2 | 1 << 0
G15_MASK = 
1 << 14 | 1 << 12 | 1 << 10 | 1 << 4 | 1 << 1
DEMERIT_POINTS_1 = 
3
DEMERIT_POINTS_2 = 
3
DEMERIT_POINTS_3 = 
40
DEMERIT_POINTS_4 = 
10
BITS_FOR_MODE = 
{
  QRMODE[:mode_number] => [10, 12, 14],
  QRMODE[:mode_alpha_numk] => [9, 11, 13],
  QRMODE[:mode_8bit_byte] => [8, 16, 16]
}.freeze
ARCH_BITS =

This value is used during the right shift zero fill step. It is auto set to 32 or 64 depending on the arch of your system running. 64 consumes a LOT more memory. In tests it’s shown changing it to 32 on 64 bit systems greatly reduces the memory footprint. You can use RQRCODE_CORE_ARCH_BITS to make this change but beware it may also have unintended consequences so use at your own risk.

ENV.fetch("RQRCODE_CORE_ARCH_BITS", nil)&.to_i || 1.size * 8

Class Method Summary collapse

Class Method Details

.demerit_points_1_same_color(modules) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 163

def self.demerit_points_1_same_color(modules)
  demerit_points = 0
  module_count = modules.size

  # level1
  (0...module_count).each do |row|
    (0...module_count).each do |col|
      same_count = 0
      dark = modules[row][col]

      (-1..1).each do |r|
        next if row + r < 0 || module_count <= row + r

        (-1..1).each do |c|
          next if col + c < 0 || module_count <= col + c
          next if r == 0 && c == 0
          if dark == modules[row + r][col + c]
            same_count += 1
          end
        end
      end

      if same_count > 5
        demerit_points += (DEMERIT_POINTS_1 + same_count - 5)
      end
    end
  end

  demerit_points
end

.demerit_points_2_full_blocks(modules) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 194

def self.demerit_points_2_full_blocks(modules)
  demerit_points = 0
  module_count = modules.size

  # level 2
  (0...(module_count - 1)).each do |row|
    (0...(module_count - 1)).each do |col|
      count = 0
      count += 1 if modules[row][col]
      count += 1 if modules[row + 1][col]
      count += 1 if modules[row][col + 1]
      count += 1 if modules[row + 1][col + 1]
      if count == 0 || count == 4
        demerit_points += DEMERIT_POINTS_2
      end
    end
  end

  demerit_points
end

.demerit_points_3_dangerous_patterns(modules) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 215

def self.demerit_points_3_dangerous_patterns(modules)
  demerit_points = 0
  module_count = modules.size

  # level 3
  modules.each do |row|
    (module_count - 6).times do |col_idx|
      if row[col_idx] &&
          !row[col_idx + 1] &&
          row[col_idx + 2] &&
          row[col_idx + 3] &&
          row[col_idx + 4] &&
          !row[col_idx + 5] &&
          row[col_idx + 6]
        demerit_points += DEMERIT_POINTS_3
      end
    end
  end

  (0...module_count).each do |col|
    (0...(module_count - 6)).each do |row|
      if modules[row][col] &&
          !modules[row + 1][col] &&
          modules[row + 2][col] &&
          modules[row + 3][col] &&
          modules[row + 4][col] &&
          !modules[row + 5][col] &&
          modules[row + 6][col]
        demerit_points += DEMERIT_POINTS_3
      end
    end
  end

  demerit_points
end

.demerit_points_4_dark_ratio(modules) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 251

def self.demerit_points_4_dark_ratio(modules)
  # level 4
  dark_count = modules.reduce(0) do |sum, col|
    sum + col.count(true)
  end

  # Convert to float to prevent integer division
  ratio = dark_count.to_f / (modules.size * modules.size)
  ratio_delta = (100 * ratio - 50).abs / 5

  ratio_delta * DEMERIT_POINTS_4
end

.get_bch_digit(data) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 96

def self.get_bch_digit(data)
  digit = 0

  while data != 0
    digit += 1
    data = QRUtil.rszf(data, 1)
  end

  digit
end

.get_bch_format_info(data) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 75

def self.get_bch_format_info(data)
  d = data << 10
  while QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G15) >= 0
    d ^= (G15 << (QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G15)))
  end
  ((data << 10) | d) ^ G15_MASK
end

.get_bch_version(data) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 88

def self.get_bch_version(data)
  d = data << 12
  while QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G18) >= 0
    d ^= (G18 << (QRUtil.get_bch_digit(d) - QRUtil.get_bch_digit(G18)))
  end
  (data << 12) | d
end

.get_error_correct_polynomial(error_correct_length) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 119

def self.get_error_correct_polynomial(error_correct_length)
  a = QRPolynomial.new([1], 0)

  (0...error_correct_length).each do |i|
    a = a.multiply(QRPolynomial.new([1, QRMath.gexp(i)], 0))
  end

  a
end

.get_length_in_bits(mode, version) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 129

def self.get_length_in_bits(mode, version)
  if !QRMODE.value?(mode)
    raise QRCodeRunTimeError, "Unknown mode: #{mode}"
  end

  if version > 40
    raise QRCodeRunTimeError, "Unknown version: #{version}"
  end

  if version.between?(1, 9)
    # 1 - 9
    macro_version = 0
  elsif version <= 26
    # 10 - 26
    macro_version = 1
  elsif version <= 40
    # 27 - 40
    macro_version = 2
  end

  BITS_FOR_MODE[mode][macro_version]
end

.get_lost_points(modules) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 152

def self.get_lost_points(modules)
  demerit_points = 0

  demerit_points += QRUtil.demerit_points_1_same_color(modules)
  demerit_points += QRUtil.demerit_points_2_full_blocks(modules)
  demerit_points += QRUtil.demerit_points_3_dangerous_patterns(modules)
  demerit_points += QRUtil.demerit_points_4_dark_ratio(modules)

  demerit_points
end

.get_mask(mask_pattern, i, j) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 111

def self.get_mask(mask_pattern, i, j)
  if mask_pattern > QRMASKCOMPUTATIONS.size
    raise QRCodeRunTimeError, "bad mask_pattern: #{mask_pattern}"
  end

  QRMASKCOMPUTATIONS[mask_pattern].call(i, j)
end

.get_pattern_positions(version) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 107

def self.get_pattern_positions(version)
  PATTERN_POSITION_TABLE[version - 1]
end

.max_size ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 71

def self.max_size
  PATTERN_POSITION_TABLE.count
end

.rszf(num, count) ⇒ Object 



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# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 83

def self.rszf(num, count)
  # right shift zero fill
  (num >> count) & ((1 << (ARCH_BITS - count)) - 1)
end