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 (rszf method). Auto-set to 32 or 64 depending on system architecture (1.size * 8).

PERFORMANCE IMPACT (64-bit vs 32-bit on 64-bit systems):

  • Memory: 70-76% reduction (e.g., 37.91 MB → 9.10 MB for 100 small QR codes)
  • Speed: 2-4% faster with 32-bit
  • Objects: 85-87% fewer allocations
  • All tests pass with ARCH_BITS=32

RECOMMENDATION: Use RQRCODE_CORE_ARCH_BITS=32 even on 64-bit systems for dramatic memory savings with no downsides. The QR code algorithm doesn't require 64-bit integers—32-bit is sufficient for all operations.

See test/benchmarks/ARCH_BITS_ANALYSIS.md for detailed benchmark data.

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 



165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 165

def self.demerit_points_1_same_color(modules)
  demerit_points = 0
  module_count = modules.size
  max_index = module_count - 1

  # level1
  module_count.times do |row|
    modules_row = modules[row]

    module_count.times do |col|
      same_count = 0
      dark = modules_row[col]

      # Check 3x3 neighborhood, but skip center cell
      # Unroll loops and eliminate range objects for performance

      # Row above (row - 1)
      if row > 0
        row_above = modules[row - 1]
        same_count += 1 if col > 0 && dark == row_above[col - 1]
        same_count += 1 if dark == row_above[col]
        same_count += 1 if col < max_index && dark == row_above[col + 1]
      end

      # Same row
      same_count += 1 if col > 0 && dark == modules_row[col - 1]
      same_count += 1 if col < max_index && dark == modules_row[col + 1]

      # Row below (row + 1)
      if row < max_index
        row_below = modules[row + 1]
        same_count += 1 if col > 0 && dark == row_below[col - 1]
        same_count += 1 if dark == row_below[col]
        same_count += 1 if col < max_index && dark == row_below[col + 1]
      end

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

  demerit_points
end

.demerit_points_2_full_blocks(modules) ⇒ Object 



208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 208

def self.demerit_points_2_full_blocks(modules)
  demerit_points = 0
  module_count = modules.size
  max_row = module_count - 1

  # level 2: Check for 2x2 blocks of same color
  # Only need to check (module_count - 1) x (module_count - 1) positions
  max_row.times do |row|
    row_curr = modules[row]
    row_next = modules[row + 1]

    max_row.times do |col|
      # Check if all 4 modules in 2x2 block have same color
      # (count == 0: all false, count == 4: all true)
      val = row_curr[col]
      if val == row_next[col] && val == row_curr[col + 1] && val == row_next[col + 1]
        demerit_points += DEMERIT_POINTS_2
      end
    end
  end

  demerit_points
end

.demerit_points_3_dangerous_patterns(modules) ⇒ Object 



232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 232

def self.demerit_points_3_dangerous_patterns(modules)
  demerit_points = 0
  module_count = modules.size
  pattern_len = 7
  max_start = module_count - pattern_len + 1

  # level 3: Check for dangerous pattern [dark, light, dark, dark, dark, light, dark]
  # Pattern: true, false, true, true, true, false, true (1:1:3:1:1 ratio)

  # Check rows
  modules.each do |row|
    max_start.times do |col|
      if row[col] && !row[col + 1] && row[col + 2] &&
          row[col + 3] && row[col + 4] && !row[col + 5] && row[col + 6]
        demerit_points += DEMERIT_POINTS_3
      end
    end
  end

  # Check columns
  module_count.times do |col|
    max_start.times 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 



264
265
266
267
268
269
270
271
272
273
274
275
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 264

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 



104
105
106
107
108
109
110
111
112
113
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 104

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 



83
84
85
86
87
88
89
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 83

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 



96
97
98
99
100
101
102
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 96

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 



125
126
127
128
129
130
131
132
133
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 125

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

Raises:



135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 135

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

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

  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 



154
155
156
157
158
159
160
161
162
163
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 154

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

Raises:



119
120
121
122
123
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 119

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

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

.get_pattern_positions(version) ⇒ Object 



115
116
117
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 115

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

.max_size ⇒ Object 



79
80
81
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 79

def self.max_size
  PATTERN_POSITION_TABLE.count
end

.rszf(num, count) ⇒ Object 



91
92
93
94
 
# File 'lib/rqrcode_core/qrcode/qr_util.rb', line 91

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