versioninfo.go raw
1 package qr
2
3 import "math"
4
5 // ErrorCorrectionLevel indicates the amount of "backup data" stored in the QR code
6 type ErrorCorrectionLevel byte
7
8 const (
9 // L recovers 7% of data
10 L ErrorCorrectionLevel = iota
11 // M recovers 15% of data
12 M
13 // Q recovers 25% of data
14 Q
15 // H recovers 30% of data
16 H
17 )
18
19 func (ecl ErrorCorrectionLevel) String() string {
20 switch ecl {
21 case L:
22 return "L"
23 case M:
24 return "M"
25 case Q:
26 return "Q"
27 case H:
28 return "H"
29 }
30 return "unknown"
31 }
32
33 type encodingMode byte
34
35 const (
36 numericMode encodingMode = 1
37 alphaNumericMode encodingMode = 2
38 byteMode encodingMode = 4
39 kanjiMode encodingMode = 8
40 )
41
42 type versionInfo struct {
43 Version byte
44 Level ErrorCorrectionLevel
45 ErrorCorrectionCodewordsPerBlock byte
46 NumberOfBlocksInGroup1 byte
47 DataCodeWordsPerBlockInGroup1 byte
48 NumberOfBlocksInGroup2 byte
49 DataCodeWordsPerBlockInGroup2 byte
50 }
51
52 var versionInfos = []*versionInfo{
53 &versionInfo{1, L, 7, 1, 19, 0, 0},
54 &versionInfo{1, M, 10, 1, 16, 0, 0},
55 &versionInfo{1, Q, 13, 1, 13, 0, 0},
56 &versionInfo{1, H, 17, 1, 9, 0, 0},
57 &versionInfo{2, L, 10, 1, 34, 0, 0},
58 &versionInfo{2, M, 16, 1, 28, 0, 0},
59 &versionInfo{2, Q, 22, 1, 22, 0, 0},
60 &versionInfo{2, H, 28, 1, 16, 0, 0},
61 &versionInfo{3, L, 15, 1, 55, 0, 0},
62 &versionInfo{3, M, 26, 1, 44, 0, 0},
63 &versionInfo{3, Q, 18, 2, 17, 0, 0},
64 &versionInfo{3, H, 22, 2, 13, 0, 0},
65 &versionInfo{4, L, 20, 1, 80, 0, 0},
66 &versionInfo{4, M, 18, 2, 32, 0, 0},
67 &versionInfo{4, Q, 26, 2, 24, 0, 0},
68 &versionInfo{4, H, 16, 4, 9, 0, 0},
69 &versionInfo{5, L, 26, 1, 108, 0, 0},
70 &versionInfo{5, M, 24, 2, 43, 0, 0},
71 &versionInfo{5, Q, 18, 2, 15, 2, 16},
72 &versionInfo{5, H, 22, 2, 11, 2, 12},
73 &versionInfo{6, L, 18, 2, 68, 0, 0},
74 &versionInfo{6, M, 16, 4, 27, 0, 0},
75 &versionInfo{6, Q, 24, 4, 19, 0, 0},
76 &versionInfo{6, H, 28, 4, 15, 0, 0},
77 &versionInfo{7, L, 20, 2, 78, 0, 0},
78 &versionInfo{7, M, 18, 4, 31, 0, 0},
79 &versionInfo{7, Q, 18, 2, 14, 4, 15},
80 &versionInfo{7, H, 26, 4, 13, 1, 14},
81 &versionInfo{8, L, 24, 2, 97, 0, 0},
82 &versionInfo{8, M, 22, 2, 38, 2, 39},
83 &versionInfo{8, Q, 22, 4, 18, 2, 19},
84 &versionInfo{8, H, 26, 4, 14, 2, 15},
85 &versionInfo{9, L, 30, 2, 116, 0, 0},
86 &versionInfo{9, M, 22, 3, 36, 2, 37},
87 &versionInfo{9, Q, 20, 4, 16, 4, 17},
88 &versionInfo{9, H, 24, 4, 12, 4, 13},
89 &versionInfo{10, L, 18, 2, 68, 2, 69},
90 &versionInfo{10, M, 26, 4, 43, 1, 44},
91 &versionInfo{10, Q, 24, 6, 19, 2, 20},
92 &versionInfo{10, H, 28, 6, 15, 2, 16},
93 &versionInfo{11, L, 20, 4, 81, 0, 0},
94 &versionInfo{11, M, 30, 1, 50, 4, 51},
95 &versionInfo{11, Q, 28, 4, 22, 4, 23},
96 &versionInfo{11, H, 24, 3, 12, 8, 13},
97 &versionInfo{12, L, 24, 2, 92, 2, 93},
98 &versionInfo{12, M, 22, 6, 36, 2, 37},
99 &versionInfo{12, Q, 26, 4, 20, 6, 21},
100 &versionInfo{12, H, 28, 7, 14, 4, 15},
101 &versionInfo{13, L, 26, 4, 107, 0, 0},
102 &versionInfo{13, M, 22, 8, 37, 1, 38},
103 &versionInfo{13, Q, 24, 8, 20, 4, 21},
104 &versionInfo{13, H, 22, 12, 11, 4, 12},
105 &versionInfo{14, L, 30, 3, 115, 1, 116},
106 &versionInfo{14, M, 24, 4, 40, 5, 41},
107 &versionInfo{14, Q, 20, 11, 16, 5, 17},
108 &versionInfo{14, H, 24, 11, 12, 5, 13},
109 &versionInfo{15, L, 22, 5, 87, 1, 88},
110 &versionInfo{15, M, 24, 5, 41, 5, 42},
111 &versionInfo{15, Q, 30, 5, 24, 7, 25},
112 &versionInfo{15, H, 24, 11, 12, 7, 13},
113 &versionInfo{16, L, 24, 5, 98, 1, 99},
114 &versionInfo{16, M, 28, 7, 45, 3, 46},
115 &versionInfo{16, Q, 24, 15, 19, 2, 20},
116 &versionInfo{16, H, 30, 3, 15, 13, 16},
117 &versionInfo{17, L, 28, 1, 107, 5, 108},
118 &versionInfo{17, M, 28, 10, 46, 1, 47},
119 &versionInfo{17, Q, 28, 1, 22, 15, 23},
120 &versionInfo{17, H, 28, 2, 14, 17, 15},
121 &versionInfo{18, L, 30, 5, 120, 1, 121},
122 &versionInfo{18, M, 26, 9, 43, 4, 44},
123 &versionInfo{18, Q, 28, 17, 22, 1, 23},
124 &versionInfo{18, H, 28, 2, 14, 19, 15},
125 &versionInfo{19, L, 28, 3, 113, 4, 114},
126 &versionInfo{19, M, 26, 3, 44, 11, 45},
127 &versionInfo{19, Q, 26, 17, 21, 4, 22},
128 &versionInfo{19, H, 26, 9, 13, 16, 14},
129 &versionInfo{20, L, 28, 3, 107, 5, 108},
130 &versionInfo{20, M, 26, 3, 41, 13, 42},
131 &versionInfo{20, Q, 30, 15, 24, 5, 25},
132 &versionInfo{20, H, 28, 15, 15, 10, 16},
133 &versionInfo{21, L, 28, 4, 116, 4, 117},
134 &versionInfo{21, M, 26, 17, 42, 0, 0},
135 &versionInfo{21, Q, 28, 17, 22, 6, 23},
136 &versionInfo{21, H, 30, 19, 16, 6, 17},
137 &versionInfo{22, L, 28, 2, 111, 7, 112},
138 &versionInfo{22, M, 28, 17, 46, 0, 0},
139 &versionInfo{22, Q, 30, 7, 24, 16, 25},
140 &versionInfo{22, H, 24, 34, 13, 0, 0},
141 &versionInfo{23, L, 30, 4, 121, 5, 122},
142 &versionInfo{23, M, 28, 4, 47, 14, 48},
143 &versionInfo{23, Q, 30, 11, 24, 14, 25},
144 &versionInfo{23, H, 30, 16, 15, 14, 16},
145 &versionInfo{24, L, 30, 6, 117, 4, 118},
146 &versionInfo{24, M, 28, 6, 45, 14, 46},
147 &versionInfo{24, Q, 30, 11, 24, 16, 25},
148 &versionInfo{24, H, 30, 30, 16, 2, 17},
149 &versionInfo{25, L, 26, 8, 106, 4, 107},
150 &versionInfo{25, M, 28, 8, 47, 13, 48},
151 &versionInfo{25, Q, 30, 7, 24, 22, 25},
152 &versionInfo{25, H, 30, 22, 15, 13, 16},
153 &versionInfo{26, L, 28, 10, 114, 2, 115},
154 &versionInfo{26, M, 28, 19, 46, 4, 47},
155 &versionInfo{26, Q, 28, 28, 22, 6, 23},
156 &versionInfo{26, H, 30, 33, 16, 4, 17},
157 &versionInfo{27, L, 30, 8, 122, 4, 123},
158 &versionInfo{27, M, 28, 22, 45, 3, 46},
159 &versionInfo{27, Q, 30, 8, 23, 26, 24},
160 &versionInfo{27, H, 30, 12, 15, 28, 16},
161 &versionInfo{28, L, 30, 3, 117, 10, 118},
162 &versionInfo{28, M, 28, 3, 45, 23, 46},
163 &versionInfo{28, Q, 30, 4, 24, 31, 25},
164 &versionInfo{28, H, 30, 11, 15, 31, 16},
165 &versionInfo{29, L, 30, 7, 116, 7, 117},
166 &versionInfo{29, M, 28, 21, 45, 7, 46},
167 &versionInfo{29, Q, 30, 1, 23, 37, 24},
168 &versionInfo{29, H, 30, 19, 15, 26, 16},
169 &versionInfo{30, L, 30, 5, 115, 10, 116},
170 &versionInfo{30, M, 28, 19, 47, 10, 48},
171 &versionInfo{30, Q, 30, 15, 24, 25, 25},
172 &versionInfo{30, H, 30, 23, 15, 25, 16},
173 &versionInfo{31, L, 30, 13, 115, 3, 116},
174 &versionInfo{31, M, 28, 2, 46, 29, 47},
175 &versionInfo{31, Q, 30, 42, 24, 1, 25},
176 &versionInfo{31, H, 30, 23, 15, 28, 16},
177 &versionInfo{32, L, 30, 17, 115, 0, 0},
178 &versionInfo{32, M, 28, 10, 46, 23, 47},
179 &versionInfo{32, Q, 30, 10, 24, 35, 25},
180 &versionInfo{32, H, 30, 19, 15, 35, 16},
181 &versionInfo{33, L, 30, 17, 115, 1, 116},
182 &versionInfo{33, M, 28, 14, 46, 21, 47},
183 &versionInfo{33, Q, 30, 29, 24, 19, 25},
184 &versionInfo{33, H, 30, 11, 15, 46, 16},
185 &versionInfo{34, L, 30, 13, 115, 6, 116},
186 &versionInfo{34, M, 28, 14, 46, 23, 47},
187 &versionInfo{34, Q, 30, 44, 24, 7, 25},
188 &versionInfo{34, H, 30, 59, 16, 1, 17},
189 &versionInfo{35, L, 30, 12, 121, 7, 122},
190 &versionInfo{35, M, 28, 12, 47, 26, 48},
191 &versionInfo{35, Q, 30, 39, 24, 14, 25},
192 &versionInfo{35, H, 30, 22, 15, 41, 16},
193 &versionInfo{36, L, 30, 6, 121, 14, 122},
194 &versionInfo{36, M, 28, 6, 47, 34, 48},
195 &versionInfo{36, Q, 30, 46, 24, 10, 25},
196 &versionInfo{36, H, 30, 2, 15, 64, 16},
197 &versionInfo{37, L, 30, 17, 122, 4, 123},
198 &versionInfo{37, M, 28, 29, 46, 14, 47},
199 &versionInfo{37, Q, 30, 49, 24, 10, 25},
200 &versionInfo{37, H, 30, 24, 15, 46, 16},
201 &versionInfo{38, L, 30, 4, 122, 18, 123},
202 &versionInfo{38, M, 28, 13, 46, 32, 47},
203 &versionInfo{38, Q, 30, 48, 24, 14, 25},
204 &versionInfo{38, H, 30, 42, 15, 32, 16},
205 &versionInfo{39, L, 30, 20, 117, 4, 118},
206 &versionInfo{39, M, 28, 40, 47, 7, 48},
207 &versionInfo{39, Q, 30, 43, 24, 22, 25},
208 &versionInfo{39, H, 30, 10, 15, 67, 16},
209 &versionInfo{40, L, 30, 19, 118, 6, 119},
210 &versionInfo{40, M, 28, 18, 47, 31, 48},
211 &versionInfo{40, Q, 30, 34, 24, 34, 25},
212 &versionInfo{40, H, 30, 20, 15, 61, 16},
213 }
214
215 func (vi *versionInfo) totalDataBytes() int {
216 g1Data := int(vi.NumberOfBlocksInGroup1) * int(vi.DataCodeWordsPerBlockInGroup1)
217 g2Data := int(vi.NumberOfBlocksInGroup2) * int(vi.DataCodeWordsPerBlockInGroup2)
218 return (g1Data + g2Data)
219 }
220
221 func (vi *versionInfo) charCountBits(m encodingMode) byte {
222 switch m {
223 case numericMode:
224 if vi.Version < 10 {
225 return 10
226 } else if vi.Version < 27 {
227 return 12
228 }
229 return 14
230
231 case alphaNumericMode:
232 if vi.Version < 10 {
233 return 9
234 } else if vi.Version < 27 {
235 return 11
236 }
237 return 13
238
239 case byteMode:
240 if vi.Version < 10 {
241 return 8
242 }
243 return 16
244
245 case kanjiMode:
246 if vi.Version < 10 {
247 return 8
248 } else if vi.Version < 27 {
249 return 10
250 }
251 return 12
252 default:
253 return 0
254 }
255 }
256
257 func (vi *versionInfo) modulWidth() int {
258 return ((int(vi.Version) - 1) * 4) + 21
259 }
260
261 func (vi *versionInfo) alignmentPatternPlacements() []int {
262 if vi.Version == 1 {
263 return make([]int, 0)
264 }
265
266 first := 6
267 last := vi.modulWidth() - 7
268 space := float64(last - first)
269 count := int(math.Ceil(space/28)) + 1
270
271 result := make([]int, count)
272 result[0] = first
273 result[len(result)-1] = last
274 if count > 2 {
275 step := int(math.Ceil(float64(last-first) / float64(count-1)))
276 if step%2 == 1 {
277 frac := float64(last-first) / float64(count-1)
278 _, x := math.Modf(frac)
279 if x >= 0.5 {
280 frac = math.Ceil(frac)
281 } else {
282 frac = math.Floor(frac)
283 }
284
285 if int(frac)%2 == 0 {
286 step--
287 } else {
288 step++
289 }
290 }
291
292 for i := 1; i <= count-2; i++ {
293 result[i] = last - (step * (count - 1 - i))
294 }
295 }
296
297 return result
298 }
299
300 func findSmallestVersionInfo(ecl ErrorCorrectionLevel, mode encodingMode, dataBits int) *versionInfo {
301 dataBits = dataBits + 4 // mode indicator
302 for _, vi := range versionInfos {
303 if vi.Level == ecl {
304 if (vi.totalDataBytes() * 8) >= (dataBits + int(vi.charCountBits(mode))) {
305 return vi
306 }
307 }
308 }
309 return nil
310 }
311