anyd 0.1.1

From-scratch encoding and decoding of 1D and 2D barcodes with lossless round-trip and live-video detection
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178

//! Static QR specification tables (ISO/IEC 18004): error-correction block layout,
//! alignment-pattern positions, character-count indicator sizes and remainder bits.

use super::{EcLevel, Version};
use crate::segment::Mode;

/// Error-correction block layout for one (version, EC level).
#[derive(Debug, Clone, Copy)]
pub struct EcBlocks {
    /// EC codewords per block.
    pub ec_per_block: usize,
    /// Number of blocks in group 1.
    pub group1_blocks: usize,
    /// Data codewords in each group-1 block.
    pub group1_data: usize,
    /// Number of blocks in group 2 (0 if the version uses a single group).
    pub group2_blocks: usize,
    /// Data codewords in each group-2 block.
    pub group2_data: usize,
}

impl EcBlocks {
    /// Total number of RS blocks.
    pub fn total_blocks(&self) -> usize {
        self.group1_blocks + self.group2_blocks
    }

    /// Total number of data codewords across all blocks.
    pub fn total_data(&self) -> usize {
        self.group1_blocks * self.group1_data + self.group2_blocks * self.group2_data
    }

    /// Total number of codewords (data + EC) across all blocks.
    pub fn total_codewords(&self) -> usize {
        self.total_data() + self.total_blocks() * self.ec_per_block
    }
}

fn level_index(level: EcLevel) -> usize {
    match level {
        EcLevel::L => 0,
        EcLevel::M => 1,
        EcLevel::Q => 2,
        EcLevel::H => 3,
    }
}

/// Error-correction block layout for a version and level.
pub fn ec_blocks(version: Version, level: EcLevel) -> EcBlocks {
    let r = EC_BLOCK_TABLE[version.number() as usize - 1][level_index(level)];
    EcBlocks {
        ec_per_block: r[0] as usize,
        group1_blocks: r[1] as usize,
        group1_data: r[2] as usize,
        group2_blocks: r[3] as usize,
        group2_data: r[4] as usize,
    }
}

/// Alignment-pattern center coordinates for a version (empty for version 1).
pub fn alignment_positions(version: Version) -> &'static [u8] {
    ALIGNMENT_POSITIONS[version.number() as usize - 1]
}

/// Number of remainder bits appended after the final codeword for a version.
pub fn remainder_bits(version: Version) -> usize {
    REMAINDER_BITS[version.number() as usize - 1] as usize
}

/// Bit length of the character-count indicator for a mode at a version.
pub fn char_count_bits(version: Version, mode: &Mode) -> usize {
    let v = version.number();
    let group = if v <= 9 {
        0
    } else if v <= 26 {
        1
    } else {
        2
    };
    match mode {
        Mode::Numeric => [10, 12, 14][group],
        Mode::Alphanumeric => [9, 11, 13][group],
        Mode::Byte => [8, 16, 16][group],
        Mode::Kanji => [8, 10, 12][group],
        Mode::Eci(_) => 0,
    }
}

/// The 4-bit mode indicator for a data mode.
pub fn mode_indicator(mode: &Mode) -> u8 {
    match mode {
        Mode::Numeric => 0b0001,
        Mode::Alphanumeric => 0b0010,
        Mode::Byte => 0b0100,
        Mode::Kanji => 0b1000,
        Mode::Eci(_) => 0b0111,
    }
}

/// Recover a data mode (no payload) from a 4-bit mode indicator, if recognized.
/// The terminator (`0000`) returns `None`.
pub fn mode_from_indicator(indicator: u8) -> Option<Mode> {
    match indicator {
        0b0001 => Some(Mode::Numeric),
        0b0010 => Some(Mode::Alphanumeric),
        0b0100 => Some(Mode::Byte),
        0b1000 => Some(Mode::Kanji),
        0b0111 => Some(Mode::Eci(0)),
        _ => None,
    }
}

// [version-1][L,M,Q,H] = [ec_per_block, g1_blocks, g1_data, g2_blocks, g2_data]
#[rustfmt::skip]
const EC_BLOCK_TABLE: [[[u16; 5]; 4]; 40] = [
    [[7,1,19,0,0],[10,1,16,0,0],[13,1,13,0,0],[17,1,9,0,0]],
    [[10,1,34,0,0],[16,1,28,0,0],[22,1,22,0,0],[28,1,16,0,0]],
    [[15,1,55,0,0],[26,1,44,0,0],[18,2,17,0,0],[22,2,13,0,0]],
    [[20,1,80,0,0],[18,2,32,0,0],[26,2,24,0,0],[16,4,9,0,0]],
    [[26,1,108,0,0],[24,2,43,0,0],[18,2,15,2,16],[22,2,11,2,12]],
    [[18,2,68,0,0],[16,4,27,0,0],[24,4,19,0,0],[28,4,15,0,0]],
    [[20,2,78,0,0],[18,4,31,0,0],[18,2,14,4,15],[26,4,13,1,14]],
    [[24,2,97,0,0],[22,2,38,2,39],[22,4,18,2,19],[26,4,14,2,15]],
    [[30,2,116,0,0],[22,3,36,2,37],[20,4,16,4,17],[24,4,12,4,13]],
    [[18,2,68,2,69],[26,4,43,1,44],[24,6,19,2,20],[28,6,15,2,16]],
    [[20,4,81,0,0],[30,1,50,4,51],[28,4,22,4,23],[24,3,12,8,13]],
    [[24,2,92,2,93],[22,6,36,2,37],[26,4,20,6,21],[28,7,14,4,15]],
    [[26,4,107,0,0],[22,8,37,1,38],[24,8,20,4,21],[22,12,11,4,12]],
    [[30,3,115,1,116],[24,4,40,5,41],[20,11,16,5,17],[24,11,12,5,13]],
    [[22,5,87,1,88],[24,5,41,5,42],[30,5,24,7,25],[24,11,12,7,13]],
    [[24,5,98,1,99],[28,7,45,3,46],[24,15,19,2,20],[30,3,15,13,16]],
    [[28,1,107,5,108],[28,10,46,1,47],[28,1,22,15,23],[28,2,14,17,15]],
    [[30,5,120,1,121],[26,9,43,4,44],[28,17,22,1,23],[28,2,14,19,15]],
    [[28,3,113,4,114],[26,3,44,11,45],[26,17,21,4,22],[26,9,13,16,14]],
    [[28,3,107,5,108],[26,3,41,13,42],[30,15,24,5,25],[28,15,15,10,16]],
    [[28,4,116,4,117],[26,17,42,0,0],[28,17,22,6,23],[30,19,16,6,17]],
    [[28,2,111,7,112],[28,17,46,0,0],[30,7,24,16,25],[24,34,13,0,0]],
    [[30,4,121,5,122],[28,4,47,14,48],[30,11,24,14,25],[30,16,15,14,16]],
    [[30,6,117,4,118],[28,6,45,14,46],[30,11,24,16,25],[30,30,16,2,17]],
    [[26,8,106,4,107],[28,8,47,13,48],[30,7,24,22,25],[30,22,15,13,16]],
    [[28,10,114,2,115],[28,19,46,4,47],[28,28,22,6,23],[30,33,16,4,17]],
    [[30,8,122,4,123],[28,22,45,3,46],[30,8,23,26,24],[30,12,15,28,16]],
    [[30,3,117,10,118],[28,3,45,23,46],[30,4,24,31,25],[30,11,15,31,16]],
    [[30,7,116,7,117],[28,21,45,7,46],[30,1,23,37,24],[30,19,15,26,16]],
    [[30,5,115,10,116],[28,19,47,10,48],[30,15,24,25,25],[30,23,15,25,16]],
    [[30,13,115,3,116],[28,2,46,29,47],[30,42,24,1,25],[30,23,15,28,16]],
    [[30,17,115,0,0],[28,10,46,23,47],[30,10,24,35,25],[30,19,15,35,16]],
    [[30,17,115,1,116],[28,14,46,21,47],[30,29,24,19,25],[30,11,15,46,16]],
    [[30,13,115,6,116],[28,14,46,23,47],[30,44,24,7,25],[30,59,16,1,17]],
    [[30,12,121,7,122],[28,12,47,26,48],[30,39,24,14,25],[30,22,15,41,16]],
    [[30,6,121,14,122],[28,6,47,34,48],[30,46,24,10,25],[30,2,15,64,16]],
    [[30,17,122,4,123],[28,29,46,14,47],[30,49,24,10,25],[30,24,15,46,16]],
    [[30,4,122,18,123],[28,13,46,32,47],[30,48,24,14,25],[30,42,15,32,16]],
    [[30,20,117,4,118],[28,40,47,7,48],[30,43,24,22,25],[30,10,15,67,16]],
    [[30,19,118,6,119],[28,18,47,31,48],[30,34,24,34,25],[30,20,15,61,16]],
];

#[rustfmt::skip]
const ALIGNMENT_POSITIONS: [&[u8]; 40] = [
    &[],
    &[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],
];

#[rustfmt::skip]
const REMAINDER_BITS: [u8; 40] = [
    0, 7, 7, 7, 7, 7, 0, 0, 0, 0, 0, 0, 0,
    3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4,
    3, 3, 3, 3, 3, 3, 3, 0, 0, 0, 0, 0, 0,
];