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
|
// Copyright © Tavian Barnes <tavianator@tavianator.com>
// SPDX-License-Identifier: 0BSD
#include "typo.h"
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
// Assume QWERTY layout for now
static const int8_t key_coords[UCHAR_MAX + 1][3] = {
['`'] = { 0, 0, 0},
['~'] = { 0, 0, 1},
['1'] = { 3, 0, 0},
['!'] = { 3, 0, 1},
['2'] = { 6, 0, 0},
['@'] = { 6, 0, 1},
['3'] = { 9, 0, 0},
['#'] = { 9, 0, 1},
['4'] = {12, 0, 0},
['$'] = {12, 0, 1},
['5'] = {15, 0, 0},
['%'] = {15, 0, 1},
['6'] = {18, 0, 0},
['^'] = {18, 0, 1},
['7'] = {21, 0, 0},
['&'] = {21, 0, 1},
['8'] = {24, 0, 0},
['*'] = {24, 0, 1},
['9'] = {27, 0, 0},
['('] = {27, 0, 1},
['0'] = {30, 0, 0},
[')'] = {30, 0, 1},
['-'] = {33, 0, 0},
['_'] = {33, 0, 1},
['='] = {36, 0, 0},
['+'] = {36, 0, 1},
['\t'] = { 1, 3, 0},
['q'] = { 4, 3, 0},
['Q'] = { 4, 3, 1},
['w'] = { 7, 3, 0},
['W'] = { 7, 3, 1},
['e'] = {10, 3, 0},
['E'] = {10, 3, 1},
['r'] = {13, 3, 0},
['R'] = {13, 3, 1},
['t'] = {16, 3, 0},
['T'] = {16, 3, 1},
['y'] = {19, 3, 0},
['Y'] = {19, 3, 1},
['u'] = {22, 3, 0},
['U'] = {22, 3, 1},
['i'] = {25, 3, 0},
['I'] = {25, 3, 1},
['o'] = {28, 3, 0},
['O'] = {28, 3, 1},
['p'] = {31, 3, 0},
['P'] = {31, 3, 1},
['['] = {34, 3, 0},
['{'] = {34, 3, 1},
[']'] = {37, 3, 0},
['}'] = {37, 3, 1},
['\\'] = {40, 3, 0},
['|'] = {40, 3, 1},
['a'] = { 5, 6, 0},
['A'] = { 5, 6, 1},
['s'] = { 8, 6, 0},
['S'] = { 8, 6, 1},
['d'] = {11, 6, 0},
['D'] = {11, 6, 1},
['f'] = {14, 6, 0},
['F'] = {14, 6, 1},
['g'] = {17, 6, 0},
['G'] = {17, 6, 1},
['h'] = {20, 6, 0},
['H'] = {20, 6, 1},
['j'] = {23, 6, 0},
['J'] = {23, 6, 1},
['k'] = {26, 6, 0},
['K'] = {26, 6, 1},
['l'] = {29, 6, 0},
['L'] = {29, 6, 1},
[';'] = {32, 6, 0},
[':'] = {32, 6, 1},
['\''] = {35, 6, 0},
['"'] = {35, 6, 1},
['\n'] = {38, 6, 0},
['z'] = { 6, 9, 0},
['Z'] = { 6, 9, 1},
['x'] = { 9, 9, 0},
['X'] = { 9, 9, 1},
['c'] = {12, 9, 0},
['C'] = {12, 9, 1},
['v'] = {15, 9, 0},
['V'] = {15, 9, 1},
['b'] = {18, 9, 0},
['B'] = {18, 9, 1},
['n'] = {21, 9, 0},
['N'] = {21, 9, 1},
['m'] = {24, 9, 0},
['M'] = {24, 9, 1},
[','] = {27, 9, 0},
['<'] = {27, 9, 1},
['.'] = {30, 9, 0},
['>'] = {30, 9, 1},
['/'] = {33, 9, 0},
['?'] = {33, 9, 1},
[' '] = {18, 12, 0},
};
static int char_distance(char a, char b) {
const int8_t *ac = key_coords[(unsigned char)a], *bc = key_coords[(unsigned char)b];
int ret = 0;
for (int i = 0; i < 3; ++i) {
ret += abs(ac[i] - bc[i]);
}
return ret;
}
int typo_distance(const char *actual, const char *expected) {
// This is the Wagner-Fischer algorithm for Levenshtein distance, using
// Manhattan distance on the keyboard for individual characters.
const int insert_cost = 12;
size_t rows = strlen(actual) + 1;
size_t cols = strlen(expected) + 1;
int arr0[cols], arr1[cols];
int *row0 = arr0, *row1 = arr1;
for (size_t j = 0; j < cols; ++j) {
row0[j] = insert_cost * j;
}
for (size_t i = 1; i < rows; ++i) {
row1[0] = row0[0] + insert_cost;
char a = actual[i - 1];
for (size_t j = 1; j < cols; ++j) {
char b = expected[j - 1];
int cost = row0[j - 1] + char_distance(a, b);
int del_cost = row0[j] + insert_cost;
if (del_cost < cost) {
cost = del_cost;
}
int ins_cost = row1[j - 1] + insert_cost;
if (ins_cost < cost) {
cost = ins_cost;
}
row1[j] = cost;
}
int *tmp = row0;
row0 = row1;
row1 = tmp;
}
return row0[cols - 1];
}
|
