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Diffstat (limited to 'src/typo.c')
| -rw-r--r-- | src/typo.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/src/typo.c b/src/typo.c new file mode 100644 index 0000000..4012730 --- /dev/null +++ b/src/typo.c @@ -0,0 +1,176 @@ +/**************************************************************************** + * bfs * + * Copyright (C) 2016 Tavian Barnes <tavianator@tavianator.com> * + * * + * Permission to use, copy, modify, and/or distribute this software for any * + * purpose with or without fee is hereby granted. * + * * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * + ****************************************************************************/ + +#include "typo.h" +#include <limits.h> +#include <stdlib.h> +#include <string.h> + +// Assume QWERTY layout for now +static const int key_coords[UCHAR_MAX][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 int *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]; +} |