diff options
| -rw-r--r-- | src/learn-your-telephone-number.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/src/learn-your-telephone-number.c b/src/learn-your-telephone-number.c new file mode 100644 index 0000000..9c9f785 --- /dev/null +++ b/src/learn-your-telephone-number.c @@ -0,0 +1,171 @@ +#include <stdio.h> +#include <stdlib.h> +#include <ctype.h> +#include <alloca.h> +#include <errno.h> +#include <string.h> + + +#define t(...) do { if (__VA_ARGS__) goto fail; } while (0) + + +static const char* argv0; + + +char* compare(const char* restrict e, const char* restrict c) +{ + size_t en = strlen(e); + size_t cn = strlen(c); + size_t** matrix = alloca((en + 1) * sizeof(size_t*)); + char** path_matrix = alloca((en + 1) * sizeof(char*)); + size_t ei, ci, ri = 0; + char* rc = NULL; + + for (ei = 0; ei <= en; ei++) + { + matrix[ei] = alloca((cn + 1) * sizeof(size_t)); + matrix[ei][0] = ei; + path_matrix[ei] = alloca((cn + 1) * sizeof(char)); + path_matrix[ei][0] = '|'; + } + for (ci = 0; ci <= cn; ci++) + { + matrix[0][ci] = ci; + path_matrix[0][ci] = '-'; + } + path_matrix[0][0] = '\0'; + + e--, c--; + + for (ei = 1; ei <= en; ei++) + for (ci = 1; ci <= cn; ci++) + { + size_t d = matrix[ei - 1][ci - 1]; + size_t l = matrix[ei + 0][ci - 1]; + size_t u = matrix[ei - 1][ci + 0]; + size_t lu = 1 + (l < u ? l : u); + int ch = (e[ei] != c[ci]); + d += (size_t)ch; + matrix[ei][ci] = d < lu ? d : lu; + path_matrix[ei][ci] = d < lu ? (ch ? '\\' : '=') : (l < u ? '-' : '|'); + } + + t (!(rc = malloc((en + cn + 2) * sizeof(char)))); + +#if 0 + for (ei = 0; ei <= en; ei++) + { + for (ci = 0; ci <= cn; ci++) + printf("%zu%s", matrix[ei][ci], ci == cn ? "" : + path_matrix[ei][ci + 1] == '-' ? "\033[1;32m-\033[m" : " "); + printf("\n"); + if (ei < en) + for (ci = 0; ci < cn; ci++) + printf("%s%s", path_matrix[ei + 1][ci + 0] == '|' ? "\033[1;31m|\033[m" : " ", + path_matrix[ei + 1][ci + 1] == '\\' ? "\033[1;33m\\\033[m" : + path_matrix[ei + 1][ci + 1] == '=' ? "\033[1;39m\\\033[m" : " "); + printf("\n"); + } +#endif + + rc[ri++] = '\0'; + for (ei = en, ci = cn; ei + ci;) + switch (path_matrix[ei][ci]) + { + case '=': ei--, ci--; rc[ri++] = '='; break; + case '\\': ei--, ci--; rc[ri++] = '!'; break; + case '|': ei--; rc[ri++] = '-'; break; + case '-': ci--; rc[ri++] = '+'; break; + default: + abort(); + } + rc[ri] = '\0'; + + fail: + return rc; +} + + +int main(int argc, char* argv[]) +{ + char* correct; + char* entered = NULL; + size_t n = 0; + void* new; + char* w; + char* r; + char* path = NULL; + char* path_; + char* p; + int rc = 0; + + argv0 = argc ? argv[0] : "learn-your-telephone-number"; + if (argc != 2) + goto usage; + + correct = alloca((2 * strlen(argv[1]) + 1) * sizeof(char)); + for (w = correct, r = argv[1]; *r; r++) + if (isdigit(*r)) *w++ = *r; + else if (isalpha(*r)) goto usage; + else if (*r == '+') *w++ = '0', *w++ = '0'; + *w = '\0'; + + t (fprintf(stdout, "Enter your telephone number: ") < 0); + t (fflush(stdout)); + t (errno = 0, getline(&entered, &n, stdin) < 0); + n = strlen(entered) - 1; + entered[n] = '\0'; + + t (!(new = realloc(entered, (2 * n + 1) * sizeof(char)))); + entered = new; + memmove(r = (entered + n), w = (entered), n + 1); + for (; *r; r++) + if (isdigit(*r)) *w++ = *r; + else if (*r == '+') *w++ = '0', *w++ = '0'; + *w = '\0'; + + if (!strcmp(entered, correct)) + goto done; + t (!(path = compare(entered, correct))); + + path_ = strchr(path + 1, '\0'); + t (fprintf(stdout, "\033[A\033[KEntered: ") < 0); + for (p = entered; *--path_;) + switch (*path_) + { + case '=': t (fprintf(stdout, "\033[39m%c", *p++) < 0); break; + case '!': t (fprintf(stdout, "\033[31m%c", *p++) < 0); break; + case '+': t (fprintf(stdout, " ") < 0); break; + case '-': t (fprintf(stdout, "\033[31m%c", *p++) < 0); break; + } + t (fprintf(stdout, "\033[m\n") < 0); + + path_ = strchr(path + 1, '\0'); + t (fprintf(stdout, "Correct: ") < 0); + for (p = correct; *--path_;) + switch (*path_) + { + case '=': t (fprintf(stdout, "\033[39m%c", *p++) < 0); break; + case '!': t (fprintf(stdout, "\033[32m%c", *p++) < 0); break; + case '+': t (fprintf(stdout, "\033[32m%c", *p++) < 0); break; + case '-': t (fprintf(stdout, " ") < 0); break; + } + t (fprintf(stdout, "\033[m\n") < 0); + + rc = 1; + done: + free(entered); + free(path); + return rc; + fail: + rc = 1; + if (errno == 0) + goto done; + perror(argv0); + rc = 2; + goto done; + usage: + fprintf(stderr, "usage: %s YOUR-TELEPHONE-NUMBER\n", argv0); + return 2; +} + |