From 861987e13efd3967037017f74152bcc1afbbe257 Mon Sep 17 00:00:00 2001 From: Dale Weiler Date: Thu, 3 Jan 2013 19:39:41 +0000 Subject: [PATCH] Work on "did you mean? " support for errors. Using a three-part Bayes Theorem expression (language model, error model and control mechanisim). --- correct.c | 402 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ util.c | 8 ++ 2 files changed, 410 insertions(+) create mode 100644 correct.c diff --git a/correct.c b/correct.c new file mode 100644 index 0000000..ded5144 --- /dev/null +++ b/correct.c @@ -0,0 +1,402 @@ +/* + * Copyright (C) 2012, 2013 + * Dale Weiler + * + * Permission is hereby granted, free of charge, to any person obtaining a copy of + * this software and associated documentation files (the "Software"), to deal in + * the Software without restriction, including without limitation the rights to + * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies + * of the Software, and to permit persons to whom the Software is furnished to do + * so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ +#include "gmqcc.h" + +/* + * This is a very clever method for correcting mistakes in QuakeC code + * most notably when invalid identifiers are used or inproper assignments; + * we can proprly lookup in multiple dictonaries (depening on the rules + * of what the task is trying to acomplish) to find the best possible + * match. + * + * + * A little about how it works, and probability theory: + * + * When given an identifier (which we will denote I), we're essentially + * just trying to choose the most likely correction for that identifier. + * (the actual "correction" can very well be the identifier itself). + * There is actually no way to know for sure that certian identifers + * such as "lates", need to be corrected to "late" or "latest" or any + * other permutations that look lexically the same. This is why we + * must advocate the usage of probabilities. This implies that we're + * trying to find the correction for C, out of all possible corrections + * that maximizes the probability of C for the original identifer I. + * + * Bayes' Therom suggests something of the following: + * AC P(I|C) P(C) / P(I) + * Since P(I) is the same for every possibly I, we can ignore it giving + * AC P(I|C) P(C) + * + * This greatly helps visualize how the parts of the expression are performed + * there is essentially three, from right to left we perform the following: + * + * 1: P(C), the probability that a proposed correction C will stand on its + * own. This is called the language model. + * + * 2: P(I|C), the probability that I would be used, when the programmer + * really meant C. This is the error model. + * + * 3: AC, the control mechanisim, which implies the enumeration of all + * feasible values of C, and then determine the one that gives the + * greatest probability score. Selecting it as the "correction" + * + * + * The requirement for complex expression involving two models: + * + * In reality the requirement for a more complex expression involving + * two seperate models is considerably a waste. But one must recognize + * that P(C|I) is already conflating two factors. It's just much simpler + * to seperate the two models and deal with them explicitaly. To properly + * estimate P(C|I) you have to consider both the probability of C and + * probability of the transposition from C to I. It's simply much more + * cleaner, and direct to seperate the two factors. + */ + +/* some hashtable management for dictonaries */ +static size_t *correct_find(ht table, const char *word) { + return (size_t*)util_htget(table, word); +} + +static int correct_update(ht *table, const char *word) { + size_t *data = correct_find(*table, word); + if (!data) + return 0; + + (*data)++; + return 1; +} + + +/* + * _ is valid in identifiers. I've yet to implement numerics however + * because they're only valid after the first character is of a _, or + * alpha character. + */ +static const char correct_alpha[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_"; +static char *correct_substr(const char *str, size_t off, size_t lim) { + char *nstr; + size_t slen = strlen(str); + + /* lots of compares */ + if ((lim > slen) || ((off + lim) > slen) || (slen < 1) || (!lim)) + return NULL; + + if (!(nstr = mem_a(lim + 1))) + return NULL; + + strncpy(nstr, str+off, lim); + nstr[lim] = '\0'; + + return nstr; +} + +static char *correct_concat(char *str1, char *str2) { + if (!str1) str1 = mem_a(1), *str1 = '\0'; + if (!str2) str2 = mem_a(1), *str2 = '\0'; + + str1 = mem_r(str1, strlen(str1) + strlen(str2) + 1); + strcat(str1, str2); + + return str1; +} + +/* + * correcting logic for the following forms of transformations: + * 1) deletion + * 2) transposition + * 3) alteration + * 4) insertion + */ +static size_t correct_deletion(const char *ident, char **array, size_t index) { + size_t itr; + size_t len = strlen(ident); + + for (itr = 0; itr < len; itr++) { + array[index + itr] = correct_concat ( + correct_substr (ident, 0, itr), + correct_substr (ident, itr+1, len-(itr+1)) + ); + } + + return itr; +} + +static size_t correct_transposition(const char *ident, char **array, size_t index) { + size_t itr; + size_t len = strlen(ident); + + for (itr = 0; itr < len - 1; itr++) { + array[index + itr] = correct_concat ( + correct_concat ( + correct_substr(ident, 0, itr), + correct_substr(ident, itr+1, 1) + ), + correct_concat ( + correct_substr(ident, itr, 1), + correct_substr(ident, itr+2, len-(itr+2)) + ) + ); + } + + return itr; +} + +static size_t correct_alteration(const char *ident, char **array, size_t index) { + size_t itr; + size_t jtr; + size_t ktr; + size_t len = strlen(ident); + char cct[2] = { 0, 0 }; /* char code table, for concatenation */ + + for (itr = 0, ktr = 0; itr < len; itr++) { + for (jtr = 0; jtr < sizeof(correct_alpha); jtr++, ktr++) { + *cct = correct_alpha[jtr]; + array[index + ktr] = correct_concat ( + correct_concat ( + correct_substr(ident, 0, itr), + (char *) &cct + ), + correct_substr ( + ident, + itr + 1, + len - (itr + 1) + ) + ); + } + } + + return ktr; +} + +static size_t correct_insertion(const char *ident, char **array, size_t index) { + size_t itr; + size_t jtr; + size_t ktr; + size_t len = strlen(ident); + char cct[2] = { 0, 0 }; /* char code table, for concatenation */ + + for (itr = 0, ktr = 0; itr <= len; itr++) { + for (jtr = 0; jtr < sizeof(correct_alpha); jtr++, ktr++) { + *cct = correct_alpha[jtr]; + array[index + ktr] = correct_concat ( + correct_concat ( + correct_substr (ident, 0, itr), + (char *) &cct + ), + correct_substr ( + ident, + itr, + len - itr + ) + ); + } + } + + return ktr; +} + +static GMQCC_INLINE size_t correct_size(const char *ident) { + /* + * deletion = len + * transposition = len - 1 + * alteration = len * sizeof(correct_alpha) + * insertion = (len + 1) * sizeof(correct_alpha) + */ + + register size_t len = strlen(ident); + return (len) + (len - 1) + (len * sizeof(correct_alpha)) + (len + 1) * sizeof(correct_alpha); +} + +static char **correct_edit(const char *ident) { + size_t next; + char **find = mem_a(correct_size(ident) * sizeof(char*)); + + if (!find) + return NULL; + + next = correct_deletion (ident, find, 0); + next += correct_transposition(ident, find, next); + next += correct_alteration (ident, find, next); + /*****/ correct_insertion (ident, find, next); + + return find; +} + +/* + * We could use a hashtable but the space complexity isn't worth it + * since we're only going to determine the "did you mean?" identifier + * on error. + */ +static int correct_exist(char **array, size_t rows, char *ident) { + size_t itr; + for (itr = 0; itr < rows; itr++) + if (!strcmp(array[itr], ident)) + return 1; + + return 0; +} + +static char **correct_known(ht table, char **array, size_t rows, size_t *next) { + size_t itr; + size_t jtr; + size_t len; + size_t row; + char **res = NULL; + char **end; + + for (itr = 0, len = 0; itr < rows; itr++) { + end = correct_edit(array[itr]); + row = correct_size(array[itr]); + + for (jtr = 0; jtr < row; jtr++) { + if (correct_find(table, end[jtr]) && !correct_exist(res, len, end[jtr])) { + res = mem_r(res, sizeof(char*) * (len + 1)); + res[len++] = end[jtr]; + } + } + } + + *next = len; + return res; +} + +static char *correct_maximum(ht table, char **array, size_t rows) { + char *str = NULL; + size_t *itm = NULL; + size_t itr; + size_t top; + + for (itr = 0, top = 0; itr < rows; itr++) { + if ((itm = correct_find(table, array[itr])) && (*itm > top)) { + top = *itm; + str = array[itr]; + } + } + + return str; +} + +static void correct_cleanup(char **array, size_t rows) { + size_t itr; + for (itr = 0; itr < rows; itr++) + mem_d(array[itr]); +} + +/* + * This is the exposed interface: + * takes a table for the dictonary a vector of sizes (used for internal + * probability calculation, and an identifier to "correct" + * + * the add function works the same. Except the identifier is used to + * add to the dictonary. + */ +void correct_add(ht table, size_t ***size, const char *ident) { + size_t *data = NULL; + const char *add = ident; + + if (!correct_update(&table, add)) { + data = (size_t*)mem_a(sizeof(size_t)); + *data = 1; + + vec_push((*size), data); + util_htset(table, add, data); + } +} + +char *correct_correct(ht table, const char *ident) { + char **e1; + char **e2; + char *e1ident; + char *e2ident; + char *found = util_strdup(ident); + + size_t e1rows; + size_t e2rows; + + /* needs to be allocated for free later */ + if (correct_find(table, ident)) + return found; + + mem_d(found); + if ((e1rows = correct_size(ident))) { + e1 = correct_edit(ident); + + if ((e1ident = correct_maximum(table, e1, e1rows))) { + found = util_strdup(e1ident); + correct_cleanup(e1, e1rows); + mem_d(e1); + return found; + } + } + + e2 = correct_known(table, e1, e1rows, &e2rows); + if (e2rows && ((e2ident = correct_maximum(table, e2, e2rows)))) + found = util_strdup(e2ident); + + correct_cleanup(e1, e1rows); + correct_cleanup(e2, e2rows); + + mem_d(e1); + mem_d(e2); + + return found; +} + +void correct_del(ht dictonary, size_t **data) { + size_t i; + for (i = 0; i < vec_size(data); i++) + mem_d(data[i]); + + vec_free(data); + util_htdel(dictonary); +} + +int main() { + opts.debug = true; + opts.memchk = true; + con_init(); + + ht t = util_htnew(1024); + size_t **d = NULL; + + correct_add(t, &d, "hellobain"); + correct_add(t, &d, "ellor"); + correct_add(t, &d, "world"); + + printf("found identifiers: (2)\n"); + printf(" 1: hello\n"); + printf(" 2: world\n"); + + char *b = correct_correct(t, "rld"); + char *a = correct_correct(t, "ello"); + + printf("%s, did you mean `%s` ?\n", "ello", a); + printf("%s, did you mean `%s` ?\n", "rld", b); + + correct_del(t, d); + mem_d(b); + mem_d(a); + + util_meminfo(); + +} diff --git a/util.c b/util.c index 5d0d683..c2393f1 100644 --- a/util.c +++ b/util.c @@ -54,7 +54,10 @@ void *util_memory_a(size_t byte, unsigned int line, const char *file) { mem_start->prev = info; mem_start = info; + #if 0 util_debug("MEM", "allocation: % 8u (bytes) address 0x%08X @ %s:%u\n", byte, data, file, line); + #endif + mem_at++; mem_ab += info->byte; @@ -67,7 +70,10 @@ void util_memory_d(void *ptrn, unsigned int line, const char *file) { if (!ptrn) return; info = ((struct memblock_t*)ptrn - 1); + #if 0 util_debug("MEM", "released: % 8u (bytes) address 0x%08X @ %s:%u\n", info->byte, ptrn, file, line); + #endif + mem_db += info->byte; mem_dt++; @@ -96,7 +102,9 @@ void *util_memory_r(void *ptrn, size_t byte, unsigned int line, const char *file oldinfo = ((struct memblock_t*)ptrn - 1); newinfo = ((struct memblock_t*)malloc(sizeof(struct memblock_t) + byte)); + #if 0 util_debug("MEM", "reallocation: % 8u -> %u (bytes) address 0x%08X -> 0x%08X @ %s:%u\n", oldinfo->byte, byte, ptrn, (void*)(newinfo+1), file, line); + #endif /* new data */ if (!newinfo) { -- 2.39.2