--- /dev/null
+/*
+ * 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();
+
+}
projects / xonotic / gmqcc.git / commitdiff