+/*
+ * regex_match_foo - Basic regex callbacks
+ *
+ * @str: the string to be searched
+ * @r: the regex structure containing the pattern string
+ * @len: the length of the string to be searched (including '\0')
+ *
+ * Note:
+ * - @str might not be NULL-terminated if it's of type DYN_STRING
+ * or STATIC_STRING
+ */
+
+static int regex_match_full(char *str, struct regex *r, int len)
+{
+ if (strncmp(str, r->pattern, len) == 0)
+ return 1;
+ return 0;
+}
+
+static int regex_match_front(char *str, struct regex *r, int len)
+{
+ if (strncmp(str, r->pattern, r->len) == 0)
+ return 1;
+ return 0;
+}
+
+static int regex_match_middle(char *str, struct regex *r, int len)
+{
+ if (strnstr(str, r->pattern, len))
+ return 1;
+ return 0;
+}
+
+static int regex_match_end(char *str, struct regex *r, int len)
+{
+ int strlen = len - 1;
+
+ if (strlen >= r->len &&
+ memcmp(str + strlen - r->len, r->pattern, r->len) == 0)
+ return 1;
+ return 0;
+}
+
+/**
+ * filter_parse_regex - parse a basic regex
+ * @buff: the raw regex
+ * @len: length of the regex
+ * @search: will point to the beginning of the string to compare
+ * @not: tell whether the match will have to be inverted
+ *
+ * This passes in a buffer containing a regex and this function will
+ * set search to point to the search part of the buffer and
+ * return the type of search it is (see enum above).
+ * This does modify buff.
+ *
+ * Returns enum type.
+ * search returns the pointer to use for comparison.
+ * not returns 1 if buff started with a '!'
+ * 0 otherwise.
+ */
+enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
+{
+ int type = MATCH_FULL;
+ int i;
+
+ if (buff[0] == '!') {
+ *not = 1;
+ buff++;
+ len--;
+ } else
+ *not = 0;
+
+ *search = buff;
+
+ for (i = 0; i < len; i++) {
+ if (buff[i] == '*') {
+ if (!i) {
+ *search = buff + 1;
+ type = MATCH_END_ONLY;
+ } else {
+ if (type == MATCH_END_ONLY)
+ type = MATCH_MIDDLE_ONLY;
+ else
+ type = MATCH_FRONT_ONLY;
+ buff[i] = 0;
+ break;
+ }
+ }
+ }
+
+ return type;
+}
+
+static void filter_build_regex(struct filter_pred *pred)
+{
+ struct regex *r = &pred->regex;
+ char *search;
+ enum regex_type type = MATCH_FULL;
+ int not = 0;
+
+ if (pred->op == OP_GLOB) {
+ type = filter_parse_regex(r->pattern, r->len, &search, ¬);
+ r->len = strlen(search);
+ memmove(r->pattern, search, r->len+1);
+ }
+
+ switch (type) {
+ case MATCH_FULL:
+ r->match = regex_match_full;
+ break;
+ case MATCH_FRONT_ONLY:
+ r->match = regex_match_front;
+ break;
+ case MATCH_MIDDLE_ONLY:
+ r->match = regex_match_middle;
+ break;
+ case MATCH_END_ONLY:
+ r->match = regex_match_end;
+ break;
+ }
+
+ pred->not ^= not;
+}
+