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/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
*
* Copyright (C) 2017 Philippe Proulx <pproulx@efficios.com>
*/
#include <linux/types.h>
#include <lttng-string-utils.h>
enum star_glob_pattern_type_flags {
STAR_GLOB_PATTERN_TYPE_FLAG_NONE = 0,
STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN = (1U << 0),
STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY = (1U << 1),
};
static
enum star_glob_pattern_type_flags strutils_test_glob_pattern(const char *pattern)
{
enum star_glob_pattern_type_flags ret =
STAR_GLOB_PATTERN_TYPE_FLAG_NONE;
const char *p;
for (p = pattern; *p != '\0'; p++) {
switch (*p) {
case '*':
ret = STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN;
if (p[1] == '\0') {
ret |= STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY;
}
goto end;
case '\\':
p++;
if (*p == '\0') {
goto end;
}
break;
default:
break;
}
}
end:
return ret;
}
/*
* Returns true if `pattern` is a star-only globbing pattern, that is,
* it contains at least one non-escaped `*`.
*/
bool strutils_is_star_glob_pattern(const char *pattern)
{
return strutils_test_glob_pattern(pattern) &
STAR_GLOB_PATTERN_TYPE_FLAG_PATTERN;
}
/*
* Returns true if `pattern` is a globbing pattern with a globbing,
* non-escaped star only at its very end.
*/
bool strutils_is_star_at_the_end_only_glob_pattern(const char *pattern)
{
return strutils_test_glob_pattern(pattern) &
STAR_GLOB_PATTERN_TYPE_FLAG_END_ONLY;
}
struct string_with_len {
const char *str;
size_t len;
};
static
char string_get_char_at_cb(size_t at, void *data)
{
struct string_with_len *string_with_len = data;
if (at >= string_with_len->len) {
return '\0';
}
return string_with_len->str[at];
}
/*
* Globbing matching function with the star feature only (`?` and
* character sets are not supported). This matches `candidate` (plain
* string) against `pattern`. A literal star can be escaped with `\` in
* `pattern`.
*
* `pattern_len` or `candidate_len` can be greater than the actual
* string length of `pattern` or `candidate` if the string is
* null-terminated.
*/
bool strutils_star_glob_match(const char *pattern, size_t pattern_len,
const char *candidate, size_t candidate_len) {
struct string_with_len pattern_with_len = {
pattern, pattern_len
};
struct string_with_len candidate_with_len = {
candidate, candidate_len
};
return strutils_star_glob_match_char_cb(string_get_char_at_cb,
&pattern_with_len, string_get_char_at_cb,
&candidate_with_len);
}
bool strutils_star_glob_match_char_cb(
strutils_get_char_at_cb pattern_get_char_at_cb,
void *pattern_get_char_at_cb_data,
strutils_get_char_at_cb candidate_get_char_at_cb,
void *candidate_get_char_at_cb_data)
{
size_t retry_p_at = 0, retry_c_at = 0, c_at, p_at;
char c, p, prev_p;
bool got_a_star = false;
retry:
c_at = retry_c_at;
c = candidate_get_char_at_cb(c_at, candidate_get_char_at_cb_data);
p_at = retry_p_at;
p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data);
/*
* The concept here is to retry a match in the specific case
* where we already got a star. The retry position for the
* pattern is just after the most recent star, and the retry
* position for the candidate is the character following the
* last try's first character.
*
* Example:
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^^
* pattern: hi*every*one
* ^^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^^
* pattern: hi*every*one
* ^^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^^
* pattern: hi*every*one
* ^^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^ MISMATCH
*
* candidate: hi ev every onyx one
* ^
* pattern: hi*every*one
* ^
*
* candidate: hi ev every onyx one
* ^^
* pattern: hi*every*one
* ^^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^
*
* candidate: hi ev every onyx one
* ^ ^
* pattern: hi*every*one
* ^ ^ SUCCESS
*/
while (c != '\0') {
if (p == '\0') {
goto end_of_pattern;
}
switch (p) {
case '*':
{
char retry_p;
got_a_star = true;
/*
* Our first try starts at the current candidate
* character and after the star in the pattern.
*/
retry_c_at = c_at;
retry_p_at = p_at + 1;
retry_p = pattern_get_char_at_cb(retry_p_at,
pattern_get_char_at_cb_data);
if (retry_p == '\0') {
/*
* Star at the end of the pattern at
* this point: automatic match.
*/
return true;
}
goto retry;
}
case '\\':
/* Go to escaped character. */
p_at++;
p = pattern_get_char_at_cb(p_at,
pattern_get_char_at_cb_data);
/*
* Fall through the default case which will
* compare the escaped character now.
*/
default:
if (p == '\0' || c != p) {
end_of_pattern:
/* Character mismatch OR end of pattern. */
if (!got_a_star) {
/*
* We didn't get any star yet,
* so this first mismatch
* automatically makes the whole
* test fail.
*/
return false;
}
/*
* Next try: next candidate character,
* original pattern character (following
* the most recent star).
*/
retry_c_at++;
goto retry;
}
break;
}
/* Next pattern and candidate characters. */
c_at++;
c = candidate_get_char_at_cb(c_at,
candidate_get_char_at_cb_data);
p_at++;
p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data);
}
/*
* We checked every candidate character and we're still in a
* success state: the only pattern character allowed to remain
* is a star.
*/
if (p == '\0') {
return true;
}
prev_p = p;
p_at++;
p = pattern_get_char_at_cb(p_at, pattern_get_char_at_cb_data);
return prev_p == '*' && p == '\0';
}
|