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Better metacharacter match

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This commit is contained in:
Sergey Lyubka 2013-09-30 19:30:50 +01:00
parent b2fb7a7126
commit 28444bb685
1 changed files with 43 additions and 27 deletions
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slre.c
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@ -32,13 +32,13 @@ static const char *static_error_invalid_set = "Invalid [] spec";
static const char *static_error_invalid_metacharacter = "Invalid metacharacter"; static const char *static_error_invalid_metacharacter = "Invalid metacharacter";
static const char *static_error_more_caps = "Caps array is too small"; static const char *static_error_more_caps = "Caps array is too small";
static const char *static_metacharacters = "^$().[]*+?|\\"; static const char *static_metacharacters = "^$().[]*+?|\\Ssd";
#define MAX_BRANCHES 100 #define MAX_BRANCHES 100
#define MAX_BRACKETS 100 #define MAX_BRACKETS 100
#define ARRAY_SIZE(ar) (int) (sizeof(ar) / sizeof((ar)[0])) #define ARRAY_SIZE(ar) (int) (sizeof(ar) / sizeof((ar)[0]))
#define FAIL_IF(cond,msg) do { if (cond) \ #define FAIL_IF(cond,msg) do { if (cond) \
{info->error_msg = msg; return 0; }} while (0) {info->error_msg = msg; return -1; }} while (0)
#ifdef SLRE_DEBUG #ifdef SLRE_DEBUG
#define DBG(x) printf x #define DBG(x) printf x
@ -144,19 +144,14 @@ static int match_op(const unsigned char *re, const unsigned char *s,
case 'x': case 'x':
/* Match byte, \xHH where HH is hexadecimal byte representaion */ /* Match byte, \xHH where HH is hexadecimal byte representaion */
FAIL_IF(!(isxdigit(re[2]) && isxdigit(re[3])),
static_error_invalid_metacharacter);
FAIL_IF(hextoi(re + 2) != *s, static_error_no_match); FAIL_IF(hextoi(re + 2) != *s, static_error_no_match);
result++; result++;
break; break;
default: default:
if (is_metacharacter(re + 1)) { /* Valid metacharacter check is done in bar() */
FAIL_IF(re[1] != s[0], static_error_no_match); FAIL_IF(re[1] != s[0], static_error_no_match);
result++; result++;
} else {
FAIL_IF(1, static_error_invalid_metacharacter);
}
break; break;
} }
break; break;
@ -180,11 +175,11 @@ static int match_op(const unsigned char *re, const unsigned char *s,
static int match_set(const char *re, int re_len, const char *s, static int match_set(const char *re, int re_len, const char *s,
struct regex_info *info) { struct regex_info *info) {
int len = 0, result = 0, invert = re[0] == '^'; int len = 0, result = -1, invert = re[0] == '^';
if (invert) re++, re_len--; if (invert) re++, re_len--;
while (len <= re_len && re[len] != ']' && result == 0) { while (len <= re_len && re[len] != ']' && result <= 0) {
/* Support character range */ /* Support character range */
if (re[len] != '-' && re[len + 1] == '-' && re[len + 2] != ']' && if (re[len] != '-' && re[len + 1] == '-' && re[len + 2] != ']' &&
re[len + 2] != '\0') { re[len + 2] != '\0') {
@ -197,7 +192,7 @@ static int match_set(const char *re, int re_len, const char *s,
len += op_len(re + len); len += op_len(re + len);
} }
} }
return (!invert && result) || (invert && !result) ? 1 : 0; return (!invert && result > 0) || (invert && result <= 0) ? 1 : -1;
} }
static int doh(const char *s, int s_len, struct regex_info *info, int bi); static int doh(const char *s, int s_len, struct regex_info *info, int bi);
@ -213,7 +208,7 @@ static int bar(const char *re, int re_len, const char *s, int s_len,
step = re[i] == '(' ? info->brackets[bi + 1].len + 2 : step = re[i] == '(' ? info->brackets[bi + 1].len + 2 :
get_op_len(re + i, re_len - i); get_op_len(re + i, re_len - i);
DBG(("%s [%.*s] [%.*s] re_len=%d step=%d i=%d j=%d\n", __func__, DBG(("%s [%.*s] [%.*s] re_len=%d step=%d i=%d j=%d\n", __func__,
re_len - i, re + i, s_len - j, s + j, re_len, step, i, j)); re_len - i, re + i, s_len - j, s + j, re_len, step, i, j));
FAIL_IF(is_quantifier(&re[i]), static_error_unexpected_quantifier); FAIL_IF(is_quantifier(&re[i]), static_error_unexpected_quantifier);
@ -222,7 +217,8 @@ static int bar(const char *re, int re_len, const char *s, int s_len,
if (i + step < re_len && is_quantifier(re + i + step)) { if (i + step < re_len && is_quantifier(re + i + step)) {
DBG(("QUANTIFIER: [%.*s] %c %d\n", step, re + i, re[i + step], j)); DBG(("QUANTIFIER: [%.*s] %c %d\n", step, re + i, re[i + step], j));
if (re[i + step] == '?') { if (re[i + step] == '?') {
j += bar(re + i, step, s + j, s_len - j, info, bi); int result = bar(re + i, step, s + j, s_len - j, info, bi);
j += result > 0 ? result : 0;
i++; i++;
} else if (re[i + step] == '+' || re[i + step] == '*') { } else if (re[i + step] == '+' || re[i + step] == '*') {
int j2 = j, nj = j, n1, n2, ni, non_greedy = 0; int j2 = j, nj = j, n1, n2, ni, non_greedy = 0;
@ -239,7 +235,7 @@ static int bar(const char *re, int re_len, const char *s, int s_len,
/* After quantifier, there is nothing */ /* After quantifier, there is nothing */
nj = j2 + n1; nj = j2 + n1;
} else if ((n2 = bar(re + ni, re_len - ni, s + j2 + n1, } else if ((n2 = bar(re + ni, re_len - ni, s + j2 + n1,
s_len - (j2 + n1), info, bi)) > 0) { s_len - (j2 + n1), info, bi)) >= 0) {
nj = j2 + n1 + n2; nj = j2 + n1 + n2;
} }
if (nj > j && non_greedy) break; if (nj > j && non_greedy) break;
@ -265,7 +261,7 @@ static int bar(const char *re, int re_len, const char *s, int s_len,
DBG(("CAPTURING [%.*s] [%.*s]\n", step, re + i, s_len - j, s + j)); DBG(("CAPTURING [%.*s] [%.*s]\n", step, re + i, s_len - j, s + j));
n = doh(s + j, s_len - j, info, bi); n = doh(s + j, s_len - j, info, bi);
DBG(("CAPTURED [%.*s] [%.*s]:%d\n", step, re + i, s_len - j, s + j, n)); DBG(("CAPTURED [%.*s] [%.*s]:%d\n", step, re + i, s_len - j, s + j, n));
FAIL_IF(n <= 0 && j < s_len, info->error_msg); FAIL_IF(n < 0, info->error_msg);
if (info->caps != NULL) { if (info->caps != NULL) {
info->caps[bi - 1].ptr = s + j; info->caps[bi - 1].ptr = s + j;
info->caps[bi - 1].len = n; info->caps[bi - 1].len = n;
@ -306,14 +302,15 @@ static int doh(const char *s, int s_len, struct regex_info *info, int bi) {
} }
static int baz(const char *s, int s_len, struct regex_info *info) { static int baz(const char *s, int s_len, struct regex_info *info) {
int i, result = 0, is_anchored = info->brackets[0].ptr[0] == '^'; int i, result = -1, is_anchored = info->brackets[0].ptr[0] == '^';
for (i = 0; i < s_len; i++) { for (i = 0; i <= s_len; i++) {
result = doh(s + i, s_len - i, info, 0); result = doh(s + i, s_len - i, info, 0);
if (result > 0 || is_anchored) { if (result >= 0) {
result += i; result += i;
break; break;
} }
if (is_anchored) break;
} }
return result; return result;
@ -372,6 +369,18 @@ static int foo(const char *re, int re_len, const char *s, int s_len,
info->num_brackets - 1 : depth; info->num_brackets - 1 : depth;
info->branches[info->num_branches].schlong = &re[i]; info->branches[info->num_branches].schlong = &re[i];
info->num_branches++; info->num_branches++;
} else if (re[i] == '\\') {
FAIL_IF(i >= re_len - 1, static_error_invalid_metacharacter);
if (re[i + 1] == 'x') {
/* Hex digit specification must follow */
FAIL_IF(re[i + 1] == 'x' && i >= re_len - 3,
static_error_invalid_metacharacter);
FAIL_IF(re[i + 1] == 'x' && !(isxdigit(re[i + 2]) &&
isxdigit(re[i + 3])), static_error_invalid_metacharacter);
} else {
FAIL_IF(!is_metacharacter((unsigned char *) re + i + 1),
static_error_invalid_metacharacter);
}
} else if (re[i] == '(') { } else if (re[i] == '(') {
FAIL_IF(info->num_brackets >= ARRAY_SIZE(info->brackets), FAIL_IF(info->num_brackets >= ARRAY_SIZE(info->brackets),
"Too many (. Increase MAX_BRACKETS"); "Too many (. Increase MAX_BRACKETS");
@ -425,7 +434,7 @@ int slre_match(const char *regexp, const char *s, int s_len,
*error_msg = info.error_msg; *error_msg = info.error_msg;
} }
return result; return result > 0 ? result : 0;
} }
@ -482,17 +491,20 @@ int main(void) {
struct slre_cap caps[10]; struct slre_cap caps[10];
/* Metacharacters */ /* Metacharacters */
#if 0
ASSERT(slre_match("$", "abcd", 4, NULL, 0, &msg) == 4); ASSERT(slre_match("$", "abcd", 4, NULL, 0, &msg) == 4);
ASSERT(slre_match("^", "abcd", 4, NULL, 0, &msg) == 0); ASSERT(slre_match("^", "abcd", 4, NULL, 0, &msg) == 0);
ASSERT(slre_match("x|^", "abcd", 4, NULL, 0, &msg) == 0); ASSERT(slre_match("x|^", "abcd", 4, NULL, 0, &msg) == 0);
ASSERT(slre_match("x|$", "abcd", 4, NULL, 0, &msg) == 4); ASSERT(slre_match("x|$", "abcd", 4, NULL, 0, &msg) == 4);
ASSERT(slre_match("x", "abcd", 4, NULL, 0, &msg) == -1); ASSERT(slre_match("x", "abcd", 4, NULL, 0, &msg) == 0);
ASSERT(slre_match("\\\\", "c:\\Tools", 8, NULL, 0, &msg) == 3); ASSERT(slre_match(".", "abcd", 4, NULL, 0, &msg) == 1);
ASSERT(slre_match("\\\\.*", "c:\\Tools", 8, NULL, 0, &msg) == 8);
ASSERT(slre_match("\\\\.*$", "c:\\Tools", 8, NULL, 0, &msg) == 8);
ASSERT(slre_match("(?i)^.*\\\\.*$", "c:\\Tools", 8, NULL, 0, &msg) == 8); ASSERT(slre_match("(?i)^.*\\\\.*$", "c:\\Tools", 8, NULL, 0, &msg) == 8);
#endif ASSERT(slre_match("\\", "a", 1, NULL, 0, &msg) == 0);
ASSERT(strcmp(msg, static_error_invalid_metacharacter) == 0);
ASSERT(slre_match("\\x", "a", 1, NULL, 0, &msg) == 0);
ASSERT(strcmp(msg, static_error_invalid_metacharacter) == 0);
ASSERT(slre_match("\\x1", "a", 1, NULL, 0, &msg) == 0);
ASSERT(strcmp(msg, static_error_invalid_metacharacter) == 0);
ASSERT(slre_match("\\x20", " ", 1, NULL, 0, &msg) == 1);
/* Character sets */ /* Character sets */
ASSERT(slre_match("[abc]", "1c2", 3, NULL, 0, &msg) == 2); ASSERT(slre_match("[abc]", "1c2", 3, NULL, 0, &msg) == 2);
@ -618,6 +630,10 @@ int main(void) {
ASSERT(slre_match("[b-z].*", "ab", 2, NULL, 0, &msg) == 2); ASSERT(slre_match("[b-z].*", "ab", 2, NULL, 0, &msg) == 2);
ASSERT(slre_match("(b|z|u).*", "ab", 2, NULL, 0, &msg) == 2); ASSERT(slre_match("(b|z|u).*", "ab", 2, NULL, 0, &msg) == 2);
ASSERT(slre_match("ab(k|z|y)?", "ab", 2, NULL, 0, &msg) == 2); ASSERT(slre_match("ab(k|z|y)?", "ab", 2, NULL, 0, &msg) == 2);
ASSERT(slre_match(".*", "ab", 2, NULL, 0, &msg) == 2);
ASSERT(slre_match(".*$", "ab", 2, NULL, 0, &msg) == 2);
ASSERT(slre_match("a+$", "a", 1, NULL, 0, &msg) == 1);
ASSERT(slre_match("a*$", "a", 1, NULL, 0, &msg) == 1);
{ {
/* Example: HTTP request */ /* Example: HTTP request */