From a064261e854317bcc48aab31f86f3cbee67855c3 Mon Sep 17 00:00:00 2001
From: Ivan Nardi <12729895+IvanNardi@users.noreply.github.com>
Date: Sat, 11 May 2024 23:37:31 +0200
Subject: Revert `ndpi_strnstr()` optimization introduced in a813121e0 (#2439)
New implementation fails tests 11b, 12 and 13.
Revert to the original (BSD) implementation (with also some basic
parameters check)
---
example/ndpiReader.c | 10 ++++++++++
src/lib/ndpi_main.c | 51 ++++++++++++++++++---------------------------------
2 files changed, 28 insertions(+), 33 deletions(-)
diff --git a/example/ndpiReader.c b/example/ndpiReader.c
index 7a326f71b..cf26d0841 100644
--- a/example/ndpiReader.c
+++ b/example/ndpiReader.c
@@ -5691,6 +5691,16 @@ void strnstrUnitTest(void) {
/* Test 10: substring equal to the string */
assert(strcmp(ndpi_strnstr("string", "string", 6), "string") == 0);
+
+ /* Test 11a,b: max_length bigger that string length */
+ assert(strcmp(ndpi_strnstr("string", "string", 66), "string") == 0);
+ assert(ndpi_strnstr("string", "a", 66) == NULL);
+
+ /* Test 12: substring longer than the string */
+ assert(ndpi_strnstr("string", "stringA", 6) == NULL);
+
+ /* Test 13 */
+ assert(ndpi_strnstr("abcdef", "abc", 2) == NULL);
}
/* *********************************************** */
diff --git a/src/lib/ndpi_main.c b/src/lib/ndpi_main.c
index f15d0cb8f..eb5959dd6 100644
--- a/src/lib/ndpi_main.c
+++ b/src/lib/ndpi_main.c
@@ -9687,42 +9687,27 @@ void ndpi_dump_risks_score(FILE *risk_out) {
* first slen characters of s.
*/
char *ndpi_strnstr(const char *s, const char *find, size_t slen) {
- if (s == NULL || find == NULL || slen == 0) {
- return NULL;
- }
-
- char c = *find;
-
- if (c == '\0') {
- return (char *)s;
- }
-
- if (*(find + 1) == '\0') {
- return (char *)memchr(s, c, slen);
- }
-
- size_t find_len = strnlen(find, slen);
+ char c;
+ size_t len;
- if (find_len > slen) {
+ if(s == NULL || find == NULL || slen == 0)
return NULL;
- }
- const char *end = s + slen - find_len;
-
- while (s <= end) {
- if (memcmp(s, find, find_len) == 0) {
- return (char *)s;
- }
-
- size_t remaining_length = end - s;
- s = (char *)memchr(s + 1, c, remaining_length);
-
- if (s == NULL || s > end) {
- return NULL;
- }
- }
-
- return NULL;
+ if((c = *find++) != '\0') {
+ len = strnlen(find, slen);
+ do {
+ char sc;
+
+ do {
+ if(slen-- < 1 || (sc = *s++) == '\0')
+ return(NULL);
+ } while(sc != c);
+ if(len > slen)
+ return(NULL);
+ } while(strncmp(s, find, len) != 0);
+ s--;
+ }
+ return((char *) s);
}
/* ****************************************************** */
--
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