int main()
{
char *text = "ababababca";
char *s = "ababca";
char *result = NULL;
int i;
KMP_MATCH *pkmp = kmp_init(s, strlen(s));
if (pkmp == NULL)
{
return 0;
}
result = kmp_match(text, strlen(text), pkmp);
if (result)
{
printf("found: offset is %d\n", result-text);
}
else
{
printf("not found\n");
}
kmp_free(pkmp);
return 0;
}
/**
* @brief kmp The kmp algorithm.
*
* @param matcher The buffer.
* @param mlen Buffer length.
* @param pattern The pattern.
* @param plen Pattern length.
*
* @return The place of pattern in buffer.
*/
int kmp(const char *matcher, int mlen, const char *pattern, int plen)
{
// this function does string matching using the KMP algothm.
// matcher and pattern are pointers to BINARY sequencies, while mlen
// and plen are their lengths respectively.
// if a match is found, return its position immediately.
// return -1 if no match can be found.
if(!mlen || !plen || mlen < plen) // take care of illegal parameters
return -1;
kmp_init(pattern, plen); // prefix-function
int i=0, j=0;
while(i < mlen && j < plen) // don't increase i and j at this level
{
if(matcher[i+j] == pattern[j])
j++;
else if(j == 0) // dismatch: matcher[i] vs pattern[0]
i++;
else // dismatch: matcher[i+j] vs pattern[j], and j>0
{
i = i + j - pi[j-1]; // i: jump forward by (j - pi[j-1])
j = pi[j-1]; // j: reset to the proper position
}
}
if(j == plen) // found a match!!
{
return i;
}
else // if no match was found
return -1;
}
tuple<int, int> match(int n) {
kmp_init(n, vr);
for (int i = 0; i < n; ++i) {
vs[i + n] = vs[i];
}
// print("next: ");
// for (int i = 0; i < n; ++i) {
// print("{} ", next[i]);
// }
// print("\n");
for (int i = 0, j = -1; i < n * 2; ++i) {
for (; j > -2 && vs[i] != vr[j + 1]; j = j == -1 ? -2 : next[j]);
++j;
if (j == n - 1) {
// print("i = {}, j = {}, nx = {}\n", i, j, next[n - 1]);
int period = n - next[n - 1] - 1;
if (n % period != 0) period = n;
return {period, (1 + i % period) % period};
}
}
return {0, 0};
}
/// Initialize pools for reusing commonly created objects
void wstream_init(void)
{
wrequest_pool = kmp_init(WRequestPool);
wbuffer_pool = kmp_init(WBufferPool);
}
// Initialise the hash tables that are needed
void initHashes() {
csPool = kmp_init(csPool);
clientStatuses = kh_init(clientStatuses); // Malloc the hash
queue = kh_init(queue);
}
