+/**********************
+ * Boyer-Moore search *
+ **********************/
+
+typedef unsigned char ubyte_t;
+
+// reference: http://www-igm.univ-mlv.fr/~lecroq/string/node14.html
+static int *ksBM_prep(const ubyte_t *pat, int m)
+{
+ int i, *suff, *prep, *bmGs, *bmBc;
+ prep = (int*)calloc(m + 256, sizeof(int));
+ bmGs = prep; bmBc = prep + m;
+ { // preBmBc()
+ for (i = 0; i < 256; ++i) bmBc[i] = m;
+ for (i = 0; i < m - 1; ++i) bmBc[pat[i]] = m - i - 1;
+ }
+ suff = (int*)calloc(m, sizeof(int));
+ { // suffixes()
+ int f = 0, g;
+ suff[m - 1] = m;
+ g = m - 1;
+ for (i = m - 2; i >= 0; --i) {
+ if (i > g && suff[i + m - 1 - f] < i - g)
+ suff[i] = suff[i + m - 1 - f];
+ else {
+ if (i < g) g = i;
+ f = i;
+ while (g >= 0 && pat[g] == pat[g + m - 1 - f]) --g;
+ suff[i] = f - g;
+ }
+ }
+ }
+ { // preBmGs()
+ int j = 0;
+ for (i = 0; i < m; ++i) bmGs[i] = m;
+ for (i = m - 1; i >= 0; --i)
+ if (suff[i] == i + 1)
+ for (; j < m - 1 - i; ++j)
+ if (bmGs[j] == m)
+ bmGs[j] = m - 1 - i;
+ for (i = 0; i <= m - 2; ++i)
+ bmGs[m - 1 - suff[i]] = m - 1 - i;
+ }
+ free(suff);
+ return prep;
+}
+
+void *kmemmem(const void *_str, int n, const void *_pat, int m, int **_prep)
+{
+ int i, j, *prep = 0, *bmGs, *bmBc;
+ const ubyte_t *str, *pat;
+ str = (const ubyte_t*)_str; pat = (const ubyte_t*)_pat;
+ prep = (_prep == 0 || *_prep == 0)? ksBM_prep(pat, m) : *_prep;
+ if (_prep && *_prep == 0) *_prep = prep;
+ bmGs = prep; bmBc = prep + m;
+ j = 0;
+ while (j <= n - m) {
+ for (i = m - 1; i >= 0 && pat[i] == str[i+j]; --i);
+ if (i >= 0) {
+ int max = bmBc[str[i+j]] - m + 1 + i;
+ if (max < bmGs[i]) max = bmGs[i];
+ j += max;
+ } else return (void*)(str + j);
+ }
+ if (_prep == 0) free(prep);
+ return 0;
+}
+
+char *kstrstr(const char *str, const char *pat, int **_prep)
+{
+ return (char*)kmemmem(str, strlen(str), pat, strlen(pat), _prep);
+}
+
+char *kstrnstr(const char *str, const char *pat, int n, int **_prep)
+{
+ return (char*)kmemmem(str, n, pat, strlen(pat), _prep);
+}
+
+/***********************
+ * The main() function *
+ ***********************/
+