--- a/lib/strcasestr.c
+++ b/lib/strcasestr.c
@@ -29,127 +29,9 @@
 
 #define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
 
-/* Knuth-Morris-Pratt algorithm.
-   See http://en.wikipedia.org/wiki/Knuth-Morris-Pratt_algorithm
-   Return a boolean indicating success.  */
-static bool
-knuth_morris_pratt (const char *haystack, const char *needle,
-		    const char **resultp)
-{
-  size_t m = strlen (needle);
-
-  /* Allocate the table.  */
-  size_t *table = (size_t *) nmalloca (m, sizeof (size_t));
-  if (table == NULL)
-    return false;
-  /* Fill the table.
-     For 0 < i < m:
-       0 < table[i] <= i is defined such that
-       forall 0 < x < table[i]: needle[x..i-1] != needle[0..i-1-x],
-       and table[i] is as large as possible with this property.
-     This implies:
-     1) For 0 < i < m:
-          If table[i] < i,
-          needle[table[i]..i-1] = needle[0..i-1-table[i]].
-     2) For 0 < i < m:
-          rhaystack[0..i-1] == needle[0..i-1]
-          and exists h, i <= h < m: rhaystack[h] != needle[h]
-          implies
-          forall 0 <= x < table[i]: rhaystack[x..x+m-1] != needle[0..m-1].
-     table[0] remains uninitialized.  */
-  {
-    size_t i, j;
-
-    /* i = 1: Nothing to verify for x = 0.  */
-    table[1] = 1;
-    j = 0;
-
-    for (i = 2; i < m; i++)
-      {
-	/* Here: j = i-1 - table[i-1].
-	   The inequality needle[x..i-1] != needle[0..i-1-x] is known to hold
-	   for x < table[i-1], by induction.
-	   Furthermore, if j>0: needle[i-1-j..i-2] = needle[0..j-1].  */
-	unsigned char b = TOLOWER ((unsigned char) needle[i - 1]);
-
-	for (;;)
-	  {
-	    /* Invariants: The inequality needle[x..i-1] != needle[0..i-1-x]
-	       is known to hold for x < i-1-j.
-	       Furthermore, if j>0: needle[i-1-j..i-2] = needle[0..j-1].  */
-	    if (b == TOLOWER ((unsigned char) needle[j]))
-	      {
-		/* Set table[i] := i-1-j.  */
-		table[i] = i - ++j;
-		break;
-	      }
-	    /* The inequality needle[x..i-1] != needle[0..i-1-x] also holds
-	       for x = i-1-j, because
-	         needle[i-1] != needle[j] = needle[i-1-x].  */
-	    if (j == 0)
-	      {
-		/* The inequality holds for all possible x.  */
-		table[i] = i;
-		break;
-	      }
-	    /* The inequality needle[x..i-1] != needle[0..i-1-x] also holds
-	       for i-1-j < x < i-1-j+table[j], because for these x:
-		 needle[x..i-2]
-		 = needle[x-(i-1-j)..j-1]
-		 != needle[0..j-1-(x-(i-1-j))]  (by definition of table[j])
-		    = needle[0..i-2-x],
-	       hence needle[x..i-1] != needle[0..i-1-x].
-	       Furthermore
-		 needle[i-1-j+table[j]..i-2]
-		 = needle[table[j]..j-1]
-		 = needle[0..j-1-table[j]]  (by definition of table[j]).  */
-	    j = j - table[j];
-	  }
-	/* Here: j = i - table[i].  */
-      }
-  }
-
-  /* Search, using the table to accelerate the processing.  */
-  {
-    size_t j;
-    const char *rhaystack;
-    const char *phaystack;
-
-    *resultp = NULL;
-    j = 0;
-    rhaystack = haystack;
-    phaystack = haystack;
-    /* Invariant: phaystack = rhaystack + j.  */
-    while (*phaystack != '\0')
-      if (TOLOWER ((unsigned char) needle[j])
-	  == TOLOWER ((unsigned char) *phaystack))
-	{
-	  j++;
-	  phaystack++;
-	  if (j == m)
-	    {
-	      /* The entire needle has been found.  */
-	      *resultp = rhaystack;
-	      break;
-	    }
-	}
-      else if (j > 0)
-	{
-	  /* Found a match of needle[0..j-1], mismatch at needle[j].  */
-	  rhaystack += table[j];
-	  j -= table[j];
-	}
-      else
-	{
-	  /* Found a mismatch at needle[0] already.  */
-	  rhaystack++;
-	  phaystack++;
-	}
-  }
-
-  freea (table);
-  return true;
-}
+/* Knuth-Morris-Pratt algorithm.  */
+#define CANON_ELEMENT(c) TOLOWER (c)
+#include "str-kmp.h"
 
 /* Find the first occurrence of NEEDLE in HAYSTACK, using case-insensitive
    comparison.
@@ -212,7 +94,7 @@
 		  /* Try the Knuth-Morris-Pratt algorithm.  */
 		  const char *result;
 		  bool success =
-		    knuth_morris_pratt (haystack, needle - 1, &result);
+		    knuth_morris_pratt_unibyte (haystack, needle - 1, &result);
 		  if (success)
 		    return (char *) result;
 		  try_kmp = false;