/* Case-insensitive searching in a string.
- Copyright (C) 2005-2007 Free Software Foundation, Inc.
+ Copyright (C) 2005-2008 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2005.
This program is free software: you can redistribute it and/or modify
#include <stddef.h> /* for NULL, in case a nonstandard string.h lacks it */
#include "malloca.h"
-#if HAVE_MBRTOWC
-# include "mbuiter.h"
-#endif
+#include "mbuiter.h"
#define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
+/* Knuth-Morris-Pratt algorithm. */
+#define CANON_ELEMENT(c) TOLOWER (c)
+#include "str-kmp.h"
+
/* Knuth-Morris-Pratt algorithm.
See http://en.wikipedia.org/wiki/Knuth-Morris-Pratt_algorithm
- Return a boolean indicating success. */
-
-static bool
-knuth_morris_pratt_unibyte (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;
-}
-
-#if HAVE_MBRTOWC
+ Return a boolean indicating success:
+ Return true and set *RESULTP if the search was completed.
+ Return false if it was aborted because not enough memory was available. */
static bool
knuth_morris_pratt_multibyte (const char *haystack, const char *needle,
const char **resultp)
freea (memory);
return true;
}
-#endif
/* Find the first occurrence of the character string NEEDLE in the character
string HAYSTACK, using case-insensitive comparison.
- haystack may be very long, and a match of needle found early,
- needle may be very long, and not even a short initial segment of
needle may be found in haystack. */
-#if HAVE_MBRTOWC
if (MB_CUR_MAX > 1)
{
mbui_iterator_t iter_needle;
return (char *) haystack;
}
else
-#endif
{
if (*needle != '\0')
{
projects / gnulib.git / blobdiff