2007-12-30 Bruno Haible <bruno@clisp.org>
+ Unify 5 copies of the KMP code.
+ * lib/str-kmp.h: New file.
+ * lib/c-strcasestr.c: Include str-kmp.h.
+ (knuth_morris_pratt): Remove function.
+ (c_strcasestr): Update.
+ * lib/c-strstr.c: Include str-kmp.h.
+ (knuth_morris_pratt): Remove function.
+ (c_strcasestr): Update.
+ * lib/mbscasestr.c: Include str-kmp.h.
+ (knuth_morris_pratt_unibyte): Remove function.
+ * lib/mbsstr.c: Include str-kmp.h.
+ (knuth_morris_pratt_unibyte): Remove function.
+ * lib/strcasestr.c: Include str-kmp.h.
+ (knuth_morris_pratt): Remove function.
+ (strcasestr): Update.
+ * modules/c-strcasestr (Files): Add lib/str-kmp.h.
+ * modules/c-strstr (Files): Likewise.
+ * modules/mbscasestr (Files): Likewise.
+ * modules/mbsstr (Files): Likewise.
+ * modules/strcasestr (Files): Likewise.
+ Suggested by Paul Eggert.
+
+2007-12-30 Bruno Haible <bruno@clisp.org>
+
* lib/xmalloca.c (xmmalloca): Don't define if HAVE_ALLOCA is not
defined.
#include "malloca.h"
#include "c-ctype.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 (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 = c_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 == c_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 (c_tolower ((unsigned char) needle[j])
- == c_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) c_tolower (c)
+#include "str-kmp.h"
/* Find the first occurrence of NEEDLE in HAYSTACK, using case-insensitive
comparison.
/* 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;
#include "malloca.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 (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 = (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 == (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 ((unsigned char) needle[j] == (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) c
+#include "str-kmp.h"
/* Find the first occurrence of NEEDLE in HAYSTACK. */
char *
/* 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;
#define TOLOWER(Ch) (isupper (Ch) ? tolower (Ch) : (Ch))
+/* Knuth-Morris-Pratt algorithm. */
+#define CANON_ELEMENT(c) TOLOWER (c)
+#include "str-kmp.h"
+
+#if HAVE_MBRTOWC
/* 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
static bool
knuth_morris_pratt_multibyte (const char *haystack, const char *needle,
const char **resultp)
# include "mbuiter.h"
#endif
+/* Knuth-Morris-Pratt algorithm. */
+#define CANON_ELEMENT(c) c
+#include "str-kmp.h"
+
+#if HAVE_MBRTOWC
/* 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 = (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 == (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 ((unsigned char) needle[j] == (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
static bool
knuth_morris_pratt_multibyte (const char *haystack, const char *needle,
const char **resultp)
--- /dev/null
+/* Substring search in a NUL terminated string of 'char' elements,
+ using the Knuth-Morris-Pratt algorithm.
+ Copyright (C) 2005-2007 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2005.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Before including this file, you need to define:
+ CANON_ELEMENT(c) A macro that canonicalizes an element right after
+ it has been fetched from one of the two strings.
+ The argument is an 'unsigned char'; the result
+ must be an 'unsigned char' as well. */
+
+/* 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 = CANON_ELEMENT ((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 == CANON_ELEMENT ((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 (CANON_ELEMENT ((unsigned char) needle[j])
+ == CANON_ELEMENT ((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;
+}
+
+#undef CANON_ELEMENT
#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.
/* 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;
Files:
lib/c-strcasestr.h
lib/c-strcasestr.c
+lib/str-kmp.h
Depends-on:
c-ctype
Files:
lib/c-strstr.h
lib/c-strstr.c
+lib/str-kmp.h
Depends-on:
stdbool
Files:
lib/mbscasestr.c
+lib/str-kmp.h
m4/mbscasestr.m4
m4/mbrtowc.m4
Files:
lib/mbsstr.c
+lib/str-kmp.h
m4/mbsstr.m4
m4/mbrtowc.m4
Files:
lib/strcasestr.c
+lib/str-kmp.h
m4/strcasestr.m4
Depends-on:
projects / gnulib.git / commitdiff