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authorJörg Frings-Fürst <debian@jff.email>2024-03-03 19:11:32 +0100
committerJörg Frings-Fürst <debian@jff.email>2024-03-03 19:11:32 +0100
commit00893e79fc62966067af1a106567db96bd170338 (patch)
tree52b35cd0b42ca28e62a2ffbecade2e13dd8332cf /lib/unistr/u-strstr.h
parent26112352a774737e1ce5580c93654a26c1e82b39 (diff)
New upstream version 1.2upstream/1.2
Diffstat (limited to 'lib/unistr/u-strstr.h')
-rw-r--r--lib/unistr/u-strstr.h139
1 files changed, 0 insertions, 139 deletions
diff --git a/lib/unistr/u-strstr.h b/lib/unistr/u-strstr.h
deleted file mode 100644
index 98dda4be..00000000
--- a/lib/unistr/u-strstr.h
+++ /dev/null
@@ -1,139 +0,0 @@
-/* Substring test for UTF-8/UTF-16/UTF-32 strings. -*- coding: utf-8 -*-
- Copyright (C) 1999, 2002, 2006, 2010-2022 Free Software Foundation, Inc.
- Written by Bruno Haible <bruno@clisp.org>, 2002, 2005.
-
- This file is free software.
- It is dual-licensed under "the GNU LGPLv3+ or the GNU GPLv2+".
- You can redistribute it and/or modify it under either
- - the terms of the GNU Lesser General Public License as published
- by the Free Software Foundation, either version 3, or (at your
- option) any later version, or
- - 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, or
- - the same dual license "the GNU LGPLv3+ or the GNU GPLv2+".
-
- This file 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
- Lesser General Public License and the GNU General Public License
- for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License and of the GNU General Public License along with this
- program. If not, see <https://www.gnu.org/licenses/>. */
-
-UNIT *
-FUNC (const UNIT *haystack, const UNIT *needle)
-{
- UNIT first = needle[0];
-
- /* Is needle empty? */
- if (first == 0)
- return (UNIT *) haystack;
-
- /* Is needle nearly empty (only one unit)? */
- if (needle[1] == 0)
- return U_STRCHR (haystack, first);
-
-#ifdef U_STRMBTOUC
- /* Is needle nearly empty (only one character)? */
- {
- ucs4_t first_uc;
- int count = U_STRMBTOUC (&first_uc, needle);
- if (count > 0 && needle[count] == 0)
- return U_STRCHR (haystack, first_uc);
- }
-#endif
-
-#if UNIT_IS_UINT8_T
- return (uint8_t *) strstr ((const char *) haystack, (const char *) needle);
-#else
- {
- /* Minimizing the worst-case complexity:
- Let n = U_STRLEN(haystack), m = U_STRLEN(needle).
- The naïve algorithm is O(n*m) worst-case.
- The Knuth-Morris-Pratt algorithm is O(n) worst-case but it needs a
- memory allocation.
- To achieve linear complexity and yet amortize the cost of the
- memory allocation, we activate the Knuth-Morris-Pratt algorithm
- only once the naïve algorithm has already run for some time; more
- precisely, when
- - the outer loop count is >= 10,
- - the average number of comparisons per outer loop is >= 5,
- - the total number of comparisons is >= m.
- But we try it only once. If the memory allocation attempt failed,
- we don't retry it. */
- bool try_kmp = true;
- size_t outer_loop_count = 0;
- size_t comparison_count = 0;
- size_t last_ccount = 0; /* last comparison count */
- const UNIT *needle_last_ccount = needle; /* = needle + last_ccount */
-
- /* Speed up the following searches of needle by caching its first
- character. */
- UNIT b = *needle++;
-
- for (;; haystack++)
- {
- if (*haystack == 0)
- /* No match. */
- return NULL;
-
- /* See whether it's advisable to use an asymptotically faster
- algorithm. */
- if (try_kmp
- && outer_loop_count >= 10
- && comparison_count >= 5 * outer_loop_count)
- {
- /* See if needle + comparison_count now reaches the end of
- needle. */
- if (needle_last_ccount != NULL)
- {
- needle_last_ccount +=
- U_STRNLEN (needle_last_ccount,
- comparison_count - last_ccount);
- if (*needle_last_ccount == 0)
- needle_last_ccount = NULL;
- last_ccount = comparison_count;
- }
- if (needle_last_ccount == NULL)
- {
- /* Try the Knuth-Morris-Pratt algorithm. */
- const UNIT *result;
- bool success =
- knuth_morris_pratt (haystack,
- needle - 1, U_STRLEN (needle - 1),
- &result);
- if (success)
- return (UNIT *) result;
- try_kmp = false;
- }
- }
-
- outer_loop_count++;
- comparison_count++;
- if (*haystack == b)
- /* The first character matches. */
- {
- const UNIT *rhaystack = haystack + 1;
- const UNIT *rneedle = needle;
-
- for (;; rhaystack++, rneedle++)
- {
- if (*rneedle == 0)
- /* Found a match. */
- return (UNIT *) haystack;
- if (*rhaystack == 0)
- /* No match. */
- return NULL;
- comparison_count++;
- if (*rhaystack != *rneedle)
- /* Nothing in this round. */
- break;
- }
- }
- }
- }
-#endif
-}