/* Case-insensitive searching in a string.
- Copyright (C) 2005-2007 Free Software Foundation, Inc.
+ Copyright (C) 2005-2014 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 UNIT unsigned char
#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. */
+ 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)
+ const char **resultp)
{
size_t m = mbslen (needle);
mbchar_t *needle_mbchars;
j = 0;
for (mbui_init (iter, needle); mbui_avail (iter); mbui_advance (iter), j++)
{
- mb_copy (&needle_mbchars[j], &mbui_cur (iter));
- if (needle_mbchars[j].wc_valid)
- needle_mbchars[j].wc = towlower (needle_mbchars[j].wc);
+ mb_copy (&needle_mbchars[j], &mbui_cur (iter));
+ if (needle_mbchars[j].wc_valid)
+ needle_mbchars[j].wc = towlower (needle_mbchars[j].wc);
}
}
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]. */
- mbchar_t *b = &needle_mbchars[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 (mb_equal (*b, needle_mbchars[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]. */
+ /* 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]. */
+ mbchar_t *b = &needle_mbchars[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 (mb_equal (*b, needle_mbchars[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]. */
}
}
/* Invariant: phaystack = rhaystack + j. */
while (mbui_avail (phaystack))
{
- mbchar_t c;
-
- mb_copy (&c, &mbui_cur (phaystack));
- if (c.wc_valid)
- c.wc = towlower (c.wc);
- if (mb_equal (needle_mbchars[j], c))
- {
- j++;
- mbui_advance (phaystack);
- if (j == m)
- {
- /* The entire needle has been found. */
- *resultp = mbui_cur_ptr (rhaystack);
- break;
- }
- }
- else if (j > 0)
- {
- /* Found a match of needle[0..j-1], mismatch at needle[j]. */
- size_t count = table[j];
- j -= count;
- for (; count > 0; count--)
- {
- if (!mbui_avail (rhaystack))
- abort ();
- mbui_advance (rhaystack);
- }
- }
- else
- {
- /* Found a mismatch at needle[0] already. */
- if (!mbui_avail (rhaystack))
- abort ();
- mbui_advance (rhaystack);
- mbui_advance (phaystack);
- }
+ mbchar_t c;
+
+ mb_copy (&c, &mbui_cur (phaystack));
+ if (c.wc_valid)
+ c.wc = towlower (c.wc);
+ if (mb_equal (needle_mbchars[j], c))
+ {
+ j++;
+ mbui_advance (phaystack);
+ if (j == m)
+ {
+ /* The entire needle has been found. */
+ *resultp = mbui_cur_ptr (rhaystack);
+ break;
+ }
+ }
+ else if (j > 0)
+ {
+ /* Found a match of needle[0..j-1], mismatch at needle[j]. */
+ size_t count = table[j];
+ j -= count;
+ for (; count > 0; count--)
+ {
+ if (!mbui_avail (rhaystack))
+ abort ();
+ mbui_advance (rhaystack);
+ }
+ }
+ else
+ {
+ /* Found a mismatch at needle[0] already. */
+ if (!mbui_avail (rhaystack))
+ abort ();
+ mbui_advance (rhaystack);
+ mbui_advance (phaystack);
+ }
}
}
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;
mbui_init (iter_needle, needle);
if (mbui_avail (iter_needle))
- {
- /* Minimizing the worst-case complexity:
- Let n = mbslen(haystack), m = mbslen(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 */
- mbui_iterator_t iter_needle_last_ccount; /* = needle + last_ccount */
-
- mbchar_t b;
- mbui_iterator_t iter_haystack;
-
- mbui_init (iter_needle_last_ccount, needle);
-
- mb_copy (&b, &mbui_cur (iter_needle));
- if (b.wc_valid)
- b.wc = towlower (b.wc);
-
- mbui_init (iter_haystack, haystack);
- for (;; mbui_advance (iter_haystack))
- {
- mbchar_t c;
-
- if (!mbui_avail (iter_haystack))
- /* 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. */
- size_t count = comparison_count - last_ccount;
- for (;
- count > 0 && mbui_avail (iter_needle_last_ccount);
- count--)
- mbui_advance (iter_needle_last_ccount);
- last_ccount = comparison_count;
- if (!mbui_avail (iter_needle_last_ccount))
- {
- /* Try the Knuth-Morris-Pratt algorithm. */
- const char *result;
- bool success =
- knuth_morris_pratt_multibyte (haystack, needle,
- &result);
- if (success)
- return (char *) result;
- try_kmp = false;
- }
- }
-
- outer_loop_count++;
- comparison_count++;
- mb_copy (&c, &mbui_cur (iter_haystack));
- if (c.wc_valid)
- c.wc = towlower (c.wc);
- if (mb_equal (c, b))
- /* The first character matches. */
- {
- mbui_iterator_t rhaystack;
- mbui_iterator_t rneedle;
-
- memcpy (&rhaystack, &iter_haystack, sizeof (mbui_iterator_t));
- mbui_advance (rhaystack);
-
- mbui_init (rneedle, needle);
- if (!mbui_avail (rneedle))
- abort ();
- mbui_advance (rneedle);
-
- for (;; mbui_advance (rhaystack), mbui_advance (rneedle))
- {
- if (!mbui_avail (rneedle))
- /* Found a match. */
- return (char *) mbui_cur_ptr (iter_haystack);
- if (!mbui_avail (rhaystack))
- /* No match. */
- return NULL;
- comparison_count++;
- if (!mb_caseequal (mbui_cur (rhaystack),
- mbui_cur (rneedle)))
- /* Nothing in this round. */
- break;
- }
- }
- }
- }
+ {
+ /* Minimizing the worst-case complexity:
+ Let n = mbslen(haystack), m = mbslen(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 */
+ mbui_iterator_t iter_needle_last_ccount; /* = needle + last_ccount */
+
+ mbchar_t b;
+ mbui_iterator_t iter_haystack;
+
+ mbui_init (iter_needle_last_ccount, needle);
+
+ mb_copy (&b, &mbui_cur (iter_needle));
+ if (b.wc_valid)
+ b.wc = towlower (b.wc);
+
+ mbui_init (iter_haystack, haystack);
+ for (;; mbui_advance (iter_haystack))
+ {
+ mbchar_t c;
+
+ if (!mbui_avail (iter_haystack))
+ /* 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. */
+ size_t count = comparison_count - last_ccount;
+ for (;
+ count > 0 && mbui_avail (iter_needle_last_ccount);
+ count--)
+ mbui_advance (iter_needle_last_ccount);
+ last_ccount = comparison_count;
+ if (!mbui_avail (iter_needle_last_ccount))
+ {
+ /* Try the Knuth-Morris-Pratt algorithm. */
+ const char *result;
+ bool success =
+ knuth_morris_pratt_multibyte (haystack, needle,
+ &result);
+ if (success)
+ return (char *) result;
+ try_kmp = false;
+ }
+ }
+
+ outer_loop_count++;
+ comparison_count++;
+ mb_copy (&c, &mbui_cur (iter_haystack));
+ if (c.wc_valid)
+ c.wc = towlower (c.wc);
+ if (mb_equal (c, b))
+ /* The first character matches. */
+ {
+ mbui_iterator_t rhaystack;
+ mbui_iterator_t rneedle;
+
+ memcpy (&rhaystack, &iter_haystack, sizeof (mbui_iterator_t));
+ mbui_advance (rhaystack);
+
+ mbui_init (rneedle, needle);
+ if (!mbui_avail (rneedle))
+ abort ();
+ mbui_advance (rneedle);
+
+ for (;; mbui_advance (rhaystack), mbui_advance (rneedle))
+ {
+ if (!mbui_avail (rneedle))
+ /* Found a match. */
+ return (char *) mbui_cur_ptr (iter_haystack);
+ if (!mbui_avail (rhaystack))
+ /* No match. */
+ return NULL;
+ comparison_count++;
+ if (!mb_caseequal (mbui_cur (rhaystack),
+ mbui_cur (rneedle)))
+ /* Nothing in this round. */
+ break;
+ }
+ }
+ }
+ }
else
- return (char *) haystack;
+ return (char *) haystack;
}
else
-#endif
{
if (*needle != '\0')
- {
- /* Minimizing the worst-case complexity:
- Let n = strlen(haystack), m = 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 char *needle_last_ccount = needle; /* = needle + last_ccount */
-
- /* Speed up the following searches of needle by caching its first
- character. */
- unsigned char b = TOLOWER ((unsigned char) *needle);
-
- 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 +=
- 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 char *result;
- bool success =
- knuth_morris_pratt_unibyte (haystack, needle - 1,
- &result);
- if (success)
- return (char *) result;
- try_kmp = false;
- }
- }
-
- outer_loop_count++;
- comparison_count++;
- if (TOLOWER ((unsigned char) *haystack) == b)
- /* The first character matches. */
- {
- const char *rhaystack = haystack + 1;
- const char *rneedle = needle;
-
- for (;; rhaystack++, rneedle++)
- {
- if (*rneedle == '\0')
- /* Found a match. */
- return (char *) haystack;
- if (*rhaystack == '\0')
- /* No match. */
- return NULL;
- comparison_count++;
- if (TOLOWER ((unsigned char) *rhaystack)
- != TOLOWER ((unsigned char) *rneedle))
- /* Nothing in this round. */
- break;
- }
- }
- }
- }
+ {
+ /* Minimizing the worst-case complexity:
+ Let n = strlen(haystack), m = 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 char *needle_last_ccount = needle; /* = needle + last_ccount */
+
+ /* Speed up the following searches of needle by caching its first
+ character. */
+ unsigned char b = TOLOWER ((unsigned char) *needle);
+
+ 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 +=
+ 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 unsigned char *result;
+ bool success =
+ knuth_morris_pratt ((const unsigned char *) haystack,
+ (const unsigned char *) (needle - 1),
+ strlen (needle - 1),
+ &result);
+ if (success)
+ return (char *) result;
+ try_kmp = false;
+ }
+ }
+
+ outer_loop_count++;
+ comparison_count++;
+ if (TOLOWER ((unsigned char) *haystack) == b)
+ /* The first character matches. */
+ {
+ const char *rhaystack = haystack + 1;
+ const char *rneedle = needle;
+
+ for (;; rhaystack++, rneedle++)
+ {
+ if (*rneedle == '\0')
+ /* Found a match. */
+ return (char *) haystack;
+ if (*rhaystack == '\0')
+ /* No match. */
+ return NULL;
+ comparison_count++;
+ if (TOLOWER ((unsigned char) *rhaystack)
+ != TOLOWER ((unsigned char) *rneedle))
+ /* Nothing in this round. */
+ break;
+ }
+ }
+ }
+ }
else
- return (char *) haystack;
+ return (char *) haystack;
}
}
projects / gnulib.git / blobdiff