source: mainline/uspace/dist/src/c/demos/edit/search.c

Last change on this file was 28a5ebd, checked in by Martin Decky <martin@…>, 5 years ago

Use char32_t instead of wchat_t to represent UTF-32 strings

The intention of the native HelenOS string API has been always to
support Unicode in the UTF-8 and UTF-32 encodings as the sole character
representations and ignore the obsolete mess of older single-byte and
multibyte character encodings. Before C11, the wchar_t type has been
slightly misused for the purpose of the UTF-32 strings. The newer
char32_t type is obviously a much more suitable option. The standard
defines char32_t as uint_least32_t, thus we can take the liberty to fix
it to uint32_t.

To maintain compatilibity with the C Standard, the putwchar(wchar_t)
functions has been replaced by our custom putuchar(char32_t) functions
where appropriate.

  • Property mode set to 100644
File size: 3.9 KB
Line 
1/*
2 * Copyright (c) 2012 Martin Sucha
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29/** @addtogroup edit
30 * @{
31 */
32/**
33 * @file
34 * @brief Simple searching facility.
35 */
36
37#include <stdlib.h>
38#include <stddef.h>
39#include <errno.h>
40
41#include "search.h"
42#include "search_impl.h"
43
44search_t *search_init(const char *pattern, void *client_data, search_ops_t ops,
45 bool reverse)
46{
47 search_t *search = calloc(1, sizeof(search_t));
48 if (search == NULL)
49 return NULL;
50
51 char32_t *p = str_to_awstr(pattern);
52 if (p == NULL) {
53 free(search);
54 return NULL;
55 }
56
57 search->pattern_length = wstr_length(p);
58
59 if (reverse) {
60 /* Reverse the pattern */
61 size_t pos, half;
62 half = search->pattern_length / 2;
63 for (pos = 0; pos < half; pos++) {
64 char32_t tmp = p[pos];
65 p[pos] = p[search->pattern_length - pos - 1];
66 p[search->pattern_length - pos - 1] = tmp;
67 }
68 }
69
70 search->pattern = p;
71
72 search->client_data = client_data;
73 search->ops = ops;
74 search->back_table = calloc(search->pattern_length, sizeof(ssize_t));
75 if (search->back_table == NULL) {
76 free(search->pattern);
77 free(search);
78 return NULL;
79 }
80
81 search->pattern_pos = 0;
82
83 search->back_table[0] = -1;
84 search->back_table[1] = 0;
85 size_t table_idx = 2;
86 size_t pattern_idx = 0;
87 while (table_idx < search->pattern_length) {
88 if (ops.equals(search->pattern[table_idx - 1],
89 search->pattern[pattern_idx])) {
90 pattern_idx++;
91 search->back_table[table_idx] = pattern_idx;
92 table_idx++;
93 } else if (pattern_idx > 0) {
94 pattern_idx = search->back_table[pattern_idx];
95 } else {
96 pattern_idx = 0;
97 table_idx++;
98 }
99 }
100
101 return search;
102}
103
104errno_t search_next_match(search_t *s, match_t *match)
105{
106 search_equals_fn eq = s->ops.equals;
107
108 char32_t cur_char;
109 errno_t rc = EOK;
110 while ((rc = s->ops.producer(s->client_data, &cur_char)) == EOK && cur_char > 0) {
111 /* Deal with mismatches */
112 while (s->pattern_pos > 0 && !eq(cur_char, s->pattern[s->pattern_pos])) {
113 s->pattern_pos = s->back_table[s->pattern_pos];
114 }
115 /* Check if the character matched */
116 if (eq(cur_char, s->pattern[s->pattern_pos])) {
117 s->pattern_pos++;
118 if (s->pattern_pos == s->pattern_length) {
119 s->pattern_pos = s->back_table[s->pattern_pos];
120 rc = s->ops.mark(s->client_data, &match->end);
121 if (rc != EOK)
122 return rc;
123 match->length = s->pattern_length;
124 return EOK;
125 }
126 }
127 }
128
129 match->end = NULL;
130 match->length = 0;
131
132 return rc;
133}
134
135void search_fini(search_t *search)
136{
137 free(search->pattern);
138 free(search->back_table);
139
140}
141
142bool char_exact_equals(const char32_t a, const char32_t b)
143{
144 return a == b;
145}
146
147/** @}
148 */
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