File: constructor-helper.c

package info (click to toggle)
glib2.0 2.84.3-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental, forky, sid, trixie, trixie-proposed-updates, trixie-updates
  • size: 66,100 kB
  • sloc: ansic: 538,905; python: 9,624; sh: 1,572; xml: 1,482; perl: 1,222; cpp: 535; makefile: 316; javascript: 11
file content (239 lines) | stat: -rw-r--r-- 5,065 bytes parent folder | download | duplicates (6)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
/* constructor-helpers.c - Helper library for the constructor test
 *
 * Copyright © 2023 Luca Bacci
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

/* This helper library manages a set of strings. Strings can be added,
 * removed and checked for presence. This library does not call into
 * libc, so can be used from module constructors in a safe manner on
 * a wide range of operating systems.
 *
 * GLib is used only for assertions or hard errors; in such cases we
 * don't really care about supported libc calls, as the test ought to
 * fail anyway.
 */

#include <stddef.h> /* for size_t */

#include <glib.h>

#if defined (_MSC_VER)
#  pragma optimize ("", off)
#else
#  if defined (__clang__)
#    pragma clang optimize off
#  elif defined (__GNUC__)
#    pragma GCC optimize ("O0")
#  endif
#endif

#if defined(_WIN32)
  #define MODULE_EXPORT \
    __declspec (dllexport)
#elif defined (__GNUC__)
  #define MODULE_EXPORT \
    __attribute__((visibility("default")))
#else
  #define MODULE_EXPORT
#endif

char buffer[500];
size_t position;

MODULE_EXPORT
void string_add (const char *string);

MODULE_EXPORT
void string_add_exclusive (const char *string);

MODULE_EXPORT
int string_remove (const char *string);

MODULE_EXPORT
int string_find (const char *string);

MODULE_EXPORT
void string_check (const char *string);

static size_t
strlen_ (const char *string)
{
  size_t i = 0;

  g_assert_nonnull (string);

  while (string[i] != 0)
    i++;

  return i;
}

static void
memmove_ (char *buf,
          size_t from,
          size_t size,
          size_t to)
{
  g_assert_true (to <= from);

  for (size_t i = 0; i < size; i++)
    buffer[to + i] = buffer[from + i];
}

static void
memcpy_ (char *dst,
         const char *src,
         size_t size)
{
  for (size_t i = 0; i < size; i++)
    dst[i] = src[i];
}

static void
memset_ (char   *dst,
         char    val,
         size_t  size)
{
  for (size_t i = 0; i < size; i++)
    dst[i] = val;
}

static size_t
string_find_index_ (const char *string)
{
  size_t string_len;
  size_t i = 0;

  g_assert_nonnull (string);
  g_assert_true ((string_len = strlen_ (string)) > 0);

  for (i = 0; (i < sizeof (buffer) - position) && (buffer[i] != 0);)
    {
      const char *iter = &buffer[i];
      size_t len = strlen_ (iter);

      if (len == string_len && strcmp (iter, string) == 0)
        return i;

      i += len + 1;
    }

  return sizeof (buffer);
}

/**< private >
 * string_add:
 *
 * @string: NULL-terminated string. Must not be empty
 *
 * Adds @string to the set
 */
MODULE_EXPORT
void
string_add (const char *string)
{
  size_t len, size;

  g_assert_nonnull (string);
  g_assert_true ((len = strlen_ (string)) > 0);

  size = len + 1;

  if (size > sizeof (buffer) - position)
    g_error ("Not enough space in the buffer");

  memcpy_ (buffer + position, string, size);

  position += size;
}

/**< private >
 * string_add_exclusive:
 *
 * @string: NULL-terminated string. Must not be empty
 *
 * Adds @string to the set, asserting that it's not already present.
 */
MODULE_EXPORT
void
string_add_exclusive (const char *string)
{
  if (string_find_index_ (string) < sizeof (buffer))
    g_error ("string %s already set", string);

  string_add (string);
}

/**< private >
 * string_remove:
 *
 * @string: NULL-terminated string. Must not be empty
 *
 * Removes the first occurrence of @string from the set.
 *
 * Returns: 1 if the string was removed, 0 otherwise.
 */
MODULE_EXPORT
int
string_remove (const char *string)
{
  size_t index = string_find_index_ (string);
  size_t len, size;

  if (index >= sizeof (buffer))
    return 0;

  g_assert_true ((len = strlen_ (string)) > 0);
  size = len + 1;

  memmove_ (buffer, index + size, index, position - (index + size));

  position -= size;

  memset_ (buffer + position, 0, size);

  return 1;
}

/**< private >
 * string_find:
 *
 * @string: NULL-terminated string. Must not be empty
 *
 * Returns 1 if the string is present, 0 otherwise
 */
MODULE_EXPORT
int string_find (const char *string)
{
  return string_find_index_ (string) < sizeof (buffer);
}

/**< private >
 * string_check:
 *
 * @string: NULL-terminated string. Must not be empty
 *
 * Asserts that @string is present in the set
 */
MODULE_EXPORT
void
string_check (const char *string)
{
  if (string_find_index_ (string) >= sizeof (buffer))
    g_error ("String %s not present", string);
}