FFmpeg 7.1.1
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avstring.h
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1/*
2 * Copyright (c) 2007 Mans Rullgard
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#ifndef AVUTIL_AVSTRING_H
22#define AVUTIL_AVSTRING_H
23
24#include <stddef.h>
25#include <stdint.h>
26#include "attributes.h"
27
28/**
29 * @addtogroup lavu_string
30 * @{
31 */
32
33/**
34 * Return non-zero if pfx is a prefix of str. If it is, *ptr is set to
35 * the address of the first character in str after the prefix.
36 *
37 * @param str input string
38 * @param pfx prefix to test
39 * @param ptr updated if the prefix is matched inside str
40 * @return non-zero if the prefix matches, zero otherwise
41 */
42int av_strstart(const char *str, const char *pfx, const char **ptr);
43
44/**
45 * Return non-zero if pfx is a prefix of str independent of case. If
46 * it is, *ptr is set to the address of the first character in str
47 * after the prefix.
48 *
49 * @param str input string
50 * @param pfx prefix to test
51 * @param ptr updated if the prefix is matched inside str
52 * @return non-zero if the prefix matches, zero otherwise
53 */
54int av_stristart(const char *str, const char *pfx, const char **ptr);
55
56/**
57 * Locate the first case-independent occurrence in the string haystack
58 * of the string needle. A zero-length string needle is considered to
59 * match at the start of haystack.
60 *
61 * This function is a case-insensitive version of the standard strstr().
62 *
63 * @param haystack string to search in
64 * @param needle string to search for
65 * @return pointer to the located match within haystack
66 * or a null pointer if no match
67 */
68char *av_stristr(const char *haystack, const char *needle);
69
70/**
71 * Locate the first occurrence of the string needle in the string haystack
72 * where not more than hay_length characters are searched. A zero-length
73 * string needle is considered to match at the start of haystack.
74 *
75 * This function is a length-limited version of the standard strstr().
76 *
77 * @param haystack string to search in
78 * @param needle string to search for
79 * @param hay_length length of string to search in
80 * @return pointer to the located match within haystack
81 * or a null pointer if no match
82 */
83char *av_strnstr(const char *haystack, const char *needle, size_t hay_length);
84
85/**
86 * Copy the string src to dst, but no more than size - 1 bytes, and
87 * null-terminate dst.
88 *
89 * This function is the same as BSD strlcpy().
90 *
91 * @param dst destination buffer
92 * @param src source string
93 * @param size size of destination buffer
94 * @return the length of src
95 *
96 * @warning since the return value is the length of src, src absolutely
97 * _must_ be a properly 0-terminated string, otherwise this will read beyond
98 * the end of the buffer and possibly crash.
99 */
100size_t av_strlcpy(char *dst, const char *src, size_t size);
101
102/**
103 * Append the string src to the string dst, but to a total length of
104 * no more than size - 1 bytes, and null-terminate dst.
105 *
106 * This function is similar to BSD strlcat(), but differs when
107 * size <= strlen(dst).
108 *
109 * @param dst destination buffer
110 * @param src source string
111 * @param size size of destination buffer
112 * @return the total length of src and dst
113 *
114 * @warning since the return value use the length of src and dst, these
115 * absolutely _must_ be a properly 0-terminated strings, otherwise this
116 * will read beyond the end of the buffer and possibly crash.
117 */
118size_t av_strlcat(char *dst, const char *src, size_t size);
119
120/**
121 * Append output to a string, according to a format. Never write out of
122 * the destination buffer, and always put a terminating 0 within
123 * the buffer.
124 * @param dst destination buffer (string to which the output is
125 * appended)
126 * @param size total size of the destination buffer
127 * @param fmt printf-compatible format string, specifying how the
128 * following parameters are used
129 * @return the length of the string that would have been generated
130 * if enough space had been available
131 */
132size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...) av_printf_format(3, 4);
133
134/**
135 * Get the count of continuous non zero chars starting from the beginning.
136 *
137 * @param s the string whose length to count
138 * @param len maximum number of characters to check in the string, that
139 * is the maximum value which is returned by the function
140 */
141static inline size_t av_strnlen(const char *s, size_t len)
142{
143 size_t i;
144 for (i = 0; i < len && s[i]; i++)
145 ;
146 return i;
147}
148
149/**
150 * Print arguments following specified format into a large enough auto
151 * allocated buffer. It is similar to GNU asprintf().
152 * @param fmt printf-compatible format string, specifying how the
153 * following parameters are used.
154 * @return the allocated string
155 * @note You have to free the string yourself with av_free().
156 */
157char *av_asprintf(const char *fmt, ...) av_printf_format(1, 2);
158
159/**
160 * Unescape the given string until a non escaped terminating char,
161 * and return the token corresponding to the unescaped string.
162 *
163 * The normal \ and ' escaping is supported. Leading and trailing
164 * whitespaces are removed, unless they are escaped with '\' or are
165 * enclosed between ''.
166 *
167 * @param buf the buffer to parse, buf will be updated to point to the
168 * terminating char
169 * @param term a 0-terminated list of terminating chars
170 * @return the malloced unescaped string, which must be av_freed by
171 * the user, NULL in case of allocation failure
172 */
173char *av_get_token(const char **buf, const char *term);
174
175/**
176 * Split the string into several tokens which can be accessed by
177 * successive calls to av_strtok().
178 *
179 * A token is defined as a sequence of characters not belonging to the
180 * set specified in delim.
181 *
182 * On the first call to av_strtok(), s should point to the string to
183 * parse, and the value of saveptr is ignored. In subsequent calls, s
184 * should be NULL, and saveptr should be unchanged since the previous
185 * call.
186 *
187 * This function is similar to strtok_r() defined in POSIX.1.
188 *
189 * @param s the string to parse, may be NULL
190 * @param delim 0-terminated list of token delimiters, must be non-NULL
191 * @param saveptr user-provided pointer which points to stored
192 * information necessary for av_strtok() to continue scanning the same
193 * string. saveptr is updated to point to the next character after the
194 * first delimiter found, or to NULL if the string was terminated
195 * @return the found token, or NULL when no token is found
196 */
197char *av_strtok(char *s, const char *delim, char **saveptr);
198
199/**
200 * Locale-independent conversion of ASCII isdigit.
201 */
202static inline av_const int av_isdigit(int c)
203{
204 return c >= '0' && c <= '9';
205}
206
207/**
208 * Locale-independent conversion of ASCII isgraph.
209 */
210static inline av_const int av_isgraph(int c)
211{
212 return c > 32 && c < 127;
213}
214
215/**
216 * Locale-independent conversion of ASCII isspace.
217 */
218static inline av_const int av_isspace(int c)
219{
220 return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' ||
221 c == '\v';
222}
223
224/**
225 * Locale-independent conversion of ASCII characters to uppercase.
226 */
227static inline av_const int av_toupper(int c)
228{
229 if (c >= 'a' && c <= 'z')
230 c ^= 0x20;
231 return c;
232}
233
234/**
235 * Locale-independent conversion of ASCII characters to lowercase.
236 */
237static inline av_const int av_tolower(int c)
238{
239 if (c >= 'A' && c <= 'Z')
240 c ^= 0x20;
241 return c;
242}
243
244/**
245 * Locale-independent conversion of ASCII isxdigit.
246 */
247static inline av_const int av_isxdigit(int c)
248{
249 c = av_tolower(c);
250 return av_isdigit(c) || (c >= 'a' && c <= 'f');
251}
252
253/**
254 * Locale-independent case-insensitive compare.
255 * @note This means only ASCII-range characters are case-insensitive
256 */
257int av_strcasecmp(const char *a, const char *b);
258
259/**
260 * Locale-independent case-insensitive compare.
261 * @note This means only ASCII-range characters are case-insensitive
262 */
263int av_strncasecmp(const char *a, const char *b, size_t n);
264
265/**
266 * Locale-independent strings replace.
267 * @note This means only ASCII-range characters are replaced.
268 */
269char *av_strireplace(const char *str, const char *from, const char *to);
270
271/**
272 * Thread safe basename.
273 * @param path the string to parse, on DOS both \ and / are considered separators.
274 * @return pointer to the basename substring.
275 * If path does not contain a slash, the function returns a copy of path.
276 * If path is a NULL pointer or points to an empty string, a pointer
277 * to a string "." is returned.
278 */
279const char *av_basename(const char *path);
280
281/**
282 * Thread safe dirname.
283 * @param path the string to parse, on DOS both \ and / are considered separators.
284 * @return A pointer to a string that's the parent directory of path.
285 * If path is a NULL pointer or points to an empty string, a pointer
286 * to a string "." is returned.
287 * @note the function may modify the contents of the path, so copies should be passed.
288 */
289const char *av_dirname(char *path);
290
291/**
292 * Match instances of a name in a comma-separated list of names.
293 * List entries are checked from the start to the end of the names list,
294 * the first match ends further processing. If an entry prefixed with '-'
295 * matches, then 0 is returned. The "ALL" list entry is considered to
296 * match all names.
297 *
298 * @param name Name to look for.
299 * @param names List of names.
300 * @return 1 on match, 0 otherwise.
301 */
302int av_match_name(const char *name, const char *names);
303
304/**
305 * Append path component to the existing path.
306 * Path separator '/' is placed between when needed.
307 * Resulting string have to be freed with av_free().
308 * @param path base path
309 * @param component component to be appended
310 * @return new path or NULL on error.
311 */
312char *av_append_path_component(const char *path, const char *component);
313
315 AV_ESCAPE_MODE_AUTO, ///< Use auto-selected escaping mode.
316 AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.
317 AV_ESCAPE_MODE_QUOTE, ///< Use single-quote escaping.
318 AV_ESCAPE_MODE_XML, ///< Use XML non-markup character data escaping.
319};
320
321/**
322 * Consider spaces special and escape them even in the middle of the
323 * string.
324 *
325 * This is equivalent to adding the whitespace characters to the special
326 * characters lists, except it is guaranteed to use the exact same list
327 * of whitespace characters as the rest of libavutil.
328 */
329#define AV_ESCAPE_FLAG_WHITESPACE (1 << 0)
330
331/**
332 * Escape only specified special characters.
333 * Without this flag, escape also any characters that may be considered
334 * special by av_get_token(), such as the single quote.
335 */
336#define AV_ESCAPE_FLAG_STRICT (1 << 1)
337
338/**
339 * Within AV_ESCAPE_MODE_XML, additionally escape single quotes for single
340 * quoted attributes.
341 */
342#define AV_ESCAPE_FLAG_XML_SINGLE_QUOTES (1 << 2)
343
344/**
345 * Within AV_ESCAPE_MODE_XML, additionally escape double quotes for double
346 * quoted attributes.
347 */
348#define AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES (1 << 3)
349
350
351/**
352 * Escape string in src, and put the escaped string in an allocated
353 * string in *dst, which must be freed with av_free().
354 *
355 * @param dst pointer where an allocated string is put
356 * @param src string to escape, must be non-NULL
357 * @param special_chars string containing the special characters which
358 * need to be escaped, can be NULL
359 * @param mode escape mode to employ, see AV_ESCAPE_MODE_* macros.
360 * Any unknown value for mode will be considered equivalent to
361 * AV_ESCAPE_MODE_BACKSLASH, but this behaviour can change without
362 * notice.
363 * @param flags flags which control how to escape, see AV_ESCAPE_FLAG_ macros
364 * @return the length of the allocated string, or a negative error code in case of error
365 * @see av_bprint_escape()
366 */
368int av_escape(char **dst, const char *src, const char *special_chars,
369 enum AVEscapeMode mode, int flags);
370
371#define AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES 1 ///< accept codepoints over 0x10FFFF
372#define AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS 2 ///< accept non-characters - 0xFFFE and 0xFFFF
373#define AV_UTF8_FLAG_ACCEPT_SURROGATES 4 ///< accept UTF-16 surrogates codes
374#define AV_UTF8_FLAG_EXCLUDE_XML_INVALID_CONTROL_CODES 8 ///< exclude control codes not accepted by XML
375
376#define AV_UTF8_FLAG_ACCEPT_ALL \
377 AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES|AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS|AV_UTF8_FLAG_ACCEPT_SURROGATES
378
379/**
380 * Read and decode a single UTF-8 code point (character) from the
381 * buffer in *buf, and update *buf to point to the next byte to
382 * decode.
383 *
384 * In case of an invalid byte sequence, the pointer will be updated to
385 * the next byte after the invalid sequence and the function will
386 * return an error code.
387 *
388 * Depending on the specified flags, the function will also fail in
389 * case the decoded code point does not belong to a valid range.
390 *
391 * @note For speed-relevant code a carefully implemented use of
392 * GET_UTF8() may be preferred.
393 *
394 * @param codep pointer used to return the parsed code in case of success.
395 * The value in *codep is set even in case the range check fails.
396 * @param bufp pointer to the address the first byte of the sequence
397 * to decode, updated by the function to point to the
398 * byte next after the decoded sequence
399 * @param buf_end pointer to the end of the buffer, points to the next
400 * byte past the last in the buffer. This is used to
401 * avoid buffer overreads (in case of an unfinished
402 * UTF-8 sequence towards the end of the buffer).
403 * @param flags a collection of AV_UTF8_FLAG_* flags
404 * @return >= 0 in case a sequence was successfully read, a negative
405 * value in case of invalid sequence
406 */
408int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
409 unsigned int flags);
410
411/**
412 * Check if a name is in a list.
413 * @returns 0 if not found, or the 1 based index where it has been found in the
414 * list.
415 */
416int av_match_list(const char *name, const char *list, char separator);
417
418/**
419 * See libc sscanf manual for more information.
420 * Locale-independent sscanf implementation.
421 */
422int av_sscanf(const char *string, const char *format, ...);
423
424/**
425 * @}
426 */
427
428#endif /* AVUTIL_AVSTRING_H */
Macro definitions for various function/variable attributes.
#define av_printf_format(fmtpos, attrpos)
Definition attributes.h:161
#define av_warn_unused_result
Definition attributes.h:62
#define av_const
Definition attributes.h:82
size_t av_strlcat(char *dst, const char *src, size_t size)
Append the string src to the string dst, but to a total length of no more than size - 1 bytes,...
size_t static size_t av_strnlen(const char *s, size_t len)
Get the count of continuous non zero chars starting from the beginning.
Definition avstring.h:141
char * av_stristr(const char *haystack, const char *needle)
Locate the first case-independent occurrence in the string haystack of the string needle.
char * av_strtok(char *s, const char *delim, char **saveptr)
Split the string into several tokens which can be accessed by successive calls to av_strtok().
av_warn_unused_result int av_escape(char **dst, const char *src, const char *special_chars, enum AVEscapeMode mode, int flags)
Escape string in src, and put the escaped string in an allocated string in *dst, which must be freed ...
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition avstring.h:237
int av_strcasecmp(const char *a, const char *b)
Locale-independent case-insensitive compare.
static av_const int av_isdigit(int c)
Locale-independent conversion of ASCII isdigit.
Definition avstring.h:202
int av_match_name(const char *name, const char *names)
Match instances of a name in a comma-separated list of names.
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
static av_const int av_isxdigit(int c)
Locale-independent conversion of ASCII isxdigit.
Definition avstring.h:247
size_t av_strlcpy(char *dst, const char *src, size_t size)
Copy the string src to dst, but no more than size - 1 bytes, and null-terminate dst.
char * av_strnstr(const char *haystack, const char *needle, size_t hay_length)
Locate the first occurrence of the string needle in the string haystack where not more than hay_lengt...
static av_const int av_isgraph(int c)
Locale-independent conversion of ASCII isgraph.
Definition avstring.h:210
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition avstring.h:218
int av_match_list(const char *name, const char *list, char separator)
Check if a name is in a list.
char char * av_get_token(const char **buf, const char *term)
Unescape the given string until a non escaped terminating char, and return the token corresponding to...
static av_const int av_toupper(int c)
Locale-independent conversion of ASCII characters to uppercase.
Definition avstring.h:227
const char * av_dirname(char *path)
Thread safe dirname.
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
const char * av_basename(const char *path)
Thread safe basename.
char * av_asprintf(const char *fmt,...) av_printf_format(1
Print arguments following specified format into a large enough auto allocated buffer.
av_warn_unused_result int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end, unsigned int flags)
Read and decode a single UTF-8 code point (character) from the buffer in *buf, and update *buf to poi...
int av_stristart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str independent of case.
char * av_append_path_component(const char *path, const char *component)
Append path component to the existing path.
char * av_strireplace(const char *str, const char *from, const char *to)
Locale-independent strings replace.
size_t av_strlcatf(char *dst, size_t size, const char *fmt,...) av_printf_format(3
Append output to a string, according to a format.
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
AVEscapeMode
Definition avstring.h:314
@ AV_ESCAPE_MODE_AUTO
Use auto-selected escaping mode.
Definition avstring.h:315
@ AV_ESCAPE_MODE_XML
Use XML non-markup character data escaping.
Definition avstring.h:318
@ AV_ESCAPE_MODE_QUOTE
Use single-quote escaping.
Definition avstring.h:317
@ AV_ESCAPE_MODE_BACKSLASH
Use backslash escaping.
Definition avstring.h:316