FFmpeg
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 #include "version.h"
28 
29 /**
30  * @addtogroup lavu_string
31  * @{
32  */
33 
34 /**
35  * Return non-zero if pfx is a prefix of str. If it is, *ptr is set to
36  * the address of the first character in str after the prefix.
37  *
38  * @param str input string
39  * @param pfx prefix to test
40  * @param ptr updated if the prefix is matched inside str
41  * @return non-zero if the prefix matches, zero otherwise
42  */
43 int av_strstart(const char *str, const char *pfx, const char **ptr);
44 
45 /**
46  * Return non-zero if pfx is a prefix of str independent of case. If
47  * it is, *ptr is set to the address of the first character in str
48  * after the prefix.
49  *
50  * @param str input string
51  * @param pfx prefix to test
52  * @param ptr updated if the prefix is matched inside str
53  * @return non-zero if the prefix matches, zero otherwise
54  */
55 int av_stristart(const char *str, const char *pfx, const char **ptr);
56 
57 /**
58  * Locate the first case-independent occurrence in the string haystack
59  * of the string needle. A zero-length string needle is considered to
60  * match at the start of haystack.
61  *
62  * This function is a case-insensitive version of the standard strstr().
63  *
64  * @param haystack string to search in
65  * @param needle string to search for
66  * @return pointer to the located match within haystack
67  * or a null pointer if no match
68  */
69 char *av_stristr(const char *haystack, const char *needle);
70 
71 /**
72  * Locate the first occurrence of the string needle in the string haystack
73  * where not more than hay_length characters are searched. A zero-length
74  * string needle is considered to match at the start of haystack.
75  *
76  * This function is a length-limited version of the standard strstr().
77  *
78  * @param haystack string to search in
79  * @param needle string to search for
80  * @param hay_length length of string to search in
81  * @return pointer to the located match within haystack
82  * or a null pointer if no match
83  */
84 char *av_strnstr(const char *haystack, const char *needle, size_t hay_length);
85 
86 /**
87  * Copy the string src to dst, but no more than size - 1 bytes, and
88  * null-terminate dst.
89  *
90  * This function is the same as BSD strlcpy().
91  *
92  * @param dst destination buffer
93  * @param src source string
94  * @param size size of destination buffer
95  * @return the length of src
96  *
97  * @warning since the return value is the length of src, src absolutely
98  * _must_ be a properly 0-terminated string, otherwise this will read beyond
99  * the end of the buffer and possibly crash.
100  */
101 size_t av_strlcpy(char *dst, const char *src, size_t size);
102 
103 /**
104  * Append the string src to the string dst, but to a total length of
105  * no more than size - 1 bytes, and null-terminate dst.
106  *
107  * This function is similar to BSD strlcat(), but differs when
108  * size <= strlen(dst).
109  *
110  * @param dst destination buffer
111  * @param src source string
112  * @param size size of destination buffer
113  * @return the total length of src and dst
114  *
115  * @warning since the return value use the length of src and dst, these
116  * absolutely _must_ be a properly 0-terminated strings, otherwise this
117  * will read beyond the end of the buffer and possibly crash.
118  */
119 size_t av_strlcat(char *dst, const char *src, size_t size);
120 
121 /**
122  * Append output to a string, according to a format. Never write out of
123  * the destination buffer, and always put a terminating 0 within
124  * the buffer.
125  * @param dst destination buffer (string to which the output is
126  * appended)
127  * @param size total size of the destination buffer
128  * @param fmt printf-compatible format string, specifying how the
129  * following parameters are used
130  * @return the length of the string that would have been generated
131  * if enough space had been available
132  */
133 size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...) av_printf_format(3, 4);
134 
135 /**
136  * Get the count of continuous non zero chars starting from the beginning.
137  *
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  */
141 static 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  */
157 char *av_asprintf(const char *fmt, ...) av_printf_format(1, 2);
158 
159 #if FF_API_D2STR
160 /**
161  * Convert a number to an av_malloced string.
162  * @deprecated use av_asprintf() with "%f" or a more specific format
163  */
165 char *av_d2str(double d);
166 #endif
167 
168 /**
169  * Unescape the given string until a non escaped terminating char,
170  * and return the token corresponding to the unescaped string.
171  *
172  * The normal \ and ' escaping is supported. Leading and trailing
173  * whitespaces are removed, unless they are escaped with '\' or are
174  * enclosed between ''.
175  *
176  * @param buf the buffer to parse, buf will be updated to point to the
177  * terminating char
178  * @param term a 0-terminated list of terminating chars
179  * @return the malloced unescaped string, which must be av_freed by
180  * the user, NULL in case of allocation failure
181  */
182 char *av_get_token(const char **buf, const char *term);
183 
184 /**
185  * Split the string into several tokens which can be accessed by
186  * successive calls to av_strtok().
187  *
188  * A token is defined as a sequence of characters not belonging to the
189  * set specified in delim.
190  *
191  * On the first call to av_strtok(), s should point to the string to
192  * parse, and the value of saveptr is ignored. In subsequent calls, s
193  * should be NULL, and saveptr should be unchanged since the previous
194  * call.
195  *
196  * This function is similar to strtok_r() defined in POSIX.1.
197  *
198  * @param s the string to parse, may be NULL
199  * @param delim 0-terminated list of token delimiters, must be non-NULL
200  * @param saveptr user-provided pointer which points to stored
201  * information necessary for av_strtok() to continue scanning the same
202  * string. saveptr is updated to point to the next character after the
203  * first delimiter found, or to NULL if the string was terminated
204  * @return the found token, or NULL when no token is found
205  */
206 char *av_strtok(char *s, const char *delim, char **saveptr);
207 
208 /**
209  * Locale-independent conversion of ASCII isdigit.
210  */
211 static inline av_const int av_isdigit(int c)
212 {
213  return c >= '0' && c <= '9';
214 }
215 
216 /**
217  * Locale-independent conversion of ASCII isgraph.
218  */
219 static inline av_const int av_isgraph(int c)
220 {
221  return c > 32 && c < 127;
222 }
223 
224 /**
225  * Locale-independent conversion of ASCII isspace.
226  */
227 static inline av_const int av_isspace(int c)
228 {
229  return c == ' ' || c == '\f' || c == '\n' || c == '\r' || c == '\t' ||
230  c == '\v';
231 }
232 
233 /**
234  * Locale-independent conversion of ASCII characters to uppercase.
235  */
236 static inline av_const int av_toupper(int c)
237 {
238  if (c >= 'a' && c <= 'z')
239  c ^= 0x20;
240  return c;
241 }
242 
243 /**
244  * Locale-independent conversion of ASCII characters to lowercase.
245  */
246 static inline av_const int av_tolower(int c)
247 {
248  if (c >= 'A' && c <= 'Z')
249  c ^= 0x20;
250  return c;
251 }
252 
253 /**
254  * Locale-independent conversion of ASCII isxdigit.
255  */
256 static inline av_const int av_isxdigit(int c)
257 {
258  c = av_tolower(c);
259  return av_isdigit(c) || (c >= 'a' && c <= 'f');
260 }
261 
262 /**
263  * Locale-independent case-insensitive compare.
264  * @note This means only ASCII-range characters are case-insensitive
265  */
266 int av_strcasecmp(const char *a, const char *b);
267 
268 /**
269  * Locale-independent case-insensitive compare.
270  * @note This means only ASCII-range characters are case-insensitive
271  */
272 int av_strncasecmp(const char *a, const char *b, size_t n);
273 
274 /**
275  * Locale-independent strings replace.
276  * @note This means only ASCII-range characters are replace
277  */
278 char *av_strireplace(const char *str, const char *from, const char *to);
279 
280 /**
281  * Thread safe basename.
282  * @param path the string to parse, on DOS both \ and / are considered separators.
283  * @return pointer to the basename substring.
284  * If path does not contain a slash, the function returns a copy of path.
285  * If path is a NULL pointer or points to an empty string, a pointer
286  * to a string "." is returned.
287  */
288 const char *av_basename(const char *path);
289 
290 /**
291  * Thread safe dirname.
292  * @param path the string to parse, on DOS both \ and / are considered separators.
293  * @return A pointer to a string that's the parent directory of path.
294  * If path is a NULL pointer or points to an empty string, a pointer
295  * to a string "." is returned.
296  * @note the function may modify the contents of the path, so copies should be passed.
297  */
298 const char *av_dirname(char *path);
299 
300 /**
301  * Match instances of a name in a comma-separated list of names.
302  * List entries are checked from the start to the end of the names list,
303  * the first match ends further processing. If an entry prefixed with '-'
304  * matches, then 0 is returned. The "ALL" list entry is considered to
305  * match all names.
306  *
307  * @param name Name to look for.
308  * @param names List of names.
309  * @return 1 on match, 0 otherwise.
310  */
311 int av_match_name(const char *name, const char *names);
312 
313 /**
314  * Append path component to the existing path.
315  * Path separator '/' is placed between when needed.
316  * Resulting string have to be freed with av_free().
317  * @param path base path
318  * @param component component to be appended
319  * @return new path or NULL on error.
320  */
321 char *av_append_path_component(const char *path, const char *component);
322 
324  AV_ESCAPE_MODE_AUTO, ///< Use auto-selected escaping mode.
325  AV_ESCAPE_MODE_BACKSLASH, ///< Use backslash escaping.
326  AV_ESCAPE_MODE_QUOTE, ///< Use single-quote escaping.
327  AV_ESCAPE_MODE_XML, ///< Use XML non-markup character data escaping.
328 };
329 
330 /**
331  * Consider spaces special and escape them even in the middle of the
332  * string.
333  *
334  * This is equivalent to adding the whitespace characters to the special
335  * characters lists, except it is guaranteed to use the exact same list
336  * of whitespace characters as the rest of libavutil.
337  */
338 #define AV_ESCAPE_FLAG_WHITESPACE (1 << 0)
339 
340 /**
341  * Escape only specified special characters.
342  * Without this flag, escape also any characters that may be considered
343  * special by av_get_token(), such as the single quote.
344  */
345 #define AV_ESCAPE_FLAG_STRICT (1 << 1)
346 
347 /**
348  * Within AV_ESCAPE_MODE_XML, additionally escape single quotes for single
349  * quoted attributes.
350  */
351 #define AV_ESCAPE_FLAG_XML_SINGLE_QUOTES (1 << 2)
352 
353 /**
354  * Within AV_ESCAPE_MODE_XML, additionally escape double quotes for double
355  * quoted attributes.
356  */
357 #define AV_ESCAPE_FLAG_XML_DOUBLE_QUOTES (1 << 3)
358 
359 
360 /**
361  * Escape string in src, and put the escaped string in an allocated
362  * string in *dst, which must be freed with av_free().
363  *
364  * @param dst pointer where an allocated string is put
365  * @param src string to escape, must be non-NULL
366  * @param special_chars string containing the special characters which
367  * need to be escaped, can be NULL
368  * @param mode escape mode to employ, see AV_ESCAPE_MODE_* macros.
369  * Any unknown value for mode will be considered equivalent to
370  * AV_ESCAPE_MODE_BACKSLASH, but this behaviour can change without
371  * notice.
372  * @param flags flags which control how to escape, see AV_ESCAPE_FLAG_ macros
373  * @return the length of the allocated string, or a negative error code in case of error
374  * @see av_bprint_escape()
375  */
377 int av_escape(char **dst, const char *src, const char *special_chars,
378  enum AVEscapeMode mode, int flags);
379 
380 #define AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES 1 ///< accept codepoints over 0x10FFFF
381 #define AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS 2 ///< accept non-characters - 0xFFFE and 0xFFFF
382 #define AV_UTF8_FLAG_ACCEPT_SURROGATES 4 ///< accept UTF-16 surrogates codes
383 #define AV_UTF8_FLAG_EXCLUDE_XML_INVALID_CONTROL_CODES 8 ///< exclude control codes not accepted by XML
384 
385 #define AV_UTF8_FLAG_ACCEPT_ALL \
386  AV_UTF8_FLAG_ACCEPT_INVALID_BIG_CODES|AV_UTF8_FLAG_ACCEPT_NON_CHARACTERS|AV_UTF8_FLAG_ACCEPT_SURROGATES
387 
388 /**
389  * Read and decode a single UTF-8 code point (character) from the
390  * buffer in *buf, and update *buf to point to the next byte to
391  * decode.
392  *
393  * In case of an invalid byte sequence, the pointer will be updated to
394  * the next byte after the invalid sequence and the function will
395  * return an error code.
396  *
397  * Depending on the specified flags, the function will also fail in
398  * case the decoded code point does not belong to a valid range.
399  *
400  * @note For speed-relevant code a carefully implemented use of
401  * GET_UTF8() may be preferred.
402  *
403  * @param codep pointer used to return the parsed code in case of success.
404  * The value in *codep is set even in case the range check fails.
405  * @param bufp pointer to the address the first byte of the sequence
406  * to decode, updated by the function to point to the
407  * byte next after the decoded sequence
408  * @param buf_end pointer to the end of the buffer, points to the next
409  * byte past the last in the buffer. This is used to
410  * avoid buffer overreads (in case of an unfinished
411  * UTF-8 sequence towards the end of the buffer).
412  * @param flags a collection of AV_UTF8_FLAG_* flags
413  * @return >= 0 in case a sequence was successfully read, a negative
414  * value in case of invalid sequence
415  */
417 int av_utf8_decode(int32_t *codep, const uint8_t **bufp, const uint8_t *buf_end,
418  unsigned int flags);
419 
420 /**
421  * Check if a name is in a list.
422  * @returns 0 if not found, or the 1 based index where it has been found in the
423  * list.
424  */
425 int av_match_list(const char *name, const char *list, char separator);
426 
427 /**
428  * See libc sscanf manual for more information.
429  * Locale-independent sscanf implementation.
430  */
431 int av_sscanf(const char *string, const char *format, ...);
432 
433 /**
434  * @}
435  */
436 
437 #endif /* AVUTIL_AVSTRING_H */
av_utf8_decode
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...
Definition: avstring.c:376
av_isxdigit
static av_const int av_isxdigit(int c)
Locale-independent conversion of ASCII isxdigit.
Definition: avstring.h:256
name
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option name
Definition: writing_filters.txt:88
av_get_token
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...
Definition: avstring.c:151
av_stristr
char * av_stristr(const char *haystack, const char *needle)
Locate the first case-independent occurrence in the string haystack of the string needle.
Definition: avstring.c:56
av_strcasecmp
int av_strcasecmp(const char *a, const char *b)
Locale-independent case-insensitive compare.
Definition: avstring.c:215
av_isspace
static av_const int av_isspace(int c)
Locale-independent conversion of ASCII isspace.
Definition: avstring.h:227
av_const
#define av_const
Definition: attributes.h:84
b
#define b
Definition: input.c:40
av_d2str
char attribute_deprecated char * av_d2str(double d)
Convert a number to an av_malloced string.
Definition: avstring.c:140
av_basename
const char * av_basename(const char *path)
Thread safe basename.
Definition: avstring.c:260
av_append_path_component
char * av_append_path_component(const char *path, const char *component)
Append path component to the existing path.
Definition: avstring.c:304
av_escape
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 ...
Definition: avstring.c:335
av_dirname
const char * av_dirname(char *path)
Thread safe dirname.
Definition: avstring.c:283
s
#define s(width, name)
Definition: cbs_vp9.c:257
av_strtok
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().
Definition: avstring.c:186
from
const char * from
Definition: jacosubdec.c:66
to
const char * to
Definition: webvttdec.c:35
av_stristart
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.
Definition: avstring.c:45
av_sscanf
int av_sscanf(const char *string, const char *format,...)
See libc sscanf manual for more information.
Definition: avsscanf.c:960
AV_ESCAPE_MODE_QUOTE
@ AV_ESCAPE_MODE_QUOTE
Use single-quote escaping.
Definition: avstring.h:326
av_match_list
int av_match_list(const char *name, const char *list, char separator)
Check if a name is in a list.
Definition: avstring.c:452
av_strireplace
char * av_strireplace(const char *str, const char *from, const char *to)
Locale-independent strings replace.
Definition: avstring.c:237
av_strnlen
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
av_printf_format
#define av_printf_format(fmtpos, attrpos)
Definition: attributes.h:161
src
#define src
Definition: vp8dsp.c:255
list
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining list
Definition: filter_design.txt:25
AV_ESCAPE_MODE_AUTO
@ AV_ESCAPE_MODE_AUTO
Use auto-selected escaping mode.
Definition: avstring.h:324
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
FFFILE::buf
unsigned char * buf
Definition: avsscanf.c:37
av_strncasecmp
int av_strncasecmp(const char *a, const char *b, size_t n)
Locale-independent case-insensitive compare.
Definition: avstring.c:225
size
int size
Definition: twinvq_data.h:10344
AV_ESCAPE_MODE_XML
@ AV_ESCAPE_MODE_XML
Use XML non-markup character data escaping.
Definition: avstring.h:327
attribute_deprecated
#define attribute_deprecated
Definition: attributes.h:104
av_isgraph
static av_const int av_isgraph(int c)
Locale-independent conversion of ASCII isgraph.
Definition: avstring.h:219
av_isdigit
static av_const int av_isdigit(int c)
Locale-independent conversion of ASCII isdigit.
Definition: avstring.h:211
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
attributes.h
av_strstart
int av_strstart(const char *str, const char *pfx, const char **ptr)
Return non-zero if pfx is a prefix of str.
Definition: avstring.c:34
av_warn_unused_result
#define av_warn_unused_result
Definition: attributes.h:64
i
int i
Definition: input.c:406
av_strlcatf
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.
av_toupper
static av_const int av_toupper(int c)
Locale-independent conversion of ASCII characters to uppercase.
Definition: avstring.h:236
len
int len
Definition: vorbis_enc_data.h:426
version.h
av_strlcat
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,...
Definition: avstring.c:93
av_strnstr
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...
Definition: avstring.c:69
av_asprintf
char * av_asprintf(const char *fmt,...) av_printf_format(1
Print arguments following specified format into a large enough auto allocated buffer.
mode
mode
Definition: ebur128.h:83
av_match_name
int av_match_name(const char *name, const char *names)
Match instances of a name in a comma-separated list of names.
Definition: avstring.c:353
AV_ESCAPE_MODE_BACKSLASH
@ AV_ESCAPE_MODE_BACKSLASH
Use backslash escaping.
Definition: avstring.h:325
format
fg outputs[0] format
Definition: ffmpeg_filter.c:175
d
d
Definition: ffmpeg_filter.c:156
int32_t
int32_t
Definition: audioconvert.c:56
convert_header.str
string str
Definition: convert_header.py:20
flags
#define flags(name, subs,...)
Definition: cbs_av1.c:561
av_strlcpy
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.
Definition: avstring.c:83
AVEscapeMode
AVEscapeMode
Definition: avstring.h:323
av_tolower
static av_const int av_tolower(int c)
Locale-independent conversion of ASCII characters to lowercase.
Definition: avstring.h:246