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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 "attributes.h"
26 
27 /**
28  * @addtogroup lavu_string
29  * @{
30  */
31 
32 /**
33  * Return non-zero if pfx is a prefix of str. If it is, *ptr is set to
34  * the address of the first character in str after the prefix.
35  *
36  * @param str input string
37  * @param pfx prefix to test
38  * @param ptr updated if the prefix is matched inside str
39  * @return non-zero if the prefix matches, zero otherwise
40  */
41 int av_strstart(const char *str, const char *pfx, const char **ptr);
42 
43 /**
44  * Return non-zero if pfx is a prefix of str independent of case. If
45  * it is, *ptr is set to the address of the first character in str
46  * after the prefix.
47  *
48  * @param str input string
49  * @param pfx prefix to test
50  * @param ptr updated if the prefix is matched inside str
51  * @return non-zero if the prefix matches, zero otherwise
52  */
53 int av_stristart(const char *str, const char *pfx, const char **ptr);
54 
55 /**
56  * Locate the first case-independent occurrence in the string haystack
57  * of the string needle. A zero-length string needle is considered to
58  * match at the start of haystack.
59  *
60  * This function is a case-insensitive version of the standard strstr().
61  *
62  * @param haystack string to search in
63  * @param needle string to search for
64  * @return pointer to the located match within haystack
65  * or a null pointer if no match
66  */
67 char *av_stristr(const char *haystack, const char *needle);
68 
69 /**
70  * Copy the string src to dst, but no more than size - 1 bytes, and
71  * null-terminate dst.
72  *
73  * This function is the same as BSD strlcpy().
74  *
75  * @param dst destination buffer
76  * @param src source string
77  * @param size size of destination buffer
78  * @return the length of src
79  *
80  * @warning since the return value is the length of src, src absolutely
81  * _must_ be a properly 0-terminated string, otherwise this will read beyond
82  * the end of the buffer and possibly crash.
83  */
84 size_t av_strlcpy(char *dst, const char *src, size_t size);
85 
86 /**
87  * Append the string src to the string dst, but to a total length of
88  * no more than size - 1 bytes, and null-terminate dst.
89  *
90  * This function is similar to BSD strlcat(), but differs when
91  * size <= strlen(dst).
92  *
93  * @param dst destination buffer
94  * @param src source string
95  * @param size size of destination buffer
96  * @return the total length of src and dst
97  *
98  * @warning since the return value use the length of src and dst, these
99  * absolutely _must_ be a properly 0-terminated strings, otherwise this
100  * will read beyond the end of the buffer and possibly crash.
101  */
102 size_t av_strlcat(char *dst, const char *src, size_t size);
103 
104 /**
105  * Append output to a string, according to a format. Never write out of
106  * the destination buffer, and always put a terminating 0 within
107  * the buffer.
108  * @param dst destination buffer (string to which the output is
109  * appended)
110  * @param size total size of the destination buffer
111  * @param fmt printf-compatible format string, specifying how the
112  * following parameters are used
113  * @return the length of the string that would have been generated
114  * if enough space had been available
115  */
116 size_t av_strlcatf(char *dst, size_t size, const char *fmt, ...) av_printf_format(3, 4);
117 
118 /**
119  * Print arguments following specified format into a large enough auto
120  * allocated buffer. It is similar to GNU asprintf().
121  * @param fmt printf-compatible format string, specifying how the
122  * following parameters are used.
123  * @return the allocated string
124  * @note You have to free the string yourself with av_free().
125  */
126 char *av_asprintf(const char *fmt, ...) av_printf_format(1, 2);
127 
128 /**
129  * Convert a number to a av_malloced string.
130  */
131 char *av_d2str(double d);
132 
133 /**
134  * Unescape the given string until a non escaped terminating char,
135  * and return the token corresponding to the unescaped string.
136  *
137  * The normal \ and ' escaping is supported. Leading and trailing
138  * whitespaces are removed, unless they are escaped with '\' or are
139  * enclosed between ''.
140  *
141  * @param buf the buffer to parse, buf will be updated to point to the
142  * terminating char
143  * @param term a 0-terminated list of terminating chars
144  * @return the malloced unescaped string, which must be av_freed by
145  * the user, NULL in case of allocation failure
146  */
147 char *av_get_token(const char **buf, const char *term);
148 
149 /**
150  * Split the string into several tokens which can be accessed by
151  * successive calls to av_strtok().
152  *
153  * A token is defined as a sequence of characters not belonging to the
154  * set specified in delim.
155  *
156  * On the first call to av_strtok(), s should point to the string to
157  * parse, and the value of saveptr is ignored. In subsequent calls, s
158  * should be NULL, and saveptr should be unchanged since the previous
159  * call.
160  *
161  * This function is similar to strtok_r() defined in POSIX.1.
162  *
163  * @param s the string to parse, may be NULL
164  * @param delim 0-terminated list of token delimiters, must be non-NULL
165  * @param saveptr user-provided pointer which points to stored
166  * information necessary for av_strtok() to continue scanning the same
167  * string. saveptr is updated to point to the next character after the
168  * first delimiter found, or to NULL if the string was terminated
169  * @return the found token, or NULL when no token is found
170  */
171 char *av_strtok(char *s, const char *delim, char **saveptr);
172 
173 /**
174  * Locale-independent conversion of ASCII characters to uppercase.
175  */
176 static inline int av_toupper(int c)
177 {
178  if (c >= 'a' && c <= 'z')
179  c ^= 0x20;
180  return c;
181 }
182 
183 /**
184  * Locale-independent conversion of ASCII characters to lowercase.
185  */
186 static inline int av_tolower(int c)
187 {
188  if (c >= 'A' && c <= 'Z')
189  c ^= 0x20;
190  return c;
191 }
192 
193 /**
194  * Locale-independent case-insensitive compare.
195  * @note This means only ASCII-range characters are case-insensitive
196  */
197 int av_strcasecmp(const char *a, const char *b);
198 
199 /**
200  * Locale-independent case-insensitive compare.
201  * @note This means only ASCII-range characters are case-insensitive
202  */
203 int av_strncasecmp(const char *a, const char *b, size_t n);
204 
205 
206 /**
207  * Thread safe basename.
208  * @param path the path, on DOS both \ and / are considered separators.
209  * @return pointer to the basename substring.
210  */
211 const char *av_basename(const char *path);
212 
213 /**
214  * Thread safe dirname.
215  * @param path the path, on DOS both \ and / are considered separators.
216  * @return the path with the separator replaced by the string terminator or ".".
217  * @note the function may change the input string.
218  */
219 const char *av_dirname(char *path);
220 
221 /**
222  * @}
223  */
224 
225 #endif /* AVUTIL_AVSTRING_H */