00001 /* 00002 * Asterisk -- An open source telephony toolkit. 00003 * 00004 * Copyright (C) 1999 - 2006, Digium, Inc. 00005 * 00006 * Mark Spencer <markster@digium.com> 00007 * 00008 * See http://www.asterisk.org for more information about 00009 * the Asterisk project. Please do not directly contact 00010 * any of the maintainers of this project for assistance; 00011 * the project provides a web site, mailing lists and IRC 00012 * channels for your use. 00013 * 00014 * This program is free software, distributed under the terms of 00015 * the GNU General Public License Version 2. See the LICENSE file 00016 * at the top of the source tree. 00017 */ 00018 00019 /*! \file 00020 * \brief String manipulation functions 00021 */ 00022 00023 #ifndef _ASTERISK_STRINGS_H 00024 #define _ASTERISK_STRINGS_H 00025 00026 #include <ctype.h> 00027 00028 #include "asterisk/inline_api.h" 00029 #include "asterisk/utils.h" 00030 #include "asterisk/threadstorage.h" 00031 00032 /* You may see casts in this header that may seem useless but they ensure this file is C++ clean */ 00033 00034 #ifdef AST_DEVMODE 00035 #define ast_strlen_zero(foo) _ast_strlen_zero(foo, __FILE__, __PRETTY_FUNCTION__, __LINE__) 00036 static force_inline int _ast_strlen_zero(const char *s, const char *file, const char *function, int line) 00037 { 00038 if (!s || (*s == '\0')) { 00039 return 1; 00040 } 00041 if (!strcmp(s, "(null)")) { 00042 ast_log(__LOG_WARNING, file, line, function, "Possible programming error: \"(null)\" is not NULL!\n"); 00043 } 00044 return 0; 00045 } 00046 00047 #else 00048 static force_inline int ast_strlen_zero(const char *s) 00049 { 00050 return (!s || (*s == '\0')); 00051 } 00052 #endif 00053 00054 /*! \brief returns the equivalent of logic or for strings: 00055 * first one if not empty, otherwise second one. 00056 */ 00057 #define S_OR(a, b) (!ast_strlen_zero(a) ? (a) : (b)) 00058 00059 /*! \brief returns the equivalent of logic or for strings, with an additional boolean check: 00060 * second one if not empty and first one is true, otherwise third one. 00061 * example: S_COR(usewidget, widget, "<no widget>") 00062 */ 00063 #define S_COR(a, b, c) ((a && !ast_strlen_zero(b)) ? (b) : (c)) 00064 00065 /*! 00066 \brief Gets a pointer to the first non-whitespace character in a string. 00067 \param str the input string 00068 \return a pointer to the first non-whitespace character 00069 */ 00070 AST_INLINE_API( 00071 char *ast_skip_blanks(const char *str), 00072 { 00073 while (*str && ((unsigned char) *str) < 33) 00074 str++; 00075 return (char *)str; 00076 } 00077 ) 00078 00079 /*! 00080 \brief Trims trailing whitespace characters from a string. 00081 \param str the input string 00082 \return a pointer to the modified string 00083 */ 00084 AST_INLINE_API( 00085 char *ast_trim_blanks(char *str), 00086 { 00087 char *work = str; 00088 00089 if (work) { 00090 work += strlen(work) - 1; 00091 /* It's tempting to only want to erase after we exit this loop, 00092 but since ast_trim_blanks *could* receive a constant string 00093 (which we presumably wouldn't have to touch), we shouldn't 00094 actually set anything unless we must, and it's easier just 00095 to set each position to \0 than to keep track of a variable 00096 for it */ 00097 while ((work >= str) && ((unsigned char) *work) < 33) 00098 *(work--) = '\0'; 00099 } 00100 return str; 00101 } 00102 ) 00103 00104 /*! 00105 \brief Gets a pointer to first whitespace character in a string. 00106 \param str the input string 00107 \return a pointer to the first whitespace character 00108 */ 00109 AST_INLINE_API( 00110 char *ast_skip_nonblanks(char *str), 00111 { 00112 while (*str && ((unsigned char) *str) > 32) 00113 str++; 00114 return str; 00115 } 00116 ) 00117 00118 /*! 00119 \brief Strip leading/trailing whitespace from a string. 00120 \param s The string to be stripped (will be modified). 00121 \return The stripped string. 00122 00123 This functions strips all leading and trailing whitespace 00124 characters from the input string, and returns a pointer to 00125 the resulting string. The string is modified in place. 00126 */ 00127 AST_INLINE_API( 00128 char *ast_strip(char *s), 00129 { 00130 s = ast_skip_blanks(s); 00131 if (s) 00132 ast_trim_blanks(s); 00133 return s; 00134 } 00135 ) 00136 00137 /*! 00138 \brief Strip leading/trailing whitespace and quotes from a string. 00139 \param s The string to be stripped (will be modified). 00140 \param beg_quotes The list of possible beginning quote characters. 00141 \param end_quotes The list of matching ending quote characters. 00142 \return The stripped string. 00143 00144 This functions strips all leading and trailing whitespace 00145 characters from the input string, and returns a pointer to 00146 the resulting string. The string is modified in place. 00147 00148 It can also remove beginning and ending quote (or quote-like) 00149 characters, in matching pairs. If the first character of the 00150 string matches any character in beg_quotes, and the last 00151 character of the string is the matching character in 00152 end_quotes, then they are removed from the string. 00153 00154 Examples: 00155 \code 00156 ast_strip_quoted(buf, "\"", "\""); 00157 ast_strip_quoted(buf, "'", "'"); 00158 ast_strip_quoted(buf, "[{(", "]})"); 00159 \endcode 00160 */ 00161 char *ast_strip_quoted(char *s, const char *beg_quotes, const char *end_quotes); 00162 00163 /*! 00164 \brief Strip backslash for "escaped" semicolons, 00165 the string to be stripped (will be modified). 00166 \return The stripped string. 00167 */ 00168 char *ast_unescape_semicolon(char *s); 00169 00170 /*! 00171 \brief Convert some C escape sequences \verbatim (\b\f\n\r\t) \endverbatim into the 00172 equivalent characters. The string to be converted (will be modified). 00173 \return The converted string. 00174 */ 00175 char *ast_unescape_c(char *s); 00176 00177 /*! 00178 \brief Size-limited null-terminating string copy. 00179 \param dst The destination buffer. 00180 \param src The source string 00181 \param size The size of the destination buffer 00182 \return Nothing. 00183 00184 This is similar to \a strncpy, with two important differences: 00185 - the destination buffer will \b always be null-terminated 00186 - the destination buffer is not filled with zeros past the copied string length 00187 These differences make it slightly more efficient, and safer to use since it will 00188 not leave the destination buffer unterminated. There is no need to pass an artificially 00189 reduced buffer size to this function (unlike \a strncpy), and the buffer does not need 00190 to be initialized to zeroes prior to calling this function. 00191 */ 00192 AST_INLINE_API( 00193 void ast_copy_string(char *dst, const char *src, size_t size), 00194 { 00195 while (*src && size) { 00196 *dst++ = *src++; 00197 size--; 00198 } 00199 if (__builtin_expect(!size, 0)) 00200 dst--; 00201 *dst = '\0'; 00202 } 00203 ) 00204 00205 00206 /*! 00207 \brief Build a string in a buffer, designed to be called repeatedly 00208 00209 \note This method is not recommended. New code should use ast_str_*() instead. 00210 00211 This is a wrapper for snprintf, that properly handles the buffer pointer 00212 and buffer space available. 00213 00214 \param buffer current position in buffer to place string into (will be updated on return) 00215 \param space remaining space in buffer (will be updated on return) 00216 \param fmt printf-style format string 00217 \retval 0 on success 00218 \retval non-zero on failure. 00219 */ 00220 int ast_build_string(char **buffer, size_t *space, const char *fmt, ...) __attribute__((format(printf, 3, 4))); 00221 00222 /*! 00223 \brief Build a string in a buffer, designed to be called repeatedly 00224 00225 This is a wrapper for snprintf, that properly handles the buffer pointer 00226 and buffer space available. 00227 00228 \return 0 on success, non-zero on failure. 00229 \param buffer current position in buffer to place string into (will be updated on return) 00230 \param space remaining space in buffer (will be updated on return) 00231 \param fmt printf-style format string 00232 \param ap varargs list of arguments for format 00233 */ 00234 int ast_build_string_va(char **buffer, size_t *space, const char *fmt, va_list ap) __attribute__((format(printf, 3, 0))); 00235 00236 /*! 00237 * \brief Make sure something is true. 00238 * Determine if a string containing a boolean value is "true". 00239 * This function checks to see whether a string passed to it is an indication of an "true" value. 00240 * It checks to see if the string is "yes", "true", "y", "t", "on" or "1". 00241 * 00242 * \retval 0 if val is a NULL pointer. 00243 * \retval -1 if "true". 00244 * \retval 0 otherwise. 00245 */ 00246 int ast_true(const char *val); 00247 00248 /*! 00249 * \brief Make sure something is false. 00250 * Determine if a string containing a boolean value is "false". 00251 * This function checks to see whether a string passed to it is an indication of an "false" value. 00252 * It checks to see if the string is "no", "false", "n", "f", "off" or "0". 00253 * 00254 * \retval 0 if val is a NULL pointer. 00255 * \retval -1 if "true". 00256 * \retval 0 otherwise. 00257 */ 00258 int ast_false(const char *val); 00259 00260 /* 00261 * \brief Join an array of strings into a single string. 00262 * \param s the resulting string buffer 00263 * \param len the length of the result buffer, s 00264 * \param w an array of strings to join. 00265 * 00266 * This function will join all of the strings in the array 'w' into a single 00267 * string. It will also place a space in the result buffer in between each 00268 * string from 'w'. 00269 */ 00270 void ast_join(char *s, size_t len, char * const w[]); 00271 00272 /* 00273 \brief Parse a time (integer) string. 00274 \param src String to parse 00275 \param dst Destination 00276 \param _default Value to use if the string does not contain a valid time 00277 \param consumed The number of characters 'consumed' in the string by the parse (see 'man sscanf' for details) 00278 \retval 0 on success 00279 \retval non-zero on failure. 00280 */ 00281 int ast_get_time_t(const char *src, time_t *dst, time_t _default, int *consumed); 00282 00283 /* 00284 \brief Parse a time (float) string. 00285 \param src String to parse 00286 \param dst Destination 00287 \param _default Value to use if the string does not contain a valid time 00288 \param consumed The number of characters 'consumed' in the string by the parse (see 'man sscanf' for details) 00289 \return zero on success, non-zero on failure 00290 */ 00291 int ast_get_timeval(const char *src, struct timeval *tv, struct timeval _default, int *consumed); 00292 00293 /*! 00294 * Support for dynamic strings. 00295 * 00296 * A dynamic string is just a C string prefixed by a few control fields 00297 * that help setting/appending/extending it using a printf-like syntax. 00298 * 00299 * One should never declare a variable with this type, but only a pointer 00300 * to it, e.g. 00301 * 00302 * struct ast_str *ds; 00303 * 00304 * The pointer can be initialized with the following: 00305 * 00306 * ds = ast_str_create(init_len); 00307 * creates a malloc()'ed dynamic string; 00308 * 00309 * ds = ast_str_alloca(init_len); 00310 * creates a string on the stack (not very dynamic!). 00311 * 00312 * ds = ast_str_thread_get(ts, init_len) 00313 * creates a malloc()'ed dynamic string associated to 00314 * the thread-local storage key ts 00315 * 00316 * Finally, the string can be manipulated with the following: 00317 * 00318 * ast_str_set(&buf, max_len, fmt, ...) 00319 * ast_str_append(&buf, max_len, fmt, ...) 00320 * 00321 * and their varargs variant 00322 * 00323 * ast_str_set_va(&buf, max_len, ap) 00324 * ast_str_append_va(&buf, max_len, ap) 00325 * 00326 * \param max_len The maximum allowed capacity of the ast_str. Note that 00327 * if the value of max_len is less than the current capacity of the 00328 * ast_str (as returned by ast_str_size), then the parameter is effectively 00329 * ignored. 00330 * 0 means unlimited, -1 means "at most the available space" 00331 * 00332 * \return All the functions return <0 in case of error, or the 00333 * length of the string added to the buffer otherwise. Note that 00334 * in most cases where an error is returned, characters ARE written 00335 * to the ast_str. 00336 */ 00337 00338 /*! \brief The descriptor of a dynamic string 00339 * XXX storage will be optimized later if needed 00340 * We use the ts field to indicate the type of storage. 00341 * Three special constants indicate malloc, alloca() or static 00342 * variables, all other values indicate a 00343 * struct ast_threadstorage pointer. 00344 */ 00345 struct ast_str { 00346 size_t len; /*!< The current maximum length of the string */ 00347 size_t used; /*!< Amount of space used */ 00348 struct ast_threadstorage *ts; /*!< What kind of storage is this ? */ 00349 #define DS_MALLOC ((struct ast_threadstorage *)1) 00350 #define DS_ALLOCA ((struct ast_threadstorage *)2) 00351 #define DS_STATIC ((struct ast_threadstorage *)3) /* not supported yet */ 00352 char str[0]; /*!< The string buffer */ 00353 }; 00354 00355 #define ast_str_size(a) ((a)->len) 00356 #define ast_str_strlen(a) ((a)->used) 00357 #define ast_str_buffer(a) ((a)->str) 00358 #define ast_str_update(a) (a)->used = strlen((a)->str) 00359 00360 /*! 00361 * \brief Create a malloc'ed dynamic length string 00362 * 00363 * \param init_len This is the initial length of the string buffer 00364 * 00365 * \return This function returns a pointer to the dynamic string length. The 00366 * result will be NULL in the case of a memory allocation error. 00367 * 00368 * \note The result of this function is dynamically allocated memory, and must 00369 * be free()'d after it is no longer needed. 00370 */ 00371 AST_INLINE_API( 00372 struct ast_str * attribute_malloc ast_str_create(size_t init_len), 00373 { 00374 struct ast_str *buf; 00375 00376 buf = (struct ast_str *)ast_calloc(1, sizeof(*buf) + init_len); 00377 if (buf == NULL) 00378 return NULL; 00379 00380 buf->len = init_len; 00381 buf->used = 0; 00382 buf->ts = DS_MALLOC; 00383 00384 return buf; 00385 } 00386 ) 00387 00388 /*! \brief Reset the content of a dynamic string. 00389 * Useful before a series of ast_str_append. 00390 */ 00391 AST_INLINE_API( 00392 void ast_str_reset(struct ast_str *buf), 00393 { 00394 if (buf) { 00395 buf->used = 0; 00396 if (buf->len) 00397 buf->str[0] = '\0'; 00398 } 00399 } 00400 ) 00401 00402 /* 00403 * AST_INLINE_API() is a macro that takes a block of code as an argument. 00404 * Using preprocessor #directives in the argument is not supported by all 00405 * compilers, and it is a bit of an obfuscation anyways, so avoid it. 00406 * As a workaround, define a macro that produces either its argument 00407 * or nothing, and use that instead of #ifdef/#endif within the 00408 * argument to AST_INLINE_API(). 00409 */ 00410 #if defined(DEBUG_THREADLOCALS) 00411 #define _DB1(x) x 00412 #else 00413 #define _DB1(x) 00414 #endif 00415 00416 /*! 00417 * Make space in a new string (e.g. to read in data from a file) 00418 */ 00419 #if (defined(MALLOC_DEBUG) && !defined(STANDALONE)) 00420 AST_INLINE_API( 00421 int _ast_str_make_space(struct ast_str **buf, size_t new_len, const char *file, int lineno, const char *function), 00422 { 00423 struct ast_str *old_buf = *buf; 00424 00425 if (new_len <= (*buf)->len) 00426 return 0; /* success */ 00427 if ((*buf)->ts == DS_ALLOCA || (*buf)->ts == DS_STATIC) 00428 return -1; /* cannot extend */ 00429 *buf = (struct ast_str *)__ast_realloc(*buf, new_len + sizeof(struct ast_str), file, lineno, function); 00430 if (*buf == NULL) { 00431 *buf = old_buf; 00432 return -1; 00433 } 00434 if ((*buf)->ts != DS_MALLOC) { 00435 pthread_setspecific((*buf)->ts->key, *buf); 00436 _DB1(__ast_threadstorage_object_replace(old_buf, *buf, new_len + sizeof(struct ast_str));) 00437 } 00438 00439 (*buf)->len = new_len; 00440 return 0; 00441 } 00442 ) 00443 #define ast_str_make_space(a,b) _ast_str_make_space(a,b,__FILE__,__LINE__,__PRETTY_FUNCTION__) 00444 #else 00445 AST_INLINE_API( 00446 int ast_str_make_space(struct ast_str **buf, size_t new_len), 00447 { 00448 struct ast_str *old_buf = *buf; 00449 00450 if (new_len <= (*buf)->len) 00451 return 0; /* success */ 00452 if ((*buf)->ts == DS_ALLOCA || (*buf)->ts == DS_STATIC) 00453 return -1; /* cannot extend */ 00454 *buf = (struct ast_str *)ast_realloc(*buf, new_len + sizeof(struct ast_str)); 00455 if (*buf == NULL) { 00456 *buf = old_buf; 00457 return -1; 00458 } 00459 if ((*buf)->ts != DS_MALLOC) { 00460 pthread_setspecific((*buf)->ts->key, *buf); 00461 _DB1(__ast_threadstorage_object_replace(old_buf, *buf, new_len + sizeof(struct ast_str));) 00462 } 00463 00464 (*buf)->len = new_len; 00465 return 0; 00466 } 00467 ) 00468 #endif 00469 00470 #define ast_str_alloca(init_len) \ 00471 ({ \ 00472 struct ast_str *__ast_str_buf; \ 00473 __ast_str_buf = alloca(sizeof(*__ast_str_buf) + init_len); \ 00474 __ast_str_buf->len = init_len; \ 00475 __ast_str_buf->used = 0; \ 00476 __ast_str_buf->ts = DS_ALLOCA; \ 00477 __ast_str_buf->str[0] = '\0'; \ 00478 (__ast_str_buf); \ 00479 }) 00480 00481 /*! 00482 * \brief Retrieve a thread locally stored dynamic string 00483 * 00484 * \param ts This is a pointer to the thread storage structure declared by using 00485 * the AST_THREADSTORAGE macro. If declared with 00486 * AST_THREADSTORAGE(my_buf, my_buf_init), then this argument would be 00487 * (&my_buf). 00488 * \param init_len This is the initial length of the thread's dynamic string. The 00489 * current length may be bigger if previous operations in this thread have 00490 * caused it to increase. 00491 * 00492 * \return This function will return the thread locally stored dynamic string 00493 * associated with the thread storage management variable passed as the 00494 * first argument. 00495 * The result will be NULL in the case of a memory allocation error. 00496 * 00497 * Example usage: 00498 * \code 00499 * AST_THREADSTORAGE(my_str, my_str_init); 00500 * #define MY_STR_INIT_SIZE 128 00501 * ... 00502 * void my_func(const char *fmt, ...) 00503 * { 00504 * struct ast_str *buf; 00505 * 00506 * if (!(buf = ast_str_thread_get(&my_str, MY_STR_INIT_SIZE))) 00507 * return; 00508 * ... 00509 * } 00510 * \endcode 00511 */ 00512 #if !defined(DEBUG_THREADLOCALS) 00513 AST_INLINE_API( 00514 struct ast_str *ast_str_thread_get(struct ast_threadstorage *ts, 00515 size_t init_len), 00516 { 00517 struct ast_str *buf; 00518 00519 buf = (struct ast_str *)ast_threadstorage_get(ts, sizeof(*buf) + init_len); 00520 if (buf == NULL) 00521 return NULL; 00522 00523 if (!buf->len) { 00524 buf->len = init_len; 00525 buf->used = 0; 00526 buf->ts = ts; 00527 } 00528 00529 return buf; 00530 } 00531 ) 00532 #else /* defined(DEBUG_THREADLOCALS) */ 00533 AST_INLINE_API( 00534 struct ast_str *__ast_str_thread_get(struct ast_threadstorage *ts, 00535 size_t init_len, const char *file, const char *function, unsigned int line), 00536 { 00537 struct ast_str *buf; 00538 00539 buf = (struct ast_str *)__ast_threadstorage_get(ts, sizeof(*buf) + init_len, file, function, line); 00540 if (buf == NULL) 00541 return NULL; 00542 00543 if (!buf->len) { 00544 buf->len = init_len; 00545 buf->used = 0; 00546 buf->ts = ts; 00547 } 00548 00549 return buf; 00550 } 00551 ) 00552 00553 #define ast_str_thread_get(ts, init_len) __ast_str_thread_get(ts, init_len, __FILE__, __PRETTY_FUNCTION__, __LINE__) 00554 #endif /* defined(DEBUG_THREADLOCALS) */ 00555 00556 /*! 00557 * \brief Error codes from __ast_str_helper() 00558 * The undelying processing to manipulate dynamic string is done 00559 * by __ast_str_helper(), which can return a success or a 00560 * permanent failure (e.g. no memory). 00561 */ 00562 enum { 00563 /*! An error has occurred and the contents of the dynamic string 00564 * are undefined */ 00565 AST_DYNSTR_BUILD_FAILED = -1, 00566 /*! The buffer size for the dynamic string had to be increased, and 00567 * __ast_str_helper() needs to be called again after 00568 * a va_end() and va_start(). This return value is legacy and will 00569 * no longer be used. 00570 */ 00571 AST_DYNSTR_BUILD_RETRY = -2 00572 }; 00573 00574 /*! 00575 * \brief Core functionality of ast_str_(set|append)_va 00576 * 00577 * The arguments to this function are the same as those described for 00578 * ast_str_set_va except for an addition argument, append. 00579 * If append is non-zero, this will append to the current string instead of 00580 * writing over it. 00581 * 00582 * AST_DYNSTR_BUILD_RETRY is a legacy define. It should probably never 00583 * again be used. 00584 * 00585 * A return of AST_DYNSTR_BUILD_FAILED indicates a memory allocation error. 00586 * 00587 * A return value greater than or equal to zero indicates the number of 00588 * characters that have been written, not including the terminating '\0'. 00589 * In the append case, this only includes the number of characters appended. 00590 * 00591 * \note This function should never need to be called directly. It should 00592 * through calling one of the other functions or macros defined in this 00593 * file. 00594 */ 00595 int __attribute__((format(printf, 4, 0))) __ast_str_helper(struct ast_str **buf, ssize_t max_len, 00596 int append, const char *fmt, va_list ap); 00597 00598 /*! 00599 * \brief Set a dynamic string from a va_list 00600 * 00601 * \param buf This is the address of a pointer to a struct ast_str. 00602 * If it is retrieved using ast_str_thread_get, the 00603 struct ast_threadstorage pointer will need to 00604 * be updated in the case that the buffer has to be reallocated to 00605 * accommodate a longer string than what it currently has space for. 00606 * \param max_len This is the maximum length to allow the string buffer to grow 00607 * to. If this is set to 0, then there is no maximum length. 00608 * \param fmt This is the format string (printf style) 00609 * \param ap This is the va_list 00610 * 00611 * \return The return value of this function is the same as that of the printf 00612 * family of functions. 00613 * 00614 * Example usage (the first part is only for thread-local storage) 00615 * \code 00616 * AST_THREADSTORAGE(my_str, my_str_init); 00617 * #define MY_STR_INIT_SIZE 128 00618 * ... 00619 * void my_func(const char *fmt, ...) 00620 * { 00621 * struct ast_str *buf; 00622 * va_list ap; 00623 * 00624 * if (!(buf = ast_str_thread_get(&my_str, MY_STR_INIT_SIZE))) 00625 * return; 00626 * ... 00627 * va_start(fmt, ap); 00628 * ast_str_set_va(&buf, 0, fmt, ap); 00629 * va_end(ap); 00630 * 00631 * printf("This is the string we just built: %s\n", buf->str); 00632 * ... 00633 * } 00634 * \endcode 00635 */ 00636 AST_INLINE_API(int __attribute__((format(printf, 3, 0))) ast_str_set_va(struct ast_str **buf, ssize_t max_len, const char *fmt, va_list ap), 00637 { 00638 return __ast_str_helper(buf, max_len, 0, fmt, ap); 00639 } 00640 ) 00641 00642 /*! 00643 * \brief Append to a dynamic string using a va_list 00644 * 00645 * Same as ast_str_set_va(), but append to the current content. 00646 */ 00647 AST_INLINE_API(int __attribute__((format(printf, 3, 0))) ast_str_append_va(struct ast_str **buf, ssize_t max_len, const char *fmt, va_list ap), 00648 { 00649 return __ast_str_helper(buf, max_len, 1, fmt, ap); 00650 } 00651 ) 00652 00653 /*! 00654 * \brief Set a dynamic string using variable arguments 00655 * 00656 * \param buf This is the address of a pointer to a struct ast_str which should 00657 * have been retrieved using ast_str_thread_get. It will need to 00658 * be updated in the case that the buffer has to be reallocated to 00659 * accomodate a longer string than what it currently has space for. 00660 * \param max_len This is the maximum length to allow the string buffer to grow 00661 * to. If this is set to 0, then there is no maximum length. 00662 * If set to -1, we are bound to the current maximum length. 00663 * \param fmt This is the format string (printf style) 00664 * 00665 * \return The return value of this function is the same as that of the printf 00666 * family of functions. 00667 * 00668 * All the rest is the same as ast_str_set_va() 00669 */ 00670 AST_INLINE_API( 00671 int __attribute__((format(printf, 3, 4))) ast_str_set( 00672 struct ast_str **buf, ssize_t max_len, const char *fmt, ...), 00673 { 00674 int res; 00675 va_list ap; 00676 00677 va_start(ap, fmt); 00678 res = ast_str_set_va(buf, max_len, fmt, ap); 00679 va_end(ap); 00680 00681 return res; 00682 } 00683 ) 00684 00685 /*! 00686 * \brief Append to a thread local dynamic string 00687 * 00688 * The arguments, return values, and usage of this function are the same as 00689 * ast_str_set(), but the new data is appended to the current value. 00690 */ 00691 AST_INLINE_API( 00692 int __attribute__((format(printf, 3, 4))) ast_str_append( 00693 struct ast_str **buf, ssize_t max_len, const char *fmt, ...), 00694 { 00695 int res; 00696 va_list ap; 00697 00698 va_start(ap, fmt); 00699 res = ast_str_append_va(buf, max_len, fmt, ap); 00700 va_end(ap); 00701 00702 return res; 00703 } 00704 ) 00705 00706 /*! 00707 * \brief Compute a hash value on a string 00708 * 00709 * This famous hash algorithm was written by Dan Bernstein and is 00710 * commonly used. 00711 * 00712 * http://www.cse.yorku.ca/~oz/hash.html 00713 */ 00714 static force_inline int ast_str_hash(const char *str) 00715 { 00716 int hash = 5381; 00717 00718 while (*str) 00719 hash = hash * 33 ^ *str++; 00720 00721 return abs(hash); 00722 } 00723 00724 /*! 00725 * \brief Compute a hash value on a string 00726 * 00727 * \param[in] str The string to add to the hash 00728 * \param[in] hash The hash value to add to 00729 * 00730 * \details 00731 * This version of the function is for when you need to compute a 00732 * string hash of more than one string. 00733 * 00734 * This famous hash algorithm was written by Dan Bernstein and is 00735 * commonly used. 00736 * 00737 * \sa http://www.cse.yorku.ca/~oz/hash.html 00738 */ 00739 static force_inline int ast_str_hash_add(const char *str, int hash) 00740 { 00741 while (*str) 00742 hash = hash * 33 ^ *str++; 00743 00744 return abs(hash); 00745 } 00746 00747 /*! 00748 * \brief Compute a hash value on a case-insensitive string 00749 * 00750 * Uses the same hash algorithm as ast_str_hash, but converts 00751 * all characters to lowercase prior to computing a hash. This 00752 * allows for easy case-insensitive lookups in a hash table. 00753 */ 00754 static force_inline int ast_str_case_hash(const char *str) 00755 { 00756 int hash = 5381; 00757 00758 while (*str) { 00759 hash = hash * 33 ^ tolower(*str++); 00760 } 00761 00762 return abs(hash); 00763 } 00764 #endif /* _ASTERISK_STRINGS_H */