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 <string.h> 00027 #include <stdarg.h> 00028 00029 #include "asterisk/inline_api.h" 00030 #include "asterisk/compiler.h" 00031 #include "asterisk/compat.h" 00032 00033 static force_inline int ast_strlen_zero(const char *s) 00034 { 00035 return (!s || (*s == '\0')); 00036 } 00037 00038 /*! \brief returns the equivalent of logic or for strings: 00039 * first one if not empty, otherwise second one. 00040 */ 00041 #define S_OR(a, b) (!ast_strlen_zero(a) ? (a) : (b)) 00042 00043 /*! 00044 \brief Gets a pointer to the first non-whitespace character in a string. 00045 \param ast_skip_blanks function being used 00046 \param str the input string 00047 \return a pointer to the first non-whitespace character 00048 */ 00049 AST_INLINE_API( 00050 char *ast_skip_blanks(const char *str), 00051 { 00052 while (*str && *str < 33) 00053 str++; 00054 return (char *)str; 00055 } 00056 ) 00057 00058 /*! 00059 \brief Trims trailing whitespace characters from a string. 00060 \param ast_trim_blanks function being used 00061 \param str the input string 00062 \return a pointer to the modified string 00063 */ 00064 AST_INLINE_API( 00065 char *ast_trim_blanks(char *str), 00066 { 00067 char *work = str; 00068 00069 if (work) { 00070 work += strlen(work) - 1; 00071 /* It's tempting to only want to erase after we exit this loop, 00072 but since ast_trim_blanks *could* receive a constant string 00073 (which we presumably wouldn't have to touch), we shouldn't 00074 actually set anything unless we must, and it's easier just 00075 to set each position to \0 than to keep track of a variable 00076 for it */ 00077 while ((work >= str) && *work < 33) 00078 *(work--) = '\0'; 00079 } 00080 return str; 00081 } 00082 ) 00083 00084 /*! 00085 \brief Gets a pointer to first whitespace character in a string. 00086 \param ast_skip_noblanks function being used 00087 \param str the input string 00088 \return a pointer to the first whitespace character 00089 */ 00090 AST_INLINE_API( 00091 char *ast_skip_nonblanks(char *str), 00092 { 00093 while (*str && *str > 32) 00094 str++; 00095 return str; 00096 } 00097 ) 00098 00099 /*! 00100 \brief Strip leading/trailing whitespace from a string. 00101 \param s The string to be stripped (will be modified). 00102 \return The stripped string. 00103 00104 This functions strips all leading and trailing whitespace 00105 characters from the input string, and returns a pointer to 00106 the resulting string. The string is modified in place. 00107 */ 00108 AST_INLINE_API( 00109 char *ast_strip(char *s), 00110 { 00111 s = ast_skip_blanks(s); 00112 if (s) 00113 ast_trim_blanks(s); 00114 return s; 00115 } 00116 ) 00117 00118 /*! 00119 \brief Strip leading/trailing whitespace and quotes from a string. 00120 \param s The string to be stripped (will be modified). 00121 \param beg_quotes The list of possible beginning quote characters. 00122 \param end_quotes The list of matching ending quote characters. 00123 \return The stripped string. 00124 00125 This functions strips all leading and trailing whitespace 00126 characters from the input string, and returns a pointer to 00127 the resulting string. The string is modified in place. 00128 00129 It can also remove beginning and ending quote (or quote-like) 00130 characters, in matching pairs. If the first character of the 00131 string matches any character in beg_quotes, and the last 00132 character of the string is the matching character in 00133 end_quotes, then they are removed from the string. 00134 00135 Examples: 00136 \code 00137 ast_strip_quoted(buf, "\"", "\""); 00138 ast_strip_quoted(buf, "'", "'"); 00139 ast_strip_quoted(buf, "[{(", "]})"); 00140 \endcode 00141 */ 00142 char *ast_strip_quoted(char *s, const char *beg_quotes, const char *end_quotes); 00143 00144 /*! 00145 \brief Size-limited null-terminating string copy. 00146 \param ast_copy_string function being used 00147 \param dst The destination buffer. 00148 \param src The source string 00149 \param size The size of the destination buffer 00150 \return Nothing. 00151 00152 This is similar to \a strncpy, with two important differences: 00153 - the destination buffer will \b always be null-terminated 00154 - the destination buffer is not filled with zeros past the copied string length 00155 These differences make it slightly more efficient, and safer to use since it will 00156 not leave the destination buffer unterminated. There is no need to pass an artificially 00157 reduced buffer size to this function (unlike \a strncpy), and the buffer does not need 00158 to be initialized to zeroes prior to calling this function. 00159 */ 00160 AST_INLINE_API( 00161 void ast_copy_string(char *dst, const char *src, size_t size), 00162 { 00163 while (*src && size) { 00164 *dst++ = *src++; 00165 size--; 00166 } 00167 if (__builtin_expect(!size, 0)) 00168 dst--; 00169 *dst = '\0'; 00170 } 00171 ) 00172 00173 00174 /*! 00175 \brief Build a string in a buffer, designed to be called repeatedly 00176 00177 This is a wrapper for snprintf, that properly handles the buffer pointer 00178 and buffer space available. 00179 00180 \param buffer current position in buffer to place string into (will be updated on return) 00181 \param space remaining space in buffer (will be updated on return) 00182 \param fmt printf-style format string 00183 \return 0 on success, non-zero on failure. 00184 */ 00185 int ast_build_string(char **buffer, size_t *space, const char *fmt, ...) __attribute__ ((format (printf, 3, 4))); 00186 00187 /*! 00188 \brief Build a string in a buffer, designed to be called repeatedly 00189 00190 This is a wrapper for snprintf, that properly handles the buffer pointer 00191 and buffer space available. 00192 00193 \return 0 on success, non-zero on failure. 00194 \param buffer current position in buffer to place string into (will be updated on return) 00195 \param space remaining space in buffer (will be updated on return) 00196 \param fmt printf-style format string 00197 \param ap varargs list of arguments for format 00198 */ 00199 int ast_build_string_va(char **buffer, size_t *space, const char *fmt, va_list ap); 00200 00201 /*! Make sure something is true */ 00202 /*! 00203 * Determine if a string containing a boolean value is "true". 00204 * This function checks to see whether a string passed to it is an indication of an "true" value. It checks to see if the string is "yes", "true", "y", "t", "on" or "1". 00205 * 00206 * Returns 0 if val is a NULL pointer, -1 if "true", and 0 otherwise. 00207 */ 00208 int ast_true(const char *val); 00209 00210 /*! Make sure something is false */ 00211 /*! 00212 * Determine if a string containing a boolean value is "false". 00213 * This function checks to see whether a string passed to it is an indication of an "false" value. It checks to see if the string is "no", "false", "n", "f", "off" or "0". 00214 * 00215 * Returns 0 if val is a NULL pointer, -1 if "false", and 0 otherwise. 00216 */ 00217 int ast_false(const char *val); 00218 00219 /* 00220 \brief Join an array of strings into a single string. 00221 \param s the resulting string buffer 00222 \param len the length of the result buffer, s 00223 \param w an array of strings to join 00224 00225 This function will join all of the strings in the array 'w' into a single 00226 string. It will also place a space in the result buffer in between each 00227 string from 'w'. 00228 */ 00229 void ast_join(char *s, size_t len, char * const w[]); 00230 00231 /* 00232 \brief Parse a time (integer) string. 00233 \param src String to parse 00234 \param dst Destination 00235 \param _default Value to use if the string does not contain a valid time 00236 \param consumed The number of characters 'consumed' in the string by the parse (see 'man sscanf' for details) 00237 \return zero on success, non-zero on failure 00238 */ 00239 int ast_get_time_t(const char *src, time_t *dst, time_t _default, int *consumed); 00240 00241 /* The realloca lets us ast_restrdupa(), but you can't mix any other ast_strdup calls! */ 00242 00243 struct ast_realloca { 00244 char *ptr; 00245 int alloclen; 00246 }; 00247 00248 #define ast_restrdupa(ra, s) \ 00249 ({ \ 00250 if ((ra)->ptr && strlen(s) + 1 < (ra)->alloclen) { \ 00251 strcpy((ra)->ptr, s); \ 00252 } else { \ 00253 (ra)->ptr = alloca(strlen(s) + 1 - (ra)->alloclen); \ 00254 if ((ra)->ptr) (ra)->alloclen = strlen(s) + 1; \ 00255 } \ 00256 (ra)->ptr; \ 00257 }) 00258 00259 #endif /* _ASTERISK_STRINGS_H */