Wed Jan 8 2020 09:50:21

Asterisk developer's documentation


strings.c File Reference

String manipulation API. More...

#include "asterisk.h"
#include "asterisk/strings.h"
#include "asterisk/pbx.h"

Go to the source code of this file.

Functions

int __ast_str_helper (struct ast_str **buf, ssize_t max_len, int append, const char *fmt, va_list ap)
 Core functionality of ast_str_(set|append)_va. More...
 
char * __ast_str_helper2 (struct ast_str **buf, ssize_t maxlen, const char *src, size_t maxsrc, int append, int escapecommas)
 

Detailed Description

String manipulation API.

Author
Tilghman Lesher tilgh.nosp@m.man@.nosp@m.digiu.nosp@m.m.co.nosp@m.m

Definition in file strings.c.

Function Documentation

int __ast_str_helper ( struct ast_str **  buf,
ssize_t  max_len,
int  append,
const char *  fmt,
va_list  ap 
)

Core functionality of ast_str_(set|append)_va.

core handler for dynamic strings. This is not meant to be called directly, but rather through the various wrapper macros ast_str_set(...) ast_str_append(...) ast_str_set_va(...) ast_str_append_va(...)

Definition at line 59 of file strings.c.

References AST_DYNSTR_BUILD_FAILED, ast_str_make_space(), ast_verbose(), if(), and len().

Referenced by ast_str_set_va().

62 {
63  int res, need;
64  int offset = (append && (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_USED : 0;
65  va_list aq;
66 
67  do {
68  if (max_len < 0) {
69  max_len = (*buf)->__AST_STR_LEN; /* don't exceed the allocated space */
70  }
71  /*
72  * Ask vsnprintf how much space we need. Remember that vsnprintf
73  * does not count the final <code>'\0'</code> so we must add 1.
74  */
75  va_copy(aq, ap);
76  res = vsnprintf((*buf)->__AST_STR_STR + offset, (*buf)->__AST_STR_LEN - offset, fmt, aq);
77 
78  need = res + offset + 1;
79  /*
80  * If there is not enough space and we are below the max length,
81  * reallocate the buffer and return a message telling to retry.
82  */
83  if (need > (*buf)->__AST_STR_LEN && (max_len == 0 || (*buf)->__AST_STR_LEN < max_len) ) {
84  int len = (int)(*buf)->__AST_STR_LEN;
85  if (max_len && max_len < need) { /* truncate as needed */
86  need = max_len;
87  } else if (max_len == 0) { /* if unbounded, give more room for next time */
88  need += 16 + need / 4;
89  }
90  if (0) { /* debugging */
91  ast_verbose("extend from %d to %d\n", len, need);
92  }
93  if (
94 #if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
95  _ast_str_make_space(buf, need, file, lineno, function)
96 #else
97  ast_str_make_space(buf, need)
98 #endif
99  ) {
100  ast_verbose("failed to extend from %d to %d\n", len, need);
101  va_end(aq);
103  }
104  (*buf)->__AST_STR_STR[offset] = '\0'; /* Truncate the partial write. */
105 
106  /* Restart va_copy before calling vsnprintf() again. */
107  va_end(aq);
108  continue;
109  }
110  va_end(aq);
111  break;
112  } while (1);
113  /* update space used, keep in mind the truncation */
114  (*buf)->__AST_STR_USED = (res + offset > (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_LEN - 1: res + offset;
115 
116  return res;
117 }
void ast_verbose(const char *fmt,...)
Definition: logger.c:1568
int ast_str_make_space(struct ast_str **buf, size_t new_len)
Definition: strings.h:588
static int len(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t buflen)
if(yyss+yystacksize-1<=yyssp)
Definition: ast_expr2.c:1874
char* __ast_str_helper2 ( struct ast_str **  buf,
ssize_t  maxlen,
const char *  src,
size_t  maxsrc,
int  append,
int  escapecommas 
)

Definition at line 119 of file strings.c.

References ast_str::__AST_STR_LEN, ast_str_make_space(), and if().

Referenced by ast_str_append_substr(), ast_str_append_va(), ast_str_set_escapecommas(), and ast_str_set_substr().

120 {
121  int dynamic = 0;
122  char *ptr = append ? &((*buf)->__AST_STR_STR[(*buf)->__AST_STR_USED]) : (*buf)->__AST_STR_STR;
123 
124  if (maxlen < 1) {
125  if (maxlen == 0) {
126  dynamic = 1;
127  }
128  maxlen = (*buf)->__AST_STR_LEN;
129  }
130 
131  while (*src && maxsrc && maxlen && (!escapecommas || (maxlen - 1))) {
132  if (escapecommas && (*src == '\\' || *src == ',')) {
133  *ptr++ = '\\';
134  maxlen--;
135  (*buf)->__AST_STR_USED++;
136  }
137  *ptr++ = *src++;
138  maxsrc--;
139  maxlen--;
140  (*buf)->__AST_STR_USED++;
141 
142  if ((ptr >= (*buf)->__AST_STR_STR + (*buf)->__AST_STR_LEN - 3) ||
143  (dynamic && (!maxlen || (escapecommas && !(maxlen - 1))))) {
144  char *oldbase = (*buf)->__AST_STR_STR;
145  size_t old = (*buf)->__AST_STR_LEN;
146  if (ast_str_make_space(buf, (*buf)->__AST_STR_LEN * 2)) {
147  /* If the buffer can't be extended, end it. */
148  break;
149  }
150  /* What we extended the buffer by */
151  maxlen = old;
152 
153  ptr += (*buf)->__AST_STR_STR - oldbase;
154  }
155  }
156  if (__builtin_expect(!maxlen, 0)) {
157  ptr--;
158  }
159  *ptr = '\0';
160  return (*buf)->__AST_STR_STR;
161 }
int ast_str_make_space(struct ast_str **buf, size_t new_len)
Definition: strings.h:588
if(yyss+yystacksize-1<=yyssp)
Definition: ast_expr2.c:1874
size_t __AST_STR_LEN
Definition: strings.h:365