Mon Oct 8 12:39:30 2012

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.
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 <tilghman@digium.com>

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, and len().

Referenced by ast_str_set_va().

00062 {
00063    int res, need;
00064    int offset = (append && (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_USED : 0;
00065    va_list aq;
00066 
00067    do {
00068       if (max_len < 0) {
00069          max_len = (*buf)->__AST_STR_LEN; /* don't exceed the allocated space */
00070       }
00071       /*
00072        * Ask vsnprintf how much space we need. Remember that vsnprintf
00073        * does not count the final <code>'\0'</code> so we must add 1.
00074        */
00075       va_copy(aq, ap);
00076       res = vsnprintf((*buf)->__AST_STR_STR + offset, (*buf)->__AST_STR_LEN - offset, fmt, aq);
00077 
00078       need = res + offset + 1;
00079       /*
00080        * If there is not enough space and we are below the max length,
00081        * reallocate the buffer and return a message telling to retry.
00082        */
00083       if (need > (*buf)->__AST_STR_LEN && (max_len == 0 || (*buf)->__AST_STR_LEN < max_len) ) {
00084          int len = (int)(*buf)->__AST_STR_LEN;
00085          if (max_len && max_len < need) { /* truncate as needed */
00086             need = max_len;
00087          } else if (max_len == 0) { /* if unbounded, give more room for next time */
00088             need += 16 + need / 4;
00089          }
00090          if (0) { /* debugging */
00091             ast_verbose("extend from %d to %d\n", len, need);
00092          }
00093          if (
00094 #if (defined(MALLOC_DEBUG) && !defined(STANDALONE))
00095                _ast_str_make_space(buf, need, file, lineno, function)
00096 #else
00097                ast_str_make_space(buf, need)
00098 #endif
00099             ) {
00100             ast_verbose("failed to extend from %d to %d\n", len, need);
00101             va_end(aq);
00102             return AST_DYNSTR_BUILD_FAILED;
00103          }
00104          (*buf)->__AST_STR_STR[offset] = '\0';  /* Truncate the partial write. */
00105 
00106          /* Restart va_copy before calling vsnprintf() again. */
00107          va_end(aq);
00108          continue;
00109       }
00110       va_end(aq);
00111       break;
00112    } while (1);
00113    /* update space used, keep in mind the truncation */
00114    (*buf)->__AST_STR_USED = (res + offset > (*buf)->__AST_STR_LEN) ? (*buf)->__AST_STR_LEN - 1: res + offset;
00115 
00116    return res;
00117 }

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, and ast_str_make_space().

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

00120 {
00121    int dynamic = 0;
00122    char *ptr = append ? &((*buf)->__AST_STR_STR[(*buf)->__AST_STR_USED]) : (*buf)->__AST_STR_STR;
00123 
00124    if (maxlen < 1) {
00125       if (maxlen == 0) {
00126          dynamic = 1;
00127       }
00128       maxlen = (*buf)->__AST_STR_LEN;
00129    }
00130 
00131    while (*src && maxsrc && maxlen && (!escapecommas || (maxlen - 1))) {
00132       if (escapecommas && (*src == '\\' || *src == ',')) {
00133          *ptr++ = '\\';
00134          maxlen--;
00135          (*buf)->__AST_STR_USED++;
00136       }
00137       *ptr++ = *src++;
00138       maxsrc--;
00139       maxlen--;
00140       (*buf)->__AST_STR_USED++;
00141 
00142       if ((ptr >= (*buf)->__AST_STR_STR + (*buf)->__AST_STR_LEN - 3) ||
00143          (dynamic && (!maxlen || (escapecommas && !(maxlen - 1))))) {
00144          char *oldbase = (*buf)->__AST_STR_STR;
00145          size_t old = (*buf)->__AST_STR_LEN;
00146          if (ast_str_make_space(buf, (*buf)->__AST_STR_LEN * 2)) {
00147             /* If the buffer can't be extended, end it. */
00148             break;
00149          }
00150          /* What we extended the buffer by */
00151          maxlen = old;
00152 
00153          ptr += (*buf)->__AST_STR_STR - oldbase;
00154       }
00155    }
00156    if (__builtin_expect(!maxlen, 0)) {
00157       ptr--;
00158    }
00159    *ptr = '\0';
00160    return (*buf)->__AST_STR_STR;
00161 }


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