utils.c

   1 /* usmb - mount SMB shares via FUSE and Samba
   2  * Copyright (C) 2006-2008 Geoff Johnstone
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <assert.h>
  18 #include <stdarg.h>
  19 #include <stddef.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include "utils.h"
  24
  25
  26
  27 #define INIT_LEN 256
  28 char * concat_strings (int num, ...)
  29 {
  30   va_list ap;
  31
  32   char *base, *out;
  33
  34   base = out = malloc (INIT_LEN);
  35   if (NULL == base)
  36     return NULL;
  37
  38   size_t buff_size = INIT_LEN;
  39
  40   va_start (ap, num);
  41   for (int i = 0; i < num; ++i)
  42   {
  43     const char *next = va_arg (ap, const char *);
  44     assert (NULL != next);
  45
  46     size_t next_len = strlen (next);
  47     /*LINTED*/
  48     size_t required = (out - base) + next_len + 1;
  49
  50     if (buff_size < required)
  51     {
  52       while (buff_size < required)
  53       {
  54         size_t dbl_len = buff_size * 2;
  55         if (dbl_len < buff_size)
  56         {
  57           free (base);
  58           return NULL;
  59         }
  60
  61         buff_size = dbl_len;
  62       }
  63
  64       /*LINTED*/
  65       ptrdiff_t diff = out - base;
  66
  67       char *newbase = realloc (base, buff_size);
  68       if (NULL == newbase)
  69       {
  70         free (base);
  71         return NULL;
  72       }
  73
  74       base = newbase;
  75       out = base + diff;
  76     }
  77
  78     memcpy (out, next, next_len);
  79     out += next_len;
  80   }
  81   va_end (ap);
  82
  83   *out = '\0';
  84   return base;
  85 }
  86
  87
  88 char * xstrdup (const char *in)
  89 {
  90   char *out = NULL;
  91
  92   if (in)
  93   {
  94     size_t len = strlen (in) + 1;
  95
  96     if ((out = malloc (len)))
  97       memcpy (out, in, len);
  98   }
  99
 100   return out;
 101 }
 102
 103
 104 // the const here lets us pass a pointer to const
 105 void xfree (const void *ptr)
 106 {
 107   if (NULL != ptr)
 108     free ((void *)ptr);
 109 }
 110
 111
 112 void clear_and_free (char *ptr)
 113 {
 114   if (NULL != ptr)
 115   {
 116     for (char *pch = ptr; '\0' != *pch; ++pch)
 117       *pch = '\0';
 118
 119     free (ptr);
 120   }
 121 }
 122