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 <errno.h>
  19 #include <stdarg.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include "utils.h"
  25
  26
  27
  28 #define INIT_LEN 256
  29 char * concat_strings (int num, ...)
  30 {
  31   va_list ap;
  32
  33   char *base, *out;
  34
  35   base = out = malloc (INIT_LEN);
  36   if (NULL == base)
  37     return NULL;
  38
  39   size_t buff_size = INIT_LEN;
  40
  41   va_start (ap, num);
  42   for (int i = 0; i < num; ++i)
  43   {
  44     const char *next = va_arg (ap, const char *);
  45     assert (NULL != next);
  46
  47     size_t next_len = strlen (next);
  48     /*LINTED*/
  49     size_t required = (out - base) + next_len + 1;
  50
  51     if (buff_size < required)
  52     {
  53       while (buff_size < required)
  54       {
  55         size_t dbl_len = buff_size * 2;
  56         if (dbl_len < buff_size)
  57         {
  58           free (base);
  59           va_end (ap);
  60           return NULL;
  61         }
  62
  63         buff_size = dbl_len;
  64       }
  65
  66       /*LINTED*/
  67       ptrdiff_t diff = out - base;
  68
  69       char *newbase = realloc (base, buff_size);
  70       if (NULL == newbase)
  71       {
  72         free (base);
  73         va_end (ap);
  74         return NULL;
  75       }
  76
  77       base = newbase;
  78       out = base + diff;
  79     }
  80
  81     memcpy (out, next, next_len);
  82     out += next_len;
  83   }
  84   va_end (ap);
  85
  86   *out = '\0';
  87   return base;
  88 }
  89
  90
  91 char * xstrdup (const char *in)
  92 {
  93   char *out = NULL;
  94
  95   if (NULL != in)
  96   {
  97     size_t len = strlen (in) + 1;
  98
  99     if ((out = malloc (len)))
 100       memcpy (out, in, len);
 101   }
 102
 103   return out;
 104 }
 105
 106
 107 // the const here lets us pass a pointer to const
 108 void xfree (const void *ptr)
 109 {
 110   if (NULL != ptr)
 111     free ((void *)ptr);
 112 }
 113
 114
 115 void clear_and_free (char *ptr)
 116 {
 117   if (NULL != ptr)
 118   {
 119     for (char *pch = ptr; '\0' != *pch; ++pch)
 120       *pch = '\0';
 121
 122     free (ptr);
 123   }
 124 }
 125
 126
 127 void free_errno (const void *ptr)
 128 {
 129   int err = errno;
 130   free ((void *)ptr);
 131   errno = err;
 132 }
 133
 134
 135 void xfree_errno (const void *ptr)
 136 {
 137   int err = errno;
 138   xfree (ptr);
 139   errno = err;
 140 }
 141