utils.c

   1 /* usmb - mount SMB shares via FUSE and Samba
   2  * Copyright (C) 2006-2009 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 "config.h"
  18 #include <assert.h>
  19 #include <errno.h>
  20 #include <stdarg.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include "utils.h"
  26
  27
  28
  29 #define INIT_LEN 256
  30 char * concat_strings (int num, ...)
  31 {
  32   va_list ap;
  33
  34   char *base, *out;
  35
  36   base = out = malloc (INIT_LEN);
  37   if (NULL == base)
  38     return NULL;
  39
  40   size_t buff_size = INIT_LEN;
  41
  42   va_start (ap, num);
  43   for (int i = 0; i < num; ++i)
  44   {
  45     const char *next = va_arg (ap, const char *);
  46     assert (NULL != next);
  47
  48     size_t next_len = strlen (next);
  49     /*LINTED*/
  50     size_t required = (out - base) + next_len + 1;
  51
  52     if (buff_size < required)
  53     {
  54       while (buff_size < required)
  55       {
  56         size_t dbl_len = buff_size * 2;
  57         if (dbl_len < buff_size)
  58         {
  59           free (base);
  60           va_end (ap);
  61           return NULL;
  62         }
  63
  64         buff_size = dbl_len;
  65       }
  66
  67       /*LINTED*/
  68       ptrdiff_t diff = out - base;
  69
  70       char *newbase = realloc (base, buff_size);
  71       if (NULL == newbase)
  72       {
  73         free (base);
  74         va_end (ap);
  75         return NULL;
  76       }
  77
  78       base = newbase;
  79       out = base + diff;
  80     }
  81
  82     memcpy (out, next, next_len);
  83     out += next_len;
  84   }
  85   va_end (ap);
  86
  87   *out = '\0';
  88   return base;
  89 }
  90
  91
  92 char * xstrdup (const char *in)
  93 {
  94   char *out = NULL;
  95
  96   if (NULL != in)
  97   {
  98     size_t len = strlen (in) + 1;
  99
 100     if ((out = malloc (len)))
 101       memcpy (out, in, len);
 102   }
 103
 104   return out;
 105 }
 106
 107
 108 // the const here lets us pass a pointer to const
 109 void xfree (const void *ptr)
 110 {
 111   if (NULL != ptr)
 112     free ((void *)ptr);
 113 }
 114
 115
 116 void clear_and_free (char *ptr)
 117 {
 118   if (NULL != ptr)
 119   {
 120     for (char *pch = ptr; '\0' != *pch; ++pch)
 121       *pch = '\0';
 122
 123     free (ptr);
 124   }
 125 }
 126
 127
 128 void free_errno (const void *ptr)
 129 {
 130   int err = errno;
 131   free ((void *)ptr);
 132   errno = err;
 133 }
 134
 135
 136 void xfree_errno (const void *ptr)
 137 {
 138   int err = errno;
 139   xfree (ptr);
 140   errno = err;
 141 }
 142