strtonum.c

   1 /*      $OpenBSD: strtonum.c,v 1.7 2013/04/17 18:40:58 tedu Exp $       */
   2
   3 /*
   4  * Copyright (c) 2004 Ted Unangst and Todd Miller
   5  * All rights reserved.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stdlib.h>
  23
  24 #define INVALID         1
  25 #define TOOSMALL        2
  26 #define TOOLARGE        3
  27
  28 long long
  29 strtonum(const char *numstr, long long minval, long long maxval,
  30     const char **errstrp)
  31 {
  32         long long ll = 0;
  33         int error = 0;
  34         char *ep;
  35         struct errval {
  36                 const char *errstr;
  37                 int err;
  38         } ev[4] = {
  39                 { NULL,         0 },
  40                 { "invalid",    EINVAL },
  41                 { "too small",  ERANGE },
  42                 { "too large",  ERANGE },
  43         };
  44
  45         ev[0].err = errno;
  46         errno = 0;
  47         if (minval > maxval) {
  48                 error = INVALID;
  49         } else {
  50                 ll = strtoll(numstr, &ep, 10);
  51                 if (numstr == ep || *ep != '\0')
  52                         error = INVALID;
  53                 else if ((ll == LLONG_MIN && errno == ERANGE) || ll < minval)
  54                         error = TOOSMALL;
  55                 else if ((ll == LLONG_MAX && errno == ERANGE) || ll > maxval)
  56                         error = TOOLARGE;
  57         }
  58         if (errstrp != NULL)
  59                 *errstrp = ev[error].errstr;
  60         errno = ev[error].err;
  61         if (error)
  62                 ll = 0;
  63
  64         return (ll);
  65 }