sys/libkern/strtouq.c

   1 /*-
   2  * Copyright (c) 1990, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Chris Torek.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * $FreeBSD: src/sys/libkern/strtouq.c,v 1.3 1999/12/01 22:56:51 archie Exp $
  37  */
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/ctype.h>
  42 #include <machine/limits.h>
  43
  44 /*
  45  * Convert a string to an unsigned quad integer.
  46  *
  47  * Ignores `locale' stuff.  Assumes that the upper and lower case
  48  * alphabets and digits are each contiguous.
  49  */
  50 u_quad_t
  51 strtouq(const char *nptr, char **endptr, int base)
  52 {
  53         const char *s;
  54         u_quad_t acc;
  55         unsigned char c;
  56         u_quad_t qbase, cutoff;
  57         int neg, any, cutlim;
  58
  59         /*
  60          * See strtoq for comments as to the logic used.
  61          */
  62         s = nptr;
  63         do {
  64                 c = *s++;
  65         } while (isspace(c));
  66         if (c == '-') {
  67                 neg = 1;
  68                 c = *s++;
  69         } else {
  70                 neg = 0;
  71                 if (c == '+')
  72                         c = *s++;
  73         }
  74         if ((base == 0 || base == 16) &&
  75             c == '0' && (*s == 'x' || *s == 'X')) {
  76                 c = s[1];
  77                 s += 2;
  78                 base = 16;
  79         }
  80         if (base == 0)
  81                 base = c == '0' ? 8 : 10;
  82         qbase = (unsigned)base;
  83         cutoff = (u_quad_t)UQUAD_MAX / qbase;
  84         cutlim = (u_quad_t)UQUAD_MAX % qbase;
  85         for (acc = 0, any = 0;; c = *s++) {
  86                 if (!isascii(c))
  87                         break;
  88                 if (isdigit(c))
  89                         c -= '0';
  90                 else if (isalpha(c))
  91                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  92                 else
  93                         break;
  94                 if (c >= base)
  95                         break;
  96                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
  97                         any = -1;
  98                 else {
  99                         any = 1;
 100                         acc *= qbase;
 101                         acc += c;
 102                 }
 103         }
 104         if (any < 0) {
 105                 acc = UQUAD_MAX;
 106         } else if (neg)
 107                 acc = -acc;
 108         if (endptr != NULL)
 109                 *((const char **)(void *)endptr) = any ? s - 1 : nptr;
 110         return (acc);
 111 }