stdlib.subproj/strtoq.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Copyright (c) 1992, 1993
  24  *      The Regents of the University of California.  All rights reserved.
  25  *
  26  * Redistribution and use in source and binary forms, with or without
  27  * modification, are permitted provided that the following conditions
  28  * are met:
  29  * 1. Redistributions of source code must retain the above copyright
  30  *    notice, this list of conditions and the following disclaimer.
  31  * 2. Redistributions in binary form must reproduce the above copyright
  32  *    notice, this list of conditions and the following disclaimer in the
  33  *    documentation and/or other materials provided with the distribution.
  34  * 3. All advertising materials mentioning features or use of this software
  35  *    must display the following acknowledgement:
  36  *      This product includes software developed by the University of
  37  *      California, Berkeley and its contributors.
  38  * 4. Neither the name of the University nor the names of its contributors
  39  *    may be used to endorse or promote products derived from this software
  40  *    without specific prior written permission.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55
  56 #include <sys/types.h>
  57
  58 #include <limits.h>
  59 #include <errno.h>
  60 #include <ctype.h>
  61 #include <stdlib.h>
  62
  63 /*
  64  * Convert a string to a quad integer.
  65  *
  66  * Ignores `locale' stuff.  Assumes that the upper and lower case
  67  * alphabets and digits are each contiguous.
  68  */
  69 quad_t
  70 strtoq(nptr, endptr, base)
  71         const char *nptr;
  72         char **endptr;
  73         register int base;
  74 {
  75         register const char *s;
  76         register u_quad_t acc;
  77         register int c;
  78         register u_quad_t qbase, cutoff;
  79         register int neg, any, cutlim;
  80
  81         /*
  82          * Skip white space and pick up leading +/- sign if any.
  83          * If base is 0, allow 0x for hex and 0 for octal, else
  84          * assume decimal; if base is already 16, allow 0x.
  85          */
  86         s = nptr;
  87         do {
  88                 c = *s++;
  89         } while (isspace(c));
  90         if (c == '-') {
  91                 neg = 1;
  92                 c = *s++;
  93         } else {
  94                 neg = 0;
  95                 if (c == '+')
  96                         c = *s++;
  97         }
  98         if ((base == 0 || base == 16) &&
  99             c == '0' && (*s == 'x' || *s == 'X')) {
 100                 c = s[1];
 101                 s += 2;
 102                 base = 16;
 103         }
 104         if (base == 0)
 105                 base = c == '0' ? 8 : 10;
 106
 107         /*
 108          * Compute the cutoff value between legal numbers and illegal
 109          * numbers.  That is the largest legal value, divided by the
 110          * base.  An input number that is greater than this value, if
 111          * followed by a legal input character, is too big.  One that
 112          * is equal to this value may be valid or not; the limit
 113          * between valid and invalid numbers is then based on the last
 114          * digit.  For instance, if the range for quads is
 115          * [-9223372036854775808..9223372036854775807] and the input base
 116          * is 10, cutoff will be set to 922337203685477580 and cutlim to
 117          * either 7 (neg==0) or 8 (neg==1), meaning that if we have
 118          * accumulated a value > 922337203685477580, or equal but the
 119          * next digit is > 7 (or 8), the number is too big, and we will
 120          * return a range error.
 121          *
 122          * Set any if any `digits' consumed; make it negative to indicate
 123          * overflow.
 124          */
 125         qbase = (unsigned)base;
 126         cutoff = neg ? -(u_quad_t)QUAD_MIN : QUAD_MAX;
 127         cutlim = cutoff % qbase;
 128         cutoff /= qbase;
 129         for (acc = 0, any = 0;; c = *s++) {
 130                 if (isdigit(c))
 131                         c -= '0';
 132                 else if (isalpha(c))
 133                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 134                 else
 135                         break;
 136                 if (c >= base)
 137                         break;
 138                 if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
 139                         any = -1;
 140                 else {
 141                         any = 1;
 142                         acc *= qbase;
 143                         acc += c;
 144                 }
 145         }
 146         if (any < 0) {
 147                 acc = neg ? QUAD_MIN : QUAD_MAX;
 148                 errno = ERANGE;
 149         } else if (neg)
 150                 acc = -acc;
 151         if (endptr != 0)
 152                 *endptr = (char *)(any ? s - 1 : nptr);
 153         return (acc);
 154 }