1 /* $OpenBSD: strtoul.c,v 1.11 2017/07/06 16:23:11 millert Exp $ */ 2 /* 3 * Copyright (c) 1990 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Neither the name of the University nor the names of its contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <ctype.h> 32 #include <errno.h> 33 #include <limits.h> 34 #include <stdlib.h> 35 36 /* 37 * Convert a string to an unsigned long integer. 38 * 39 * Ignores `locale' stuff. Assumes that the upper and lower case 40 * alphabets and digits are each contiguous. 41 */ 42 unsigned long 43 strtoul(const char *nptr, char **endptr, int base) 44 { 45 const char *s; 46 unsigned long acc, cutoff; 47 int c; 48 int neg, any, cutlim; 49 50 /* 51 * See strtol for comments as to the logic used. 52 */ 53 if (base < 0 || base == 1 || base > 36) { 54 if (endptr != 0) 55 *endptr = (char *)nptr; 56 errno = EINVAL; 57 return 0; 58 } 59 60 s = nptr; 61 do { 62 c = (unsigned char) *s++; 63 } while (isspace(c)); 64 if (c == '-') { 65 neg = 1; 66 c = *s++; 67 } else { 68 neg = 0; 69 if (c == '+') 70 c = *s++; 71 } 72 if ((base == 0 || base == 16) && c == '0' && 73 (*s == 'x' || *s == 'X') && isxdigit((unsigned char)s[1])) { 74 c = s[1]; 75 s += 2; 76 base = 16; 77 } 78 if (base == 0) 79 base = c == '0' ? 8 : 10; 80 81 cutoff = ULONG_MAX / (unsigned long)base; 82 cutlim = ULONG_MAX % (unsigned long)base; 83 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 84 if (isdigit(c)) 85 c -= '0'; 86 else if (isalpha(c)) 87 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 88 else 89 break; 90 if (c >= base) 91 break; 92 if (any < 0) 93 continue; 94 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 95 any = -1; 96 acc = ULONG_MAX; 97 errno = ERANGE; 98 } else { 99 any = 1; 100 acc *= (unsigned long)base; 101 acc += c; 102 } 103 } 104 if (neg && any > 0) 105 acc = -acc; 106 if (endptr != 0) 107 *endptr = (char *) (any ? s - 1 : nptr); 108 return (acc); 109 } 110 DEF_STRONG(strtoul); 111