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