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. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * From: static char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93"; 33 * 34 * $FreeBSD: src/sys/libkern/strtoul.c,v 1.3 1999/12/01 22:56:51 archie Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/ctype.h> 40 #include <machine/limits.h> 41 42 /* 43 * Convert a string to an unsigned long integer. 44 * 45 * Ignores `locale' stuff. Assumes that the upper and lower case 46 * alphabets and digits are each contiguous. 47 */ 48 unsigned long 49 strtoul(const char *nptr, char **endptr, int base) 50 { 51 const char *s = nptr; 52 unsigned long acc; 53 unsigned char c; 54 unsigned long cutoff; 55 int neg = 0, any, cutlim; 56 57 /* 58 * See strtol for comments as to the logic used. 59 */ 60 do { 61 c = *s++; 62 } while (isspace(c)); 63 if (c == '-') { 64 neg = 1; 65 c = *s++; 66 } else if (c == '+') 67 c = *s++; 68 if ((base == 0 || base == 16) && 69 c == '0' && (*s == 'x' || *s == 'X')) { 70 c = s[1]; 71 s += 2; 72 base = 16; 73 } 74 if (base == 0) 75 base = c == '0' ? 8 : 10; 76 cutoff = (unsigned long)ULONG_MAX / (unsigned long)base; 77 cutlim = (unsigned long)ULONG_MAX % (unsigned long)base; 78 for (acc = 0, any = 0;; c = *s++) { 79 if (!isascii(c)) 80 break; 81 if (isdigit(c)) 82 c -= '0'; 83 else if (isalpha(c)) 84 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 85 else 86 break; 87 if (c >= base) 88 break; 89 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 90 any = -1; 91 else { 92 any = 1; 93 acc *= base; 94 acc += c; 95 } 96 } 97 if (any < 0) { 98 acc = ULONG_MAX; 99 } else if (neg) 100 acc = -acc; 101 if (endptr != NULL) 102 *((const char **)(void *)endptr) = any ? s - 1 : nptr; 103 return (acc); 104 } 105