1 /* 2 * Copyright (c) 1990 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if defined(LIBC_SCCS) && !defined(lint) 31 static char *rcsid = "$OpenBSD: strtoul.c,v 1.5 2003/06/02 20:18:38 millert Exp $"; 32 #endif /* LIBC_SCCS and not lint */ 33 34 #include <ctype.h> 35 #include <errno.h> 36 #include <limits.h> 37 #include <stdlib.h> 38 39 /* 40 * Convert a string to an unsigned long integer. 41 * 42 * Ignores `locale' stuff. Assumes that the upper and lower case 43 * alphabets and digits are each contiguous. 44 */ 45 unsigned long 46 strtoul(nptr, endptr, base) 47 const char *nptr; 48 char **endptr; 49 register int base; 50 { 51 register const char *s; 52 register unsigned long acc, cutoff; 53 register int c; 54 register int neg, any, cutlim; 55 56 /* 57 * See strtol for comments as to the logic used. 58 */ 59 s = nptr; 60 do { 61 c = (unsigned char) *s++; 62 } while (isspace(c)); 63 if (c == '-') { 64 neg = 1; 65 c = *s++; 66 } else { 67 neg = 0; 68 if (c == '+') 69 c = *s++; 70 } 71 if ((base == 0 || base == 16) && 72 c == '0' && (*s == 'x' || *s == 'X')) { 73 c = s[1]; 74 s += 2; 75 base = 16; 76 } 77 if (base == 0) 78 base = c == '0' ? 8 : 10; 79 80 cutoff = ULONG_MAX / (unsigned long)base; 81 cutlim = ULONG_MAX % (unsigned long)base; 82 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 83 if (isdigit(c)) 84 c -= '0'; 85 else if (isalpha(c)) 86 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 87 else 88 break; 89 if (c >= base) 90 break; 91 if (any < 0) 92 continue; 93 if (acc > cutoff || acc == cutoff && c > cutlim) { 94 any = -1; 95 acc = ULONG_MAX; 96 errno = ERANGE; 97 } else { 98 any = 1; 99 acc *= (unsigned long)base; 100 acc += c; 101 } 102 } 103 if (neg && any > 0) 104 acc = -acc; 105 if (endptr != 0) 106 *endptr = (char *) (any ? s - 1 : nptr); 107 return (acc); 108 } 109