strtoul.c revision 1573
11573Srgrimes/* 21573Srgrimes * Copyright (c) 1990, 1993 31573Srgrimes * The Regents of the University of California. All rights reserved. 41573Srgrimes * 51573Srgrimes * Redistribution and use in source and binary forms, with or without 61573Srgrimes * modification, are permitted provided that the following conditions 71573Srgrimes * are met: 81573Srgrimes * 1. Redistributions of source code must retain the above copyright 91573Srgrimes * notice, this list of conditions and the following disclaimer. 101573Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 111573Srgrimes * notice, this list of conditions and the following disclaimer in the 121573Srgrimes * documentation and/or other materials provided with the distribution. 131573Srgrimes * 3. All advertising materials mentioning features or use of this software 141573Srgrimes * must display the following acknowledgement: 151573Srgrimes * This product includes software developed by the University of 161573Srgrimes * California, Berkeley and its contributors. 171573Srgrimes * 4. Neither the name of the University nor the names of its contributors 181573Srgrimes * may be used to endorse or promote products derived from this software 191573Srgrimes * without specific prior written permission. 201573Srgrimes * 211573Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 221573Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 231573Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 241573Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 251573Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 261573Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 271573Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 281573Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 291573Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 301573Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 311573Srgrimes * SUCH DAMAGE. 321573Srgrimes */ 331573Srgrimes 341573Srgrimes#if defined(LIBC_SCCS) && !defined(lint) 351573Srgrimesstatic char sccsid[] = "@(#)strtoul.c 8.1 (Berkeley) 6/4/93"; 361573Srgrimes#endif /* LIBC_SCCS and not lint */ 371573Srgrimes 381573Srgrimes#include <limits.h> 391573Srgrimes#include <ctype.h> 401573Srgrimes#include <errno.h> 411573Srgrimes#include <stdlib.h> 421573Srgrimes 431573Srgrimes/* 441573Srgrimes * Convert a string to an unsigned long integer. 451573Srgrimes * 461573Srgrimes * Ignores `locale' stuff. Assumes that the upper and lower case 471573Srgrimes * alphabets and digits are each contiguous. 481573Srgrimes */ 491573Srgrimesunsigned long 501573Srgrimesstrtoul(nptr, endptr, base) 511573Srgrimes const char *nptr; 521573Srgrimes char **endptr; 531573Srgrimes register int base; 541573Srgrimes{ 551573Srgrimes register const char *s = nptr; 561573Srgrimes register unsigned long acc; 571573Srgrimes register int c; 581573Srgrimes register unsigned long cutoff; 591573Srgrimes register int neg = 0, any, cutlim; 601573Srgrimes 611573Srgrimes /* 621573Srgrimes * See strtol for comments as to the logic used. 631573Srgrimes */ 641573Srgrimes do { 651573Srgrimes c = *s++; 661573Srgrimes } while (isspace(c)); 671573Srgrimes if (c == '-') { 681573Srgrimes neg = 1; 691573Srgrimes c = *s++; 701573Srgrimes } else if (c == '+') 711573Srgrimes c = *s++; 721573Srgrimes if ((base == 0 || base == 16) && 731573Srgrimes c == '0' && (*s == 'x' || *s == 'X')) { 741573Srgrimes c = s[1]; 751573Srgrimes s += 2; 761573Srgrimes base = 16; 771573Srgrimes } 781573Srgrimes if (base == 0) 791573Srgrimes base = c == '0' ? 8 : 10; 801573Srgrimes cutoff = (unsigned long)ULONG_MAX / (unsigned long)base; 811573Srgrimes cutlim = (unsigned long)ULONG_MAX % (unsigned long)base; 821573Srgrimes for (acc = 0, any = 0;; c = *s++) { 831573Srgrimes if (isdigit(c)) 841573Srgrimes c -= '0'; 851573Srgrimes else if (isalpha(c)) 861573Srgrimes c -= isupper(c) ? 'A' - 10 : 'a' - 10; 871573Srgrimes else 881573Srgrimes break; 891573Srgrimes if (c >= base) 901573Srgrimes break; 911573Srgrimes if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) 921573Srgrimes any = -1; 931573Srgrimes else { 941573Srgrimes any = 1; 951573Srgrimes acc *= base; 961573Srgrimes acc += c; 971573Srgrimes } 981573Srgrimes } 991573Srgrimes if (any < 0) { 1001573Srgrimes acc = ULONG_MAX; 1011573Srgrimes errno = ERANGE; 1021573Srgrimes } else if (neg) 1031573Srgrimes acc = -acc; 1041573Srgrimes if (endptr != 0) 1051573Srgrimes *endptr = (char *)(any ? s - 1 : nptr); 1061573Srgrimes return (acc); 1071573Srgrimes} 108