strtol.c revision 82975
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[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 361573Srgrimes#endif /* LIBC_SCCS and not lint */ 371573Srgrimes 3882975Sache#ifndef lint 3982975Sachestatic const char rcsid[] = 4082975Sache"$FreeBSD: head/lib/libc/stdlib/strtol.c 82975 2001-09-04 16:39:11Z ache $"; 4182975Sache#endif 4282975Sache 431573Srgrimes#include <limits.h> 441573Srgrimes#include <ctype.h> 451573Srgrimes#include <errno.h> 461573Srgrimes#include <stdlib.h> 471573Srgrimes 481573Srgrimes 491573Srgrimes/* 501573Srgrimes * Convert a string to a long integer. 511573Srgrimes * 5282975Sache * Assumes that the upper and lower case 531573Srgrimes * alphabets and digits are each contiguous. 541573Srgrimes */ 551573Srgrimeslong 561573Srgrimesstrtol(nptr, endptr, base) 571573Srgrimes const char *nptr; 581573Srgrimes char **endptr; 591573Srgrimes register int base; 601573Srgrimes{ 6182975Sache register const char *s; 621573Srgrimes register unsigned long acc; 639843Sache register unsigned char c; 641573Srgrimes register unsigned long cutoff; 6582975Sache register int neg, any, cutlim; 661573Srgrimes 671573Srgrimes /* 681573Srgrimes * Skip white space and pick up leading +/- sign if any. 691573Srgrimes * If base is 0, allow 0x for hex and 0 for octal, else 701573Srgrimes * assume decimal; if base is already 16, allow 0x. 711573Srgrimes */ 7282975Sache s = nptr; 731573Srgrimes do { 741573Srgrimes c = *s++; 751573Srgrimes } while (isspace(c)); 761573Srgrimes if (c == '-') { 771573Srgrimes neg = 1; 781573Srgrimes c = *s++; 7982975Sache } else { 8082975Sache neg = 0; 8182975Sache if (c == '+') 8282975Sache c = *s++; 8382975Sache } 841573Srgrimes if ((base == 0 || base == 16) && 851573Srgrimes c == '0' && (*s == 'x' || *s == 'X')) { 861573Srgrimes c = s[1]; 871573Srgrimes s += 2; 881573Srgrimes base = 16; 891573Srgrimes } 901573Srgrimes if (base == 0) 911573Srgrimes base = c == '0' ? 8 : 10; 9282975Sache any = 0; 9382975Sache if (base < 2 || base > 36) 9482975Sache goto noconv; 951573Srgrimes 961573Srgrimes /* 971573Srgrimes * Compute the cutoff value between legal numbers and illegal 981573Srgrimes * numbers. That is the largest legal value, divided by the 991573Srgrimes * base. An input number that is greater than this value, if 1001573Srgrimes * followed by a legal input character, is too big. One that 1011573Srgrimes * is equal to this value may be valid or not; the limit 1021573Srgrimes * between valid and invalid numbers is then based on the last 1031573Srgrimes * digit. For instance, if the range for longs is 1041573Srgrimes * [-2147483648..2147483647] and the input base is 10, 1051573Srgrimes * cutoff will be set to 214748364 and cutlim to either 1061573Srgrimes * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 1071573Srgrimes * a value > 214748364, or equal but the next digit is > 7 (or 8), 1081573Srgrimes * the number is too big, and we will return a range error. 1091573Srgrimes * 11082975Sache * Set 'any' if any `digits' consumed; make it negative to indicate 1111573Srgrimes * overflow. 1121573Srgrimes */ 11382975Sache cutoff = neg ? (unsigned long)-(LONG_MIN + LONG_MAX) + LONG_MAX 11482975Sache : LONG_MAX; 11582975Sache cutlim = cutoff % base; 11682975Sache cutoff /= base; 11782975Sache for (acc = 0; ; c = *s++) { 1189843Sache if (!isascii(c)) 1199843Sache break; 1201573Srgrimes if (isdigit(c)) 1211573Srgrimes c -= '0'; 1221573Srgrimes else if (isalpha(c)) 1231573Srgrimes c -= isupper(c) ? 'A' - 10 : 'a' - 10; 1241573Srgrimes else 1251573Srgrimes break; 1261573Srgrimes if (c >= base) 1271573Srgrimes break; 12817141Sjkh if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 1291573Srgrimes any = -1; 1301573Srgrimes else { 1311573Srgrimes any = 1; 1321573Srgrimes acc *= base; 1331573Srgrimes acc += c; 1341573Srgrimes } 1351573Srgrimes } 1361573Srgrimes if (any < 0) { 1371573Srgrimes acc = neg ? LONG_MIN : LONG_MAX; 1381573Srgrimes errno = ERANGE; 13982975Sache } else if (!any) { 14082975Sachenoconv: 14182975Sache errno = EINVAL; 1421573Srgrimes } else if (neg) 1431573Srgrimes acc = -acc; 14482975Sache if (endptr != NULL) 1451573Srgrimes *endptr = (char *)(any ? s - 1 : nptr); 1461573Srgrimes return (acc); 1471573Srgrimes} 148