strtol.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[] = "@(#)strtol.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/* 451573Srgrimes * Convert a string to a long integer. 461573Srgrimes * 471573Srgrimes * Ignores `locale' stuff. Assumes that the upper and lower case 481573Srgrimes * alphabets and digits are each contiguous. 491573Srgrimes */ 501573Srgrimeslong 511573Srgrimesstrtol(nptr, endptr, base) 521573Srgrimes const char *nptr; 531573Srgrimes char **endptr; 541573Srgrimes register int base; 551573Srgrimes{ 561573Srgrimes register const char *s = nptr; 571573Srgrimes register unsigned long acc; 581573Srgrimes register int c; 591573Srgrimes register unsigned long cutoff; 601573Srgrimes register int neg = 0, any, cutlim; 611573Srgrimes 621573Srgrimes /* 631573Srgrimes * Skip white space and pick up leading +/- sign if any. 641573Srgrimes * If base is 0, allow 0x for hex and 0 for octal, else 651573Srgrimes * assume decimal; if base is already 16, allow 0x. 661573Srgrimes */ 671573Srgrimes do { 681573Srgrimes c = *s++; 691573Srgrimes } while (isspace(c)); 701573Srgrimes if (c == '-') { 711573Srgrimes neg = 1; 721573Srgrimes c = *s++; 731573Srgrimes } else if (c == '+') 741573Srgrimes c = *s++; 751573Srgrimes if ((base == 0 || base == 16) && 761573Srgrimes c == '0' && (*s == 'x' || *s == 'X')) { 771573Srgrimes c = s[1]; 781573Srgrimes s += 2; 791573Srgrimes base = 16; 801573Srgrimes } 811573Srgrimes if (base == 0) 821573Srgrimes base = c == '0' ? 8 : 10; 831573Srgrimes 841573Srgrimes /* 851573Srgrimes * Compute the cutoff value between legal numbers and illegal 861573Srgrimes * numbers. That is the largest legal value, divided by the 871573Srgrimes * base. An input number that is greater than this value, if 881573Srgrimes * followed by a legal input character, is too big. One that 891573Srgrimes * is equal to this value may be valid or not; the limit 901573Srgrimes * between valid and invalid numbers is then based on the last 911573Srgrimes * digit. For instance, if the range for longs is 921573Srgrimes * [-2147483648..2147483647] and the input base is 10, 931573Srgrimes * cutoff will be set to 214748364 and cutlim to either 941573Srgrimes * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 951573Srgrimes * a value > 214748364, or equal but the next digit is > 7 (or 8), 961573Srgrimes * the number is too big, and we will return a range error. 971573Srgrimes * 981573Srgrimes * Set any if any `digits' consumed; make it negative to indicate 991573Srgrimes * overflow. 1001573Srgrimes */ 1011573Srgrimes cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 1021573Srgrimes cutlim = cutoff % (unsigned long)base; 1031573Srgrimes cutoff /= (unsigned long)base; 1041573Srgrimes for (acc = 0, any = 0;; c = *s++) { 1051573Srgrimes if (isdigit(c)) 1061573Srgrimes c -= '0'; 1071573Srgrimes else if (isalpha(c)) 1081573Srgrimes c -= isupper(c) ? 'A' - 10 : 'a' - 10; 1091573Srgrimes else 1101573Srgrimes break; 1111573Srgrimes if (c >= base) 1121573Srgrimes break; 1131573Srgrimes if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim) 1141573Srgrimes any = -1; 1151573Srgrimes else { 1161573Srgrimes any = 1; 1171573Srgrimes acc *= base; 1181573Srgrimes acc += c; 1191573Srgrimes } 1201573Srgrimes } 1211573Srgrimes if (any < 0) { 1221573Srgrimes acc = neg ? LONG_MIN : LONG_MAX; 1231573Srgrimes errno = ERANGE; 1241573Srgrimes } else if (neg) 1251573Srgrimes acc = -acc; 1261573Srgrimes if (endptr != 0) 1271573Srgrimes *endptr = (char *)(any ? s - 1 : nptr); 1281573Srgrimes return (acc); 1291573Srgrimes} 130