strtol.c revision 84221
138451Smsmith/*- 238451Smsmith * Copyright (c) 1990, 1993 338451Smsmith * The Regents of the University of California. All rights reserved. 438451Smsmith * 538451Smsmith * Redistribution and use in source and binary forms, with or without 638451Smsmith * modification, are permitted provided that the following conditions 738451Smsmith * are met: 838451Smsmith * 1. Redistributions of source code must retain the above copyright 938451Smsmith * notice, this list of conditions and the following disclaimer. 1038451Smsmith * 2. Redistributions in binary form must reproduce the above copyright 1138451Smsmith * notice, this list of conditions and the following disclaimer in the 1238451Smsmith * documentation and/or other materials provided with the distribution. 1338451Smsmith * 3. All advertising materials mentioning features or use of this software 1438451Smsmith * must display the following acknowledgement: 1538451Smsmith * This product includes software developed by the University of 1638451Smsmith * California, Berkeley and its contributors. 1738451Smsmith * 4. Neither the name of the University nor the names of its contributors 1838451Smsmith * may be used to endorse or promote products derived from this software 1938451Smsmith * without specific prior written permission. 2038451Smsmith * 2138451Smsmith * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2238451Smsmith * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2338451Smsmith * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2438451Smsmith * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2538451Smsmith * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2638451Smsmith * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2738451Smsmith * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2838451Smsmith * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2938451Smsmith * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3038451Smsmith * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3138451Smsmith * SUCH DAMAGE. 3238451Smsmith */ 3338451Smsmith 3484221Sdillon#include <sys/cdefs.h> 3584221Sdillon__FBSDID("$FreeBSD: head/lib/libstand/strtol.c 84221 2001-09-30 22:28:01Z dillon $"); 3684221Sdillon 3738451Smsmith#if defined(LIBC_SCCS) && !defined(lint) 3838451Smsmithstatic char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 3938451Smsmith#endif /* LIBC_SCCS and not lint */ 4038451Smsmith 4138451Smsmith#include "stand.h" 4238451Smsmith#include <limits.h> 4338451Smsmith 4438451Smsmith/* 4538451Smsmith * Convert a string to a long integer. 4638451Smsmith * 4738451Smsmith * Ignores `locale' stuff. Assumes that the upper and lower case 4838451Smsmith * alphabets and digits are each contiguous. 4938451Smsmith */ 5038451Smsmithlong 5138451Smsmithstrtol(nptr, endptr, base) 5238451Smsmith const char *nptr; 5338451Smsmith char **endptr; 5438451Smsmith register int base; 5538451Smsmith{ 5638451Smsmith register const char *s; 5738451Smsmith register unsigned long acc; 5838451Smsmith register unsigned char c; 5938451Smsmith register unsigned long cutoff; 6038451Smsmith register int neg = 0, any, cutlim; 6138451Smsmith 6238451Smsmith /* Be sensible about NULL strings */ 6338451Smsmith if (nptr == NULL) 6438451Smsmith nptr = ""; 6538451Smsmith s = nptr; 6638451Smsmith 6738451Smsmith /* 6838451Smsmith * Skip white space and pick up leading +/- sign if any. 6938451Smsmith * If base is 0, allow 0x for hex and 0 for octal, else 7038451Smsmith * assume decimal; if base is already 16, allow 0x. 7138451Smsmith */ 7238451Smsmith do { 7338451Smsmith c = *s++; 7438451Smsmith } while (isspace(c)); 7538451Smsmith if (c == '-') { 7638451Smsmith neg = 1; 7738451Smsmith c = *s++; 7838451Smsmith } else if (c == '+') 7938451Smsmith c = *s++; 8038451Smsmith if ((base == 0 || base == 16) && 8138451Smsmith c == '0' && (*s == 'x' || *s == 'X')) { 8238451Smsmith c = s[1]; 8338451Smsmith s += 2; 8438451Smsmith base = 16; 8538451Smsmith } 8638451Smsmith if (base == 0) 8738451Smsmith base = c == '0' ? 8 : 10; 8838451Smsmith 8938451Smsmith /* 9038451Smsmith * Compute the cutoff value between legal numbers and illegal 9138451Smsmith * numbers. That is the largest legal value, divided by the 9238451Smsmith * base. An input number that is greater than this value, if 9338451Smsmith * followed by a legal input character, is too big. One that 9438451Smsmith * is equal to this value may be valid or not; the limit 9538451Smsmith * between valid and invalid numbers is then based on the last 9638451Smsmith * digit. For instance, if the range for longs is 9738451Smsmith * [-2147483648..2147483647] and the input base is 10, 9838451Smsmith * cutoff will be set to 214748364 and cutlim to either 9938451Smsmith * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 10038451Smsmith * a value > 214748364, or equal but the next digit is > 7 (or 8), 10138451Smsmith * the number is too big, and we will return a range error. 10238451Smsmith * 10338451Smsmith * Set any if any `digits' consumed; make it negative to indicate 10438451Smsmith * overflow. 10538451Smsmith */ 10638451Smsmith cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 10738451Smsmith cutlim = cutoff % (unsigned long)base; 10838451Smsmith cutoff /= (unsigned long)base; 10938451Smsmith for (acc = 0, any = 0;; c = *s++) { 11038451Smsmith if (!isascii(c)) 11138451Smsmith break; 11238451Smsmith if (isdigit(c)) 11338451Smsmith c -= '0'; 11438451Smsmith else if (isalpha(c)) 11538451Smsmith c -= isupper(c) ? 'A' - 10 : 'a' - 10; 11638451Smsmith else 11738451Smsmith break; 11838451Smsmith if (c >= base) 11938451Smsmith break; 12038451Smsmith if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 12138451Smsmith any = -1; 12238451Smsmith else { 12338451Smsmith any = 1; 12438451Smsmith acc *= base; 12538451Smsmith acc += c; 12638451Smsmith } 12738451Smsmith } 12838451Smsmith if (any < 0) { 12938451Smsmith acc = neg ? LONG_MIN : LONG_MAX; 13038451Smsmith errno = ERANGE; 13138451Smsmith } else if (neg) 13238451Smsmith acc = -acc; 13338451Smsmith if (endptr != 0) 13438451Smsmith *endptr = (char *)(any ? s - 1 : nptr); 13538451Smsmith return (acc); 13638451Smsmith} 137