1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * From: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 33 * 34 * $FreeBSD: src/sys/libkern/strtol.c,v 1.5 1999/12/01 22:56:50 archie Exp $ 35 */ 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/ctype.h> 40 #include <machine/limits.h> 41 42 /* 43 * Convert a string to a long integer. 44 * 45 * Ignores `locale' stuff. Assumes that the upper and lower case 46 * alphabets and digits are each contiguous. 47 */ 48 long 49 strtol(const char *nptr, char **endptr, int base) 50 { 51 const char *s = nptr; 52 unsigned long acc; 53 unsigned char c; 54 unsigned long cutoff; 55 int neg = 0, any, cutlim; 56 57 /* 58 * Skip white space and pick up leading +/- sign if any. 59 * If base is 0, allow 0x for hex and 0 for octal, else 60 * assume decimal; if base is already 16, allow 0x. 61 */ 62 do { 63 c = *s++; 64 } while (isspace(c)); 65 if (c == '-') { 66 neg = 1; 67 c = *s++; 68 } else if (c == '+') 69 c = *s++; 70 if ((base == 0 || base == 16) && 71 c == '0' && (*s == 'x' || *s == 'X')) { 72 c = s[1]; 73 s += 2; 74 base = 16; 75 } 76 if (base == 0) 77 base = c == '0' ? 8 : 10; 78 79 /* 80 * Compute the cutoff value between legal numbers and illegal 81 * numbers. That is the largest legal value, divided by the 82 * base. An input number that is greater than this value, if 83 * followed by a legal input character, is too big. One that 84 * is equal to this value may be valid or not; the limit 85 * between valid and invalid numbers is then based on the last 86 * digit. For instance, if the range for longs is 87 * [-2147483648..2147483647] and the input base is 10, 88 * cutoff will be set to 214748364 and cutlim to either 89 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 90 * a value > 214748364, or equal but the next digit is > 7 (or 8), 91 * the number is too big, and we will return a range error. 92 * 93 * Set any if any `digits' consumed; make it negative to indicate 94 * overflow. 95 */ 96 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 97 cutlim = cutoff % (unsigned long)base; 98 cutoff /= (unsigned long)base; 99 for (acc = 0, any = 0;; c = *s++) { 100 if (!isascii(c)) 101 break; 102 if (isdigit(c)) 103 c -= '0'; 104 else if (isalpha(c)) 105 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 106 else 107 break; 108 if (c >= base) 109 break; 110 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 111 any = -1; 112 else { 113 any = 1; 114 acc *= base; 115 acc += c; 116 } 117 } 118 if (any < 0) { 119 acc = neg ? LONG_MIN : LONG_MAX; 120 } else if (neg) 121 acc = -acc; 122 if (endptr != NULL) 123 *((const char **)(void *)endptr) = any ? s - 1 : nptr; 124 return (acc); 125 } 126