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: @(#)strtol.c 8.1 (Berkeley) 6/4/93 33 */ 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/ctype.h> 41 #include <sys/limits.h> 42 43 /* 44 * Convert a string to a long integer. 45 * 46 * Ignores `locale' stuff. Assumes that the upper and lower case 47 * alphabets and digits are each contiguous. 48 */ 49 long 50 strtol(nptr, endptr, base) 51 const char *nptr; 52 char **endptr; 53 int base; 54 { 55 const char *s = nptr; 56 unsigned long acc; 57 unsigned char c; 58 unsigned long cutoff; 59 int neg = 0, any, cutlim; 60 61 /* 62 * Skip white space and pick up leading +/- sign if any. 63 * If base is 0, allow 0x for hex and 0 for octal, else 64 * assume decimal; if base is already 16, allow 0x. 65 */ 66 do { 67 c = *s++; 68 } while (isspace(c)); 69 if (c == '-') { 70 neg = 1; 71 c = *s++; 72 } else if (c == '+') 73 c = *s++; 74 if ((base == 0 || base == 16) && 75 c == '0' && (*s == 'x' || *s == 'X')) { 76 c = s[1]; 77 s += 2; 78 base = 16; 79 } 80 if (base == 0) 81 base = c == '0' ? 8 : 10; 82 83 /* 84 * Compute the cutoff value between legal numbers and illegal 85 * numbers. That is the largest legal value, divided by the 86 * base. An input number that is greater than this value, if 87 * followed by a legal input character, is too big. One that 88 * is equal to this value may be valid or not; the limit 89 * between valid and invalid numbers is then based on the last 90 * digit. For instance, if the range for longs is 91 * [-2147483648..2147483647] and the input base is 10, 92 * cutoff will be set to 214748364 and cutlim to either 93 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 94 * a value > 214748364, or equal but the next digit is > 7 (or 8), 95 * the number is too big, and we will return a range error. 96 * 97 * Set any if any `digits' consumed; make it negative to indicate 98 * overflow. 99 */ 100 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 101 cutlim = cutoff % (unsigned long)base; 102 cutoff /= (unsigned long)base; 103 for (acc = 0, any = 0;; c = *s++) { 104 if (!isascii(c)) 105 break; 106 if (isdigit(c)) 107 c -= '0'; 108 else if (isalpha(c)) 109 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 110 else 111 break; 112 if (c >= base) 113 break; 114 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 115 any = -1; 116 else { 117 any = 1; 118 acc *= base; 119 acc += c; 120 } 121 } 122 if (any < 0) { 123 acc = neg ? LONG_MIN : LONG_MAX; 124 } else if (neg) 125 acc = -acc; 126 if (endptr != NULL) 127 *endptr = __DECONST(char *, any ? s - 1 : nptr); 128 return (acc); 129 } 130