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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * From: static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 37 * 38 * $FreeBSD$ 39 */ 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/ctype.h> 44 #include <machine/limits.h> 45 46 /* 47 * Convert a string to a long integer. 48 * 49 * Ignores `locale' stuff. Assumes that the upper and lower case 50 * alphabets and digits are each contiguous. 51 */ 52 long 53 strtol(nptr, endptr, base) 54 const char *nptr; 55 char **endptr; 56 int base; 57 { 58 const char *s = nptr; 59 unsigned long acc; 60 unsigned char c; 61 unsigned long cutoff; 62 int neg = 0, any, cutlim; 63 64 /* 65 * Skip white space and pick up leading +/- sign if any. 66 * If base is 0, allow 0x for hex and 0 for octal, else 67 * assume decimal; if base is already 16, allow 0x. 68 */ 69 do { 70 c = *s++; 71 } while (isspace(c)); 72 if (c == '-') { 73 neg = 1; 74 c = *s++; 75 } else if (c == '+') 76 c = *s++; 77 if ((base == 0 || base == 16) && 78 c == '0' && (*s == 'x' || *s == 'X')) { 79 c = s[1]; 80 s += 2; 81 base = 16; 82 } 83 if (base == 0) 84 base = c == '0' ? 8 : 10; 85 86 /* 87 * Compute the cutoff value between legal numbers and illegal 88 * numbers. That is the largest legal value, divided by the 89 * base. An input number that is greater than this value, if 90 * followed by a legal input character, is too big. One that 91 * is equal to this value may be valid or not; the limit 92 * between valid and invalid numbers is then based on the last 93 * digit. For instance, if the range for longs is 94 * [-2147483648..2147483647] and the input base is 10, 95 * cutoff will be set to 214748364 and cutlim to either 96 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 97 * a value > 214748364, or equal but the next digit is > 7 (or 8), 98 * the number is too big, and we will return a range error. 99 * 100 * Set any if any `digits' consumed; make it negative to indicate 101 * overflow. 102 */ 103 cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX; 104 cutlim = cutoff % (unsigned long)base; 105 cutoff /= (unsigned long)base; 106 for (acc = 0, any = 0;; c = *s++) { 107 if (!isascii(c)) 108 break; 109 if (isdigit(c)) 110 c -= '0'; 111 else if (isalpha(c)) 112 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 113 else 114 break; 115 if (c >= base) 116 break; 117 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 118 any = -1; 119 else { 120 any = 1; 121 acc *= base; 122 acc += c; 123 } 124 } 125 if (any < 0) { 126 acc = neg ? LONG_MIN : LONG_MAX; 127 } else if (neg) 128 acc = -acc; 129 if (endptr != 0) 130 *((const char **)endptr) = any ? s - 1 : nptr; 131 return (acc); 132 } 133