1 /* $NetBSD: strtol.c,v 1.17 2005/11/29 03:12:00 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: strtol.c,v 1.17 2005/11/29 03:12:00 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <assert.h> 42 #include <ctype.h> 43 #include <errno.h> 44 #include <limits.h> 45 #include <stdlib.h> 46 47 48 /* 49 * Convert a string to a long integer. 50 * 51 * Ignores `locale' stuff. Assumes that the upper and lower case 52 * alphabets and digits are each contiguous. 53 */ 54 long 55 strtol(nptr, endptr, base) 56 const char *nptr; 57 char **endptr; 58 int base; 59 { 60 const char *s; 61 long acc, cutoff; 62 int c; 63 int neg, any, cutlim; 64 65 _DIAGASSERT(nptr != NULL); 66 /* endptr may be NULL */ 67 68 /* 69 * Skip white space and pick up leading +/- sign if any. 70 * If base is 0, allow 0x for hex and 0 for octal, else 71 * assume decimal; if base is already 16, allow 0x. 72 */ 73 s = nptr; 74 do { 75 c = (unsigned char) *s++; 76 } while (isspace(c)); 77 if (c == '-') { 78 neg = 1; 79 c = *s++; 80 } else { 81 neg = 0; 82 if (c == '+') 83 c = *s++; 84 } 85 if ((base == 0 || base == 16) && 86 c == '0' && (*s == 'x' || *s == 'X')) { 87 c = s[1]; 88 s += 2; 89 base = 16; 90 } 91 if (base == 0) 92 base = c == '0' ? 8 : 10; 93 94 /* 95 * Compute the cutoff value between legal numbers and illegal 96 * numbers. That is the largest legal value, divided by the 97 * base. An input number that is greater than this value, if 98 * followed by a legal input character, is too big. One that 99 * is equal to this value may be valid or not; the limit 100 * between valid and invalid numbers is then based on the last 101 * digit. For instance, if the range for longs is 102 * [-2147483648..2147483647] and the input base is 10, 103 * cutoff will be set to 214748364 and cutlim to either 104 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 105 * a value > 214748364, or equal but the next digit is > 7 (or 8), 106 * the number is too big, and we will return a range error. 107 * 108 * Set any if any `digits' consumed; make it negative to indicate 109 * overflow. 110 */ 111 cutoff = neg ? LONG_MIN : LONG_MAX; 112 cutlim = (int)(cutoff % base); 113 cutoff /= base; 114 if (neg) { 115 if (cutlim > 0) { 116 cutlim -= base; 117 cutoff += 1; 118 } 119 cutlim = -cutlim; 120 } 121 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 122 if (isdigit(c)) 123 c -= '0'; 124 else if (isalpha(c)) 125 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 126 else 127 break; 128 if (c >= base) 129 break; 130 if (any < 0) 131 continue; 132 if (neg) { 133 if (acc < cutoff || (acc == cutoff && c > cutlim)) { 134 any = -1; 135 acc = LONG_MIN; 136 errno = ERANGE; 137 } else { 138 any = 1; 139 acc *= base; 140 acc -= c; 141 } 142 } else { 143 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 144 any = -1; 145 acc = LONG_MAX; 146 errno = ERANGE; 147 } else { 148 any = 1; 149 acc *= base; 150 acc += c; 151 } 152 } 153 } 154 if (endptr != 0) 155 *endptr = __UNCONST(any ? s - 1 : nptr); 156 return (acc); 157 } 158