1 /* $NetBSD: strtol.c,v 1.15 1999/09/20 04:39:42 lukem 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char sccsid[] = "@(#)strtol.c 8.1 (Berkeley) 6/4/93"; 40 #else 41 __RCSID("$NetBSD: strtol.c,v 1.15 1999/09/20 04:39:42 lukem Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include <assert.h> 46 #include <ctype.h> 47 #include <errno.h> 48 #include <limits.h> 49 #include <stdlib.h> 50 51 52 /* 53 * Convert a string to a long integer. 54 * 55 * Ignores `locale' stuff. Assumes that the upper and lower case 56 * alphabets and digits are each contiguous. 57 */ 58 long 59 strtol(nptr, endptr, base) 60 const char *nptr; 61 char **endptr; 62 int base; 63 { 64 const char *s; 65 long acc, cutoff; 66 int c; 67 int neg, any, cutlim; 68 69 _DIAGASSERT(nptr != NULL); 70 /* endptr may be NULL */ 71 72 /* 73 * Skip white space and pick up leading +/- sign if any. 74 * If base is 0, allow 0x for hex and 0 for octal, else 75 * assume decimal; if base is already 16, allow 0x. 76 */ 77 s = nptr; 78 do { 79 c = (unsigned char) *s++; 80 } while (isspace(c)); 81 if (c == '-') { 82 neg = 1; 83 c = *s++; 84 } else { 85 neg = 0; 86 if (c == '+') 87 c = *s++; 88 } 89 if ((base == 0 || base == 16) && 90 c == '0' && (*s == 'x' || *s == 'X')) { 91 c = s[1]; 92 s += 2; 93 base = 16; 94 } 95 if (base == 0) 96 base = c == '0' ? 8 : 10; 97 98 /* 99 * Compute the cutoff value between legal numbers and illegal 100 * numbers. That is the largest legal value, divided by the 101 * base. An input number that is greater than this value, if 102 * followed by a legal input character, is too big. One that 103 * is equal to this value may be valid or not; the limit 104 * between valid and invalid numbers is then based on the last 105 * digit. For instance, if the range for longs is 106 * [-2147483648..2147483647] and the input base is 10, 107 * cutoff will be set to 214748364 and cutlim to either 108 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 109 * a value > 214748364, or equal but the next digit is > 7 (or 8), 110 * the number is too big, and we will return a range error. 111 * 112 * Set any if any `digits' consumed; make it negative to indicate 113 * overflow. 114 */ 115 cutoff = neg ? LONG_MIN : LONG_MAX; 116 cutlim = (int)(cutoff % base); 117 cutoff /= base; 118 if (neg) { 119 if (cutlim > 0) { 120 cutlim -= base; 121 cutoff += 1; 122 } 123 cutlim = -cutlim; 124 } 125 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 126 if (isdigit(c)) 127 c -= '0'; 128 else if (isalpha(c)) 129 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 130 else 131 break; 132 if (c >= base) 133 break; 134 if (any < 0) 135 continue; 136 if (neg) { 137 if (acc < cutoff || (acc == cutoff && c > cutlim)) { 138 any = -1; 139 acc = LONG_MIN; 140 errno = ERANGE; 141 } else { 142 any = 1; 143 acc *= base; 144 acc -= c; 145 } 146 } else { 147 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 148 any = -1; 149 acc = LONG_MAX; 150 errno = ERANGE; 151 } else { 152 any = 1; 153 acc *= base; 154 acc += c; 155 } 156 } 157 } 158 if (endptr != 0) 159 /* LINTED interface specification */ 160 *endptr = (char *)(any ? s - 1 : nptr); 161 return (acc); 162 } 163