1 /* $NetBSD: strtol.c,v 1.9 1996/07/20 01:00:55 jtc Exp $ */ 2 3 /*- 4 * Copyright (c) 1990 The Regents of the University of California. 5 * 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 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char *sccsid = "from: @(#)strtol.c 5.4 (Berkeley) 2/23/91"; 39 #else 40 static char *rcsid = "$NetBSD: strtol.c,v 1.9 1996/07/20 01:00:55 jtc Exp $"; 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #include <ctype.h> 45 #include <errno.h> 46 #include <limits.h> 47 #include <stdlib.h> 48 49 50 /* 51 * Convert a string to a long integer. 52 * 53 * Ignores `locale' stuff. Assumes that the upper and lower case 54 * alphabets and digits are each contiguous. 55 */ 56 long 57 strtol(nptr, endptr, base) 58 const char *nptr; 59 char **endptr; 60 register int base; 61 { 62 register const char *s; 63 register long acc, cutoff; 64 register int c; 65 register int neg, any, cutlim; 66 67 /* 68 * Skip white space and pick up leading +/- sign if any. 69 * If base is 0, allow 0x for hex and 0 for octal, else 70 * assume decimal; if base is already 16, allow 0x. 71 */ 72 s = nptr; 73 do { 74 c = (unsigned char) *s++; 75 } while (isspace(c)); 76 if (c == '-') { 77 neg = 1; 78 c = *s++; 79 } else { 80 neg = 0; 81 if (c == '+') 82 c = *s++; 83 } 84 if ((base == 0 || base == 16) && 85 c == '0' && (*s == 'x' || *s == 'X')) { 86 c = s[1]; 87 s += 2; 88 base = 16; 89 } 90 if (base == 0) 91 base = c == '0' ? 8 : 10; 92 93 /* 94 * Compute the cutoff value between legal numbers and illegal 95 * numbers. That is the largest legal value, divided by the 96 * base. An input number that is greater than this value, if 97 * followed by a legal input character, is too big. One that 98 * is equal to this value may be valid or not; the limit 99 * between valid and invalid numbers is then based on the last 100 * digit. For instance, if the range for longs is 101 * [-2147483648..2147483647] and the input base is 10, 102 * cutoff will be set to 214748364 and cutlim to either 103 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 104 * a value > 214748364, or equal but the next digit is > 7 (or 8), 105 * the number is too big, and we will return a range error. 106 * 107 * Set any if any `digits' consumed; make it negative to indicate 108 * overflow. 109 */ 110 cutoff = neg ? LONG_MIN : LONG_MAX; 111 cutlim = cutoff % base; 112 cutoff /= base; 113 if (neg) { 114 if (cutlim > 0) { 115 cutlim -= base; 116 cutoff += 1; 117 } 118 cutlim = -cutlim; 119 } 120 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 121 if (isdigit(c)) 122 c -= '0'; 123 else if (isalpha(c)) 124 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 125 else 126 break; 127 if (c >= base) 128 break; 129 if (any < 0) 130 continue; 131 if (neg) { 132 if (acc < cutoff || acc == cutoff && c > cutlim) { 133 any = -1; 134 acc = LONG_MIN; 135 errno = ERANGE; 136 } else { 137 any = 1; 138 acc *= base; 139 acc -= c; 140 } 141 } else { 142 if (acc > cutoff || acc == cutoff && c > cutlim) { 143 any = -1; 144 acc = LONG_MAX; 145 errno = ERANGE; 146 } else { 147 any = 1; 148 acc *= base; 149 acc += c; 150 } 151 } 152 } 153 if (endptr != 0) 154 *endptr = (char *) (any ? s - 1 : nptr); 155 return (acc); 156 } 157