1 /* $NetBSD: _strtol.h,v 1.2 2009/05/20 22:03:29 christos Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-3-Clause 5 * 6 * Copyright (c) 1990, 1993 7 * The Regents of the University of California. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Original version ID: 34 * NetBSD: src/lib/libc/locale/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp 35 */ 36 37 /* 38 * function template for strtol, strtoll and strtoimax. 39 * 40 * parameters: 41 * _FUNCNAME : function name 42 * __INT : return type 43 * __INT_MIN : lower limit of the return type 44 * __INT_MAX : upper limit of the return type 45 */ 46 47 __INT 48 _FUNCNAME(const char *nptr, char **endptr, int base) 49 { 50 const char *s; 51 __INT acc, cutoff; 52 unsigned char c; 53 int any, cutlim, i, neg; 54 55 /* check base value */ 56 if (base && (base < 2 || base > 36)) { 57 #if !defined(_KERNEL) && !defined(_STANDALONE) 58 errno = EINVAL; 59 if (endptr != NULL) 60 /* LINTED interface specification */ 61 *endptr = __DECONST(void *, nptr); 62 return (0); 63 #else 64 panic("%s: invalid base %d", __func__, base); 65 #endif 66 } 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 = *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 ? __INT_MIN : __INT_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 = *s++) { 122 if (isdigit(c)) 123 i = c - '0'; 124 else if (isalpha(c)) 125 i = c - (isupper(c) ? 'A' - 10 : 'a' - 10); 126 else 127 break; 128 if (i >= base) 129 break; 130 if (any < 0) 131 continue; 132 if (neg) { 133 if (acc < cutoff || (acc == cutoff && i > cutlim)) { 134 acc = __INT_MIN; 135 #if !defined(_KERNEL) && !defined(_STANDALONE) 136 any = -1; 137 errno = ERANGE; 138 #else 139 any = 0; 140 break; 141 #endif 142 } else { 143 any = 1; 144 acc *= base; 145 acc -= i; 146 } 147 } else { 148 if (acc > cutoff || (acc == cutoff && i > cutlim)) { 149 acc = __INT_MAX; 150 #if !defined(_KERNEL) && !defined(_STANDALONE) 151 any = -1; 152 errno = ERANGE; 153 #else 154 any = 0; 155 break; 156 #endif 157 } else { 158 any = 1; 159 acc *= base; 160 acc += i; 161 } 162 } 163 } 164 if (endptr != NULL) 165 /* LINTED interface specification */ 166 *endptr = __DECONST(void *, any ? s - 1 : nptr); 167 return(acc); 168 } 169