1 /* $NetBSD: strtoq.c,v 1.18 2006/12/18 00:40:14 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1992, 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[] = "@(#)strtoq.c 8.1 (Berkeley) 6/4/93"; 36 #else 37 __RCSID("$NetBSD: strtoq.c,v 1.18 2006/12/18 00:40:14 christos Exp $"); 38 #endif 39 #endif /* LIBC_SCCS and not lint */ 40 41 #include <sys/types.h> 42 43 #include <assert.h> 44 #include <ctype.h> 45 #include <errno.h> 46 #include <limits.h> 47 #include <stdlib.h> 48 49 /* 50 * Convert a string to a quad integer. 51 * 52 * Ignores `locale' stuff. Assumes that the upper and lower case 53 * alphabets and digits are each contiguous. 54 */ 55 quad_t 56 strtoq(nptr, endptr, base) 57 const char *nptr; 58 char **endptr; 59 int base; 60 { 61 const char *s; 62 quad_t acc, cutoff; 63 int c; 64 int neg, any, cutlim; 65 66 _DIAGASSERT(nptr != NULL); 67 /* endptr may be NULL */ 68 69 /* 70 * Skip white space and pick up leading +/- sign if any. 71 * If base is 0, allow 0x for hex and 0 for octal, else 72 * assume decimal; if base is already 16, allow 0x. 73 */ 74 s = nptr; 75 do { 76 c = (unsigned char) *s++; 77 } while (isspace(c)); 78 if (c == '-') { 79 neg = 1; 80 c = *s++; 81 } else { 82 neg = 0; 83 if (c == '+') 84 c = *s++; 85 } 86 if ((base == 0 || base == 16) && 87 c == '0' && (*s == 'x' || *s == 'X')) { 88 c = s[1]; 89 s += 2; 90 base = 16; 91 } 92 if (base == 0) 93 base = c == '0' ? 8 : 10; 94 95 /* 96 * Compute the cutoff value between legal numbers and illegal 97 * numbers. That is the largest legal value, divided by the 98 * base. An input number that is greater than this value, if 99 * followed by a legal input character, is too big. One that 100 * is equal to this value may be valid or not; the limit 101 * between valid and invalid numbers is then based on the last 102 * digit. For instance, if the range for quads is 103 * [-9223372036854775808..9223372036854775807] and the input base 104 * is 10, cutoff will be set to 922337203685477580 and cutlim to 105 * either 7 (neg==0) or 8 (neg==1), meaning that if we have 106 * accumulated a value > 922337203685477580, or equal but the 107 * next digit is > 7 (or 8), the number is too big, and we will 108 * return a range error. 109 * 110 * Set any if any `digits' consumed; make it negative to indicate 111 * overflow. 112 */ 113 cutoff = neg ? QUAD_MIN : QUAD_MAX; 114 cutlim = (int)(cutoff % base); 115 cutoff /= base; 116 if (neg) { 117 if (cutlim > 0) { 118 cutlim -= base; 119 cutoff += 1; 120 } 121 cutlim = -cutlim; 122 } 123 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 124 if (isdigit(c)) 125 c -= '0'; 126 else if (isalpha(c)) 127 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 128 else 129 break; 130 if (c >= base) 131 break; 132 if (any < 0) 133 continue; 134 if (neg) { 135 if (acc < cutoff || (acc == cutoff && c > cutlim)) { 136 any = -1; 137 acc = QUAD_MIN; 138 errno = ERANGE; 139 } else { 140 any = 1; 141 acc *= base; 142 acc -= c; 143 } 144 } else { 145 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 146 any = -1; 147 acc = QUAD_MAX; 148 errno = ERANGE; 149 } else { 150 any = 1; 151 acc *= base; 152 acc += c; 153 } 154 } 155 } 156 if (endptr != 0) 157 *endptr = __UNCONST(any ? s - 1 : nptr); 158 return (acc); 159 } 160