1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD: src/sys/libkern/strtoq.c,v 1.3 1999/12/01 22:56:51 archie Exp $ 37 * $DragonFly: src/sys/libkern/strtoq.c,v 1.2 2003/06/17 04:28:42 dillon Exp $ 38 */ 39 40 #include <sys/param.h> 41 #include <sys/systm.h> 42 #include <sys/ctype.h> 43 #include <machine/limits.h> 44 45 /* 46 * Convert a string to a quad integer. 47 * 48 * Ignores `locale' stuff. Assumes that the upper and lower case 49 * alphabets and digits are each contiguous. 50 */ 51 quad_t 52 strtoq(const char *nptr, char **endptr, int base) 53 { 54 const char *s; 55 u_quad_t acc; 56 unsigned char c; 57 u_quad_t qbase, cutoff; 58 int neg, any, cutlim; 59 60 /* 61 * Skip white space and pick up leading +/- sign if any. 62 * If base is 0, allow 0x for hex and 0 for octal, else 63 * assume decimal; if base is already 16, allow 0x. 64 */ 65 s = nptr; 66 do { 67 c = *s++; 68 } while (isspace(c)); 69 if (c == '-') { 70 neg = 1; 71 c = *s++; 72 } else { 73 neg = 0; 74 if (c == '+') 75 c = *s++; 76 } 77 if ((base == 0 || base == 16) && 78 c == '0' && (*s == 'x' || *s == 'X')) { 79 c = s[1]; 80 s += 2; 81 base = 16; 82 } 83 if (base == 0) 84 base = c == '0' ? 8 : 10; 85 86 /* 87 * Compute the cutoff value between legal numbers and illegal 88 * numbers. That is the largest legal value, divided by the 89 * base. An input number that is greater than this value, if 90 * followed by a legal input character, is too big. One that 91 * is equal to this value may be valid or not; the limit 92 * between valid and invalid numbers is then based on the last 93 * digit. For instance, if the range for quads is 94 * [-9223372036854775808..9223372036854775807] and the input base 95 * is 10, cutoff will be set to 922337203685477580 and cutlim to 96 * either 7 (neg==0) or 8 (neg==1), meaning that if we have 97 * accumulated a value > 922337203685477580, or equal but the 98 * next digit is > 7 (or 8), the number is too big, and we will 99 * return a range error. 100 * 101 * Set any if any `digits' consumed; make it negative to indicate 102 * overflow. 103 */ 104 qbase = (unsigned)base; 105 cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX; 106 cutlim = cutoff % qbase; 107 cutoff /= qbase; 108 for (acc = 0, any = 0;; c = *s++) { 109 if (!isascii(c)) 110 break; 111 if (isdigit(c)) 112 c -= '0'; 113 else if (isalpha(c)) 114 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 115 else 116 break; 117 if (c >= base) 118 break; 119 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 120 any = -1; 121 else { 122 any = 1; 123 acc *= qbase; 124 acc += c; 125 } 126 } 127 if (any < 0) { 128 acc = neg ? QUAD_MIN : QUAD_MAX; 129 } else if (neg) 130 acc = -acc; 131 if (endptr != 0) 132 *((const char **)endptr) = any ? s - 1 : nptr; 133 return (acc); 134 } 135