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