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 * $FreeBSD$ 37 */ 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/ctype.h> 42 #include <machine/limits.h> 43 44 /* 45 * Convert a string to a quad integer. 46 * 47 * Ignores `locale' stuff. Assumes that the upper and lower case 48 * alphabets and digits are each contiguous. 49 */ 50 quad_t 51 strtoq(const char *nptr, char **endptr, int base) 52 { 53 const char *s; 54 u_quad_t acc; 55 unsigned char c; 56 u_quad_t qbase, cutoff; 57 int neg, any, cutlim; 58 59 /* 60 * Skip white space and pick up leading +/- sign if any. 61 * If base is 0, allow 0x for hex and 0 for octal, else 62 * assume decimal; if base is already 16, allow 0x. 63 */ 64 s = nptr; 65 do { 66 c = *s++; 67 } while (isspace(c)); 68 if (c == '-') { 69 neg = 1; 70 c = *s++; 71 } else { 72 neg = 0; 73 if (c == '+') 74 c = *s++; 75 } 76 if ((base == 0 || base == 16) && 77 c == '0' && (*s == 'x' || *s == 'X')) { 78 c = s[1]; 79 s += 2; 80 base = 16; 81 } 82 if (base == 0) 83 base = c == '0' ? 8 : 10; 84 85 /* 86 * Compute the cutoff value between legal numbers and illegal 87 * numbers. That is the largest legal value, divided by the 88 * base. An input number that is greater than this value, if 89 * followed by a legal input character, is too big. One that 90 * is equal to this value may be valid or not; the limit 91 * between valid and invalid numbers is then based on the last 92 * digit. For instance, if the range for quads is 93 * [-9223372036854775808..9223372036854775807] and the input base 94 * is 10, cutoff will be set to 922337203685477580 and cutlim to 95 * either 7 (neg==0) or 8 (neg==1), meaning that if we have 96 * accumulated a value > 922337203685477580, or equal but the 97 * next digit is > 7 (or 8), the number is too big, and we will 98 * return a range error. 99 * 100 * Set any if any `digits' consumed; make it negative to indicate 101 * overflow. 102 */ 103 qbase = (unsigned)base; 104 cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX; 105 cutlim = cutoff % qbase; 106 cutoff /= qbase; 107 for (acc = 0, any = 0;; c = *s++) { 108 if (!isascii(c)) 109 break; 110 if (isdigit(c)) 111 c -= '0'; 112 else if (isalpha(c)) 113 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 114 else 115 break; 116 if (c >= base) 117 break; 118 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 119 any = -1; 120 else { 121 any = 1; 122 acc *= qbase; 123 acc += c; 124 } 125 } 126 if (any < 0) { 127 acc = neg ? QUAD_MIN : QUAD_MAX; 128 } else if (neg) 129 acc = -acc; 130 if (endptr != 0) 131 *((const char **)endptr) = any ? s - 1 : nptr; 132 return (acc); 133 } 134