strtoq.c revision 53648
152845Sphk/*- 252845Sphk * Copyright (c) 1990, 1993 352845Sphk * The Regents of the University of California. All rights reserved. 452845Sphk * 552845Sphk * This code is derived from software contributed to Berkeley by 652845Sphk * Chris Torek. 752845Sphk * 852845Sphk * Redistribution and use in source and binary forms, with or without 952845Sphk * modification, are permitted provided that the following conditions 1052845Sphk * are met: 1152845Sphk * 1. Redistributions of source code must retain the above copyright 1252845Sphk * notice, this list of conditions and the following disclaimer. 1352845Sphk * 2. Redistributions in binary form must reproduce the above copyright 1452845Sphk * notice, this list of conditions and the following disclaimer in the 1552845Sphk * documentation and/or other materials provided with the distribution. 1652845Sphk * 3. All advertising materials mentioning features or use of this software 1752845Sphk * must display the following acknowledgement: 1852845Sphk * This product includes software developed by the University of 1952845Sphk * California, Berkeley and its contributors. 2052845Sphk * 4. Neither the name of the University nor the names of its contributors 2152845Sphk * may be used to endorse or promote products derived from this software 2252845Sphk * without specific prior written permission. 2352845Sphk * 2452845Sphk * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2552845Sphk * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2652845Sphk * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2752845Sphk * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2852845Sphk * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2952845Sphk * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 3052845Sphk * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 3152845Sphk * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 3252845Sphk * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3352845Sphk * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3452845Sphk * SUCH DAMAGE. 3552845Sphk * 3652845Sphk * $FreeBSD: head/sys/libkern/strtoq.c 53648 1999-11-24 01:03:08Z archie $ 3752845Sphk */ 3852845Sphk 3952845Sphk#include <sys/param.h> 4052845Sphk#include <sys/systm.h> 4152845Sphk#include <sys/ctype.h> 4252845Sphk#include <machine/limits.h> 4352845Sphk 4452845Sphk/* 4552845Sphk * Convert a string to a quad integer. 4652845Sphk * 4752845Sphk * Ignores `locale' stuff. Assumes that the upper and lower case 4852845Sphk * alphabets and digits are each contiguous. 4952845Sphk */ 5052845Sphkquad_t 5153648Sarchiestrtoq(const char *nptr, char **endptr, int base) 5252845Sphk{ 5352845Sphk const char *s; 5452845Sphk u_quad_t acc; 5552845Sphk unsigned char c; 5652845Sphk u_quad_t qbase, cutoff; 5752845Sphk int neg, any, cutlim; 5852845Sphk 5952845Sphk /* 6052845Sphk * Skip white space and pick up leading +/- sign if any. 6152845Sphk * If base is 0, allow 0x for hex and 0 for octal, else 6252845Sphk * assume decimal; if base is already 16, allow 0x. 6352845Sphk */ 6452845Sphk s = nptr; 6552845Sphk do { 6652845Sphk c = *s++; 6752845Sphk } while (isspace(c)); 6852845Sphk if (c == '-') { 6952845Sphk neg = 1; 7052845Sphk c = *s++; 7152845Sphk } else { 7252845Sphk neg = 0; 7352845Sphk if (c == '+') 7452845Sphk c = *s++; 7552845Sphk } 7652845Sphk if ((base == 0 || base == 16) && 7752845Sphk c == '0' && (*s == 'x' || *s == 'X')) { 7852845Sphk c = s[1]; 7952845Sphk s += 2; 8052845Sphk base = 16; 8152845Sphk } 8252845Sphk if (base == 0) 8352845Sphk base = c == '0' ? 8 : 10; 8452845Sphk 8552845Sphk /* 8652845Sphk * Compute the cutoff value between legal numbers and illegal 8752845Sphk * numbers. That is the largest legal value, divided by the 8852845Sphk * base. An input number that is greater than this value, if 8952845Sphk * followed by a legal input character, is too big. One that 9052845Sphk * is equal to this value may be valid or not; the limit 9152845Sphk * between valid and invalid numbers is then based on the last 9252845Sphk * digit. For instance, if the range for quads is 9352845Sphk * [-9223372036854775808..9223372036854775807] and the input base 9452845Sphk * is 10, cutoff will be set to 922337203685477580 and cutlim to 9552845Sphk * either 7 (neg==0) or 8 (neg==1), meaning that if we have 9652845Sphk * accumulated a value > 922337203685477580, or equal but the 9752845Sphk * next digit is > 7 (or 8), the number is too big, and we will 9852845Sphk * return a range error. 9952845Sphk * 10052845Sphk * Set any if any `digits' consumed; make it negative to indicate 10152845Sphk * overflow. 10252845Sphk */ 10352845Sphk qbase = (unsigned)base; 10452845Sphk cutoff = neg ? (u_quad_t)-(QUAD_MIN + QUAD_MAX) + QUAD_MAX : QUAD_MAX; 10552845Sphk cutlim = cutoff % qbase; 10652845Sphk cutoff /= qbase; 10752845Sphk for (acc = 0, any = 0;; c = *s++) { 10852845Sphk if (!isascii(c)) 10952845Sphk break; 11052845Sphk if (isdigit(c)) 11152845Sphk c -= '0'; 11252845Sphk else if (isalpha(c)) 11352845Sphk c -= isupper(c) ? 'A' - 10 : 'a' - 10; 11452845Sphk else 11552845Sphk break; 11652845Sphk if (c >= base) 11752845Sphk break; 11852845Sphk if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) 11952845Sphk any = -1; 12052845Sphk else { 12152845Sphk any = 1; 12252845Sphk acc *= qbase; 12352845Sphk acc += c; 12452845Sphk } 12552845Sphk } 12652845Sphk if (any < 0) { 12752845Sphk acc = neg ? QUAD_MIN : QUAD_MAX; 12852845Sphk } else if (neg) 12952845Sphk acc = -acc; 13052845Sphk if (endptr != 0) 13153648Sarchie *endptr = (char *)(any ? s - 1 : nptr); 13252845Sphk return (acc); 13352845Sphk} 134