1 /* $OpenBSD: strtoll.c,v 1.1 2006/09/18 21:12:57 mpf Exp $ */ 2 /* Modified strtoll() from stdlib */ 3 /*- 4 * Copyright (c) 1992 The Regents of the University of California. 5 * 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/param.h> 33 #include "stand.h" 34 35 /* 36 * Convert a string to a long long. 37 * 38 * Ignores `locale' stuff. Assumes that the upper and lower case 39 * alphabets and digits are each contiguous. 40 */ 41 long long 42 strtoll(const char *nptr, char **endptr, int base) 43 { 44 const char *s; 45 long long acc, cutoff; 46 int c; 47 int neg, any, cutlim; 48 49 /* 50 * Skip white space and pick up leading +/- sign if any. 51 * If base is 0, allow 0x for hex and 0 for octal, else 52 * assume decimal; if base is already 16, allow 0x. 53 */ 54 s = nptr; 55 do { 56 c = (unsigned char) *s++; 57 } while (isspace(c)); 58 if (c == '-') { 59 neg = 1; 60 c = *s++; 61 } else { 62 neg = 0; 63 if (c == '+') 64 c = *s++; 65 } 66 if ((base == 0 || base == 16) && 67 c == '0' && (*s == 'x' || *s == 'X')) { 68 c = s[1]; 69 s += 2; 70 base = 16; 71 } 72 if (base == 0) 73 base = c == '0' ? 8 : 10; 74 75 /* 76 * Compute the cutoff value between legal numbers and illegal 77 * numbers. That is the largest legal value, divided by the 78 * base. An input number that is greater than this value, if 79 * followed by a legal input character, is too big. One that 80 * is equal to this value may be valid or not; the limit 81 * between valid and invalid numbers is then based on the last 82 * digit. For instance, if the range for long longs is 83 * [-9223372036854775808..9223372036854775807] and the input base 84 * is 10, cutoff will be set to 922337203685477580 and cutlim to 85 * either 7 (neg==0) or 8 (neg==1), meaning that if we have 86 * accumulated a value > 922337203685477580, or equal but the 87 * next digit is > 7 (or 8), the number is too big, and we will 88 * return a range error. 89 * 90 * Set any if any `digits' consumed; make it negative to indicate 91 * overflow. 92 */ 93 cutoff = neg ? LLONG_MIN : LLONG_MAX; 94 cutlim = cutoff % base; 95 cutoff /= base; 96 if (neg) { 97 if (cutlim > 0) { 98 cutlim -= base; 99 cutoff += 1; 100 } 101 cutlim = -cutlim; 102 } 103 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 104 if (isdigit(c)) 105 c -= '0'; 106 else if (isalpha(c)) 107 c -= isupper(c) ? 'A' - 10 : 'a' - 10; 108 else 109 break; 110 if (c >= base) 111 break; 112 if (any < 0) 113 continue; 114 if (neg) { 115 if (acc < cutoff || (acc == cutoff && c > cutlim)) { 116 any = -1; 117 acc = LLONG_MIN; 118 } else { 119 any = 1; 120 acc *= base; 121 acc -= c; 122 } 123 } else { 124 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 125 any = -1; 126 acc = LLONG_MAX; 127 } else { 128 any = 1; 129 acc *= base; 130 acc += c; 131 } 132 } 133 } 134 if (endptr != 0) 135 *endptr = (char *) (any ? s - 1 : nptr); 136 return (acc); 137 } 138