1 /* $OpenBSD: strtol.c,v 1.3 1998/05/20 00:07:17 art Exp $ */ 2 /* Modified strtol() from stdlib */ 3 /*- 4 * Copyright (c) 1990 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/param.h> 37 38 /* 39 * Convert a string to a long integer. 40 * 41 * Ignores `locale' stuff. Assumes that the upper and lower case 42 * alphabets and digits are each contiguous. 43 */ 44 long 45 strtol(nptr, endptr, base) 46 const char *nptr; 47 char **endptr; 48 register int base; 49 { 50 register const char *s; 51 register long acc, cutoff; 52 register int c; 53 register 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 = (unsigned char) *s++; 63 } while (c <= ' ' || c >= 0x7f); 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 longs is 89 * [-2147483648..2147483647] and the input base is 10, 90 * cutoff will be set to 214748364 and cutlim to either 91 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated 92 * a value > 214748364, or equal but the next digit is > 7 (or 8), 93 * the number is too big, and we will return a range error. 94 * 95 * Set any if any `digits' consumed; make it negative to indicate 96 * overflow. 97 */ 98 cutoff = neg ? LONG_MIN : LONG_MAX; 99 cutlim = cutoff % base; 100 cutoff /= base; 101 if (neg) { 102 if (cutlim > 0) { 103 cutlim -= base; 104 cutoff += 1; 105 } 106 cutlim = -cutlim; 107 } 108 for (acc = 0, any = 0;; c = (unsigned char) *s++) { 109 if (c >= '0' && c <= '9') 110 c -= '0'; 111 else if (c >= 'A' && c <= 'Z') 112 c -= 'A' - 10; 113 else if (c >= 'a' && c <= 'z') 114 c -= 'a' - 10; 115 else 116 break; 117 if (c >= base) 118 break; 119 if (any < 0) 120 continue; 121 if (neg) { 122 if (acc < cutoff || (acc == cutoff && c > cutlim)) { 123 any = -1; 124 acc = LONG_MIN; 125 } else { 126 any = 1; 127 acc *= base; 128 acc -= c; 129 } 130 } else { 131 if (acc > cutoff || (acc == cutoff && c > cutlim)) { 132 any = -1; 133 acc = LONG_MAX; 134 } else { 135 any = 1; 136 acc *= base; 137 acc += c; 138 } 139 } 140 } 141 if (endptr != 0) 142 *endptr = (char *) (any ? s - 1 : nptr); 143 return (acc); 144 } 145