Annotation of sys/lib/libsa/strtol.c, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: strtol.c,v 1.6 2003/08/11 06:23:09 deraadt 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. 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 integer.
! 37: *
! 38: * Ignores `locale' stuff. Assumes that the upper and lower case
! 39: * alphabets and digits are each contiguous.
! 40: */
! 41: long
! 42: strtol(const char *nptr, char **endptr, int base)
! 43: {
! 44: const char *s;
! 45: 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 (c <= ' ' || c >= 0x7f);
! 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 longs is
! 83: * [-2147483648..2147483647] and the input base is 10,
! 84: * cutoff will be set to 214748364 and cutlim to either
! 85: * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
! 86: * a value > 214748364, or equal but the next digit is > 7 (or 8),
! 87: * the number is too big, and we will return a range error.
! 88: *
! 89: * Set any if any `digits' consumed; make it negative to indicate
! 90: * overflow.
! 91: */
! 92: cutoff = neg ? LONG_MIN : LONG_MAX;
! 93: cutlim = cutoff % base;
! 94: cutoff /= base;
! 95: if (neg) {
! 96: if (cutlim > 0) {
! 97: cutlim -= base;
! 98: cutoff += 1;
! 99: }
! 100: cutlim = -cutlim;
! 101: }
! 102: for (acc = 0, any = 0;; c = (unsigned char) *s++) {
! 103: if (c >= '0' && c <= '9')
! 104: c -= '0';
! 105: else if (c >= 'A' && c <= 'Z')
! 106: c -= 'A' - 10;
! 107: else if (c >= 'a' && c <= 'z')
! 108: c -= 'a' - 10;
! 109: else
! 110: break;
! 111: if (c >= base)
! 112: break;
! 113: if (any < 0)
! 114: continue;
! 115: if (neg) {
! 116: if (acc < cutoff || (acc == cutoff && c > cutlim)) {
! 117: any = -1;
! 118: acc = LONG_MIN;
! 119: } else {
! 120: any = 1;
! 121: acc *= base;
! 122: acc -= c;
! 123: }
! 124: } else {
! 125: if (acc > cutoff || (acc == cutoff && c > cutlim)) {
! 126: any = -1;
! 127: acc = LONG_MAX;
! 128: } else {
! 129: any = 1;
! 130: acc *= base;
! 131: acc += c;
! 132: }
! 133: }
! 134: }
! 135: if (endptr != 0)
! 136: *endptr = (char *) (any ? s - 1 : nptr);
! 137: return (acc);
! 138: }
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