Return to strtoul.c CVS log

Up to [local] / prex-old / usr / lib / libc / stdlib

Annotation of prex-old/usr/lib/libc/stdlib/strtoul.c, Revision 1.1.1.1

1.1       nbrk        1: /*
                      2:  * Copyright (c) 1990, 1993
                      3:  *     The Regents of the University of California.  All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms, with or without
                      6:  * modification, are permitted provided that the following conditions
                      7:  * are met:
                      8:  * 1. Redistributions of source code must retain the above copyright
                      9:  *    notice, this list of conditions and the following disclaimer.
                     10:  * 2. Redistributions in binary form must reproduce the above copyright
                     11:  *    notice, this list of conditions and the following disclaimer in the
                     12:  *    documentation and/or other materials provided with the distribution.
                     13:  * 3. Neither the name of the University nor the names of its contributors
                     14:  *    may be used to endorse or promote products derived from this software
                     15:  *    without specific prior written permission.
                     16:  *
                     17:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     18:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     19:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     20:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     21:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     22:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     23:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     24:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     25:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     26:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     27:  * SUCH DAMAGE.
                     28:  */
                     29:
                     30: #include <limits.h>
                     31: #include <ctype.h>
                     32: #include <errno.h>
                     33: #include <stdlib.h>
                     34:
                     35: /*
                     36:  * Convert a string to an unsigned long integer.
                     37:  *
                     38:  * Ignores `locale' stuff.  Assumes that the upper and lower case
                     39:  * alphabets and digits are each contiguous.
                     40:  */
                     41: unsigned long
                     42: strtoul(nptr, endptr, base)
                     43:        const char *nptr;
                     44:        char **endptr;
                     45:        register int base;
                     46: {
                     47:        const char *s;
                     48:        unsigned long acc, cutoff;
                     49:        int c;
                     50:        int neg, any, cutlim;
                     51:
                     52:        /*
                     53:         * See strtol for comments as to the logic used.
                     54:         */
                     55:        s = nptr;
                     56:        do {
                     57:                c = (unsigned char) *s++;
                     58:        } while (isspace(c));
                     59:        if (c == '-') {
                     60:                neg = 1;
                     61:                c = *s++;
                     62:        } else {
                     63:                neg = 0;
                     64:                if (c == '+')
                     65:                        c = *s++;
                     66:        }
                     67:        if ((base == 0 || base == 16) &&
                     68:            c == '0' && (*s == 'x' || *s == 'X')) {
                     69:                c = s[1];
                     70:                s += 2;
                     71:                base = 16;
                     72:        }
                     73:        if (base == 0)
                     74:                base = c == '0' ? 8 : 10;
                     75:
                     76:        cutoff = ULONG_MAX / (unsigned long)base;
                     77:        cutlim = (int)(ULONG_MAX % (unsigned long)base);
                     78:        for (acc = 0, any = 0;; c = (unsigned char) *s++) {
                     79:                if (isdigit(c))
                     80:                        c -= '0';
                     81:                else if (isalpha(c))
                     82:                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                     83:                else
                     84:                        break;
                     85:                if (c >= base)
                     86:                        break;
                     87:                if (any < 0)
                     88:                        continue;
                     89:                if (acc > cutoff || (acc == cutoff && c > cutlim)) {
                     90:                        any = -1;
                     91:                        acc = ULONG_MAX;
                     92:                        errno = ERANGE;
                     93:                } else {
                     94:                        any = 1;
                     95:                        acc *= (unsigned long)base;
                     96:                        acc += c;
                     97:                }
                     98:        }
                     99:        if (neg && any > 0)
                    100:                acc = -acc;
                    101:        if (endptr != 0)
                    102:                /* LINTED interface specification */
                    103:                *endptr = (char *)(any ? s - 1 : nptr);
                    104:        return (acc);
                    105: }