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Annotation of 43BSDReno/lib/libc/stdlib/strtoul.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1990 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that: (1) source distributions retain this entire copyright
                      7:  * notice and comment, and (2) distributions including binaries display
                      8:  * the following acknowledgement:  ``This product includes software
                      9:  * developed by the University of California, Berkeley and its contributors''
                     10:  * in the documentation or other materials provided with the distribution
                     11:  * and in all advertising materials mentioning features or use of this
                     12:  * software. Neither the name of the University nor the names of its
                     13:  * contributors may be used to endorse or promote products derived
                     14:  * from this software without specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)strtoul.c  5.2 (Berkeley) 5/17/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: #include <limits.h>
                     25: #include <ctype.h>
                     26: #include <errno.h>
                     27: #include <stdlib.h>
                     28: 
                     29: /*
                     30:  * Convert a string to an unsigned long integer.
                     31:  *
                     32:  * Ignores `locale' stuff.  Assumes that the upper and lower case
                     33:  * alphabets and digits are each contiguous.
                     34:  */
                     35: unsigned long
                     36: strtoul(nptr, endptr, base)
                     37:        char *nptr, **endptr;
                     38:        register int base;
                     39: {
                     40:        register char *s = nptr;
                     41:        register unsigned long acc;
                     42:        register int c;
                     43:        register unsigned long cutoff;
                     44:        register int neg = 0, any, cutlim;
                     45: 
                     46:        /*
                     47:         * See strtol for comments as to the logic used.
                     48:         */
                     49:        do {
                     50:                c = *s++;
                     51:        } while (isspace(c));
                     52:        if (c == '-') {
                     53:                neg = 1;
                     54:                c = *s++;
                     55:        } else if (c == '+')
                     56:                c = *s++;
                     57:        if ((base == 0 || base == 16) &&
                     58:            c == '0' && (*s == 'x' || *s == 'X')) {
                     59:                c = s[1];
                     60:                s += 2;
                     61:                base = 16;
                     62:        }
                     63:        if (base == 0)
                     64:                base = c == '0' ? 8 : 10;
                     65:        cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
                     66:        cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
                     67:        for (acc = 0, any = 0;; c = *s++) {
                     68:                if (isdigit(c))
                     69:                        c -= '0';
                     70:                else if (isalpha(c))
                     71:                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;
                     72:                else
                     73:                        break;
                     74:                if (c >= base)
                     75:                        break;
                     76:                if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
                     77:                        any = -1;
                     78:                else {
                     79:                        any = 1;
                     80:                        acc *= base;
                     81:                        acc += c;
                     82:                }
                     83:        }
                     84:        if (any < 0) {
                     85:                acc = ULONG_MAX;
                     86:                errno = ERANGE;
                     87:        } else if (neg)
                     88:                acc = -acc;
                     89:        if (endptr != 0)
                     90:                *endptr = any ? s - 1 : nptr;
                     91:        return (acc);
                     92: }

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