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_strtol.h revision 1.1 
      1 /* $NetBSD: _strtol.h,v 1.1 2008/08/20 12:42:26 joerg Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  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  * Original version ID:
     32  * NetBSD: src/lib/libc/locale/_wcstol.h,v 1.2 2003/08/07 16:43:03 agc Exp
     33  */
     34 
     35 /*
     36  * function template for strtol, strtoll and strtoimax.
     37  *
     38  * parameters:
     39  *	_FUNCNAME : function name
     40  *      __INT     : return type
     41  *      __INT_MIN : lower limit of the return type
     42  *      __INT_MAX : upper limit of the return type
     43  */
     44 
     45 __INT
     46 _FUNCNAME(const char *nptr, char **endptr, int base)
     47 {
     48 	const char *s;
     49 	__INT acc, cutoff;
     50 	unsigned char c;
     51 	int i, neg, any, cutlim;
     52 
     53 	_DIAGASSERT(nptr != NULL);
     54 	/* endptr may be NULL */
     55 
     56 	/* check base value */
     57 	if (base && (base < 2 || base > 36)) {
     58 #if !defined(_KERNEL) && !defined(_STANDALONE)
     59 		errno = EINVAL;
     60 		return(0);
     61 #else
     62 		panic("%s: invalid base %d", __func__, base);
     63 #endif
     64 	}
     65 
     66 	/*
     67 	 * Skip white space and pick up leading +/- sign if any.
     68 	 * If base is 0, allow 0x for hex and 0 for octal, else
     69 	 * assume decimal; if base is already 16, allow 0x.
     70 	 */
     71 	s = nptr;
     72 	do {
     73 		c = *s++;
     74 	} while (isspace(c));
     75 	if (c == '-') {
     76 		neg = 1;
     77 		c = *s++;
     78 	} else {
     79 		neg = 0;
     80 		if (c == '+')
     81 			c = *s++;
     82 	}
     83 	if ((base == 0 || base == 16) &&
     84 	    c == '0' && (*s == 'x' || *s == 'X')) {
     85 		c = s[1];
     86 		s += 2;
     87 		base = 16;
     88 	}
     89 	if (base == 0)
     90 		base = (c == '0' ? 8 : 10);
     91 
     92 	/*
     93 	 * Compute the cutoff value between legal numbers and illegal
     94 	 * numbers.  That is the largest legal value, divided by the
     95 	 * base.  An input number that is greater than this value, if
     96 	 * followed by a legal input character, is too big.  One that
     97 	 * is equal to this value may be valid or not; the limit
     98 	 * between valid and invalid numbers is then based on the last
     99 	 * digit.  For instance, if the range for longs is
    100 	 * [-2147483648..2147483647] and the input base is 10,
    101 	 * cutoff will be set to 214748364 and cutlim to either
    102 	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
    103 	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
    104 	 * the number is too big, and we will return a range error.
    105 	 *
    106 	 * Set any if any `digits' consumed; make it negative to indicate
    107 	 * overflow.
    108 	 */
    109 	cutoff = (neg ? __INT_MIN : __INT_MAX);
    110 	cutlim = (int)(cutoff % base);
    111 	cutoff /= base;
    112 	if (neg) {
    113 		if (cutlim > 0) {
    114 			cutlim -= base;
    115 			cutoff += 1;
    116 		}
    117 		cutlim = -cutlim;
    118 	}
    119 	for (acc = 0, any = 0;; c = *s++) {
    120 		if (isdigit(c))
    121 			i = c - '0';
    122 		else if (isalpha(c))
    123 			i = c - (isupper(c) ? 'A' - 10 : 'a' - 10);
    124 		else
    125 			break;
    126 		if (i >= base)
    127 			break;
    128 		if (any < 0)
    129 			continue;
    130 		if (neg) {
    131 			if (acc < cutoff || (acc == cutoff && i > cutlim)) {
    132 				acc = __INT_MIN;
    133 #if !defined(_KERNEL) && !defined(_STANDALONE)
    134 				any = -1;
    135 				errno = ERANGE;
    136 #else
    137 				any = 0;
    138 				break;
    139 #endif
    140 			} else {
    141 				any = 1;
    142 				acc *= base;
    143 				acc -= i;
    144 			}
    145 		} else {
    146 			if (acc > cutoff || (acc == cutoff && i > cutlim)) {
    147 				acc = __INT_MAX;
    148 #if !defined(_KERNEL) && !defined(_STANDALONE)
    149 				any = -1;
    150 				errno = ERANGE;
    151 #else
    152 				any = 0;
    153 				break;
    154 #endif
    155 			} else {
    156 				any = 1;
    157 				acc *= base;
    158 				acc += i;
    159 			}
    160 		}
    161 	}
    162 	if (endptr != NULL)
    163 		/* LINTED interface specification */
    164 		*endptr = __UNCONST(any ? s - 1 : nptr);
    165 	return(acc);
    166 }
    167