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. All advertising materials mentioning features or use of this software
  14:  *    must display the following acknowledgement:
  15:  *	This product includes software developed by the University of
  16:  *	California, Berkeley and its contributors.
  17:  * 4. Neither the name of the University nor the names of its contributors
  18:  *    may be used to endorse or promote products derived from this software
  19:  *    without specific prior written permission.
  20:  *
  21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31:  * SUCH DAMAGE.
  32:  */
  33: 
  34: #if defined(LIBC_SCCS) && !defined(lint)
  35: static char sccsid[] = "@(#)strtol.c	8.1.1 (2.11BSD) 1996/1/11";
  36: #endif /* LIBC_SCCS and not lint */
  37: 
  38: #include <limits.h>
  39: #include <ctype.h>
  40: #include <errno.h>
  41: #include <stdlib.h>
  42: 
  43: 
  44: /*
  45:  * Convert a string to a long integer.
  46:  *
  47:  * Ignores `locale' stuff.  Assumes that the upper and lower case
  48:  * alphabets and digits are each contiguous.
  49:  */
  50: long
  51: strtol(nptr, endptr, base)
  52:     char *nptr;
  53:     char **endptr;
  54:     register int base;
  55: {
  56:     register char *s = nptr;
  57:     register unsigned long acc;
  58:     register int c;
  59:     register unsigned long cutoff;
  60:     register int neg = 0, any, cutlim;
  61: 
  62:     /*
  63: 	 * Skip white space and pick up leading +/- sign if any.
  64: 	 * If base is 0, allow 0x for hex and 0 for octal, else
  65: 	 * assume decimal; if base is already 16, allow 0x.
  66: 	 */
  67:     do {
  68:         c = *s++;
  69:     } while (isspace(c));
  70:     if (c == '-') {
  71:         neg = 1;
  72:         c = *s++;
  73:     } else if (c == '+')
  74:         c = *s++;
  75:     if ((base == 0 || base == 16) &&
  76:         c == '0' && (*s == 'x' || *s == 'X')) {
  77:         c = s[1];
  78:         s += 2;
  79:         base = 16;
  80:     }
  81:     if (base == 0)
  82:         base = c == '0' ? 8 : 10;
  83: 
  84:     /*
  85: 	 * Compute the cutoff value between legal numbers and illegal
  86: 	 * numbers.  That is the largest legal value, divided by the
  87: 	 * base.  An input number that is greater than this value, if
  88: 	 * followed by a legal input character, is too big.  One that
  89: 	 * is equal to this value may be valid or not; the limit
  90: 	 * between valid and invalid numbers is then based on the last
  91: 	 * digit.  For instance, if the range for longs is
  92: 	 * [-2147483648..2147483647] and the input base is 10,
  93: 	 * cutoff will be set to 214748364 and cutlim to either
  94: 	 * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
  95: 	 * a value > 214748364, or equal but the next digit is > 7 (or 8),
  96: 	 * the number is too big, and we will return a range error.
  97: 	 *
  98: 	 * Set any if any `digits' consumed; make it negative to indicate
  99: 	 * overflow.
 100: 	 */
 101:     cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
 102:     cutlim = cutoff % (unsigned long)base;
 103:     cutoff /= (unsigned long)base;
 104:     for (acc = 0, any = 0;; c = *s++) {
 105:         if (isdigit(c))
 106:             c -= '0';
 107:         else if (isalpha(c))
 108:             c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 109:         else
 110:             break;
 111:         if (c >= base)
 112:             break;
 113:         if (any < 0 || acc > cutoff || acc == cutoff && c > cutlim)
 114:             any = -1;
 115:         else {
 116:             any = 1;
 117:             acc *= base;
 118:             acc += c;
 119:         }
 120:     }
 121:     if (any < 0) {
 122:         acc = neg ? LONG_MIN : LONG_MAX;
 123:         errno = ERANGE;
 124:     } else if (neg)
 125:         acc = -acc;
 126:     if (endptr != 0)
 127:         *endptr = (char *)(any ? s - 1 : nptr);
 128:     return (acc);
 129: }
Last modified: 1996-01-12
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