usr/src/lib/libbc/libc/gen/common/strtol.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*      Copyright (c) 1984 AT&T */
  23 /*        All Rights Reserved   */
  24
  25 #pragma ident   "%Z%%M% %I%     %E% SMI"  /* from S5R2 2.1 */
  26
  27 /*LINTLIBRARY*/
  28 #include <ctype.h>
  29 #define DIGIT(x)        (isdigit(x) ? (x) - '0' : \
  30                         islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')
  31 #define MBASE   ('z' - 'a' + 1 + 10)
  32
  33 long
  34 strtol(str, ptr, base)
  35 register char *str;
  36 char **ptr;
  37 register int base;
  38 {
  39         register long val;
  40         register int c;
  41         int xx, neg = 0;
  42
  43         if (ptr != (char **)0)
  44                 *ptr = str; /* in case no number is formed */
  45         if (base < 0 || base > MBASE)
  46                 return (0); /* base is invalid -- should be a fatal error */
  47         if (!isalnum(c = *str)) {
  48                 while (isspace(c))
  49                         c = *++str;
  50                 switch (c) {
  51                 case '-':
  52                         neg++;
  53                 case '+': /* fall-through */
  54                         c = *++str;
  55                 }
  56         }
  57         if (base == 0)
  58                 if (c != '0')
  59                         base = 10;
  60                 else if (str[1] == 'x' || str[1] == 'X')
  61                         base = 16;
  62                 else
  63                         base = 8;
  64         /*
  65          * for any base > 10, the digits incrementally following
  66          *      9 are assumed to be "abc...z" or "ABC...Z"
  67          */
  68         if (!isalnum(c) || (xx = DIGIT(c)) >= base)
  69                 return (0); /* no number formed */
  70         if (base == 16 && c == '0' && isxdigit(str[2]) &&
  71             (str[1] == 'x' || str[1] == 'X'))
  72                 c = *(str += 2); /* skip over leading "0x" or "0X" */
  73         for (val = -DIGIT(c); isalnum(c = *++str) && (xx = DIGIT(c)) < base; )
  74                 /* accumulate neg avoids surprises near MAXLONG */
  75                 val = base * val - xx;
  76         if (ptr != (char **)0)
  77                 *ptr = str;
  78         return (neg ? val : -val);
  79 }