usr/src/lib/libbc/libc/gen/common/atoi.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
  30 #define ATOI
  31
  32 #ifdef  ATOI
  33 typedef int TYPE;
  34 #define NAME    atoi
  35 #else
  36 typedef long TYPE;
  37 #define NAME    atol
  38 #endif
  39
  40 TYPE
  41 NAME(p)
  42 register char *p;
  43 {
  44         register TYPE n;
  45         register int c, neg = 0;
  46
  47         if (!isdigit(c = *p)) {
  48                 while (isspace(c))
  49                         c = *++p;
  50                 switch (c) {
  51                 case '-':
  52                         neg++;
  53                 case '+': /* fall-through */
  54                         c = *++p;
  55                 }
  56                 if (!isdigit(c))
  57                         return (0);
  58         }
  59         for (n = '0' - c; isdigit(c = *++p); ) {
  60                 n *= 10; /* two steps to avoid unnecessary overflow */
  61                 n += '0' - c; /* accum neg to avoid surprises at MAX */
  62         }
  63         return (neg ? n : -n);
  64 }