usr/src/lib/libc/port/gen/atol.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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1988 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include "lint.h"
  33 #include <ctype.h>
  34 #include <sys/types.h>
  35 #include <stdlib.h>
  36
  37 #define ATOL
  38
  39 #ifdef  ATOI
  40 typedef int TYPE;
  41 #define NAME    atoi
  42 #else
  43 typedef long TYPE;
  44 #define NAME    atol
  45 #endif
  46
  47 TYPE
  48 NAME(const char *p)
  49 {
  50         TYPE n;
  51         int c, neg = 0;
  52         unsigned char   *up = (unsigned char *)p;
  53
  54         if (!isdigit(c = *up)) {
  55                 while (isspace(c))
  56                         c = *++up;
  57                 switch (c) {
  58                 case '-':
  59                         neg++;
  60                         /* FALLTHROUGH */
  61                 case '+':
  62                         c = *++up;
  63                 }
  64                 if (!isdigit(c))
  65                         return (0);
  66         }
  67         for (n = '0' - c; isdigit(c = *++up); ) {
  68                 n *= 10; /* two steps to avoid unnecessary overflow */
  69                 n += '0' - c; /* accum neg to avoid surprises at MAX */
  70         }
  71         return (neg ? n : -n);
  72 }