1 /* num2long.c: bcmath library file. */
2 /*
3 Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
4 Copyright (C) 2000 Philip A. Nelson
5
6 This library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2 of the License, or (at your option) any later version.
10
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details. (COPYING.LIB)
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with this library; if not, write to:
18
19 The Free Software Foundation, Inc.
20 59 Temple Place, Suite 330
21 Boston, MA 02111-1307 USA.
22
23 You may contact the author by:
24 e-mail: philnelson@acm.org
25 us-mail: Philip A. Nelson
26 Computer Science Department, 9062
27 Western Washington University
28 Bellingham, WA 98226-9062
29
30 *************************************************************************/
31
32 #include <config.h>
33 #include <stdio.h>
34 #include <assert.h>
35 #include <stdlib.h>
36 #include <ctype.h>
37 #include <stdarg.h>
38 #include "bcmath.h"
39 #include "private.h"
40
41 /* Convert a number NUM to a long. The function returns only the integer
42 part of the number. For numbers that are too large to represent as
43 a long, this function returns a zero. This can be detected by checking
44 the NUM for zero after having a zero returned. */
45
46 long
bc_num2long(num)47 bc_num2long (num)
48 bc_num num;
49 {
50 long val;
51 char *nptr;
52 int index;
53
54 /* Extract the int value, ignore the fraction. */
55 val = 0;
56 nptr = num->n_value;
57 for (index = num->n_len; index > 0; index--) {
58 char n = *nptr++;
59
60 if (val > LONG_MAX/BASE) {
61 return 0;
62 }
63 val *= BASE;
64
65 if (val > LONG_MAX - n) {
66 return 0;
67 }
68 val += n;
69 }
70
71 /* Return the value. */
72 if (num->n_sign == PLUS)
73 return (val);
74 else
75 return (-val);
76 }
77
