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. (LICENSE)
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 <stdlib.h>
35 #include <ctype.h>
36 #include <stdarg.h>
37 #include "bcmath.h"
38 #include "private.h"
39
40 /* Convert a number NUM to a long. The function returns only the integer
41 part of the number. For numbers that are too large to represent as
42 a long, this function returns a zero. This can be detected by checking
43 the NUM for zero after having a zero returned. */
44
45 long
bc_num2long(num)46 bc_num2long (num)
47 bc_num num;
48 {
49 long val;
50 char *nptr;
51 int index;
52
53 /* Extract the int value, ignore the fraction. */
54 val = 0;
55 nptr = num->n_value;
56 for (index = num->n_len; index > 0; index--) {
57 char n = *nptr++;
58
59 if (val > LONG_MAX/BASE) {
60 return 0;
61 }
62 val *= BASE;
63
64 if (val > LONG_MAX - n) {
65 return 0;
66 }
67 val += n;
68 }
69
70 /* Return the value. */
71 if (num->n_sign == PLUS)
72 return (val);
73 else
74 return (-val);
75 }
76
