xref: /PHP-8.2/ext/bcmath/libbcmath/src/num2long.c (revision eb9ad31b)
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