xref: /PHP-7.3/ext/bcmath/libbcmath/src/num2long.c (revision e7d40afb)
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