1/* Plural expression evaluation.
2 Copyright (C) 2000-2023 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU Lesser General Public License as published by
6 the Free Software Foundation; either version 2.1 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17#ifndef STATIC
18#define STATIC static
19#endif
20
21/* Evaluate the plural expression and return an index value. */
22STATIC
23unsigned long int
24plural_eval (const struct expression *pexp, unsigned long int n)
25{
26 switch (pexp->nargs)
27 {
28 case 0:
29 switch (pexp->operation)
30 {
31 case var:
32 return n;
33 case num:
34 return pexp->val.num;
35 default:
36 break;
37 }
38 /* NOTREACHED */
39 break;
40 case 1:
41 {
42 /* pexp->operation must be lnot. */
43 unsigned long int arg = plural_eval (pexp->val.args[0], n);
44 return ! arg;
45 }
46 case 2:
47 {
48 unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
49 if (pexp->operation == lor)
50 return leftarg || plural_eval (pexp->val.args[1], n);
51 else if (pexp->operation == land)
52 return leftarg && plural_eval (pexp->val.args[1], n);
53 else
54 {
55 unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
56
57 switch (pexp->operation)
58 {
59 case mult:
60 return leftarg * rightarg;
61 case divide:
62#if !INTDIV0_RAISES_SIGFPE
63 if (rightarg == 0)
64 raise (SIGFPE);
65#endif
66 return leftarg / rightarg;
67 case module:
68#if !INTDIV0_RAISES_SIGFPE
69 if (rightarg == 0)
70 raise (SIGFPE);
71#endif
72 return leftarg % rightarg;
73 case plus:
74 return leftarg + rightarg;
75 case minus:
76 return leftarg - rightarg;
77 case less_than:
78 return leftarg < rightarg;
79 case greater_than:
80 return leftarg > rightarg;
81 case less_or_equal:
82 return leftarg <= rightarg;
83 case greater_or_equal:
84 return leftarg >= rightarg;
85 case equal:
86 return leftarg == rightarg;
87 case not_equal:
88 return leftarg != rightarg;
89 default:
90 break;
91 }
92 }
93 /* NOTREACHED */
94 break;
95 }
96 case 3:
97 {
98 /* pexp->operation must be qmop. */
99 unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
100 return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
101 }
102 }
103 /* NOTREACHED */
104 return 0;
105}
106