1/* Plural expression evaluation.
2 Copyright (C) 2000-2017 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 <http://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
24internal_function
25plural_eval (const struct expression *pexp, unsigned long int n)
26{
27 switch (pexp->nargs)
28 {
29 case 0:
30 switch (pexp->operation)
31 {
32 case var:
33 return n;
34 case num:
35 return pexp->val.num;
36 default:
37 break;
38 }
39 /* NOTREACHED */
40 break;
41 case 1:
42 {
43 /* pexp->operation must be lnot. */
44 unsigned long int arg = plural_eval (pexp->val.args[0], n);
45 return ! arg;
46 }
47 case 2:
48 {
49 unsigned long int leftarg = plural_eval (pexp->val.args[0], n);
50 if (pexp->operation == lor)
51 return leftarg || plural_eval (pexp->val.args[1], n);
52 else if (pexp->operation == land)
53 return leftarg && plural_eval (pexp->val.args[1], n);
54 else
55 {
56 unsigned long int rightarg = plural_eval (pexp->val.args[1], n);
57
58 switch (pexp->operation)
59 {
60 case mult:
61 return leftarg * rightarg;
62 case divide:
63#if !INTDIV0_RAISES_SIGFPE
64 if (rightarg == 0)
65 raise (SIGFPE);
66#endif
67 return leftarg / rightarg;
68 case module:
69#if !INTDIV0_RAISES_SIGFPE
70 if (rightarg == 0)
71 raise (SIGFPE);
72#endif
73 return leftarg % rightarg;
74 case plus:
75 return leftarg + rightarg;
76 case minus:
77 return leftarg - rightarg;
78 case less_than:
79 return leftarg < rightarg;
80 case greater_than:
81 return leftarg > rightarg;
82 case less_or_equal:
83 return leftarg <= rightarg;
84 case greater_or_equal:
85 return leftarg >= rightarg;
86 case equal:
87 return leftarg == rightarg;
88 case not_equal:
89 return leftarg != rightarg;
90 default:
91 break;
92 }
93 }
94 /* NOTREACHED */
95 break;
96 }
97 case 3:
98 {
99 /* pexp->operation must be qmop. */
100 unsigned long int boolarg = plural_eval (pexp->val.args[0], n);
101 return plural_eval (pexp->val.args[boolarg ? 1 : 2], n);
102 }
103 }
104 /* NOTREACHED */
105 return 0;
106}
107