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lwbasic: Added basic character input framework
author lost@l-w.ca
date Sat, 22 Jan 2011 21:13:09 -0700
parents
children 87590f43e76d
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22:7c35fa8dbc91 23:25a4aef9c5ed
1 /*
2 input.c
3
4 Copyright © 2011 William Astle
5
6 This file is part of LWTOOLS.
7
8 LWTOOLS is free software: you can redistribute it and/or modify it under the
9 terms of the GNU General Public License as published by the Free Software
10 Foundation, either version 3 of the License, or (at your option) any later
11 version.
12
13 This program is distributed in the hope that it will be useful, but WITHOUT
14 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
16 more details.
17
18 You should have received a copy of the GNU General Public License along with
19 this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 /*
23 handle reading input for the rest of the system
24 */
25
26 #include <stdlib.h>
27 #include <stdio.h>
28 #include <string.h>
29
30 #include <lw_alloc.h>
31
32 #define __input_c_seen__
33 #include "lwbasic.h"
34
35 struct input_state
36 {
37 FILE *fp;
38 int error;
39 };
40
41 static void input_init(cstate *state)
42 {
43 struct input_state *sp;
44
45 sp = lw_alloc(sizeof(struct input_state));
46 sp -> error = 0;
47
48 if (!(state -> input_file) || strcmp(state -> input_file, "-"))
49 {
50 sp -> fp = stdin;
51 }
52 else
53 {
54 sp -> fp = fopen(state -> input_file, "rb");
55 if (!(sp -> fp))
56 {
57 fprintf(stderr, "Cannot open input file\n");
58 exit(1);
59 }
60 }
61
62 state -> input_state = sp;
63 }
64
65 int input_getchar(cstate *state)
66 {
67 int r;
68 struct input_state *sp;
69
70 if (!(state -> input_state))
71 input_init(state);
72 sp = state -> input_state;
73
74
75 if (sp -> error)
76 return -2;
77
78 if (feof(sp -> fp))
79 return -1;
80
81 r = fgetc(sp -> fp);
82 if (r == EOF)
83 return -1;
84 return r;
85 }