1 /* $NetBSD: data.c,v 1.9 2020/04/04 21:21:35 fox Exp $ */
2
3 /*
4 * Copyright (c) 1999 Lennart Augustsson <augustss@NetBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __RCSID("$NetBSD: data.c,v 1.9 2020/04/04 21:21:35 fox Exp $");
31
32 #include <assert.h>
33 #include <stdlib.h>
34 #include "usbhid.h"
35
36 int
hid_get_data(const void * p,const hid_item_t * h)37 hid_get_data(const void *p, const hid_item_t *h)
38 {
39 const unsigned char *buf;
40 unsigned int hpos;
41 unsigned int hsize;
42 uint32_t data;
43 int i, end, offs;
44
45 _DIAGASSERT(p != NULL);
46 _DIAGASSERT(h != NULL);
47
48 buf = p;
49 hpos = h->pos; /* bit position of data */
50 hsize = h->report_size; /* bit length of data */
51
52 if (hsize == 0)
53 return (0);
54 offs = hpos / 8;
55 end = (hpos + hsize + 7) / 8 - offs;
56 data = 0;
57 for (i = 0; i < end; i++)
58 data |= ((uint32_t)buf[offs + i]) << (i*8);
59 data >>= hpos % 8;
60 if (hsize < 32) {
61 data &= (1 << hsize) - 1;
62 if (h->logical_minimum < 0 && (data & (1<<(hsize-1)))) {
63 /* Need to sign extend */
64 data |= 0xffffffff & ~((1<<hsize)-1);
65 }
66 }
67 return (int)(data);
68 }
69
70 void
hid_set_data(void * p,const hid_item_t * h,int data)71 hid_set_data(void *p, const hid_item_t *h, int data)
72 {
73 unsigned char *buf;
74 unsigned int hpos;
75 unsigned int hsize;
76 int i, end, offs, mask;
77
78 _DIAGASSERT(p != NULL);
79 _DIAGASSERT(h != NULL);
80
81 buf = p;
82 hpos = h->pos; /* bit position of data */
83 hsize = h->report_size; /* bit length of data */
84
85 if (hsize != 32) {
86 mask = (1 << hsize) - 1;
87 data &= mask;
88 } else
89 mask = ~0;
90
91 data = ((uint32_t)data) << (hpos % 8);
92 mask = ((uint32_t)mask) << (hpos % 8);
93 mask = ~mask;
94
95 offs = hpos / 8;
96 end = (hpos + hsize) / 8 - offs;
97
98 for (i = 0; i < end; i++)
99 buf[offs + i] = (buf[offs + i] & ((uint32_t)mask >> (i*8))) |
100 (((uint32_t)data >> (i*8)) & 0xff);
101 }
102