xref: /openbsd-src/lib/libusbhid/data.c (revision 5c77300749d0759783325d774c5cb9745fc7f602)
1*5c773007Smpi /*	$OpenBSD: data.c,v 1.8 2014/06/04 12:13:30 mpi Exp $	*/
27517eab2Snate /*	$NetBSD: data.c,v 1.1 2001/12/28 17:45:26 augustss Exp $	*/
3be8f1931Spvalchev 
4be8f1931Spvalchev /*
5be8f1931Spvalchev  * Copyright (c) 1999 Lennart Augustsson <augustss@netbsd.org>
6be8f1931Spvalchev  * All rights reserved.
7be8f1931Spvalchev  *
8be8f1931Spvalchev  * Redistribution and use in source and binary forms, with or without
9be8f1931Spvalchev  * modification, are permitted provided that the following conditions
10be8f1931Spvalchev  * are met:
11be8f1931Spvalchev  * 1. Redistributions of source code must retain the above copyright
12be8f1931Spvalchev  *    notice, this list of conditions and the following disclaimer.
13be8f1931Spvalchev  * 2. Redistributions in binary form must reproduce the above copyright
14be8f1931Spvalchev  *    notice, this list of conditions and the following disclaimer in the
15be8f1931Spvalchev  *    documentation and/or other materials provided with the distribution.
16be8f1931Spvalchev  *
17be8f1931Spvalchev  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18be8f1931Spvalchev  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19be8f1931Spvalchev  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20be8f1931Spvalchev  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21be8f1931Spvalchev  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22be8f1931Spvalchev  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23be8f1931Spvalchev  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24be8f1931Spvalchev  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25be8f1931Spvalchev  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26be8f1931Spvalchev  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27be8f1931Spvalchev  * SUCH DAMAGE.
28be8f1931Spvalchev  */
29be8f1931Spvalchev 
30be8f1931Spvalchev #include <stdlib.h>
31be8f1931Spvalchev #include "usbhid.h"
32be8f1931Spvalchev 
33b3eedbb4Smpi int32_t
hid_get_data(const void * p,const hid_item_t * h)34be8f1931Spvalchev hid_get_data(const void *p, const hid_item_t *h)
35be8f1931Spvalchev {
36b3eedbb4Smpi 	const uint8_t *buf;
37b3eedbb4Smpi 	uint32_t hpos;
38b3eedbb4Smpi 	uint32_t hsize;
39b3eedbb4Smpi 	uint32_t data;
40b3eedbb4Smpi 	int i, end, offs;
41be8f1931Spvalchev 
42b3eedbb4Smpi 	buf = p;
43b3eedbb4Smpi 
44*5c773007Smpi #if 0
45b3eedbb4Smpi 	/* Skip report ID byte. */
46b3eedbb4Smpi 	if (h->report_ID > 0)
47b3eedbb4Smpi 		buf++;
48*5c773007Smpi #endif
49b3eedbb4Smpi 
50b3eedbb4Smpi 	hpos = h->pos;			/* bit position of data */
51b3eedbb4Smpi 	hsize = h->report_size;		/* bit length of data */
52b3eedbb4Smpi 
53b3eedbb4Smpi 	/* Range check and limit */
54be8f1931Spvalchev 	if (hsize == 0)
55be8f1931Spvalchev 		return (0);
56b3eedbb4Smpi 	if (hsize > 32)
57b3eedbb4Smpi 		hsize = 32;
58b3eedbb4Smpi 
59be8f1931Spvalchev 	offs = hpos / 8;
60be8f1931Spvalchev 	end = (hpos + hsize) / 8 - offs;
61be8f1931Spvalchev 	data = 0;
62be8f1931Spvalchev 	for (i = 0; i <= end; i++)
63be8f1931Spvalchev 		data |= buf[offs + i] << (i*8);
64b3eedbb4Smpi 
65b3eedbb4Smpi 	/* Correctly shift down data */
66be8f1931Spvalchev 	data >>= hpos % 8;
67b3eedbb4Smpi 	hsize = 32 - hsize;
68b3eedbb4Smpi 
69b3eedbb4Smpi 	/* Mask and sign extend in one */
70b3eedbb4Smpi 	if ((h->logical_minimum < 0) || (h->logical_maximum < 0))
71b3eedbb4Smpi 		data = (int32_t)((int32_t)data << hsize) >> hsize;
72b3eedbb4Smpi 	else
73b3eedbb4Smpi 		data = (uint32_t)((uint32_t)data << hsize) >> hsize;
74b3eedbb4Smpi 
75be8f1931Spvalchev 	return (data);
76be8f1931Spvalchev }
77be8f1931Spvalchev 
78be8f1931Spvalchev void
hid_set_data(void * p,const hid_item_t * h,int32_t data)79b3eedbb4Smpi hid_set_data(void *p, const hid_item_t *h, int32_t data)
80be8f1931Spvalchev {
81b3eedbb4Smpi 	uint8_t *buf;
82b3eedbb4Smpi 	uint32_t hpos;
83b3eedbb4Smpi 	uint32_t hsize;
84b3eedbb4Smpi 	uint32_t mask;
85b3eedbb4Smpi 	int i;
86b3eedbb4Smpi 	int end;
87b3eedbb4Smpi 	int offs;
88b3eedbb4Smpi 
89b3eedbb4Smpi 	buf = p;
90b3eedbb4Smpi 
91*5c773007Smpi #if 0
92b3eedbb4Smpi 	/* Set report ID byte. */
93b3eedbb4Smpi 	if (h->report_ID > 0)
94b3eedbb4Smpi 		*buf++ = h->report_ID & 0xff;
95*5c773007Smpi #endif
96b3eedbb4Smpi 
97b3eedbb4Smpi 	hpos = h->pos;			/* bit position of data */
98b3eedbb4Smpi 	hsize = h->report_size;		/* bit length of data */
99be8f1931Spvalchev 
100be8f1931Spvalchev 	if (hsize != 32) {
101be8f1931Spvalchev 		mask = (1 << hsize) - 1;
102be8f1931Spvalchev 		data &= mask;
103be8f1931Spvalchev 	} else
104be8f1931Spvalchev 		mask = ~0;
105be8f1931Spvalchev 
106be8f1931Spvalchev 	data <<= (hpos % 8);
107be8f1931Spvalchev 	mask <<= (hpos % 8);
108be8f1931Spvalchev 	mask = ~mask;
109be8f1931Spvalchev 
110be8f1931Spvalchev 	offs = hpos / 8;
111be8f1931Spvalchev 	end = (hpos + hsize) / 8 - offs;
112be8f1931Spvalchev 
113be8f1931Spvalchev 	for (i = 0; i <= end; i++)
114be8f1931Spvalchev 		buf[offs + i] = (buf[offs + i] & (mask >> (i*8))) |
115be8f1931Spvalchev 		    ((data >> (i*8)) & 0xff);
116be8f1931Spvalchev }
117