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/* $OpenBSD: data.c,v 1.8 2014/06/04 12:13:30 mpi Exp $ */
/* $NetBSD: data.c,v 1.1 2001/12/28 17:45:26 augustss Exp $ */
/*
* Copyright (c) 1999 Lennart Augustsson <augustss@netbsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdlib.h>
#include "usbhid.h"
int32_t
hid_get_data(const void *p, const hid_item_t *h)
{
const uint8_t *buf;
uint32_t hpos;
uint32_t hsize;
uint32_t data;
int i, end, offs;
buf = p;
#if 0
/* Skip report ID byte. */
if (h->report_ID > 0)
buf++;
#endif
hpos = h->pos; /* bit position of data */
hsize = h->report_size; /* bit length of data */
/* Range check and limit */
if (hsize == 0)
return (0);
if (hsize > 32)
hsize = 32;
offs = hpos / 8;
end = (hpos + hsize) / 8 - offs;
data = 0;
for (i = 0; i <= end; i++)
data |= buf[offs + i] << (i*8);
/* Correctly shift down data */
data >>= hpos % 8;
hsize = 32 - hsize;
/* Mask and sign extend in one */
if ((h->logical_minimum < 0) || (h->logical_maximum < 0))
data = (int32_t)((int32_t)data << hsize) >> hsize;
else
data = (uint32_t)((uint32_t)data << hsize) >> hsize;
return (data);
}
void
hid_set_data(void *p, const hid_item_t *h, int32_t data)
{
uint8_t *buf;
uint32_t hpos;
uint32_t hsize;
uint32_t mask;
int i;
int end;
int offs;
buf = p;
#if 0
/* Set report ID byte. */
if (h->report_ID > 0)
*buf++ = h->report_ID & 0xff;
#endif
hpos = h->pos; /* bit position of data */
hsize = h->report_size; /* bit length of data */
if (hsize != 32) {
mask = (1 << hsize) - 1;
data &= mask;
} else
mask = ~0;
data <<= (hpos % 8);
mask <<= (hpos % 8);
mask = ~mask;
offs = hpos / 8;
end = (hpos + hsize) / 8 - offs;
for (i = 0; i <= end; i++)
buf[offs + i] = (buf[offs + i] & (mask >> (i*8))) |
((data >> (i*8)) & 0xff);
}
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