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Annotation of src/lib/libusbhid/data.c, Revision 1.3

1.3     ! salo        1: /*     $NetBSD: data.c,v 1.2 2003/03/08 07:45:57 lukem Exp $   */
1.1       augustss    2:
                      3: /*
1.3     ! salo        4:  * Copyright (c) 1999 Lennart Augustsson <augustss@NetBSD.org>
1.1       augustss    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:  */
1.2       lukem      28:
                     29: #include <sys/cdefs.h>
1.3     ! salo       30: __RCSID("$NetBSD: data.c,v 1.2 2003/03/08 07:45:57 lukem Exp $");
1.1       augustss   31:
                     32: #include <assert.h>
                     33: #include <stdlib.h>
                     34: #include "usbhid.h"
                     35:
                     36: int
                     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:        int 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) / 8 - offs;
                     56:        data = 0;
                     57:        for (i = 0; i <= end; i++)
                     58:                data |= buf[offs + i] << (i*8);
                     59:        data >>= hpos % 8;
                     60:        data &= (1 << hsize) - 1;
                     61:        if (h->logical_minimum < 0) {
                     62:                /* Need to sign extend */
                     63:                hsize = sizeof data * 8 - hsize;
                     64:                data = (data << hsize) >> hsize;
                     65:        }
                     66:        return (data);
                     67: }
                     68:
                     69: void
                     70: hid_set_data(void *p, const hid_item_t *h, int data)
                     71: {
                     72:        unsigned char *buf;
                     73:        unsigned int hpos;
                     74:        unsigned int hsize;
                     75:        int i, end, offs, mask;
                     76:
                     77:        _DIAGASSERT(p != NULL);
                     78:        _DIAGASSERT(h != NULL);
                     79:
                     80:        buf = p;
                     81:        hpos = h->pos;                  /* bit position of data */
                     82:        hsize = h->report_size;         /* bit length of data */
                     83:
                     84:        if (hsize != 32) {
                     85:                mask = (1 << hsize) - 1;
                     86:                data &= mask;
                     87:        } else
                     88:                mask = ~0;
                     89:
                     90:        data <<= (hpos % 8);
                     91:        mask <<= (hpos % 8);
                     92:        mask = ~mask;
                     93:
                     94:        offs = hpos / 8;
                     95:        end = (hpos + hsize) / 8 - offs;
                     96:
                     97:        for (i = 0; i <= end; i++)
                     98:                buf[offs + i] = (buf[offs + i] & (mask >> (i*8))) |
                     99:                        ((data >> (i*8)) & 0xff);
                    100: }

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