1 /* $NetBSD: data.c,v 1.3 2003/07/26 19:25:08 salo 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 1.3 2003/07/26 19:25:08 salo Exp $"); 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 } 101