1 /* $NetBSD: data.c,v 1.8 2000/04/02 11:10:53 augustss 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 * $FreeBSD$ 29 */ 30 31 #include <assert.h> 32 #include <stdlib.h> 33 #include "libusb.h" 34 35 int 36 hid_get_data(const void *p, const hid_item_t *h) 37 { 38 const unsigned char *buf; 39 unsigned int hpos; 40 unsigned int hsize; 41 int data; 42 int i, end, offs; 43 44 buf = p; 45 hpos = h->pos; /* bit position of data */ 46 hsize = h->report_size; /* bit length of data */ 47 48 if (hsize == 0) 49 return (0); 50 offs = hpos / 8; 51 end = (hpos + hsize) / 8 - offs; 52 data = 0; 53 for (i = 0; i <= end; i++) 54 data |= buf[offs + i] << (i*8); 55 data >>= hpos % 8; 56 data &= (1 << hsize) - 1; 57 if (h->logical_minimum < 0) { 58 /* Need to sign extend */ 59 hsize = sizeof data * 8 - hsize; 60 data = (data << hsize) >> hsize; 61 } 62 return (data); 63 } 64 65 void 66 hid_set_data(void *p, const hid_item_t *h, int data) 67 { 68 unsigned char *buf; 69 unsigned int hpos; 70 unsigned int hsize; 71 int i, end, offs, mask; 72 73 buf = p; 74 hpos = h->pos; /* bit position of data */ 75 hsize = h->report_size; /* bit length of data */ 76 77 if (hsize != 32) { 78 mask = (1 << hsize) - 1; 79 data &= mask; 80 } else 81 mask = ~0; 82 83 data <<= (hpos % 8); 84 mask <<= (hpos % 8); 85 mask = ~mask; 86 87 offs = hpos / 8; 88 end = (hpos + hsize) / 8 - offs; 89 90 for (i = 0; i <= end; i++) 91 buf[offs + i] = (buf[offs + i] & (mask >> (i*8))) | 92 ((data >> (i*8)) & 0xff); 93 } 94