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 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #include <assert.h> 34 #include <stdlib.h> 35 #include "usbhid.h" 36 37 int32_t 38 hid_get_data(const void *p, const hid_item_t *h) 39 { 40 const uint8_t *buf; 41 uint32_t hpos; 42 uint32_t hsize; 43 uint32_t data; 44 int i, end, offs; 45 46 buf = p; 47 48 /* Skip report ID byte. */ 49 if (h->report_ID > 0) 50 buf++; 51 52 hpos = h->pos; /* bit position of data */ 53 hsize = h->report_size; /* bit length of data */ 54 55 /* Range check and limit */ 56 if (hsize == 0) 57 return (0); 58 if (hsize > 32) 59 hsize = 32; 60 61 offs = hpos / 8; 62 end = (hpos + hsize) / 8 - offs; 63 data = 0; 64 for (i = 0; i <= end; i++) 65 data |= buf[offs + i] << (i*8); 66 67 /* Correctly shift down data */ 68 data >>= hpos % 8; 69 hsize = 32 - hsize; 70 71 /* Mask and sign extend in one */ 72 if ((h->logical_minimum < 0) || (h->logical_maximum < 0)) 73 data = (int32_t)((int32_t)data << hsize) >> hsize; 74 else 75 data = (uint32_t)((uint32_t)data << hsize) >> hsize; 76 77 return (data); 78 } 79 80 void 81 hid_set_data(void *p, const hid_item_t *h, int32_t data) 82 { 83 uint8_t *buf; 84 uint32_t hpos; 85 uint32_t hsize; 86 uint32_t mask; 87 int i; 88 int end; 89 int offs; 90 91 buf = p; 92 93 /* Set report ID byte. */ 94 if (h->report_ID > 0) 95 *buf++ = h->report_ID & 0xff; 96 97 hpos = h->pos; /* bit position of data */ 98 hsize = h->report_size; /* bit length of data */ 99 100 if (hsize != 32) { 101 mask = (1 << hsize) - 1; 102 data &= mask; 103 } else 104 mask = ~0; 105 106 data <<= (hpos % 8); 107 mask <<= (hpos % 8); 108 mask = ~mask; 109 110 offs = hpos / 8; 111 end = (hpos + hsize) / 8 - offs; 112 113 for (i = 0; i <= end; i++) 114 buf[offs + i] = (buf[offs + i] & (mask >> (i*8))) | 115 ((data >> (i*8)) & 0xff); 116 } 117