1 /* $OpenBSD: data.c,v 1.8 2014/06/04 12:13:30 mpi Exp $ */ 2 /* $NetBSD: data.c,v 1.1 2001/12/28 17:45:26 augustss Exp $ */ 3 4 /* 5 * Copyright (c) 1999 Lennart Augustsson <augustss@netbsd.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <stdlib.h> 31 #include "usbhid.h" 32 33 int32_t 34 hid_get_data(const void *p, const hid_item_t *h) 35 { 36 const uint8_t *buf; 37 uint32_t hpos; 38 uint32_t hsize; 39 uint32_t data; 40 int i, end, offs; 41 42 buf = p; 43 44 #if 0 45 /* Skip report ID byte. */ 46 if (h->report_ID > 0) 47 buf++; 48 #endif 49 50 hpos = h->pos; /* bit position of data */ 51 hsize = h->report_size; /* bit length of data */ 52 53 /* Range check and limit */ 54 if (hsize == 0) 55 return (0); 56 if (hsize > 32) 57 hsize = 32; 58 59 offs = hpos / 8; 60 end = (hpos + hsize) / 8 - offs; 61 data = 0; 62 for (i = 0; i <= end; i++) 63 data |= buf[offs + i] << (i*8); 64 65 /* Correctly shift down data */ 66 data >>= hpos % 8; 67 hsize = 32 - hsize; 68 69 /* Mask and sign extend in one */ 70 if ((h->logical_minimum < 0) || (h->logical_maximum < 0)) 71 data = (int32_t)((int32_t)data << hsize) >> hsize; 72 else 73 data = (uint32_t)((uint32_t)data << hsize) >> hsize; 74 75 return (data); 76 } 77 78 void 79 hid_set_data(void *p, const hid_item_t *h, int32_t data) 80 { 81 uint8_t *buf; 82 uint32_t hpos; 83 uint32_t hsize; 84 uint32_t mask; 85 int i; 86 int end; 87 int offs; 88 89 buf = p; 90 91 #if 0 92 /* Set report ID byte. */ 93 if (h->report_ID > 0) 94 *buf++ = h->report_ID & 0xff; 95 #endif 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