xref: /openbsd-src/lib/libusbhid/parse.c (revision 3a3fbb3f2e2521ab7c4a56b7ff7462ebd9095ec5)
1 /*	$OpenBSD: parse.c,v 1.1 2001/12/30 07:04:38 pvalchev Exp $	*/
2 /*	$NetBSD: parse.c,v 1.11 2000/09/24 02:19:54 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 <string.h>
32 #include <sys/time.h>
33 
34 #include <dev/usb/usb.h>
35 #include <dev/usb/usbhid.h>
36 
37 #include "usbhid.h"
38 #include "usbvar.h"
39 
40 #define MAXUSAGE 100
41 struct hid_data {
42 	u_char *start;
43 	u_char *end;
44 	u_char *p;
45 	hid_item_t cur;
46 	unsigned int usages[MAXUSAGE];
47 	int nusage;
48 	int minset;
49 	int multi;
50 	int multimax;
51 	int kindset;
52 
53 	/* Absolute data position (bits) for input/output/feature.
54            Assumes that hid_input, hid_output and hid_feature have
55            values 0, 1 and 2. */
56         unsigned int kindpos[3];
57 };
58 
59 static int min(int x, int y) { return x < y ? x : y; }
60 
61 static void
62 hid_clear_local(hid_item_t *c)
63 {
64 
65 	c->usage = 0;
66 	c->usage_minimum = 0;
67 	c->usage_maximum = 0;
68 	c->designator_index = 0;
69 	c->designator_minimum = 0;
70 	c->designator_maximum = 0;
71 	c->string_index = 0;
72 	c->string_minimum = 0;
73 	c->string_maximum = 0;
74 	c->set_delimiter = 0;
75 }
76 
77 hid_data_t
78 hid_start_parse(report_desc_t d, int kindset)
79 {
80 	struct hid_data *s = malloc(sizeof *s);
81 
82 	memset(s, 0, sizeof *s);
83 	s->start = s->p = d->data;
84 	s->end = d->data + d->size;
85 	s->kindset = kindset;
86 	return (s);
87 }
88 
89 void
90 hid_end_parse(hid_data_t s)
91 {
92 
93 	while (s->cur.next) {
94 		hid_item_t *hi = s->cur.next->next;
95 		free(s->cur.next);
96 		s->cur.next = hi;
97 	}
98 	free(s);
99 }
100 
101 int
102 hid_get_item(hid_data_t s, hid_item_t *h)
103 {
104 	hid_item_t *c;
105 	unsigned int bTag = 0, bType = 0, bSize;
106 	unsigned char *data;
107 	int dval;
108 	unsigned char *p;
109 	hid_item_t *hi;
110 	int i;
111 	hid_kind_t retkind;
112 
113 	c = &s->cur;
114 
115  top:
116 	if (s->multimax) {
117 		if (s->multi < s->multimax) {
118 			c->usage = s->usages[min(s->multi, s->nusage-1)];
119 			s->multi++;
120 			*h = *c;
121 
122 			/* 'multimax' is only non-zero if the current
123                            item kind is input/output/feature */
124 			h->pos = s->kindpos[c->kind];
125 			s->kindpos[c->kind] += c->report_size;
126 			h->next = 0;
127 			return (1);
128 		} else {
129 			c->report_count = s->multimax;
130 			s->multimax = 0;
131 			s->nusage = 0;
132 			hid_clear_local(c);
133 		}
134 	}
135 	for (;;) {
136 		p = s->p;
137 		if (p >= s->end)
138 			return (0);
139 
140 		bSize = *p++;
141 		if (bSize == 0xfe) {
142 			/* long item */
143 			bSize = *p++;
144 			bSize |= *p++ << 8;
145 			bTag = *p++;
146 			data = p;
147 			p += bSize;
148 		} else {
149 			/* short item */
150 			bTag = bSize >> 4;
151 			bType = (bSize >> 2) & 3;
152 			bSize &= 3;
153 			if (bSize == 3) bSize = 4;
154 			data = p;
155 			p += bSize;
156 		}
157 		s->p = p;
158 		/*
159 		 * The spec is unclear if the data is signed or unsigned.
160 		 */
161 		switch(bSize) {
162 		case 0:
163 			dval = 0;
164 			break;
165 		case 1:
166 			dval = (int8_t)*data++;
167 			break;
168 		case 2:
169 			dval = *data++;
170 			dval |= *data++ << 8;
171 			dval = (int16_t)dval;
172 			break;
173 		case 4:
174 			dval = *data++;
175 			dval |= *data++ << 8;
176 			dval |= *data++ << 16;
177 			dval |= *data++ << 24;
178 			break;
179 		default:
180 			return (-1);
181 		}
182 
183 		switch (bType) {
184 		case 0:			/* Main */
185 			switch (bTag) {
186 			case 8:		/* Input */
187 				retkind = hid_input;
188 			ret:
189 				if (!(s->kindset & (1 << retkind))) {
190 					/* Drop the items of this kind */
191 					s->nusage = 0;
192 					continue;
193 				}
194 				c->kind = retkind;
195 				c->flags = dval;
196 				if (c->flags & HIO_VARIABLE) {
197 					s->multimax = c->report_count;
198 					s->multi = 0;
199 					c->report_count = 1;
200 					if (s->minset) {
201 						for (i = c->usage_minimum;
202 						     i <= c->usage_maximum;
203 						     i++) {
204 							s->usages[s->nusage] = i;
205 							if (s->nusage < MAXUSAGE-1)
206 								s->nusage++;
207 						}
208 						s->minset = 0;
209 					}
210 					goto top;
211 				} else {
212 					if (s->minset)
213 						c->usage = c->usage_minimum;
214 					*h = *c;
215 					h->next = 0;
216 					h->pos = s->kindpos[c->kind];
217 					s->kindpos[c->kind] += c->report_size * c->report_count;
218 					hid_clear_local(c);
219 					s->minset = 0;
220 					return (1);
221 				}
222 			case 9:		/* Output */
223 				retkind = hid_output;
224 				goto ret;
225 			case 10:	/* Collection */
226 				c->kind = hid_collection;
227 				c->collection = dval;
228 				c->collevel++;
229 				*h = *c;
230 				hid_clear_local(c);
231 				c->report_ID = NO_REPORT_ID;
232 				s->nusage = 0;
233 				return (1);
234 			case 11:	/* Feature */
235 				retkind = hid_feature;
236 				goto ret;
237 			case 12:	/* End collection */
238 				c->kind = hid_endcollection;
239 				c->collevel--;
240 				*h = *c;
241 				/*hid_clear_local(c);*/
242 				s->nusage = 0;
243 				return (1);
244 			default:
245 				return (-2);
246 			}
247 
248 		case 1:		/* Global */
249 			switch (bTag) {
250 			case 0:
251 				c->_usage_page = dval << 16;
252 				break;
253 			case 1:
254 				c->logical_minimum = dval;
255 				break;
256 			case 2:
257 				c->logical_maximum = dval;
258 				break;
259 			case 3:
260 				c->physical_maximum = dval;
261 				break;
262 			case 4:
263 				c->physical_maximum = dval;
264 				break;
265 			case 5:
266 				c->unit_exponent = dval;
267 				break;
268 			case 6:
269 				c->unit = dval;
270 				break;
271 			case 7:
272 				c->report_size = dval;
273 				break;
274 			case 8:
275 				c->report_ID = dval;
276 				break;
277 			case 9:
278 				c->report_count = dval;
279 				break;
280 			case 10: /* Push */
281 				hi = malloc(sizeof *hi);
282 				*hi = s->cur;
283 				c->next = hi;
284 				break;
285 			case 11: /* Pop */
286 				hi = c->next;
287 				s->cur = *hi;
288 				free(hi);
289 				break;
290 			default:
291 				return (-3);
292 			}
293 			break;
294 		case 2:		/* Local */
295 			switch (bTag) {
296 			case 0:
297 				if (bSize == 1)
298 					dval = c->_usage_page | (dval&0xff);
299 				else if (bSize == 2)
300 					dval = c->_usage_page | (dval&0xffff);
301 				c->usage = dval;
302 				if (s->nusage < MAXUSAGE)
303 					s->usages[s->nusage++] = dval;
304 				/* else XXX */
305 				break;
306 			case 1:
307 				s->minset = 1;
308 				if (bSize == 1)
309 					dval = c->_usage_page | (dval&0xff);
310 				else if (bSize == 2)
311 					dval = c->_usage_page | (dval&0xffff);
312 				c->usage_minimum = dval;
313 				break;
314 			case 2:
315 				if (bSize == 1)
316 					dval = c->_usage_page | (dval&0xff);
317 				else if (bSize == 2)
318 					dval = c->_usage_page | (dval&0xffff);
319 				c->usage_maximum = dval;
320 				break;
321 			case 3:
322 				c->designator_index = dval;
323 				break;
324 			case 4:
325 				c->designator_minimum = dval;
326 				break;
327 			case 5:
328 				c->designator_maximum = dval;
329 				break;
330 			case 7:
331 				c->string_index = dval;
332 				break;
333 			case 8:
334 				c->string_minimum = dval;
335 				break;
336 			case 9:
337 				c->string_maximum = dval;
338 				break;
339 			case 10:
340 				c->set_delimiter = dval;
341 				break;
342 			default:
343 				return (-4);
344 			}
345 			break;
346 		default:
347 			return (-5);
348 		}
349 	}
350 }
351 
352 int
353 hid_report_size(report_desc_t r, enum hid_kind k, int *idp)
354 {
355 	struct hid_data *d;
356 	hid_item_t h;
357 	int size, id;
358 
359 	id = 0;
360 	if (idp)
361 		*idp = 0;
362 	memset(&h, 0, sizeof h);
363 	for (d = hid_start_parse(r, 1<<k); hid_get_item(d, &h); ) {
364 		if (h.report_ID != NO_REPORT_ID) {
365 			if (idp)
366 				*idp = h.report_ID;
367 			id = 8;
368 		}
369 	}
370 
371 	size = d->kindpos[k] + id;
372 	hid_end_parse(d);
373 	return ((size + 7) / 8);
374 }
375 
376 int
377 hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k, hid_item_t *h)
378 {
379 	hid_data_t d;
380 
381 	for (d = hid_start_parse(desc, 1<<k); hid_get_item(d, h); ) {
382 		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
383 			hid_end_parse(d);
384 			return (1);
385 		}
386 	}
387 	hid_end_parse(d);
388 	h->report_size = 0;
389 	return (0);
390 }
391