xref: /freebsd/lib/libusbhid/parse.c (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
1 /*	$NetBSD: parse.c,v 1.9 2000/03/17 18:09:17 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 
32 #include <assert.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <sys/time.h>
36 
37 #include <dev/usb/usb.h>
38 #include <dev/usb/usbhid.h>
39 
40 #include "libusb.h"
41 #include "usbvar.h"
42 
43 #define MAXUSAGE 100
44 struct hid_data {
45 	u_char *start;
46 	u_char *end;
47 	u_char *p;
48 	hid_item_t cur;
49 	unsigned int usages[MAXUSAGE];
50 	int nusage;
51 	int minset;
52 	int multi;
53 	int multimax;
54 	int kindset;
55 };
56 
57 static int min(int x, int y) { return x < y ? x : y; }
58 
59 static void
60 hid_clear_local(hid_item_t *c)
61 {
62 
63 	_DIAGASSERT(c != NULL);
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;
81 
82 	_DIAGASSERT(d != NULL);
83 
84 	s = malloc(sizeof *s);
85 	memset(s, 0, sizeof *s);
86 	s->start = s->p = d->data;
87 	s->end = d->data + d->size;
88 	s->kindset = kindset;
89 	return (s);
90 }
91 
92 void
93 hid_end_parse(hid_data_t s)
94 {
95 
96 	_DIAGASSERT(s != NULL);
97 
98 	while (s->cur.next) {
99 		hid_item_t *hi = s->cur.next->next;
100 		free(s->cur.next);
101 		s->cur.next = hi;
102 	}
103 	free(s);
104 }
105 
106 int
107 hid_get_item(hid_data_t s, hid_item_t *h)
108 {
109 	hid_item_t *c;
110 	unsigned int bTag = 0, bType = 0, bSize, oldpos;
111 	unsigned char *data;
112 	int dval;
113 	unsigned char *p;
114 	hid_item_t *hi;
115 	int i;
116 
117 	_DIAGASSERT(s != NULL);
118 	_DIAGASSERT(h != NULL);
119 
120 	c = &s->cur;
121 
122  top:
123 	if (s->multimax) {
124 		if (s->multi < s->multimax) {
125 			c->usage = s->usages[min(s->multi, s->nusage-1)];
126 			s->multi++;
127 			*h = *c;
128 			c->pos += c->report_size;
129 			h->next = 0;
130 			return (1);
131 		} else {
132 			c->report_count = s->multimax;
133 			s->multimax = 0;
134 			s->nusage = 0;
135 			hid_clear_local(c);
136 		}
137 	}
138 	for (;;) {
139 		p = s->p;
140 		if (p >= s->end)
141 			return (0);
142 
143 		bSize = *p++;
144 		if (bSize == 0xfe) {
145 			/* long item */
146 			bSize = *p++;
147 			bSize |= *p++ << 8;
148 			bTag = *p++;
149 			data = p;
150 			p += bSize;
151 		} else {
152 			/* short item */
153 			bTag = bSize >> 4;
154 			bType = (bSize >> 2) & 3;
155 			bSize &= 3;
156 			if (bSize == 3) bSize = 4;
157 			data = p;
158 			p += bSize;
159 		}
160 		s->p = p;
161 		/*
162 		 * The spec is unclear if the data is signed or unsigned.
163 		 */
164 		switch(bSize) {
165 		case 0:
166 			dval = 0;
167 			break;
168 		case 1:
169 			dval = (int8_t)*data++;
170 			break;
171 		case 2:
172 			dval = *data++;
173 			dval |= *data++ << 8;
174 			dval = (int16_t)dval;
175 			break;
176 		case 4:
177 			dval = *data++;
178 			dval |= *data++ << 8;
179 			dval |= *data++ << 16;
180 			dval |= *data++ << 24;
181 			break;
182 		default:
183 			return (-1);
184 		}
185 
186 		switch (bType) {
187 		case 0:			/* Main */
188 			switch (bTag) {
189 			case 8:		/* Input */
190 				if (!(s->kindset & (1 << hid_input)))
191 					continue;
192 				c->kind = hid_input;
193 				c->flags = dval;
194 			ret:
195 				if (c->flags & HIO_VARIABLE) {
196 					s->multimax = c->report_count;
197 					s->multi = 0;
198 					c->report_count = 1;
199 					if (s->minset) {
200 						for (i = c->usage_minimum;
201 						     i <= c->usage_maximum;
202 						     i++) {
203 							s->usages[s->nusage] = i;
204 							if (s->nusage < MAXUSAGE-1)
205 								s->nusage++;
206 						}
207 						s->minset = 0;
208 					}
209 					goto top;
210 				} else {
211 					if (s->minset)
212 						c->usage = c->usage_minimum;
213 					*h = *c;
214 					h->next = 0;
215 					c->pos += c->report_size * c->report_count;
216 					hid_clear_local(c);
217 					s->minset = 0;
218 					return (1);
219 				}
220 			case 9:		/* Output */
221 				if (!(s->kindset & (1 << hid_output)))
222 					continue;
223 				c->kind = hid_output;
224 				c->flags = dval;
225 				goto ret;
226 			case 10:	/* Collection */
227 				c->kind = hid_collection;
228 				c->collection = dval;
229 				c->collevel++;
230 				*h = *c;
231 				hid_clear_local(c);
232 				c->report_ID = NO_REPORT_ID;
233 				s->nusage = 0;
234 				return (1);
235 			case 11:	/* Feature */
236 				if (!(s->kindset & (1 << hid_feature)))
237 					continue;
238 				c->kind = hid_feature;
239 				c->flags = dval;
240 				goto ret;
241 			case 12:	/* End collection */
242 				c->kind = hid_endcollection;
243 				c->collevel--;
244 				*h = *c;
245 				/*hid_clear_local(c);*/
246 				s->nusage = 0;
247 				return (1);
248 			default:
249 				return (-2);
250 			}
251 
252 		case 1:		/* Global */
253 			switch (bTag) {
254 			case 0:
255 				c->_usage_page = dval << 16;
256 				break;
257 			case 1:
258 				c->logical_minimum = dval;
259 				break;
260 			case 2:
261 				c->logical_maximum = dval;
262 				break;
263 			case 3:
264 				c->physical_maximum = dval;
265 				break;
266 			case 4:
267 				c->physical_maximum = dval;
268 				break;
269 			case 5:
270 				c->unit_exponent = dval;
271 				break;
272 			case 6:
273 				c->unit = dval;
274 				break;
275 			case 7:
276 				c->report_size = dval;
277 				break;
278 			case 8:
279 				c->report_ID = dval;
280 				break;
281 			case 9:
282 				c->report_count = dval;
283 				break;
284 			case 10: /* Push */
285 				hi = malloc(sizeof *hi);
286 				*hi = s->cur;
287 				c->next = hi;
288 				break;
289 			case 11: /* Pop */
290 				hi = c->next;
291 				oldpos = c->pos;
292 				s->cur = *hi;
293 				c->pos = oldpos;
294 				free(hi);
295 				break;
296 			default:
297 				return (-3);
298 			}
299 			break;
300 		case 2:		/* Local */
301 			switch (bTag) {
302 			case 0:
303 				if (bSize == 1)
304 					dval = c->_usage_page | (dval&0xff);
305 				else if (bSize == 2)
306 					dval = c->_usage_page | (dval&0xffff);
307 				c->usage = dval;
308 				if (s->nusage < MAXUSAGE)
309 					s->usages[s->nusage++] = dval;
310 				/* else XXX */
311 				break;
312 			case 1:
313 				s->minset = 1;
314 				if (bSize == 1)
315 					dval = c->_usage_page | (dval&0xff);
316 				else if (bSize == 2)
317 					dval = c->_usage_page | (dval&0xffff);
318 				c->usage_minimum = dval;
319 				break;
320 			case 2:
321 				if (bSize == 1)
322 					dval = c->_usage_page | (dval&0xff);
323 				else if (bSize == 2)
324 					dval = c->_usage_page | (dval&0xffff);
325 				c->usage_maximum = dval;
326 				break;
327 			case 3:
328 				c->designator_index = dval;
329 				break;
330 			case 4:
331 				c->designator_minimum = dval;
332 				break;
333 			case 5:
334 				c->designator_maximum = dval;
335 				break;
336 			case 7:
337 				c->string_index = dval;
338 				break;
339 			case 8:
340 				c->string_minimum = dval;
341 				break;
342 			case 9:
343 				c->string_maximum = dval;
344 				break;
345 			case 10:
346 				c->set_delimiter = dval;
347 				break;
348 			default:
349 				return (-4);
350 			}
351 			break;
352 		default:
353 			return (-5);
354 		}
355 	}
356 }
357 
358 int
359 hid_report_size(report_desc_t r, enum hid_kind k, int *idp)
360 {
361 	struct hid_data *d;
362 	hid_item_t h;
363 	int size, id;
364 
365 	_DIAGASSERT(r != NULL);
366 	/* idp may be NULL */
367 
368 	id = 0;
369 	if (idp)
370 		*idp = 0;
371 	memset(&h, 0, sizeof h);
372 	for (d = hid_start_parse(r, 1<<k); hid_get_item(d, &h); ) {
373 		if (h.report_ID != NO_REPORT_ID) {
374 			if (idp)
375 				*idp = h.report_ID;
376 			id = 8;
377 		}
378 	}
379 	hid_end_parse(d);
380 	size = h.pos + id;
381 	return ((size + 7) / 8);
382 }
383 
384 int
385 hid_locate(desc, u, k, h)
386 	report_desc_t desc;
387 	unsigned int u;
388 	enum hid_kind k;
389 	hid_item_t *h;
390 {
391 	hid_data_t d;
392 
393 	_DIAGASSERT(desc != NULL);
394 	_DIAGASSERT(h != NULL);
395 
396 	for (d = hid_start_parse(desc, 1<<k); hid_get_item(d, h); ) {
397 		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
398 			hid_end_parse(d);
399 			return (1);
400 		}
401 	}
402 	hid_end_parse(d);
403 	h->report_size = 0;
404 	return (0);
405 }
406