parse.c revision 205728 
1/*	$NetBSD: parse.c,v 1.11 2000/09/24 02:19:54 augustss Exp $	*/
2
3/*
4 * Copyright (c) 1999, 2001 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: head/lib/libusbhid/parse.c 205728 2010-03-27 08:00:16Z kaiw $");
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 "usbhid.h"
41#include "usbvar.h"
42
43#define	MAXUSAGE 100
44#define	MAXPUSH 4
45#define	MAXID 64
46
47struct hid_pos_data {
48	int32_t rid;
49	uint32_t pos;
50};
51
52struct hid_data {
53	const uint8_t *start;
54	const uint8_t *end;
55	const uint8_t *p;
56	struct hid_item cur[MAXPUSH];
57	struct hid_pos_data last_pos[MAXID];
58	int32_t usages_min[MAXUSAGE];
59	int32_t usages_max[MAXUSAGE];
60	int32_t usage_last;	/* last seen usage */
61	uint32_t loc_size;	/* last seen size */
62	uint32_t loc_count;	/* last seen count */
63	uint8_t	kindset;	/* we have 5 kinds so 8 bits are enough */
64	uint8_t	pushlevel;	/* current pushlevel */
65	uint8_t	ncount;		/* end usage item count */
66	uint8_t icount;		/* current usage item count */
67	uint8_t	nusage;		/* end "usages_min/max" index */
68	uint8_t	iusage;		/* current "usages_min/max" index */
69	uint8_t ousage;		/* current "usages_min/max" offset */
70	uint8_t	susage;		/* usage set flags */
71};
72
73/*------------------------------------------------------------------------*
74 *	hid_clear_local
75 *------------------------------------------------------------------------*/
76static void
77hid_clear_local(hid_item_t *c)
78{
79
80	c->usage = 0;
81	c->usage_minimum = 0;
82	c->usage_maximum = 0;
83	c->designator_index = 0;
84	c->designator_minimum = 0;
85	c->designator_maximum = 0;
86	c->string_index = 0;
87	c->string_minimum = 0;
88	c->string_maximum = 0;
89	c->set_delimiter = 0;
90}
91
92static void
93hid_switch_rid(struct hid_data *s, struct hid_item *c, int32_t next_rID)
94{
95	uint8_t i;
96
97	/* check for same report ID - optimise */
98
99	if (c->report_ID == next_rID)
100		return;
101
102	/* save current position for current rID */
103
104	if (c->report_ID == 0) {
105		i = 0;
106	} else {
107		for (i = 1; i != MAXID; i++) {
108			if (s->last_pos[i].rid == c->report_ID)
109				break;
110			if (s->last_pos[i].rid == 0)
111				break;
112		}
113	}
114	if (i != MAXID) {
115		s->last_pos[i].rid = c->report_ID;
116		s->last_pos[i].pos = c->pos;
117	}
118
119	/* store next report ID */
120
121	c->report_ID = next_rID;
122
123	/* lookup last position for next rID */
124
125	if (next_rID == 0) {
126		i = 0;
127	} else {
128		for (i = 1; i != MAXID; i++) {
129			if (s->last_pos[i].rid == next_rID)
130				break;
131			if (s->last_pos[i].rid == 0)
132				break;
133		}
134	}
135	if (i != MAXID) {
136		s->last_pos[i].rid = next_rID;
137		c->pos = s->last_pos[i].pos;
138	} else
139		c->pos = 0;	/* Out of RID entries. */
140}
141
142/*------------------------------------------------------------------------*
143 *	hid_start_parse
144 *------------------------------------------------------------------------*/
145hid_data_t
146hid_start_parse(report_desc_t d, int kindset, int id __unused)
147{
148	struct hid_data *s;
149
150	s = malloc(sizeof *s);
151	memset(s, 0, sizeof *s);
152	s->start = s->p = d->data;
153	s->end = d->data + d->size;
154	s->kindset = kindset;
155	return (s);
156}
157
158/*------------------------------------------------------------------------*
159 *	hid_end_parse
160 *------------------------------------------------------------------------*/
161void
162hid_end_parse(hid_data_t s)
163{
164
165	if (s == NULL)
166		return;
167
168	free(s);
169}
170
171/*------------------------------------------------------------------------*
172 *	get byte from HID descriptor
173 *------------------------------------------------------------------------*/
174static uint8_t
175hid_get_byte(struct hid_data *s, const uint16_t wSize)
176{
177	const uint8_t *ptr;
178	uint8_t retval;
179
180	ptr = s->p;
181
182	/* check if end is reached */
183	if (ptr == s->end)
184		return (0);
185
186	/* read out a byte */
187	retval = *ptr;
188
189	/* check if data pointer can be advanced by "wSize" bytes */
190	if ((s->end - ptr) < wSize)
191		ptr = s->end;
192	else
193		ptr += wSize;
194
195	/* update pointer */
196	s->p = ptr;
197
198	return (retval);
199}
200
201/*------------------------------------------------------------------------*
202 *	hid_get_item
203 *------------------------------------------------------------------------*/
204int
205hid_get_item(hid_data_t s, hid_item_t *h)
206{
207	hid_item_t *c;
208	unsigned int bTag, bType, bSize;
209	uint32_t oldpos;
210	int32_t mask;
211	int32_t dval;
212
213	if (s == NULL)
214		return (0);
215
216	c = &s->cur[s->pushlevel];
217
218 top:
219	/* check if there is an array of items */
220	if (s->icount < s->ncount) {
221		/* get current usage */
222		if (s->iusage < s->nusage) {
223			dval = s->usages_min[s->iusage] + s->ousage;
224			c->usage = dval;
225			s->usage_last = dval;
226			if (dval == s->usages_max[s->iusage]) {
227				s->iusage ++;
228				s->ousage = 0;
229			} else {
230				s->ousage ++;
231			}
232		} else {
233			/* Using last usage */
234			dval = s->usage_last;
235		}
236		s->icount ++;
237		/*
238		 * Only copy HID item, increment position and return
239		 * if correct kindset!
240		 */
241		if (s->kindset & (1 << c->kind)) {
242			*h = *c;
243			c->pos += c->report_size * c->report_count;
244			return (1);
245		}
246	}
247
248	/* reset state variables */
249	s->icount = 0;
250	s->ncount = 0;
251	s->iusage = 0;
252	s->nusage = 0;
253	s->susage = 0;
254	s->ousage = 0;
255	hid_clear_local(c);
256
257	/* get next item */
258	while (s->p != s->end) {
259
260		bSize = hid_get_byte(s, 1);
261		if (bSize == 0xfe) {
262			/* long item */
263			bSize = hid_get_byte(s, 1);
264			bSize |= hid_get_byte(s, 1) << 8;
265			bTag = hid_get_byte(s, 1);
266			bType = 0xff;	/* XXX what should it be */
267		} else {
268			/* short item */
269			bTag = bSize >> 4;
270			bType = (bSize >> 2) & 3;
271			bSize &= 3;
272			if (bSize == 3)
273				bSize = 4;
274		}
275
276		switch(bSize) {
277		case 0:
278			dval = 0;
279			mask = 0;
280			break;
281		case 1:
282			dval = (int8_t)hid_get_byte(s, 1);
283			mask = 0xFF;
284			break;
285		case 2:
286			dval = hid_get_byte(s, 1);
287			dval |= hid_get_byte(s, 1) << 8;
288			dval = (int16_t)dval;
289			mask = 0xFFFF;
290			break;
291		case 4:
292			dval = hid_get_byte(s, 1);
293			dval |= hid_get_byte(s, 1) << 8;
294			dval |= hid_get_byte(s, 1) << 16;
295			dval |= hid_get_byte(s, 1) << 24;
296			mask = 0xFFFFFFFF;
297			break;
298		default:
299			dval = hid_get_byte(s, bSize);
300			continue;
301		}
302
303		switch (bType) {
304		case 0:		/* Main */
305			switch (bTag) {
306			case 8:	/* Input */
307				c->kind = hid_input;
308				c->flags = dval;
309		ret:
310				c->report_count = s->loc_count;
311				c->report_size = s->loc_size;
312
313				if (c->flags & HIO_VARIABLE) {
314					/* range check usage count */
315					if (c->report_count > 255) {
316						s->ncount = 255;
317					} else
318						s->ncount = c->report_count;
319
320					/*
321					 * The "top" loop will return
322					 * one and one item:
323					 */
324					c->report_count = 1;
325				} else {
326					s->ncount = 1;
327				}
328				goto top;
329
330			case 9:	/* Output */
331				c->kind = hid_output;
332				c->flags = dval;
333				goto ret;
334			case 10:	/* Collection */
335				c->kind = hid_collection;
336				c->collection = dval;
337				c->collevel++;
338				c->usage = s->usage_last;
339				*h = *c;
340				return (1);
341			case 11:	/* Feature */
342				c->kind = hid_feature;
343				c->flags = dval;
344				goto ret;
345			case 12:	/* End collection */
346				c->kind = hid_endcollection;
347				if (c->collevel == 0) {
348					/* Invalid end collection. */
349					return (0);
350				}
351				c->collevel--;
352				*h = *c;
353				return (1);
354			default:
355				break;
356			}
357			break;
358
359		case 1:		/* Global */
360			switch (bTag) {
361			case 0:
362				c->_usage_page = dval << 16;
363				break;
364			case 1:
365				c->logical_minimum = dval;
366				break;
367			case 2:
368				c->logical_maximum = dval;
369				break;
370			case 3:
371				c->physical_minimum = dval;
372				break;
373			case 4:
374				c->physical_maximum = dval;
375				break;
376			case 5:
377				c->unit_exponent = dval;
378				break;
379			case 6:
380				c->unit = dval;
381				break;
382			case 7:
383				/* mask because value is unsigned */
384				s->loc_size = dval & mask;
385				break;
386			case 8:
387				hid_switch_rid(s, c, dval);
388				break;
389			case 9:
390				/* mask because value is unsigned */
391				s->loc_count = dval & mask;
392				break;
393			case 10:	/* Push */
394				s->pushlevel ++;
395				if (s->pushlevel < MAXPUSH) {
396					s->cur[s->pushlevel] = *c;
397					/* store size and count */
398					c->report_size = s->loc_size;
399					c->report_count = s->loc_count;
400					/* update current item pointer */
401					c = &s->cur[s->pushlevel];
402				}
403				break;
404			case 11:	/* Pop */
405				s->pushlevel --;
406				if (s->pushlevel < MAXPUSH) {
407					/* preserve position */
408					oldpos = c->pos;
409					c = &s->cur[s->pushlevel];
410					/* restore size and count */
411					s->loc_size = c->report_size;
412					s->loc_count = c->report_count;
413					/* set default item location */
414					c->pos = oldpos;
415					c->report_size = 0;
416					c->report_count = 0;
417				}
418				break;
419			default:
420				break;
421			}
422			break;
423		case 2:		/* Local */
424			switch (bTag) {
425			case 0:
426				if (bSize != 4)
427					dval = (dval & mask) | c->_usage_page;
428
429				/* set last usage, in case of a collection */
430				s->usage_last = dval;
431
432				if (s->nusage < MAXUSAGE) {
433					s->usages_min[s->nusage] = dval;
434					s->usages_max[s->nusage] = dval;
435					s->nusage ++;
436				}
437				/* else XXX */
438
439				/* clear any pending usage sets */
440				s->susage = 0;
441				break;
442			case 1:
443				s->susage |= 1;
444
445				if (bSize != 4)
446					dval = (dval & mask) | c->_usage_page;
447				c->usage_minimum = dval;
448
449				goto check_set;
450			case 2:
451				s->susage |= 2;
452
453				if (bSize != 4)
454					dval = (dval & mask) | c->_usage_page;
455				c->usage_maximum = dval;
456
457			check_set:
458				if (s->susage != 3)
459					break;
460
461				/* sanity check */
462				if ((s->nusage < MAXUSAGE) &&
463				    (c->usage_minimum <= c->usage_maximum)) {
464					/* add usage range */
465					s->usages_min[s->nusage] =
466					    c->usage_minimum;
467					s->usages_max[s->nusage] =
468					    c->usage_maximum;
469					s->nusage ++;
470				}
471				/* else XXX */
472
473				s->susage = 0;
474				break;
475			case 3:
476				c->designator_index = dval;
477				break;
478			case 4:
479				c->designator_minimum = dval;
480				break;
481			case 5:
482				c->designator_maximum = dval;
483				break;
484			case 7:
485				c->string_index = dval;
486				break;
487			case 8:
488				c->string_minimum = dval;
489				break;
490			case 9:
491				c->string_maximum = dval;
492				break;
493			case 10:
494				c->set_delimiter = dval;
495				break;
496			default:
497				break;
498			}
499			break;
500		default:
501			break;
502		}
503	}
504	return (0);
505}
506
507int
508hid_report_size(report_desc_t r, enum hid_kind k, int id)
509{
510	struct hid_data *d;
511	struct hid_item h;
512	uint32_t temp;
513	uint32_t hpos;
514	uint32_t lpos;
515
516	hpos = 0;
517	lpos = 0xFFFFFFFF;
518
519	memset(&h, 0, sizeof h);
520	for (d = hid_start_parse(r, 1 << k, id); hid_get_item(d, &h); ) {
521		if (h.report_ID == id && h.kind == k) {
522			/* compute minimum */
523			if (lpos > h.pos)
524				lpos = h.pos;
525			/* compute end position */
526			temp = h.pos + (h.report_size * h.report_count);
527			/* compute maximum */
528			if (hpos < temp)
529				hpos = temp;
530		}
531	}
532	hid_end_parse(d);
533
534	/* safety check - can happen in case of currupt descriptors */
535	if (lpos > hpos)
536		temp = 0;
537	else
538		temp = hpos - lpos;
539
540	if (id)
541		temp += 8;
542
543	/* return length in bytes rounded up */
544	return ((temp + 7) / 8);
545}
546
547int
548hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k,
549	   hid_item_t *h, int id)
550{
551	struct hid_data *d;
552
553	for (d = hid_start_parse(desc, 1 << k, id); hid_get_item(d, h); ) {
554		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
555			hid_end_parse(d);
556			return (1);
557		}
558	}
559	hid_end_parse(d);
560	h->report_size = 0;
561	return (0);
562}
563