parse.c revision 67217 
1/*	$NetBSD: parse.c,v 1.11 2000/09/24 02:19:54 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: head/lib/libusbhid/parse.c 67217 2000-10-16 18:13:59Z n_hibma $
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
44struct 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	/* Absolute data position (bits) for input/output/feature.
57           Assumes that hid_input, hid_output and hid_feature have
58           values 0, 1 and 2. */
59        unsigned int kindpos[3];
60};
61
62static int min(int x, int y) { return x < y ? x : y; }
63
64static void
65hid_clear_local(hid_item_t *c)
66{
67	c->usage = 0;
68	c->usage_minimum = 0;
69	c->usage_maximum = 0;
70	c->designator_index = 0;
71	c->designator_minimum = 0;
72	c->designator_maximum = 0;
73	c->string_index = 0;
74	c->string_minimum = 0;
75	c->string_maximum = 0;
76	c->set_delimiter = 0;
77}
78
79hid_data_t
80hid_start_parse(report_desc_t d, int kindset)
81{
82	struct hid_data *s;
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
92void
93hid_end_parse(hid_data_t s)
94{
95	while (s->cur.next) {
96		hid_item_t *hi = s->cur.next->next;
97		free(s->cur.next);
98		s->cur.next = hi;
99	}
100	free(s);
101}
102
103int
104hid_get_item(hid_data_t s, hid_item_t *h)
105{
106	hid_item_t *c;
107	unsigned int bTag = 0, bType = 0, bSize;
108	unsigned char *data;
109	int dval;
110	unsigned char *p;
111	hid_item_t *hi;
112	int i;
113	hid_kind_t retkind;
114
115	c = &s->cur;
116
117 top:
118	if (s->multimax) {
119		if (s->multi < s->multimax) {
120			c->usage = s->usages[min(s->multi, s->nusage-1)];
121			s->multi++;
122			*h = *c;
123
124			/* 'multimax' is only non-zero if the current
125                           item kind is input/output/feature */
126			h->pos = s->kindpos[c->kind];
127			s->kindpos[c->kind] += c->report_size;
128			h->next = 0;
129			return (1);
130		} else {
131			c->report_count = s->multimax;
132			s->multimax = 0;
133			s->nusage = 0;
134			hid_clear_local(c);
135		}
136	}
137	for (;;) {
138		p = s->p;
139		if (p >= s->end)
140			return (0);
141
142		bSize = *p++;
143		if (bSize == 0xfe) {
144			/* long item */
145			bSize = *p++;
146			bSize |= *p++ << 8;
147			bTag = *p++;
148			data = p;
149			p += bSize;
150		} else {
151			/* short item */
152			bTag = bSize >> 4;
153			bType = (bSize >> 2) & 3;
154			bSize &= 3;
155			if (bSize == 3) bSize = 4;
156			data = p;
157			p += bSize;
158		}
159		s->p = p;
160		/*
161		 * The spec is unclear if the data is signed or unsigned.
162		 */
163		switch(bSize) {
164		case 0:
165			dval = 0;
166			break;
167		case 1:
168			dval = (int8_t)*data++;
169			break;
170		case 2:
171			dval = *data++;
172			dval |= *data++ << 8;
173			dval = (int16_t)dval;
174			break;
175		case 4:
176			dval = *data++;
177			dval |= *data++ << 8;
178			dval |= *data++ << 16;
179			dval |= *data++ << 24;
180			break;
181		default:
182			return (-1);
183		}
184
185		switch (bType) {
186		case 0:			/* Main */
187			switch (bTag) {
188			case 8:		/* Input */
189				retkind = hid_input;
190			ret:
191				if (!(s->kindset & (1 << retkind))) {
192					/* Drop the items of this kind */
193					s->nusage = 0;
194					continue;
195				}
196				c->kind = retkind;
197				c->flags = dval;
198				if (c->flags & HIO_VARIABLE) {
199					s->multimax = c->report_count;
200					s->multi = 0;
201					c->report_count = 1;
202					if (s->minset) {
203						for (i = c->usage_minimum;
204						     i <= c->usage_maximum;
205						     i++) {
206							s->usages[s->nusage] = i;
207							if (s->nusage < MAXUSAGE-1)
208								s->nusage++;
209						}
210						s->minset = 0;
211					}
212					goto top;
213				} else {
214					if (s->minset)
215						c->usage = c->usage_minimum;
216					*h = *c;
217					h->next = 0;
218					h->pos = s->kindpos[c->kind];
219					s->kindpos[c->kind] += c->report_size * c->report_count;
220					hid_clear_local(c);
221					s->minset = 0;
222					return (1);
223				}
224			case 9:		/* Output */
225				retkind = hid_output;
226				goto ret;
227			case 10:	/* Collection */
228				c->kind = hid_collection;
229				c->collection = dval;
230				c->collevel++;
231				*h = *c;
232				hid_clear_local(c);
233				c->report_ID = NO_REPORT_ID;
234				s->nusage = 0;
235				return (1);
236			case 11:	/* Feature */
237				retkind = hid_feature;
238				goto ret;
239			case 12:	/* End collection */
240				c->kind = hid_endcollection;
241				c->collevel--;
242				*h = *c;
243				/*hid_clear_local(c);*/
244				s->nusage = 0;
245				return (1);
246			default:
247				return (-2);
248			}
249
250		case 1:		/* Global */
251			switch (bTag) {
252			case 0:
253				c->_usage_page = dval << 16;
254				break;
255			case 1:
256				c->logical_minimum = dval;
257				break;
258			case 2:
259				c->logical_maximum = dval;
260				break;
261			case 3:
262				c->physical_maximum = dval;
263				break;
264			case 4:
265				c->physical_maximum = dval;
266				break;
267			case 5:
268				c->unit_exponent = dval;
269				break;
270			case 6:
271				c->unit = dval;
272				break;
273			case 7:
274				c->report_size = dval;
275				break;
276			case 8:
277				c->report_ID = dval;
278				break;
279			case 9:
280				c->report_count = dval;
281				break;
282			case 10: /* Push */
283				hi = malloc(sizeof *hi);
284				*hi = s->cur;
285				c->next = hi;
286				break;
287			case 11: /* Pop */
288				hi = c->next;
289				s->cur = *hi;
290				free(hi);
291				break;
292			default:
293				return (-3);
294			}
295			break;
296		case 2:		/* Local */
297			switch (bTag) {
298			case 0:
299				if (bSize == 1)
300					dval = c->_usage_page | (dval&0xff);
301				else if (bSize == 2)
302					dval = c->_usage_page | (dval&0xffff);
303				c->usage = dval;
304				if (s->nusage < MAXUSAGE)
305					s->usages[s->nusage++] = dval;
306				/* else XXX */
307				break;
308			case 1:
309				s->minset = 1;
310				if (bSize == 1)
311					dval = c->_usage_page | (dval&0xff);
312				else if (bSize == 2)
313					dval = c->_usage_page | (dval&0xffff);
314				c->usage_minimum = dval;
315				break;
316			case 2:
317				if (bSize == 1)
318					dval = c->_usage_page | (dval&0xff);
319				else if (bSize == 2)
320					dval = c->_usage_page | (dval&0xffff);
321				c->usage_maximum = dval;
322				break;
323			case 3:
324				c->designator_index = dval;
325				break;
326			case 4:
327				c->designator_minimum = dval;
328				break;
329			case 5:
330				c->designator_maximum = dval;
331				break;
332			case 7:
333				c->string_index = dval;
334				break;
335			case 8:
336				c->string_minimum = dval;
337				break;
338			case 9:
339				c->string_maximum = dval;
340				break;
341			case 10:
342				c->set_delimiter = dval;
343				break;
344			default:
345				return (-4);
346			}
347			break;
348		default:
349			return (-5);
350		}
351	}
352}
353
354int
355hid_report_size(report_desc_t r, unsigned int id, enum hid_kind k)
356{
357	struct hid_data *d;
358	hid_item_t h;
359	unsigned int size = 0;
360
361	memset(&h, 0, sizeof h);
362	d = hid_start_parse(r, 1<<k);
363	while (hid_get_item(d, &h)) {
364		if (h.report_ID == id && h.kind == k) {
365			unsigned int newsize = h.pos + h.report_size;
366			if (newsize > size)
367			    size = newsize;
368		}
369	}
370	hid_end_parse(d);
371
372	if (id != NO_REPORT_ID)
373		size += 8;		/* add 8 bits for the report ID */
374
375	return ((size + 7) / 8);	/* return size in bytes */
376}
377
378int
379hid_locate(report_desc_t desc, unsigned int u, enum hid_kind k, hid_item_t *h)
380{
381	hid_data_t d;
382
383	for (d = hid_start_parse(desc, 1<<k); hid_get_item(d, h); ) {
384		if (h->kind == k && !(h->flags & HIO_CONST) && h->usage == u) {
385			hid_end_parse(d);
386			return (1);
387		}
388	}
389	hid_end_parse(d);
390	h->report_size = 0;
391	return (0);
392}
393