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ftpd(8): Remove weird line with just '#'.
[dragonfly.git] / lib / libusb / libusb20_desc.c
blob583ede47c88131e2d8947c4c2325505af963fcd0
1 /* $FreeBSD: head/lib/libusb/libusb20_desc.c 248236 2013-03-13 12:23:14Z hselasky $ */
2 /*-
3 * Copyright (c) 2008 Hans Petter Selasky. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #ifdef LIBUSB_GLOBAL_INCLUDE_FILE
28 #include LIBUSB_GLOBAL_INCLUDE_FILE
29 #else
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <time.h>
34 #include <sys/queue.h>
35 #endif
36
37 #include "libusb20.h"
38 #include "libusb20_desc.h"
39 #include "libusb20_int.h"
40
41 static const uint32_t libusb20_me_encode_empty[2]; /* dummy */
42
43 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_DEVICE_DESC);
44 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_ENDPOINT_DESC);
45 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_INTERFACE_DESC);
46 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_CONFIG_DESC);
47 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_CONTROL_SETUP);
48 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_SS_ENDPT_COMP_DESC);
49 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_USB_20_DEVCAP_DESC);
50 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_SS_USB_DEVCAP_DESC);
51 LIBUSB20_MAKE_STRUCT_FORMAT(LIBUSB20_BOS_DESCRIPTOR);
52
53 /*------------------------------------------------------------------------*
54 * libusb20_parse_config_desc
55 *
56 * Return values:
57 * NULL: Out of memory.
58 * Else: A valid config structure pointer which must be passed to "free()"
59 *------------------------------------------------------------------------*/
60 struct libusb20_config *
61 libusb20_parse_config_desc(const void *config_desc)
62 {
63 struct libusb20_config *lub_config;
64 struct libusb20_interface *lub_interface;
65 struct libusb20_interface *lub_alt_interface;
66 struct libusb20_interface *last_if;
67 struct libusb20_endpoint *lub_endpoint;
68 struct libusb20_endpoint *last_ep;
69
70 struct libusb20_me_struct pcdesc;
71 const uint8_t *ptr;
72 uint32_t size;
73 uint16_t niface_no_alt;
74 uint16_t niface;
75 uint16_t nendpoint;
76 uint16_t iface_no;
77
78 ptr = config_desc;
79 if (ptr[1] != LIBUSB20_DT_CONFIG) {
80 return (NULL); /* not config descriptor */
81 }
82 /*
83 * The first "bInterfaceNumber" should never have the value 0xff.
84 * Then it is corrupt.
85 */
86 niface_no_alt = 0;
87 nendpoint = 0;
88 niface = 0;
89 iface_no = 0xFFFF;
90 ptr = NULL;
91
92 /* get "wTotalLength" and setup "pcdesc" */
93 pcdesc.ptr = LIBUSB20_ADD_BYTES(config_desc, 0);
94 pcdesc.len =
95 ((const uint8_t *)config_desc)[2] |
96 (((const uint8_t *)config_desc)[3] << 8);
97 pcdesc.type = LIBUSB20_ME_IS_RAW;
98
99 /* descriptor pre-scan */
100 while ((ptr = libusb20_desc_foreach(&pcdesc, ptr))) {
101 if (ptr[1] == LIBUSB20_DT_ENDPOINT) {
102 nendpoint++;
103 } else if ((ptr[1] == LIBUSB20_DT_INTERFACE) && (ptr[0] >= 4)) {
104 niface++;
105 /* check "bInterfaceNumber" */
106 if (ptr[2] != iface_no) {
107 iface_no = ptr[2];
108 niface_no_alt++;
109 }
110 }
111 }
112
113 /* sanity checking */
114 if (niface >= 256) {
115 return (NULL); /* corrupt */
116 }
117 if (nendpoint >= 256) {
118 return (NULL); /* corrupt */
119 }
120 size = sizeof(*lub_config) +
121 (niface * sizeof(*lub_interface)) +
122 (nendpoint * sizeof(*lub_endpoint)) +
123 pcdesc.len;
124
125 lub_config = malloc(size);
126 if (lub_config == NULL) {
127 return (NULL); /* out of memory */
128 }
129 /* make sure memory is initialised */
130 memset(lub_config, 0, size);
131
132 lub_interface = (void *)(lub_config + 1);
133 lub_alt_interface = (void *)(lub_interface + niface_no_alt);
134 lub_endpoint = (void *)(lub_interface + niface);
135
136 /*
137 * Make a copy of the config descriptor, so that the caller can free
138 * the inital config descriptor pointer!
139 */
140 ptr = (void *)(lub_endpoint + nendpoint);
141 memcpy(LIBUSB20_ADD_BYTES(ptr, 0), config_desc, pcdesc.len);
142 pcdesc.ptr = LIBUSB20_ADD_BYTES(ptr, 0);
143 config_desc = LIBUSB20_ADD_BYTES(ptr, 0);
144
145 /* init config structure */
146
147 ptr = config_desc;
148
149 LIBUSB20_INIT(LIBUSB20_CONFIG_DESC, &lub_config->desc);
150
151 if (libusb20_me_decode(ptr, ptr[0], &lub_config->desc)) {
152 /* ignore */
153 }
154 lub_config->num_interface = 0;
155 lub_config->interface = lub_interface;
156 lub_config->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
157 lub_config->extra.len = -ptr[0];
158 lub_config->extra.type = LIBUSB20_ME_IS_RAW;
159
160 /* reset states */
161 niface = 0;
162 iface_no = 0xFFFF;
163 ptr = NULL;
164 lub_interface--;
165 lub_endpoint--;
166 last_if = NULL;
167 last_ep = NULL;
168
169 /* descriptor pre-scan */
170 while ((ptr = libusb20_desc_foreach(&pcdesc, ptr))) {
171 if (ptr[1] == LIBUSB20_DT_ENDPOINT) {
172 if (last_if) {
173 lub_endpoint++;
174 last_ep = lub_endpoint;
175 last_if->num_endpoints++;
176
177 LIBUSB20_INIT(LIBUSB20_ENDPOINT_DESC, &last_ep->desc);
178
179 if (libusb20_me_decode(ptr, ptr[0], &last_ep->desc)) {
180 /* ignore */
181 }
182 last_ep->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
183 last_ep->extra.len = 0;
184 last_ep->extra.type = LIBUSB20_ME_IS_RAW;
185 } else {
186 lub_config->extra.len += ptr[0];
187 }
188
189 } else if ((ptr[1] == LIBUSB20_DT_INTERFACE) && (ptr[0] >= 4)) {
190 if (ptr[2] != iface_no) {
191 /* new interface */
192 iface_no = ptr[2];
193 lub_interface++;
194 lub_config->num_interface++;
195 last_if = lub_interface;
196 niface++;
197 } else {
198 /* one more alternate setting */
199 lub_interface->num_altsetting++;
200 last_if = lub_alt_interface;
201 lub_alt_interface++;
202 }
203
204 LIBUSB20_INIT(LIBUSB20_INTERFACE_DESC, &last_if->desc);
205
206 if (libusb20_me_decode(ptr, ptr[0], &last_if->desc)) {
207 /* ignore */
208 }
209 /*
210 * Sometimes USB devices have corrupt interface
211 * descriptors and we need to overwrite the provided
212 * interface number!
213 */
214 last_if->desc.bInterfaceNumber = niface - 1;
215 last_if->extra.ptr = LIBUSB20_ADD_BYTES(ptr, ptr[0]);
216 last_if->extra.len = 0;
217 last_if->extra.type = LIBUSB20_ME_IS_RAW;
218 last_if->endpoints = lub_endpoint + 1;
219 last_if->altsetting = lub_alt_interface;
220 last_if->num_altsetting = 0;
221 last_if->num_endpoints = 0;
222 last_ep = NULL;
223 } else {
224 /* unknown descriptor */
225 if (last_if) {
226 if (last_ep) {
227 last_ep->extra.len += ptr[0];
228 } else {
229 last_if->extra.len += ptr[0];
230 }
231 } else {
232 lub_config->extra.len += ptr[0];
233 }
234 }
235 }
236 return (lub_config);
237 }
238
239 /*------------------------------------------------------------------------*
240 * libusb20_desc_foreach
241 *
242 * Safe traversal of USB descriptors.
243 *
244 * Return values:
245 * NULL: End of descriptors
246 * Else: Pointer to next descriptor
247 *------------------------------------------------------------------------*/
248 const uint8_t *
249 libusb20_desc_foreach(const struct libusb20_me_struct *pdesc,
250 const uint8_t *psubdesc)
251 {
252 const uint8_t *start;
253 const uint8_t *end;
254 const uint8_t *desc_next;
255
256 /* be NULL safe */
257 if (pdesc == NULL)
258 return (NULL);
259
260 start = (const uint8_t *)pdesc->ptr;
261 end = LIBUSB20_ADD_BYTES(start, pdesc->len);
262
263 /* get start of next descriptor */
264 if (psubdesc == NULL)
265 psubdesc = start;
266 else
267 psubdesc = psubdesc + psubdesc[0];
268
269 /* check that the next USB descriptor is within the range */
270 if ((psubdesc < start) || (psubdesc >= end))
271 return (NULL); /* out of range, or EOD */
272
273 /* check start of the second next USB descriptor, if any */
274 desc_next = psubdesc + psubdesc[0];
275 if ((desc_next < start) || (desc_next > end))
276 return (NULL); /* out of range */
277
278 /* check minimum descriptor length */
279 if (psubdesc[0] < 3)
280 return (NULL); /* too short descriptor */
281
282 return (psubdesc); /* return start of next descriptor */
283 }
284
285 /*------------------------------------------------------------------------*
286 * libusb20_me_get_1 - safety wrapper to read out one byte
287 *------------------------------------------------------------------------*/
288 uint8_t
289 libusb20_me_get_1(const struct libusb20_me_struct *ie, uint16_t offset)
290 {
291 if (offset < ie->len) {
292 return (*((uint8_t *)LIBUSB20_ADD_BYTES(ie->ptr, offset)));
293 }
294 return (0);
295 }
296
297 /*------------------------------------------------------------------------*
298 * libusb20_me_get_2 - safety wrapper to read out one word
299 *------------------------------------------------------------------------*/
300 uint16_t
301 libusb20_me_get_2(const struct libusb20_me_struct *ie, uint16_t offset)
302 {
303 return (libusb20_me_get_1(ie, offset) |
304 (libusb20_me_get_1(ie, offset + 1) << 8));
305 }
306
307 /*------------------------------------------------------------------------*
308 * libusb20_me_encode - encode a message structure
309 *
310 * Description of parameters:
311 * "len" - maximum length of output buffer
312 * "ptr" - pointer to output buffer. If NULL, no data will be written
313 * "pd" - source structure
314 *
315 * Return values:
316 * 0..65535 - Number of bytes used, limited by the "len" input parameter.
317 *------------------------------------------------------------------------*/
318 uint16_t
319 libusb20_me_encode(void *ptr, uint16_t len, const void *pd)
320 {
321 const uint8_t *pf; /* pointer to format data */
322 uint8_t *buf; /* pointer to output buffer */
323
324 uint32_t pd_offset; /* decoded structure offset */
325 uint16_t len_old; /* old length */
326 uint16_t pd_count; /* decoded element count */
327 uint8_t me; /* message element */
328
329 /* initialise */
330
331 len_old = len;
332 buf = ptr;
333 pd_offset = sizeof(void *);
334 pf = (*((struct libusb20_me_format *const *)pd))->format;
335
336 /* scan */
337
338 while (1) {
339
340 /* get information element */
341
342 me = (pf[0]) & LIBUSB20_ME_MASK;
343 pd_count = pf[1] | (pf[2] << 8);
344 pf += 3;
345
346 /* encode the message element */
347
348 switch (me) {
349 case LIBUSB20_ME_INT8:
350 while (pd_count--) {
351 uint8_t temp;
352
353 if (len < 1) /* overflow */
354 goto done;
355 if (buf) {
356 temp = *((const uint8_t *)
357 LIBUSB20_ADD_BYTES(pd, pd_offset));
358 buf[0] = temp;
359 buf += 1;
360 }
361 pd_offset += 1;
362 len -= 1;
363 }
364 break;
365
366 case LIBUSB20_ME_INT16:
367 pd_offset = -((-pd_offset) & ~1); /* align */
368 while (pd_count--) {
369 uint16_t temp;
370
371 if (len < 2) /* overflow */
372 goto done;
373
374 if (buf) {
375 temp = *((const uint16_t *)
376 LIBUSB20_ADD_BYTES(pd, pd_offset));
377 buf[1] = (temp >> 8) & 0xFF;
378 buf[0] = temp & 0xFF;
379 buf += 2;
380 }
381 pd_offset += 2;
382 len -= 2;
383 }
384 break;
385
386 case LIBUSB20_ME_INT32:
387 pd_offset = -((-pd_offset) & ~3); /* align */
388 while (pd_count--) {
389 uint32_t temp;
390
391 if (len < 4) /* overflow */
392 goto done;
393 if (buf) {
394 temp = *((const uint32_t *)
395 LIBUSB20_ADD_BYTES(pd, pd_offset));
396 buf[3] = (temp >> 24) & 0xFF;
397 buf[2] = (temp >> 16) & 0xFF;
398 buf[1] = (temp >> 8) & 0xFF;
399 buf[0] = temp & 0xFF;
400 buf += 4;
401 }
402 pd_offset += 4;
403 len -= 4;
404 }
405 break;
406
407 case LIBUSB20_ME_INT64:
408 pd_offset = -((-pd_offset) & ~7); /* align */
409 while (pd_count--) {
410 uint64_t temp;
411
412 if (len < 8) /* overflow */
413 goto done;
414 if (buf) {
415
416 temp = *((const uint64_t *)
417 LIBUSB20_ADD_BYTES(pd, pd_offset));
418 buf[7] = (temp >> 56) & 0xFF;
419 buf[6] = (temp >> 48) & 0xFF;
420 buf[5] = (temp >> 40) & 0xFF;
421 buf[4] = (temp >> 32) & 0xFF;
422 buf[3] = (temp >> 24) & 0xFF;
423 buf[2] = (temp >> 16) & 0xFF;
424 buf[1] = (temp >> 8) & 0xFF;
425 buf[0] = temp & 0xFF;
426 buf += 8;
427 }
428 pd_offset += 8;
429 len -= 8;
430 }
431 break;
432
433 case LIBUSB20_ME_STRUCT:
434 pd_offset = -((-pd_offset) &
435 ~(LIBUSB20_ME_STRUCT_ALIGN - 1)); /* align */
436 while (pd_count--) {
437 void *src_ptr;
438 uint16_t src_len;
439 struct libusb20_me_struct *ps;
440
441 ps = LIBUSB20_ADD_BYTES(pd, pd_offset);
442
443 switch (ps->type) {
444 case LIBUSB20_ME_IS_RAW:
445 src_len = ps->len;
446 src_ptr = ps->ptr;
447 break;
448
449 case LIBUSB20_ME_IS_ENCODED:
450 if (ps->len == 0) {
451 /*
452 * Length is encoded
453 * in the data itself
454 * and should be
455 * correct:
456 */
457 ps->len = 0xFFFF;
458 }
459 src_len = libusb20_me_get_1(pd, 0);
460 src_ptr = LIBUSB20_ADD_BYTES(ps->ptr, 1);
461 if (src_len == 0xFF) {
462 /* length is escaped */
463 src_len = libusb20_me_get_2(pd, 1);
464 src_ptr =
465 LIBUSB20_ADD_BYTES(ps->ptr, 3);
466 }
467 break;
468
469 case LIBUSB20_ME_IS_DECODED:
470 /* reserve 3 length bytes */
471 src_len = libusb20_me_encode(NULL,
472 0xFFFF - 3, ps->ptr);
473 src_ptr = NULL;
474 break;
475
476 default: /* empty structure */
477 src_len = 0;
478 src_ptr = NULL;
479 break;
480 }
481
482 if (src_len > 0xFE) {
483 if (src_len > (0xFFFF - 3))
484 /* overflow */
485 goto done;
486
487 if (len < (src_len + 3))
488 /* overflow */
489 goto done;
490
491 if (buf) {
492 buf[0] = 0xFF;
493 buf[1] = (src_len & 0xFF);
494 buf[2] = (src_len >> 8) & 0xFF;
495 buf += 3;
496 }
497 len -= (src_len + 3);
498 } else {
499 if (len < (src_len + 1))
500 /* overflow */
501 goto done;
502
503 if (buf) {
504 buf[0] = (src_len & 0xFF);
505 buf += 1;
506 }
507 len -= (src_len + 1);
508 }
509
510 /* check for buffer and non-zero length */
511
512 if (buf && src_len) {
513 if (ps->type == LIBUSB20_ME_IS_DECODED) {
514 /*
515 * Repeat encode
516 * procedure - we have
517 * room for the
518 * complete structure:
519 */
520 uint16_t dummy;
521
522 dummy = libusb20_me_encode(buf,
523 0xFFFF - 3, ps->ptr);
524 } else {
525 bcopy(src_ptr, buf, src_len);
526 }
527 buf += src_len;
528 }
529 pd_offset += sizeof(struct libusb20_me_struct);
530 }
531 break;
532
533 default:
534 goto done;
535 }
536 }
537 done:
538 return (len_old - len);
539 }
540
541 /*------------------------------------------------------------------------*
542 * libusb20_me_decode - decode a message into a decoded structure
543 *
544 * Description of parameters:
545 * "ptr" - message pointer
546 * "len" - message length
547 * "pd" - pointer to decoded structure
548 *
549 * Returns:
550 * "0..65535" - number of bytes decoded, limited by "len"
551 *------------------------------------------------------------------------*/
552 uint16_t
553 libusb20_me_decode(const void *ptr, uint16_t len, void *pd)
554 {
555 const uint8_t *pf; /* pointer to format data */
556 const uint8_t *buf; /* pointer to input buffer */
557
558 uint32_t pd_offset; /* decoded structure offset */
559 uint16_t len_old; /* old length */
560 uint16_t pd_count; /* decoded element count */
561 uint8_t me; /* message element */
562
563 /* initialise */
564
565 len_old = len;
566 buf = ptr;
567 pd_offset = sizeof(void *);
568 pf = (*((struct libusb20_me_format **)pd))->format;
569
570 /* scan */
571
572 while (1) {
573
574 /* get information element */
575
576 me = (pf[0]) & LIBUSB20_ME_MASK;
577 pd_count = pf[1] | (pf[2] << 8);
578 pf += 3;
579
580 /* decode the message element by type */
581
582 switch (me) {
583 case LIBUSB20_ME_INT8:
584 while (pd_count--) {
585 uint8_t temp;
586
587 if (len < 1) {
588 len = 0;
589 temp = 0;
590 } else {
591 len -= 1;
592 temp = buf[0];
593 buf++;
594 }
595 *((uint8_t *)LIBUSB20_ADD_BYTES(pd,
596 pd_offset)) = temp;
597 pd_offset += 1;
598 }
599 break;
600
601 case LIBUSB20_ME_INT16:
602 pd_offset = -((-pd_offset) & ~1); /* align */
603 while (pd_count--) {
604 uint16_t temp;
605
606 if (len < 2) {
607 len = 0;
608 temp = 0;
609 } else {
610 len -= 2;
611 temp = buf[1] << 8;
612 temp |= buf[0];
613 buf += 2;
614 }
615 *((uint16_t *)LIBUSB20_ADD_BYTES(pd,
616 pd_offset)) = temp;
617 pd_offset += 2;
618 }
619 break;
620
621 case LIBUSB20_ME_INT32:
622 pd_offset = -((-pd_offset) & ~3); /* align */
623 while (pd_count--) {
624 uint32_t temp;
625
626 if (len < 4) {
627 len = 0;
628 temp = 0;
629 } else {
630 len -= 4;
631 temp = buf[3] << 24;
632 temp |= buf[2] << 16;
633 temp |= buf[1] << 8;
634 temp |= buf[0];
635 buf += 4;
636 }
637
638 *((uint32_t *)LIBUSB20_ADD_BYTES(pd,
639 pd_offset)) = temp;
640 pd_offset += 4;
641 }
642 break;
643
644 case LIBUSB20_ME_INT64:
645 pd_offset = -((-pd_offset) & ~7); /* align */
646 while (pd_count--) {
647 uint64_t temp;
648
649 if (len < 8) {
650 len = 0;
651 temp = 0;
652 } else {
653 len -= 8;
654 temp = ((uint64_t)buf[7]) << 56;
655 temp |= ((uint64_t)buf[6]) << 48;
656 temp |= ((uint64_t)buf[5]) << 40;
657 temp |= ((uint64_t)buf[4]) << 32;
658 temp |= buf[3] << 24;
659 temp |= buf[2] << 16;
660 temp |= buf[1] << 8;
661 temp |= buf[0];
662 buf += 8;
663 }
664
665 *((uint64_t *)LIBUSB20_ADD_BYTES(pd,
666 pd_offset)) = temp;
667 pd_offset += 8;
668 }
669 break;
670
671 case LIBUSB20_ME_STRUCT:
672 pd_offset = -((-pd_offset) &
673 ~(LIBUSB20_ME_STRUCT_ALIGN - 1)); /* align */
674 while (pd_count--) {
675 uint16_t temp;
676 uint16_t dummy;
677 struct libusb20_me_struct *ps;
678
679 ps = LIBUSB20_ADD_BYTES(pd, pd_offset);
680
681 if (ps->type == LIBUSB20_ME_IS_ENCODED) {
682 /*
683 * Pre-store a de-constified
684 * pointer to the raw
685 * structure:
686 */
687 ps->ptr = LIBUSB20_ADD_BYTES(buf, 0);
688
689 /*
690 * Get the correct number of
691 * length bytes:
692 */
693 if (len != 0) {
694 if (buf[0] == 0xFF) {
695 ps->len = 3;
696 } else {
697 ps->len = 1;
698 }
699 } else {
700 ps->len = 0;
701 }
702 }
703 /* get the structure length */
704
705 if (len != 0) {
706 if (buf[0] == 0xFF) {
707 if (len < 3) {
708 len = 0;
709 temp = 0;
710 } else {
711 len -= 3;
712 temp = buf[1] |
713 (buf[2] << 8);
714 buf += 3;
715 }
716 } else {
717 len -= 1;
718 temp = buf[0];
719 buf += 1;
720 }
721 } else {
722 len = 0;
723 temp = 0;
724 }
725 /* check for invalid length */
726
727 if (temp > len) {
728 len = 0;
729 temp = 0;
730 }
731 /* check wanted structure type */
732
733 switch (ps->type) {
734 case LIBUSB20_ME_IS_ENCODED:
735 /* check for zero length */
736 if (temp == 0) {
737 /*
738 * The pointer must
739 * be valid:
740 */
741 ps->ptr = LIBUSB20_ADD_BYTES(
742 libusb20_me_encode_empty, 0);
743 ps->len = 1;
744 } else {
745 ps->len += temp;
746 }
747 break;
748
749 case LIBUSB20_ME_IS_RAW:
750 /* update length and pointer */
751 ps->len = temp;
752 ps->ptr = LIBUSB20_ADD_BYTES(buf, 0);
753 break;
754
755 case LIBUSB20_ME_IS_EMPTY:
756 case LIBUSB20_ME_IS_DECODED:
757 /* check for non-zero length */
758 if (temp != 0) {
759 /* update type */
760 ps->type = LIBUSB20_ME_IS_DECODED;
761 ps->len = 0;
762 /*
763 * Recursivly decode
764 * the next structure
765 */
766 dummy = libusb20_me_decode(buf,
767 temp, ps->ptr);
768 } else {
769 /* update type */
770 ps->type = LIBUSB20_ME_IS_EMPTY;
771 ps->len = 0;
772 }
773 break;
774
775 default:
776 /*
777 * nothing to do - should
778 * not happen
779 */
780 ps->ptr = NULL;
781 ps->len = 0;
782 break;
783 }
784 buf += temp;
785 len -= temp;
786 pd_offset += sizeof(struct libusb20_me_struct);
787 }
788 break;
789
790 default:
791 goto done;
792 }
793 }
794 done:
795 return (len_old - len);
796 }
DragonFly BSD