aboutsummaryrefslogtreecommitdiffstats
path: root/skeletons/constr_CHOICE.c
blob: 4f0d9922521d8087bc1d60fc119bddba5189473a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
/*
 * Copyright (c) 2003, 2004, 2005, 2006, 2007 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#include <asn_internal.h>
#include <constr_CHOICE.h>
#include <per_opentype.h>

/*
 * Number of bytes left for this structure.
 * (ctx->left) indicates the number of bytes _transferred_ for the structure.
 * (size) contains the number of bytes in the buffer passed.
 */
#define	LEFT	((size<(size_t)ctx->left)?size:(size_t)ctx->left)

/*
 * If the subprocessor function returns with an indication that it wants
 * more data, it may well be a fatal decoding problem, because the
 * size is constrained by the <TLV>'s L, even if the buffer size allows
 * reading more data.
 * For example, consider the buffer containing the following TLVs:
 * <T:5><L:1><V> <T:6>...
 * The TLV length clearly indicates that one byte is expected in V, but
 * if the V processor returns with "want more data" even if the buffer
 * contains way more data than the V processor have seen.
 */
#define	SIZE_VIOLATION	(ctx->left >= 0 && (size_t)ctx->left <= size)

/*
 * This macro "eats" the part of the buffer which is definitely "consumed",
 * i.e. was correctly converted into local representation or rightfully skipped.
 */
#undef	ADVANCE
#define	ADVANCE(num_bytes)	do {		\
		size_t num = num_bytes;		\
		ptr = ((const char *)ptr) + num;\
		size -= num;			\
		if(ctx->left >= 0)		\
			ctx->left -= num;	\
		consumed_myself += num;		\
	} while(0)

/*
 * Switch to the next phase of parsing.
 */
#undef	NEXT_PHASE
#define	NEXT_PHASE(ctx)	do {			\
		ctx->phase++;			\
		ctx->step = 0;			\
	} while(0)

/*
 * Return a standardized complex structure.
 */
#undef	RETURN
#define	RETURN(_code)	do {			\
		rval.code = _code;		\
		rval.consumed = consumed_myself;\
		return rval;			\
	} while(0)

/*
 * See the definitions.
 */
static int _fetch_present_idx(const void *struct_ptr, int off, int size);
static void _set_present_idx(void *sptr, int offset, int size, int pres);

/*
 * Tags are canonically sorted in the tag to member table.
 */
static int
_search4tag(const void *ap, const void *bp) {
	const asn_TYPE_tag2member_t *a = (const asn_TYPE_tag2member_t *)ap;
	const asn_TYPE_tag2member_t *b = (const asn_TYPE_tag2member_t *)bp;

	int a_class = BER_TAG_CLASS(a->el_tag);
	int b_class = BER_TAG_CLASS(b->el_tag);

	if(a_class == b_class) {
		ber_tlv_tag_t a_value = BER_TAG_VALUE(a->el_tag);
		ber_tlv_tag_t b_value = BER_TAG_VALUE(b->el_tag);

		if(a_value == b_value)
			return 0;
		else if(a_value < b_value)
			return -1;
		else
			return 1;
	} else if(a_class < b_class) {
		return -1;
	} else {
		return 1;
	}
}

/*
 * The decoder of the CHOICE type.
 */
asn_dec_rval_t
CHOICE_decode_ber(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
	void **struct_ptr, const void *ptr, size_t size, int tag_mode) {
	/*
	 * Bring closer parts of structure description.
	 */
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	asn_TYPE_member_t *elements = td->elements;

	/*
	 * Parts of the structure being constructed.
	 */
	void *st = *struct_ptr;	/* Target structure. */
	asn_struct_ctx_t *ctx;	/* Decoder context */

	ber_tlv_tag_t tlv_tag;	/* T from TLV */
	ssize_t tag_len;	/* Length of TLV's T */
	asn_dec_rval_t rval;	/* Return code from subparsers */

	ssize_t consumed_myself = 0;	/* Consumed bytes from ptr */

	ASN_DEBUG("Decoding %s as CHOICE", td->name);

	/*
	 * Create the target structure if it is not present already.
	 */
	if(st == 0) {
		st = *struct_ptr = CALLOC(1, specs->struct_size);
		if(st == 0) {
			RETURN(RC_FAIL);
		}
	}

	/*
	 * Restore parsing context.
	 */
	ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
	
	/*
	 * Start to parse where left previously
	 */
	switch(ctx->phase) {
	case 0:
		/*
		 * PHASE 0.
		 * Check that the set of tags associated with given structure
		 * perfectly fits our expectations.
		 */

		if(tag_mode || td->tags_count) {
			rval = ber_check_tags(opt_codec_ctx, td, ctx, ptr, size,
				tag_mode, -1, &ctx->left, 0);
			if(rval.code != RC_OK) {
				ASN_DEBUG("%s tagging check failed: %d",
					td->name, rval.code);
				return rval;
			}

			if(ctx->left >= 0) {
				/* ?Substracted below! */
				ctx->left += rval.consumed;
			}
			ADVANCE(rval.consumed);
		} else {
			ctx->left = -1;
		}

		NEXT_PHASE(ctx);

		ASN_DEBUG("Structure consumes %ld bytes, buffer %ld",
			(long)ctx->left, (long)size);

		/* Fall through */
	case 1:
		/*
		 * Fetch the T from TLV.
		 */
		tag_len = ber_fetch_tag(ptr, LEFT, &tlv_tag);
		ASN_DEBUG("In %s CHOICE tag length %d", td->name, (int)tag_len);
		switch(tag_len) {
		case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
			/* Fall through */
		case -1: RETURN(RC_FAIL);
		}

		do {
			asn_TYPE_tag2member_t *t2m;
			asn_TYPE_tag2member_t key;

			key.el_tag = tlv_tag;
			t2m = (asn_TYPE_tag2member_t *)bsearch(&key,
					specs->tag2el, specs->tag2el_count,
					sizeof(specs->tag2el[0]), _search4tag);
			if(t2m) {
				/*
				 * Found the element corresponding to the tag.
				 */
				NEXT_PHASE(ctx);
				ctx->step = t2m->el_no;
				break;
			} else if(specs->ext_start == -1) {
				ASN_DEBUG("Unexpected tag %s "
					"in non-extensible CHOICE %s",
					ber_tlv_tag_string(tlv_tag), td->name);
				RETURN(RC_FAIL);
			} else {
				/* Skip this tag */
				ssize_t skip;

				ASN_DEBUG("Skipping unknown tag %s",
					ber_tlv_tag_string(tlv_tag));

				skip = ber_skip_length(opt_codec_ctx,
					BER_TLV_CONSTRUCTED(ptr),
					(const char *)ptr + tag_len,
					LEFT - tag_len);

				switch(skip) {
				case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
					/* Fall through */
				case -1: RETURN(RC_FAIL);
				}

				ADVANCE(skip + tag_len);
				RETURN(RC_OK);
			}
		} while(0);

	case 2:
		/*
		 * PHASE 2.
		 * Read in the element.
		 */
	    do {
		asn_TYPE_member_t *elm;/* CHOICE's element */
		void *memb_ptr;		/* Pointer to the member */
		void **memb_ptr2;	/* Pointer to that pointer */

		elm = &elements[ctx->step];

		/*
		 * Compute the position of the member inside a structure,
		 * and also a type of containment (it may be contained
		 * as pointer or using inline inclusion).
		 */
		if(elm->flags & ATF_POINTER) {
			/* Member is a pointer to another structure */
			memb_ptr2 = (void **)((char *)st + elm->memb_offset);
		} else {
			/*
			 * A pointer to a pointer
			 * holding the start of the structure
			 */
			memb_ptr = (char *)st + elm->memb_offset;
			memb_ptr2 = &memb_ptr;
		}
		/* Set presence to be able to free it properly at any time */
		_set_present_idx(st, specs->pres_offset,
				specs->pres_size, ctx->step + 1);
		/*
		 * Invoke the member fetch routine according to member's type
		 */
		rval = elm->type->ber_decoder(opt_codec_ctx, elm->type,
				memb_ptr2, ptr, LEFT, elm->tag_mode);
		switch(rval.code) {
		case RC_OK:
			break;
		case RC_WMORE: /* More data expected */
			if(!SIZE_VIOLATION) {
				ADVANCE(rval.consumed);
				RETURN(RC_WMORE);
			}
			RETURN(RC_FAIL);
		case RC_FAIL: /* Fatal error */
			RETURN(rval.code);
		} /* switch(rval) */
		
		ADVANCE(rval.consumed);
	  } while(0);

		NEXT_PHASE(ctx);

		/* Fall through */
	case 3:
		ASN_DEBUG("CHOICE %s Leftover: %ld, size = %ld, tm=%d, tc=%d",
			td->name, (long)ctx->left, (long)size,
			tag_mode, td->tags_count);

		if(ctx->left > 0) {
			/*
			 * The type must be fully decoded
			 * by the CHOICE member-specific decoder.
			 */
			RETURN(RC_FAIL);
		}

		if(ctx->left == -1
		&& !(tag_mode || td->tags_count)) {
			/*
			 * This is an untagged CHOICE.
			 * It doesn't contain nothing
			 * except for the member itself, including all its tags.
			 * The decoding is completed.
			 */
			NEXT_PHASE(ctx);
			break;
		}

		/*
		 * Read in the "end of data chunks"'s.
		 */
		while(ctx->left < 0) {
			ssize_t tl;

			tl = ber_fetch_tag(ptr, LEFT, &tlv_tag);
			switch(tl) {
			case 0: if(!SIZE_VIOLATION) RETURN(RC_WMORE);
				/* Fall through */
			case -1: RETURN(RC_FAIL);
			}

			/*
			 * Expected <0><0>...
			 */
			if(((const uint8_t *)ptr)[0] == 0) {
				if(LEFT < 2) {
					if(SIZE_VIOLATION)
						RETURN(RC_FAIL);
					else
						RETURN(RC_WMORE);
				} else if(((const uint8_t *)ptr)[1] == 0) {
					/*
					 * Correctly finished with <0><0>.
					 */
					ADVANCE(2);
					ctx->left++;
					continue;
				}
			} else {
				ASN_DEBUG("Unexpected continuation in %s",
					td->name);
				RETURN(RC_FAIL);
			}

			/* UNREACHABLE */
		}

		NEXT_PHASE(ctx);
	case 4:
		/* No meaningful work here */
		break;
	}
	
	RETURN(RC_OK);
}

asn_enc_rval_t
CHOICE_encode_der(asn_TYPE_descriptor_t *td, void *sptr,
		int tag_mode, ber_tlv_tag_t tag,
		asn_app_consume_bytes_f *cb, void *app_key) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	asn_TYPE_member_t *elm;	/* CHOICE element */
	asn_enc_rval_t erval;
	void *memb_ptr;
	size_t computed_size = 0;
	int present;

	if(!sptr) _ASN_ENCODE_FAILED;

	ASN_DEBUG("%s %s as CHOICE",
		cb?"Encoding":"Estimating", td->name);

	present = _fetch_present_idx(sptr,
		specs->pres_offset, specs->pres_size);

	/*
	 * If the structure was not initialized, it cannot be encoded:
	 * can't deduce what to encode in the choice type.
	 */
	if(present <= 0 || present > td->elements_count) {
		if(present == 0 && td->elements_count == 0) {
			/* The CHOICE is empty?! */
			erval.encoded = 0;
			_ASN_ENCODED_OK(erval);
		}
		_ASN_ENCODE_FAILED;
	}

	/*
	 * Seek over the present member of the structure.
	 */
	elm = &td->elements[present-1];
	if(elm->flags & ATF_POINTER) {
		memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
		if(memb_ptr == 0) {
			if(elm->optional) {
				erval.encoded = 0;
				_ASN_ENCODED_OK(erval);
			}
			/* Mandatory element absent */
			_ASN_ENCODE_FAILED;
		}
	} else {
		memb_ptr = (void *)((char *)sptr + elm->memb_offset);
	}

	/*
	 * If the CHOICE itself is tagged EXPLICIT:
	 * T ::= [2] EXPLICIT CHOICE { ... }
	 * Then emit the appropriate tags.
	 */
	if(tag_mode == 1 || td->tags_count) {
		/*
		 * For this, we need to pre-compute the member.
		 */
		ssize_t ret;

		/* Encode member with its tag */
		erval = elm->type->der_encoder(elm->type, memb_ptr,
			elm->tag_mode, elm->tag, 0, 0);
		if(erval.encoded == -1)
			return erval;

		/* Encode CHOICE with parent or my own tag */
		ret = der_write_tags(td, erval.encoded, tag_mode, 1, tag,
			cb, app_key);
		if(ret == -1)
			_ASN_ENCODE_FAILED;
		computed_size += ret;
	}

	/*
	 * Encode the single underlying member.
	 */
	erval = elm->type->der_encoder(elm->type, memb_ptr,
		elm->tag_mode, elm->tag, cb, app_key);
	if(erval.encoded == -1)
		return erval;

	ASN_DEBUG("Encoded CHOICE member in %ld bytes (+%ld)",
		(long)erval.encoded, (long)computed_size);

	erval.encoded += computed_size;

	return erval;
}

ber_tlv_tag_t
CHOICE_outmost_tag(asn_TYPE_descriptor_t *td, const void *ptr, int tag_mode, ber_tlv_tag_t tag) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	int present;

	assert(tag_mode == 0); (void)tag_mode;
	assert(tag == 0); (void)tag;

	/*
	 * Figure out which CHOICE element is encoded.
	 */
	present = _fetch_present_idx(ptr, specs->pres_offset, specs->pres_size);

	if(present > 0 || present <= td->elements_count) {
		asn_TYPE_member_t *elm = &td->elements[present-1];
		const void *memb_ptr;

		if(elm->flags & ATF_POINTER) {
			memb_ptr = *(const void * const *)
					((const char *)ptr + elm->memb_offset);
		} else {
			memb_ptr = (const void *)
					((const char *)ptr + elm->memb_offset);
		}

		return asn_TYPE_outmost_tag(elm->type, memb_ptr,
			elm->tag_mode, elm->tag);
	} else {
		return (ber_tlv_tag_t)-1;
	}
}

int
CHOICE_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
		asn_app_constraint_failed_f *ctfailcb, void *app_key) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	int present;

	if(!sptr) {
		_ASN_CTFAIL(app_key, td, sptr,
			"%s: value not given (%s:%d)",
			td->name, __FILE__, __LINE__);
		return -1;
	}

	/*
	 * Figure out which CHOICE element is encoded.
	 */
	present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);
	if(present > 0 && present <= td->elements_count) {
		asn_TYPE_member_t *elm = &td->elements[present-1];
		const void *memb_ptr;

		if(elm->flags & ATF_POINTER) {
			memb_ptr = *(const void * const *)((const char *)sptr + elm->memb_offset);
			if(!memb_ptr) {
				if(elm->optional)
					return 0;
				_ASN_CTFAIL(app_key, td, sptr,
					"%s: mandatory CHOICE element %s absent (%s:%d)",
					td->name, elm->name, __FILE__, __LINE__);
				return -1;
			}
		} else {
			memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
		}

		if(elm->memb_constraints) {
			return elm->memb_constraints(elm->type, memb_ptr,
				ctfailcb, app_key);
		} else {
			int ret = elm->type->check_constraints(elm->type,
					memb_ptr, ctfailcb, app_key);
			/*
			 * Cannot inherit it eralier:
			 * need to make sure we get the updated version.
			 */
			elm->memb_constraints = elm->type->check_constraints;
			return ret;
		}
	} else {
		_ASN_CTFAIL(app_key, td, sptr,
			"%s: no CHOICE element given (%s:%d)",
			td->name, __FILE__, __LINE__);
		return -1;
	}
}

#undef	XER_ADVANCE
#define	XER_ADVANCE(num_bytes)	do {			\
		size_t num = num_bytes;			\
		buf_ptr = ((const char *)buf_ptr) + num;\
		size -= num;				\
		consumed_myself += num;			\
	} while(0)

/*
 * Decode the XER (XML) data.
 */
asn_dec_rval_t
CHOICE_decode_xer(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
	void **struct_ptr, const char *opt_mname,
		const void *buf_ptr, size_t size) {
	/*
	 * Bring closer parts of structure description.
	 */
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	const char *xml_tag = opt_mname ? opt_mname : td->xml_tag;

	/*
	 * Parts of the structure being constructed.
	 */
	void *st = *struct_ptr;	/* Target structure. */
	asn_struct_ctx_t *ctx;	/* Decoder context */

	asn_dec_rval_t rval;		/* Return value of a decoder */
	ssize_t consumed_myself = 0;	/* Consumed bytes from ptr */
	int edx;			/* Element index */

	/*
	 * Create the target structure if it is not present already.
	 */
	if(st == 0) {
		st = *struct_ptr = CALLOC(1, specs->struct_size);
		if(st == 0) RETURN(RC_FAIL);
	}

	/*
	 * Restore parsing context.
	 */
	ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
	if(ctx->phase == 0 && !*xml_tag)
		ctx->phase = 1;	/* Skip the outer tag checking phase */

	/*
	 * Phases of XER/XML processing:
	 * Phase 0: Check that the opening tag matches our expectations.
	 * Phase 1: Processing body and reacting on closing tag.
	 * Phase 2: Processing inner type.
	 * Phase 3: Only waiting for closing tag.
	 * Phase 4: Skipping unknown extensions.
	 * Phase 5: PHASED OUT
	 */
	for(edx = ctx->step; ctx->phase <= 4;) {
		pxer_chunk_type_e ch_type;	/* XER chunk type */
		ssize_t ch_size;		/* Chunk size */
		xer_check_tag_e tcv;		/* Tag check value */
		asn_TYPE_member_t *elm;

		/*
		 * Go inside the member.
		 */
		if(ctx->phase == 2) {
			asn_dec_rval_t tmprval;
			void *memb_ptr;		/* Pointer to the member */
			void **memb_ptr2;	/* Pointer to that pointer */

			elm = &td->elements[edx];

			if(elm->flags & ATF_POINTER) {
				/* Member is a pointer to another structure */
				memb_ptr2 = (void **)((char *)st
					+ elm->memb_offset);
			} else {
				memb_ptr = (char *)st + elm->memb_offset;
				memb_ptr2 = &memb_ptr;
			}

			/* Start/Continue decoding the inner member */
			tmprval = elm->type->xer_decoder(opt_codec_ctx,
					elm->type, memb_ptr2, elm->name,
					buf_ptr, size);
			XER_ADVANCE(tmprval.consumed);
			ASN_DEBUG("XER/CHOICE: itdf: [%s] code=%d",
				elm->type->name, tmprval.code);
			if(tmprval.code != RC_OK)
				RETURN(tmprval.code);
			assert(_fetch_present_idx(st,
				specs->pres_offset, specs->pres_size) == 0);
			/* Record what we've got */
			_set_present_idx(st,
				specs->pres_offset, specs->pres_size, edx + 1);
			ctx->phase = 3;
			/* Fall through */
		}

		/* No need to wait for closing tag; special mode. */
		if(ctx->phase == 3 && !*xml_tag) {
			ctx->phase = 5;	/* Phase out */
			RETURN(RC_OK);
		}

		/*
		 * Get the next part of the XML stream.
		 */
		ch_size = xer_next_token(&ctx->context, buf_ptr, size, &ch_type);
		switch(ch_size) {
		case -1: RETURN(RC_FAIL);
		case 0:  RETURN(RC_WMORE);
		default:
			switch(ch_type) {
			case PXER_COMMENT:	/* Got XML comment */
			case PXER_TEXT:		/* Ignore free-standing text */
				XER_ADVANCE(ch_size);	/* Skip silently */
				continue;
			case PXER_TAG:
				break;	/* Check the rest down there */
			}
		}

		tcv = xer_check_tag(buf_ptr, ch_size, xml_tag);
		ASN_DEBUG("XER/CHOICE checked [%c%c%c%c] vs [%s], tcv=%d",
			ch_size>0?((const uint8_t *)buf_ptr)[0]:'?',
			ch_size>1?((const uint8_t *)buf_ptr)[1]:'?',
			ch_size>2?((const uint8_t *)buf_ptr)[2]:'?',
			ch_size>3?((const uint8_t *)buf_ptr)[3]:'?',
		xml_tag, tcv);

		/* Skip the extensions section */
		if(ctx->phase == 4) {
			ASN_DEBUG("skip_unknown(%d, %ld)",
				tcv, (long)ctx->left);
			switch(xer_skip_unknown(tcv, &ctx->left)) {
			case -1:
				ctx->phase = 5;
				RETURN(RC_FAIL);
				continue;
			case 1:
				ctx->phase = 3;
				/* Fall through */
			case 0:
				XER_ADVANCE(ch_size);
				continue;
			case 2:
				ctx->phase = 3;
				break;
			}
		}

		switch(tcv) {
		case XCT_BOTH:
			break;	/* No CHOICE? */
		case XCT_CLOSING:
			if(ctx->phase != 3)
				break;
			XER_ADVANCE(ch_size);
			ctx->phase = 5;	/* Phase out */
			RETURN(RC_OK);
		case XCT_OPENING:
			if(ctx->phase == 0) {
				XER_ADVANCE(ch_size);
				ctx->phase = 1;	/* Processing body phase */
				continue;
			}
			/* Fall through */
		case XCT_UNKNOWN_OP:
		case XCT_UNKNOWN_BO:

			if(ctx->phase != 1)
				break;	/* Really unexpected */

			/*
			 * Search which inner member corresponds to this tag.
			 */
			for(edx = 0; edx < td->elements_count; edx++) {
				elm = &td->elements[edx];
				tcv = xer_check_tag(buf_ptr,ch_size,elm->name);
				switch(tcv) {
				case XCT_BOTH:
				case XCT_OPENING:
					/*
					 * Process this member.
					 */
					ctx->step = edx;
					ctx->phase = 2;
					break;
				case XCT_UNKNOWN_OP:
				case XCT_UNKNOWN_BO:
					continue;
				default:
					edx = td->elements_count;
					break;	/* Phase out */
				}
				break;
			}
			if(edx != td->elements_count)
				continue;

			/* It is expected extension */
			if(specs->ext_start != -1) {
				ASN_DEBUG("Got anticipated extension");
				/*
				 * Check for (XCT_BOTH or XCT_UNKNOWN_BO)
				 * By using a mask. Only record a pure
				 * <opening> tags.
				 */
				if(tcv & XCT_CLOSING) {
					/* Found </extension> without body */
					ctx->phase = 3; /* Terminating */
				} else {
					ctx->left = 1;
					ctx->phase = 4; /* Skip ...'s */
				}
				XER_ADVANCE(ch_size);
				continue;
			}

			/* Fall through */
		default:
			break;
		}

		ASN_DEBUG("Unexpected XML tag [%c%c%c%c] in CHOICE [%s]"
			" (ph=%d, tag=%s)",
			ch_size>0?((const uint8_t *)buf_ptr)[0]:'?',
			ch_size>1?((const uint8_t *)buf_ptr)[1]:'?',
			ch_size>2?((const uint8_t *)buf_ptr)[2]:'?',
			ch_size>3?((const uint8_t *)buf_ptr)[3]:'?',
			td->name, ctx->phase, xml_tag);
		break;
	}

	ctx->phase = 5;	/* Phase out, just in case */
	RETURN(RC_FAIL);
}


asn_enc_rval_t
CHOICE_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
	int ilevel, enum xer_encoder_flags_e flags,
		asn_app_consume_bytes_f *cb, void *app_key) {
	asn_CHOICE_specifics_t *specs=(asn_CHOICE_specifics_t *)td->specifics;
	asn_enc_rval_t er;
	int present;

	if(!sptr)
		_ASN_ENCODE_FAILED;

	/*
	 * Figure out which CHOICE element is encoded.
	 */
	present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);

	if(present <= 0 || present > td->elements_count) {
		_ASN_ENCODE_FAILED;
	}  else {
		asn_enc_rval_t tmper;
		asn_TYPE_member_t *elm = &td->elements[present-1];
		void *memb_ptr;
		const char *mname = elm->name;
		unsigned int mlen = strlen(mname);

		if(elm->flags & ATF_POINTER) {
			memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
			if(!memb_ptr) _ASN_ENCODE_FAILED;
		} else {
			memb_ptr = (void *)((char *)sptr + elm->memb_offset);
		}

		er.encoded = 0;

                if(!(flags & XER_F_CANONICAL)) _i_ASN_TEXT_INDENT(1, ilevel);
		_ASN_CALLBACK3("<", 1, mname, mlen, ">", 1);

		tmper = elm->type->xer_encoder(elm->type, memb_ptr,
				ilevel + 1, flags, cb, app_key);
		if(tmper.encoded == -1) return tmper;

		_ASN_CALLBACK3("</", 2, mname, mlen, ">", 1);

		er.encoded += 5 + (2 * mlen) + tmper.encoded;
	}

	if(!(flags & XER_F_CANONICAL)) _i_ASN_TEXT_INDENT(1, ilevel - 1);

	_ASN_ENCODED_OK(er);
cb_failed:
	_ASN_ENCODE_FAILED;
}

asn_dec_rval_t
CHOICE_decode_uper(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
	asn_per_constraints_t *constraints, void **sptr, asn_per_data_t *pd) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	asn_dec_rval_t rv;
	asn_per_constraint_t *ct;
	asn_TYPE_member_t *elm;	/* CHOICE's element */
	void *memb_ptr;
	void **memb_ptr2;
	void *st = *sptr;
	int value;

	if(_ASN_STACK_OVERFLOW_CHECK(opt_codec_ctx))
		_ASN_DECODE_FAILED;

	/*
	 * Create the target structure if it is not present already.
	 */
	if(!st) {
		st = *sptr = CALLOC(1, specs->struct_size);
		if(!st) _ASN_DECODE_FAILED;
	}

	if(constraints) ct = &constraints->value;
	else if(td->per_constraints) ct = &td->per_constraints->value;
	else ct = 0;

	if(ct && ct->flags & APC_EXTENSIBLE) {
		value = per_get_few_bits(pd, 1);
		if(value < 0) _ASN_DECODE_STARVED;
		if(value) ct = 0;	/* Not restricted */
	}

	if(ct && ct->range_bits >= 0) {
		value = per_get_few_bits(pd, ct->range_bits);
		if(value < 0) _ASN_DECODE_STARVED;
		ASN_DEBUG("CHOICE %s got index %d in range %d",
			td->name, value, ct->range_bits);
		if(value > ct->upper_bound)
			_ASN_DECODE_FAILED;
	} else {
		if(specs->ext_start == -1)
			_ASN_DECODE_FAILED;
		value = uper_get_nsnnwn(pd);
		if(value < 0) _ASN_DECODE_STARVED;
		value += specs->ext_start;
		if(value >= td->elements_count)
			_ASN_DECODE_FAILED;
	}

	/* Adjust if canonical order is different from natural order */
	if(specs->canonical_order)
		value = specs->canonical_order[value];

	/* Set presence to be able to free it later */
	_set_present_idx(st, specs->pres_offset, specs->pres_size, value + 1);

	elm = &td->elements[value];
	if(elm->flags & ATF_POINTER) {
		/* Member is a pointer to another structure */
		memb_ptr2 = (void **)((char *)st + elm->memb_offset);
	} else {
		memb_ptr = (char *)st + elm->memb_offset;
		memb_ptr2 = &memb_ptr;
	}
	ASN_DEBUG("Discovered CHOICE %s encodes %s", td->name, elm->name);

	if(ct && ct->range_bits >= 0) {
		rv = elm->type->uper_decoder(opt_codec_ctx, elm->type,
			elm->per_constraints, memb_ptr2, pd);
	} else {
		rv = uper_open_type_get(opt_codec_ctx, elm->type,
			elm->per_constraints, memb_ptr2, pd);
	}

	if(rv.code != RC_OK)
		ASN_DEBUG("Failed to decode %s in %s (CHOICE) %d",
			elm->name, td->name, rv.code);
	return rv;
}
   
asn_enc_rval_t
CHOICE_encode_uper(asn_TYPE_descriptor_t *td,
	asn_per_constraints_t *constraints, void *sptr, asn_per_outp_t *po) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	asn_TYPE_member_t *elm;	/* CHOICE's element */
	asn_per_constraint_t *ct;
	void *memb_ptr;
	int present;

	if(!sptr) _ASN_ENCODE_FAILED;

	ASN_DEBUG("Encoding %s as CHOICE", td->name);

	if(constraints) ct = &constraints->value;
	else if(td->per_constraints) ct = &td->per_constraints->value;
	else ct = 0;

	present = _fetch_present_idx(sptr,
		specs->pres_offset, specs->pres_size);

	/*
	 * If the structure was not initialized properly, it cannot be encoded:
	 * can't deduce what to encode in the choice type.
	 */
	if(present <= 0 || present > td->elements_count)
		_ASN_ENCODE_FAILED;
	else
		present--;

	/* Adjust if canonical order is different from natural order */
	if(specs->canonical_order)
		present = specs->canonical_order[present];

	ASN_DEBUG("Encoding %s CHOICE element %d", td->name, present);

	if(ct && ct->range_bits >= 0) {
		if(present < ct->lower_bound
		|| present > ct->upper_bound) {
			if(ct->flags & APC_EXTENSIBLE) {
				if(per_put_few_bits(po, 1, 1))
					_ASN_ENCODE_FAILED;
			} else {
				_ASN_ENCODE_FAILED;
			}
			ct = 0;
		}
	}
	if(ct && ct->flags & APC_EXTENSIBLE)
		if(per_put_few_bits(po, 0, 1))
			_ASN_ENCODE_FAILED;

	elm = &td->elements[present];
	if(elm->flags & ATF_POINTER) {
		/* Member is a pointer to another structure */
		memb_ptr = *(void **)((char *)sptr + elm->memb_offset);
		if(!memb_ptr) _ASN_ENCODE_FAILED;
	} else {
		memb_ptr = (char *)sptr + elm->memb_offset;
	}

	if(ct && ct->range_bits >= 0) {
		if(per_put_few_bits(po, present, ct->range_bits))
			_ASN_ENCODE_FAILED;

		return elm->type->uper_encoder(elm->type, elm->per_constraints,
			memb_ptr, po);
	} else {
		asn_enc_rval_t rval;
		if(specs->ext_start == -1)
			_ASN_ENCODE_FAILED;
		if(uper_put_nsnnwn(po, present - specs->ext_start))
			_ASN_ENCODE_FAILED;
		if(uper_open_type_put(elm->type, elm->per_constraints,
			memb_ptr, po))
			_ASN_ENCODE_FAILED;
		rval.encoded = 0;
		_ASN_ENCODED_OK(rval);
	}
}
   

int
CHOICE_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
		asn_app_consume_bytes_f *cb, void *app_key) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	int present;

	if(!sptr) return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;

	/*
	 * Figure out which CHOICE element is encoded.
	 */
	present = _fetch_present_idx(sptr, specs->pres_offset,specs->pres_size);

	/*
	 * Print that element.
	 */
	if(present > 0 && present <= td->elements_count) {
		asn_TYPE_member_t *elm = &td->elements[present-1];
		const void *memb_ptr;

		if(elm->flags & ATF_POINTER) {
			memb_ptr = *(const void * const *)((const char *)sptr + elm->memb_offset);
			if(!memb_ptr) return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;
		} else {
			memb_ptr = (const void *)((const char *)sptr + elm->memb_offset);
		}

		/* Print member's name and stuff */
		if(cb(elm->name, strlen(elm->name), app_key) < 0
		|| cb(": ", 2, app_key) < 0)
			return -1;

		return elm->type->print_struct(elm->type, memb_ptr, ilevel,
			cb, app_key);
	} else {
		return (cb("<absent>", 8, app_key) < 0) ? -1 : 0;
	}
}

void
CHOICE_free(asn_TYPE_descriptor_t *td, void *ptr, int contents_only) {
	asn_CHOICE_specifics_t *specs = (asn_CHOICE_specifics_t *)td->specifics;
	int present;

	if(!td || !ptr)
		return;

	ASN_DEBUG("Freeing %s as CHOICE", td->name);

	/*
	 * Figure out which CHOICE element is encoded.
	 */
	present = _fetch_present_idx(ptr, specs->pres_offset, specs->pres_size);

	/*
	 * Free that element.
	 */
	if(present > 0 && present <= td->elements_count) {
		asn_TYPE_member_t *elm = &td->elements[present-1];
		void *memb_ptr;

		if(elm->flags & ATF_POINTER) {
			memb_ptr = *(void **)((char *)ptr + elm->memb_offset);
			if(memb_ptr)
				ASN_STRUCT_FREE(*elm->type, memb_ptr);
		} else {
			memb_ptr = (void *)((char *)ptr + elm->memb_offset);
			ASN_STRUCT_FREE_CONTENTS_ONLY(*elm->type, memb_ptr);
		}
	}

	if(!contents_only) {
		FREEMEM(ptr);
	}
}


/*
 * The following functions functions offer protection against -fshort-enums,
 * compatible with little- and big-endian machines.
 * If assertion is triggered, either disable -fshort-enums, or add an entry
 * here with the ->pres_size of your target stracture.
 * Unless the target structure is packed, the ".present" member
 * is guaranteed to be aligned properly. ASN.1 compiler itself does not
 * produce packed code.
 */
static int
_fetch_present_idx(const void *struct_ptr, int pres_offset, int pres_size) {
	const void *present_ptr;
	int present;

	present_ptr = ((const char *)struct_ptr) + pres_offset;

	switch(pres_size) {
	case sizeof(int):	present =   *(const int *)present_ptr; break;
	case sizeof(short):	present = *(const short *)present_ptr; break;
	case sizeof(char):	present =  *(const char *)present_ptr; break;
	default:
		/* ANSI C mandates enum to be equivalent to integer */
		assert(pres_size != sizeof(int));
		return 0;	/* If not aborted, pass back safe value */
	}

	return present;
}

static void
_set_present_idx(void *struct_ptr, int pres_offset, int pres_size, int present) {
	void *present_ptr;
	present_ptr = ((char *)struct_ptr) + pres_offset;

	switch(pres_size) {
	case sizeof(int):	*(int *)present_ptr   = present; break;
	case sizeof(short):	*(short *)present_ptr = present; break;
	case sizeof(char):	*(char *)present_ptr  = present; break;
	default:
		/* ANSI C mandates enum to be equivalent to integer */
		assert(pres_size != sizeof(int));
	}
}