xref: /freebsd/crypto/heimdal/lib/asn1/gen_decode.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*
2  * Copyright (c) 1997 - 2006 Kungliga Tekniska H�gskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of the Institute nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "gen_locl.h"
35 #include "lex.h"
36 
37 RCSID("$Id: gen_decode.c 21503 2007-07-12 11:57:19Z lha $");
38 
39 static void
40 decode_primitive (const char *typename, const char *name, const char *forwstr)
41 {
42 #if 0
43     fprintf (codefile,
44 	     "e = decode_%s(p, len, %s, &l);\n"
45 	     "%s;\n",
46 	     typename,
47 	     name,
48 	     forwstr);
49 #else
50     fprintf (codefile,
51 	     "e = der_get_%s(p, len, %s, &l);\n"
52 	     "if(e) %s;\np += l; len -= l; ret += l;\n",
53 	     typename,
54 	     name,
55 	     forwstr);
56 #endif
57 }
58 
59 static int
60 is_primitive_type(int type)
61 {
62     switch(type) {
63     case TInteger:
64     case TBoolean:
65     case TOctetString:
66     case TBitString:
67     case TEnumerated:
68     case TGeneralizedTime:
69     case TGeneralString:
70     case TOID:
71     case TUTCTime:
72     case TUTF8String:
73     case TPrintableString:
74     case TIA5String:
75     case TBMPString:
76     case TUniversalString:
77     case TVisibleString:
78     case TNull:
79 	return 1;
80     default:
81 	return 0;
82     }
83 }
84 
85 static void
86 find_tag (const Type *t,
87 	  Der_class *cl, Der_type *ty, unsigned *tag)
88 {
89     switch (t->type) {
90     case TBitString:
91 	*cl  = ASN1_C_UNIV;
92 	*ty  = PRIM;
93 	*tag = UT_BitString;
94 	break;
95     case TBoolean:
96 	*cl  = ASN1_C_UNIV;
97 	*ty  = PRIM;
98 	*tag = UT_Boolean;
99 	break;
100     case TChoice:
101 	errx(1, "Cannot have recursive CHOICE");
102     case TEnumerated:
103 	*cl  = ASN1_C_UNIV;
104 	*ty  = PRIM;
105 	*tag = UT_Enumerated;
106 	break;
107     case TGeneralString:
108 	*cl  = ASN1_C_UNIV;
109 	*ty  = PRIM;
110 	*tag = UT_GeneralString;
111 	break;
112     case TGeneralizedTime:
113 	*cl  = ASN1_C_UNIV;
114 	*ty  = PRIM;
115 	*tag = UT_GeneralizedTime;
116 	break;
117     case TIA5String:
118 	*cl  = ASN1_C_UNIV;
119 	*ty  = PRIM;
120 	*tag = UT_IA5String;
121 	break;
122     case TInteger:
123 	*cl  = ASN1_C_UNIV;
124 	*ty  = PRIM;
125 	*tag = UT_Integer;
126 	break;
127     case TNull:
128 	*cl  = ASN1_C_UNIV;
129 	*ty  = PRIM;
130 	*tag = UT_Null;
131 	break;
132     case TOID:
133 	*cl  = ASN1_C_UNIV;
134 	*ty  = PRIM;
135 	*tag = UT_OID;
136 	break;
137     case TOctetString:
138 	*cl  = ASN1_C_UNIV;
139 	*ty  = PRIM;
140 	*tag = UT_OctetString;
141 	break;
142     case TPrintableString:
143 	*cl  = ASN1_C_UNIV;
144 	*ty  = PRIM;
145 	*tag = UT_PrintableString;
146 	break;
147     case TSequence:
148     case TSequenceOf:
149 	*cl  = ASN1_C_UNIV;
150 	*ty  = CONS;
151 	*tag = UT_Sequence;
152 	break;
153     case TSet:
154     case TSetOf:
155 	*cl  = ASN1_C_UNIV;
156 	*ty  = CONS;
157 	*tag = UT_Set;
158 	break;
159     case TTag:
160 	*cl  = t->tag.tagclass;
161 	*ty  = is_primitive_type(t->subtype->type) ? PRIM : CONS;
162 	*tag = t->tag.tagvalue;
163 	break;
164     case TType:
165 	if ((t->symbol->stype == Stype && t->symbol->type == NULL)
166 	    || t->symbol->stype == SUndefined) {
167 	    error_message("%s is imported or still undefined, "
168 			  " can't generate tag checking data in CHOICE "
169 			  "without this information",
170 			  t->symbol->name);
171 	    exit(1);
172 	}
173 	find_tag(t->symbol->type, cl, ty, tag);
174 	return;
175     case TUTCTime:
176 	*cl  = ASN1_C_UNIV;
177 	*ty  = PRIM;
178 	*tag = UT_UTCTime;
179 	break;
180     case TUTF8String:
181 	*cl  = ASN1_C_UNIV;
182 	*ty  = PRIM;
183 	*tag = UT_UTF8String;
184 	break;
185     case TBMPString:
186 	*cl  = ASN1_C_UNIV;
187 	*ty  = PRIM;
188 	*tag = UT_BMPString;
189 	break;
190     case TUniversalString:
191 	*cl  = ASN1_C_UNIV;
192 	*ty  = PRIM;
193 	*tag = UT_UniversalString;
194 	break;
195     case TVisibleString:
196 	*cl  = ASN1_C_UNIV;
197 	*ty  = PRIM;
198 	*tag = UT_VisibleString;
199 	break;
200     default:
201 	abort();
202     }
203 }
204 
205 static void
206 range_check(const char *name,
207 	    const char *length,
208 	    const char *forwstr,
209 	    struct range *r)
210 {
211     if (r->min == r->max + 2 || r->min < r->max)
212 	fprintf (codefile,
213 		 "if ((%s)->%s > %d) {\n"
214 		 "e = ASN1_MAX_CONSTRAINT; %s;\n"
215 		 "}\n",
216 		 name, length, r->max, forwstr);
217     if (r->min - 1 == r->max || r->min < r->max)
218 	fprintf (codefile,
219 		 "if ((%s)->%s < %d) {\n"
220 		 "e = ASN1_MIN_CONSTRAINT; %s;\n"
221 		 "}\n",
222 		 name, length, r->min, forwstr);
223     if (r->max == r->min)
224 	fprintf (codefile,
225 		 "if ((%s)->%s != %d) {\n"
226 		 "e = ASN1_EXACT_CONSTRAINT; %s;\n"
227 		 "}\n",
228 		 name, length, r->min, forwstr);
229 }
230 
231 static int
232 decode_type (const char *name, const Type *t, int optional,
233 	     const char *forwstr, const char *tmpstr)
234 {
235     switch (t->type) {
236     case TType: {
237 	if (optional)
238 	    fprintf(codefile,
239 		    "%s = calloc(1, sizeof(*%s));\n"
240 		    "if (%s == NULL) %s;\n",
241 		    name, name, name, forwstr);
242 	fprintf (codefile,
243 		 "e = decode_%s(p, len, %s, &l);\n",
244 		 t->symbol->gen_name, name);
245 	if (optional) {
246 	    fprintf (codefile,
247 		     "if(e) {\n"
248 		     "free(%s);\n"
249 		     "%s = NULL;\n"
250 		     "} else {\n"
251 		     "p += l; len -= l; ret += l;\n"
252 		     "}\n",
253 		     name, name);
254 	} else {
255 	    fprintf (codefile,
256 		     "if(e) %s;\n",
257 		     forwstr);
258 	    fprintf (codefile,
259 		     "p += l; len -= l; ret += l;\n");
260 	}
261 	break;
262     }
263     case TInteger:
264 	if(t->members) {
265 	    fprintf(codefile,
266 		    "{\n"
267 		    "int enumint;\n");
268 	    decode_primitive ("integer", "&enumint", forwstr);
269 	    fprintf(codefile,
270 		    "*%s = enumint;\n"
271 		    "}\n",
272 		    name);
273 	} else if (t->range == NULL) {
274 	    decode_primitive ("heim_integer", name, forwstr);
275 	} else if (t->range->min == INT_MIN && t->range->max == INT_MAX) {
276 	    decode_primitive ("integer", name, forwstr);
277 	} else if (t->range->min == 0 && t->range->max == UINT_MAX) {
278 	    decode_primitive ("unsigned", name, forwstr);
279 	} else if (t->range->min == 0 && t->range->max == INT_MAX) {
280 	    decode_primitive ("unsigned", name, forwstr);
281 	} else
282 	    errx(1, "%s: unsupported range %d -> %d",
283 		 name, t->range->min, t->range->max);
284 	break;
285     case TBoolean:
286       decode_primitive ("boolean", name, forwstr);
287       break;
288     case TEnumerated:
289 	decode_primitive ("enumerated", name, forwstr);
290 	break;
291     case TOctetString:
292 	decode_primitive ("octet_string", name, forwstr);
293 	if (t->range)
294 	    range_check(name, "length", forwstr, t->range);
295 	break;
296     case TBitString: {
297 	Member *m;
298 	int pos = 0;
299 
300 	if (ASN1_TAILQ_EMPTY(t->members)) {
301 	    decode_primitive ("bit_string", name, forwstr);
302 	    break;
303 	}
304 	fprintf(codefile,
305 		"if (len < 1) return ASN1_OVERRUN;\n"
306 		"p++; len--; ret++;\n");
307 	fprintf(codefile,
308 		"do {\n"
309 		"if (len < 1) break;\n");
310 	ASN1_TAILQ_FOREACH(m, t->members, members) {
311 	    while (m->val / 8 > pos / 8) {
312 		fprintf (codefile,
313 			 "p++; len--; ret++;\n"
314 			 "if (len < 1) break;\n");
315 		pos += 8;
316 	    }
317 	    fprintf (codefile,
318 		     "(%s)->%s = (*p >> %d) & 1;\n",
319 		     name, m->gen_name, 7 - m->val % 8);
320 	}
321 	fprintf(codefile,
322 		"} while(0);\n");
323 	fprintf (codefile,
324 		 "p += len; ret += len;\n");
325 	break;
326     }
327     case TSequence: {
328 	Member *m;
329 
330 	if (t->members == NULL)
331 	    break;
332 
333 	ASN1_TAILQ_FOREACH(m, t->members, members) {
334 	    char *s;
335 
336 	    if (m->ellipsis)
337 		continue;
338 
339 	    asprintf (&s, "%s(%s)->%s", m->optional ? "" : "&",
340 		      name, m->gen_name);
341 	    if (s == NULL)
342 		errx(1, "malloc");
343 	    decode_type (s, m->type, m->optional, forwstr, m->gen_name);
344 	    free (s);
345 	}
346 
347 	break;
348     }
349     case TSet: {
350 	Member *m;
351 	unsigned int memno;
352 
353 	if(t->members == NULL)
354 	    break;
355 
356 	fprintf(codefile, "{\n");
357 	fprintf(codefile, "unsigned int members = 0;\n");
358 	fprintf(codefile, "while(len > 0) {\n");
359 	fprintf(codefile,
360 		"Der_class class;\n"
361 		"Der_type type;\n"
362 		"int tag;\n"
363 		"e = der_get_tag (p, len, &class, &type, &tag, NULL);\n"
364 		"if(e) %s;\n", forwstr);
365 	fprintf(codefile, "switch (MAKE_TAG(class, type, tag)) {\n");
366 	memno = 0;
367 	ASN1_TAILQ_FOREACH(m, t->members, members) {
368 	    char *s;
369 
370 	    assert(m->type->type == TTag);
371 
372 	    fprintf(codefile, "case MAKE_TAG(%s, %s, %s):\n",
373 		    classname(m->type->tag.tagclass),
374 		    is_primitive_type(m->type->subtype->type) ? "PRIM" : "CONS",
375 		    valuename(m->type->tag.tagclass, m->type->tag.tagvalue));
376 
377 	    asprintf (&s, "%s(%s)->%s", m->optional ? "" : "&", name, m->gen_name);
378 	    if (s == NULL)
379 		errx(1, "malloc");
380 	    if(m->optional)
381 		fprintf(codefile,
382 			"%s = calloc(1, sizeof(*%s));\n"
383 			"if (%s == NULL) { e = ENOMEM; %s; }\n",
384 			s, s, s, forwstr);
385 	    decode_type (s, m->type, 0, forwstr, m->gen_name);
386 	    free (s);
387 
388 	    fprintf(codefile, "members |= (1 << %d);\n", memno);
389 	    memno++;
390 	    fprintf(codefile, "break;\n");
391 	}
392 	fprintf(codefile,
393 		"default:\n"
394 		"return ASN1_MISPLACED_FIELD;\n"
395 		"break;\n");
396 	fprintf(codefile, "}\n");
397 	fprintf(codefile, "}\n");
398 	memno = 0;
399 	ASN1_TAILQ_FOREACH(m, t->members, members) {
400 	    char *s;
401 
402 	    asprintf (&s, "%s->%s", name, m->gen_name);
403 	    if (s == NULL)
404 		errx(1, "malloc");
405 	    fprintf(codefile, "if((members & (1 << %d)) == 0)\n", memno);
406 	    if(m->optional)
407 		fprintf(codefile, "%s = NULL;\n", s);
408 	    else if(m->defval)
409 		gen_assign_defval(s, m->defval);
410 	    else
411 		fprintf(codefile, "return ASN1_MISSING_FIELD;\n");
412 	    free(s);
413 	    memno++;
414 	}
415 	fprintf(codefile, "}\n");
416 	break;
417     }
418     case TSetOf:
419     case TSequenceOf: {
420 	char *n;
421 	char *sname;
422 
423 	fprintf (codefile,
424 		 "{\n"
425 		 "size_t %s_origlen = len;\n"
426 		 "size_t %s_oldret = ret;\n"
427 		 "size_t %s_olen = 0;\n"
428 		 "void *%s_tmp;\n"
429 		 "ret = 0;\n"
430 		 "(%s)->len = 0;\n"
431 		 "(%s)->val = NULL;\n",
432 		 tmpstr,
433 		 tmpstr,
434 		 tmpstr,
435 		 tmpstr,
436 		 name,
437 		 name);
438 
439 	fprintf (codefile,
440 		 "while(ret < %s_origlen) {\n"
441 		 "size_t %s_nlen = %s_olen + sizeof(*((%s)->val));\n"
442 		 "if (%s_olen > %s_nlen) { e = ASN1_OVERFLOW; %s; }\n"
443 		 "%s_olen = %s_nlen;\n"
444 		 "%s_tmp = realloc((%s)->val, %s_olen);\n"
445 		 "if (%s_tmp == NULL) { e = ENOMEM; %s; }\n"
446 		 "(%s)->val = %s_tmp;\n",
447 		 tmpstr,
448 		 tmpstr, tmpstr, name,
449 		 tmpstr, tmpstr, forwstr,
450 		 tmpstr, tmpstr,
451 		 tmpstr, name, tmpstr,
452 		 tmpstr, forwstr,
453 		 name, tmpstr);
454 
455 	asprintf (&n, "&(%s)->val[(%s)->len]", name, name);
456 	if (n == NULL)
457 	    errx(1, "malloc");
458 	asprintf (&sname, "%s_s_of", tmpstr);
459 	if (sname == NULL)
460 	    errx(1, "malloc");
461 	decode_type (n, t->subtype, 0, forwstr, sname);
462 	fprintf (codefile,
463 		 "(%s)->len++;\n"
464 		 "len = %s_origlen - ret;\n"
465 		 "}\n"
466 		 "ret += %s_oldret;\n"
467 		 "}\n",
468 		 name,
469 		 tmpstr, tmpstr);
470 	if (t->range)
471 	    range_check(name, "len", forwstr, t->range);
472 	free (n);
473 	free (sname);
474 	break;
475     }
476     case TGeneralizedTime:
477 	decode_primitive ("generalized_time", name, forwstr);
478 	break;
479     case TGeneralString:
480 	decode_primitive ("general_string", name, forwstr);
481 	break;
482     case TTag:{
483     	char *tname;
484 
485 	fprintf(codefile,
486 		"{\n"
487 		"size_t %s_datalen, %s_oldlen;\n",
488 		tmpstr, tmpstr);
489 	if(dce_fix)
490 	    fprintf(codefile,
491 		    "int dce_fix;\n");
492 	fprintf(codefile, "e = der_match_tag_and_length(p, len, %s, %s, %s, "
493 		"&%s_datalen, &l);\n",
494 		classname(t->tag.tagclass),
495 		is_primitive_type(t->subtype->type) ? "PRIM" : "CONS",
496 		valuename(t->tag.tagclass, t->tag.tagvalue),
497 		tmpstr);
498 	if(optional) {
499 	    fprintf(codefile,
500 		    "if(e) {\n"
501 		    "%s = NULL;\n"
502 		    "} else {\n"
503 		     "%s = calloc(1, sizeof(*%s));\n"
504 		     "if (%s == NULL) { e = ENOMEM; %s; }\n",
505 		     name, name, name, name, forwstr);
506 	} else {
507 	    fprintf(codefile, "if(e) %s;\n", forwstr);
508 	}
509 	fprintf (codefile,
510 		 "p += l; len -= l; ret += l;\n"
511 		 "%s_oldlen = len;\n",
512 		 tmpstr);
513 	if(dce_fix)
514 	    fprintf (codefile,
515 		     "if((dce_fix = _heim_fix_dce(%s_datalen, &len)) < 0)\n"
516 		     "{ e = ASN1_BAD_FORMAT; %s; }\n",
517 		     tmpstr, forwstr);
518 	else
519 	    fprintf(codefile,
520 		    "if (%s_datalen > len) { e = ASN1_OVERRUN; %s; }\n"
521 		    "len = %s_datalen;\n", tmpstr, forwstr, tmpstr);
522 	asprintf (&tname, "%s_Tag", tmpstr);
523 	if (tname == NULL)
524 	    errx(1, "malloc");
525 	decode_type (name, t->subtype, 0, forwstr, tname);
526 	if(dce_fix)
527 	    fprintf(codefile,
528 		    "if(dce_fix){\n"
529 		    "e = der_match_tag_and_length (p, len, "
530 		    "(Der_class)0,(Der_type)0, UT_EndOfContent, "
531 		    "&%s_datalen, &l);\n"
532 		    "if(e) %s;\np += l; len -= l; ret += l;\n"
533 		    "} else \n", tmpstr, forwstr);
534 	fprintf(codefile,
535 		"len = %s_oldlen - %s_datalen;\n",
536 		tmpstr, tmpstr);
537 	if(optional)
538 	    fprintf(codefile,
539 		    "}\n");
540 	fprintf(codefile,
541 		"}\n");
542 	free(tname);
543 	break;
544     }
545     case TChoice: {
546 	Member *m, *have_ellipsis = NULL;
547 	const char *els = "";
548 
549 	if (t->members == NULL)
550 	    break;
551 
552 	ASN1_TAILQ_FOREACH(m, t->members, members) {
553 	    const Type *tt = m->type;
554 	    char *s;
555 	    Der_class cl;
556 	    Der_type  ty;
557 	    unsigned  tag;
558 
559 	    if (m->ellipsis) {
560 		have_ellipsis = m;
561 		continue;
562 	    }
563 
564 	    find_tag(tt, &cl, &ty, &tag);
565 
566 	    fprintf(codefile,
567 		    "%sif (der_match_tag(p, len, %s, %s, %s, NULL) == 0) {\n",
568 		    els,
569 		    classname(cl),
570 		    ty ? "CONS" : "PRIM",
571 		    valuename(cl, tag));
572 	    asprintf (&s, "%s(%s)->u.%s", m->optional ? "" : "&",
573 		      name, m->gen_name);
574 	    if (s == NULL)
575 		errx(1, "malloc");
576 	    decode_type (s, m->type, m->optional, forwstr, m->gen_name);
577 	    fprintf(codefile,
578 		    "(%s)->element = %s;\n",
579 		    name, m->label);
580 	    free(s);
581 	    fprintf(codefile,
582 		    "}\n");
583 	    els = "else ";
584 	}
585 	if (have_ellipsis) {
586 	    fprintf(codefile,
587 		    "else {\n"
588 		    "(%s)->u.%s.data = calloc(1, len);\n"
589 		    "if ((%s)->u.%s.data == NULL) {\n"
590 		    "e = ENOMEM; %s;\n"
591 		    "}\n"
592 		    "(%s)->u.%s.length = len;\n"
593 		    "memcpy((%s)->u.%s.data, p, len);\n"
594 		    "(%s)->element = %s;\n"
595 		    "p += len;\n"
596 		    "ret += len;\n"
597 		    "len -= len;\n"
598 		    "}\n",
599 		    name, have_ellipsis->gen_name,
600 		    name, have_ellipsis->gen_name,
601 		    forwstr,
602 		    name, have_ellipsis->gen_name,
603 		    name, have_ellipsis->gen_name,
604 		    name, have_ellipsis->label);
605 	} else {
606 	    fprintf(codefile,
607 		    "else {\n"
608 		    "e = ASN1_PARSE_ERROR;\n"
609 		    "%s;\n"
610 		    "}\n",
611 		    forwstr);
612 	}
613 	break;
614     }
615     case TUTCTime:
616 	decode_primitive ("utctime", name, forwstr);
617 	break;
618     case TUTF8String:
619 	decode_primitive ("utf8string", name, forwstr);
620 	break;
621     case TPrintableString:
622 	decode_primitive ("printable_string", name, forwstr);
623 	break;
624     case TIA5String:
625 	decode_primitive ("ia5_string", name, forwstr);
626 	break;
627     case TBMPString:
628 	decode_primitive ("bmp_string", name, forwstr);
629 	break;
630     case TUniversalString:
631 	decode_primitive ("universal_string", name, forwstr);
632 	break;
633     case TVisibleString:
634 	decode_primitive ("visible_string", name, forwstr);
635 	break;
636     case TNull:
637 	fprintf (codefile, "/* NULL */\n");
638 	break;
639     case TOID:
640 	decode_primitive ("oid", name, forwstr);
641 	break;
642     default :
643 	abort ();
644     }
645     return 0;
646 }
647 
648 void
649 generate_type_decode (const Symbol *s)
650 {
651     int preserve = preserve_type(s->name) ? TRUE : FALSE;
652 
653     fprintf (headerfile,
654 	     "int    "
655 	     "decode_%s(const unsigned char *, size_t, %s *, size_t *);\n",
656 	     s->gen_name, s->gen_name);
657 
658     fprintf (codefile, "int\n"
659 	     "decode_%s(const unsigned char *p,"
660 	     " size_t len, %s *data, size_t *size)\n"
661 	     "{\n",
662 	     s->gen_name, s->gen_name);
663 
664     switch (s->type->type) {
665     case TInteger:
666     case TBoolean:
667     case TOctetString:
668     case TOID:
669     case TGeneralizedTime:
670     case TGeneralString:
671     case TUTF8String:
672     case TPrintableString:
673     case TIA5String:
674     case TBMPString:
675     case TUniversalString:
676     case TVisibleString:
677     case TUTCTime:
678     case TNull:
679     case TEnumerated:
680     case TBitString:
681     case TSequence:
682     case TSequenceOf:
683     case TSet:
684     case TSetOf:
685     case TTag:
686     case TType:
687     case TChoice:
688 	fprintf (codefile,
689 		 "size_t ret = 0;\n"
690 		 "size_t l;\n"
691 		 "int e;\n");
692 	if (preserve)
693 	    fprintf (codefile, "const unsigned char *begin = p;\n");
694 
695 	fprintf (codefile, "\n");
696 	fprintf (codefile, "memset(data, 0, sizeof(*data));\n"); /* hack to avoid `unused variable' */
697 
698 	decode_type ("data", s->type, 0, "goto fail", "Top");
699 	if (preserve)
700 	    fprintf (codefile,
701 		     "data->_save.data = calloc(1, ret);\n"
702 		     "if (data->_save.data == NULL) { \n"
703 		     "e = ENOMEM; goto fail; \n"
704 		     "}\n"
705 		     "data->_save.length = ret;\n"
706 		     "memcpy(data->_save.data, begin, ret);\n");
707 	fprintf (codefile,
708 		 "if(size) *size = ret;\n"
709 		 "return 0;\n");
710 	fprintf (codefile,
711 		 "fail:\n"
712 		 "free_%s(data);\n"
713 		 "return e;\n",
714 		 s->gen_name);
715 	break;
716     default:
717 	abort ();
718     }
719     fprintf (codefile, "}\n\n");
720 }
721