BIT STRING now stores the number of unused octets in a separate field.

13 files changed, 174 insertions, 144 deletions

diff --git a/ChangeLog b/ChangeLog
index dc3f32ef..9e990741 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,7 @@
 	* Fixed CHOICE code spin when indefinite length structures appear
 	  in the extensions (Severity: medium, Security impact: medium).
 	  Reported by <siden@ul-gsm.ru>.
+	* BIT STRING now stores the number of unused octets in a separate field.
 
 0.9.6:	2004-Sep-29
 
diff --git a/asn1c/tests/check-25.c b/asn1c/tests/check-25.c
index 9352a802..f2145dab 100644
--- a/asn1c/tests/check-25.c
+++ b/asn1c/tests/check-25.c
@@ -105,18 +105,19 @@ check(int is_ok, uint8_t *buf, int size, size_t consumed) {
 		assert(strcmp(t.e->buf, "xyz") == 0);
 		assert(strcmp(t.f->buf, "love_it") == 0);
 
-		assert(t.g->size == 3);
-		assert(t.g->buf[0] == 2);
-		assert(t.g->buf[1] == 147);
-		assert(t.g->buf[2] != 150);
-		assert(t.g->buf[2] == 148);
+		assert(t.g->size == 2);
+		assert(t.g->bits_unused == 2);
+		printf("%d %d\n", t.g->buf[0], t.g->buf[1]);
+		assert(t.g->buf[0] == 147);
+		assert(t.g->buf[1] != 150);
+		assert(t.g->buf[1] == 148);
 
 		printf("%d\n", t.h->buf[3]);
-		assert(t.h->size == 4);
-		assert(t.h->buf[0] == 1);
-		assert(t.h->buf[1] == 140);
-		assert(t.h->buf[2] == 141);
-		assert(t.h->buf[3] == 142);
+		assert(t.h->size == 3);
+		assert(t.h->bits_unused == 1);
+		assert(t.h->buf[0] == 140);
+		assert(t.h->buf[1] == 141);
+		assert(t.h->buf[2] == 142);
 	} else {
 		if(rval.code == RC_OK) {
 			assert(t.a.size != 2
@@ -127,9 +128,9 @@ check(int is_ok, uint8_t *buf, int size, size_t consumed) {
 			|| !t.f
 			|| t.f->size != 7
 			|| !t.g
-			|| t.g->size != 3
+			|| t.g->size != 2
 			|| !t.h
-			|| t.h->size != 4
+			|| t.h->size != 3
 			);
 		}
 		fprintf(stderr, "%d %d\n", (int)rval.consumed, (int)consumed);
diff --git a/examples/sample.source.PKIX1/Makefile b/examples/sample.source.PKIX1/Makefile
index b97d035c..949021a8 100644
--- a/examples/sample.source.PKIX1/Makefile
+++ b/examples/sample.source.PKIX1/Makefile
@@ -256,8 +256,6 @@ ASN_MODULE_HEADERS=	\
 
 ASN_MODULE_HEADERS+=ANY.h
 ASN_MODULE_SOURCES+=ANY.c
-ASN_MODULE_HEADERS+=BIT_STRING.h
-ASN_MODULE_SOURCES+=BIT_STRING.c
 ASN_MODULE_HEADERS+=BMPString.h
 ASN_MODULE_SOURCES+=BMPString.c
 ASN_MODULE_HEADERS+=BOOLEAN.h
@@ -305,6 +303,8 @@ ASN_MODULE_HEADERS+=asn_internal.h
 ASN_MODULE_HEADERS+=asn_types.h
 ASN_MODULE_HEADERS+=OCTET_STRING.h
 ASN_MODULE_SOURCES+=OCTET_STRING.c
+ASN_MODULE_HEADERS+=BIT_STRING.h
+ASN_MODULE_SOURCES+=BIT_STRING.c
 ASN_MODULE_HEADERS+=ber_decoder.h
 ASN_MODULE_SOURCES+=ber_decoder.c
 ASN_MODULE_SOURCES+=ber_codec_prim.c
diff --git a/libasn1parser/Makefile.in b/libasn1parser/Makefile.in
index cb9ebd03..76a6ef23 100644
--- a/libasn1parser/Makefile.in
+++ b/libasn1parser/Makefile.in
@@ -448,8 +448,8 @@ maintainer-clean-generic:
 	@echo "This command is intended for maintainers to use"
 	@echo "it deletes files that may require special tools to rebuild."
 	-rm -f asn1p_l.c
-	-rm -f asn1p_y.c
 	-rm -f asn1p_y.h
+	-rm -f asn1p_y.c
 clean: clean-am
 
 clean-am: clean-generic clean-libtool clean-noinstLTLIBRARIES \
diff --git a/skeletons/ANY.c b/skeletons/ANY.c
index ae19ab5d..d501ca1a 100644
--- a/skeletons/ANY.c
+++ b/skeletons/ANY.c
@@ -7,6 +7,11 @@
 #include <assert.h>
 #include <errno.h>
 
+static asn_OCTET_STRING_specifics_t asn_DEF_ANY_specs = {
+	sizeof(ANY_t),
+	offsetof(ANY_t, _asn_ctx),
+	2	/* Special indicator that this is an ANY type */
+};
 asn_TYPE_descriptor_t asn_DEF_ANY = {
 	"ANY",
 	OCTET_STRING_free,
@@ -19,7 +24,7 @@ asn_TYPE_descriptor_t asn_DEF_ANY = {
 	0, /* Use generic outmost tag fetcher */
 	0, 0, 0, 0,
 	0, 0,	/* No members */
-	(void *)2	/* Special indicator that this is an ANY type */
+	&asn_DEF_ANY_specs,
 };
 
 
@@ -94,7 +99,7 @@ ANY_new_fromType(asn_TYPE_descriptor_t *td, void *sptr) {
 
 	if(ANY_fromType(&tmp, td, sptr)) return 0;
 
-	st = (ANY_t *)MALLOC(sizeof(*st));
+	st = (ANY_t *)CALLOC(1, sizeof(ANY_t *));
 	if(st) {
 		*st = tmp;
 		return st;
diff --git a/skeletons/ANY.h b/skeletons/ANY.h
index 588f2951..cabc411b 100644
--- a/skeletons/ANY.h
+++ b/skeletons/ANY.h
@@ -5,7 +5,7 @@
 #ifndef ASN_TYPE_ANY_H
 #define ASN_TYPE_ANY_H
 
-#include <OCTET_STRING.h>	/* Implemented via OCTET SRING type */
+#include <OCTET_STRING.h>	/* Implemented via OCTET STRING type */
 
 typedef struct ANY {
 	uint8_t *buf;	/* BER-encoded ANY contents */
diff --git a/skeletons/BIT_STRING.c b/skeletons/BIT_STRING.c
index 19c81e72..6c582a04 100644
--- a/skeletons/BIT_STRING.c
+++ b/skeletons/BIT_STRING.c
@@ -12,6 +12,11 @@
 static ber_tlv_tag_t asn_DEF_BIT_STRING_tags[] = {
 	(ASN_TAG_CLASS_UNIVERSAL | (3 << 2))
 };
+static asn_OCTET_STRING_specifics_t asn_DEF_BIT_STRING_specs = {
+	sizeof(BIT_STRING_t),
+	offsetof(BIT_STRING_t, _asn_ctx),
+	1,	/* Special indicator that this is a BIT STRING type */
+};
 asn_TYPE_descriptor_t asn_DEF_BIT_STRING = {
 	"BIT STRING",
 	OCTET_STRING_free,         /* Implemented in terms of OCTET STRING */
@@ -29,7 +34,7 @@ asn_TYPE_descriptor_t asn_DEF_BIT_STRING = {
 	sizeof(asn_DEF_BIT_STRING_tags)
 	  / sizeof(asn_DEF_BIT_STRING_tags[0]),
 	0, 0,	/* No members */
-	(void *)1	/* Special indicator that this is a BIT STRING */
+	&asn_DEF_BIT_STRING_specs
 };
 
 /*
@@ -41,16 +46,9 @@ BIT_STRING_constraint(asn_TYPE_descriptor_t *td, const void *sptr,
 	const BIT_STRING_t *st = (const BIT_STRING_t *)sptr;
 
 	if(st && st->buf) {
-		if(st->size) {
-			if(st->size == 1 && st->buf[0] != 0) {
-				_ASN_ERRLOG(app_errlog, app_key,
-					"%s: invalid padding byte (%s:%d)",
-					td->name, __FILE__, __LINE__);
-				return -1;
-			}
-		} else {
+		if(st->size == 1 && st->bits_unused) {
 			_ASN_ERRLOG(app_errlog, app_key,
-				"%s: no padding byte (%s:%d)",
+				"%s: invalid padding byte (%s:%d)",
 				td->name, __FILE__, __LINE__);
 			return -1;
 		}
@@ -93,9 +91,9 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
 	/*
 	 * Binary dump
 	 */
-	for(buf++; buf < end; buf++) {
+	for(; buf < end; buf++) {
 		int v = *buf;
-		int nline = xcan?0:((((buf - st->buf) - 1) % 8) == 0);
+		int nline = xcan?0:(((buf - st->buf) % 8) == 0);
 		if(p >= scend || nline) {
 			er.encoded += p - scratch;
 			_ASN_CALLBACK(scratch, p - scratch);
@@ -107,7 +105,7 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
 		p += 8;
 	}
 
-	if(!xcan && (((buf - st->buf) - 1) % 8) == 0)
+	if(!xcan && ((buf - st->buf) % 8) == 0)
 		_i_ASN_TEXT_INDENT(1, ilevel);
 	er.encoded += p - scratch;
 	_ASN_CALLBACK(scratch, p - scratch);
@@ -115,9 +113,9 @@ BIT_STRING_encode_xer(asn_TYPE_descriptor_t *td, void *sptr,
 
 	if(buf == end) {
 		int v = *buf;
-		int mbit = st->buf[0];	/* bits to skip from the right */
+		int ubits = st->bits_unused;
 		int i;
-		for(i = 7; i >= mbit; i--)
+		for(i = 7; i >= ubits; i--)
 			*p++ = (v & (1 << i)) ? 0x31 : 0x30;
 		er.encoded += p - scratch;
 		_ASN_CALLBACK(scratch, p - scratch);
@@ -156,9 +154,9 @@ BIT_STRING_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
 	/*
 	 * Hexadecimal dump.
 	 */
-	for(buf++; buf < end; buf++) {
-		if(((buf - st->buf) - 1) % 16 == 0 && (st->size > 17)
-				&& buf != st->buf+1) {
+	for(; buf < end; buf++) {
+		if((buf - st->buf) % 16 == 0 && (st->size > 16)
+				&& buf != st->buf) {
 			_i_INDENT(1);
 			/* Dump the string */
 			if(cb(scratch, p - scratch, app_key) < 0) return -1;
@@ -172,7 +170,7 @@ BIT_STRING_print(asn_TYPE_descriptor_t *td, const void *sptr, int ilevel,
 	if(p > scratch) {
 		p--;	/* Eat the tailing space */
 
-		if((st->size > 17)) {
+		if((st->size > 16)) {
 			_i_INDENT(1);
 		}
 
diff --git a/skeletons/BIT_STRING.h b/skeletons/BIT_STRING.h
index 665d036d..1601231f 100644
--- a/skeletons/BIT_STRING.h
+++ b/skeletons/BIT_STRING.h
@@ -5,9 +5,16 @@
 #ifndef	_BIT_STRING_H_
 #define	_BIT_STRING_H_
 
-#include <OCTET_STRING.h>
+#include <OCTET_STRING.h>	/* Some help from OCTET STRING */
 
-typedef OCTET_STRING_t BIT_STRING_t; /* Implemented via OCTET STRING */
+typedef struct BIT_STRING_s {
+	uint8_t *buf;	/* BIT STRING body */
+	int size;	/* Size of the above buffer */
+
+	int bits_unused;/* Unused trailing bits in the last octet (0..7) */
+
+	asn_struct_ctx_t _asn_ctx;	/* Parsing across buffer boundaries */
+} BIT_STRING_t;
 
 extern asn_TYPE_descriptor_t asn_DEF_BIT_STRING;
 
diff --git a/skeletons/OCTET_STRING.c b/skeletons/OCTET_STRING.c
index 3ba25abe..66f3a4ba 100644
--- a/skeletons/OCTET_STRING.c
+++ b/skeletons/OCTET_STRING.c
@@ -4,6 +4,7 @@
  */
 #include <asn_internal.h>
 #include <OCTET_STRING.h>
+#include <BIT_STRING.h>	/* for .bits_unused member */
 #include <assert.h>
 #include <errno.h>
 
@@ -13,6 +14,11 @@
 static ber_tlv_tag_t asn_DEF_OCTET_STRING_tags[] = {
 	(ASN_TAG_CLASS_UNIVERSAL | (4 << 2))
 };
+static asn_OCTET_STRING_specifics_t asn_DEF_OCTET_STRING_specs = {
+	sizeof(OCTET_STRING_t),
+	offsetof(OCTET_STRING_t, _asn_ctx),
+	0
+};
 asn_TYPE_descriptor_t asn_DEF_OCTET_STRING = {
 	"OCTET STRING",
 	OCTET_STRING_free,
@@ -30,7 +36,7 @@ asn_TYPE_descriptor_t asn_DEF_OCTET_STRING = {
 	sizeof(asn_DEF_OCTET_STRING_tags)
 	  / sizeof(asn_DEF_OCTET_STRING_tags[0]),
 	0, 0,	/* No members */
-	0	/* No specifics */
+	&asn_DEF_OCTET_STRING_specs
 };
 
 #undef	_CH_PHASE
@@ -148,12 +154,7 @@ OS__add_stack_el(struct _stack *st) {
 
 static struct _stack *
 _new_stack() {
-	struct _stack *st;
-	(void *)st = CALLOC(1, sizeof(struct _stack));
-	if(st == NULL)
-		return NULL;
-
-	return st;
+	return (struct _stack *)CALLOC(1, sizeof(struct _stack));
 }
 
 /*
@@ -163,31 +164,34 @@ ber_dec_rval_t
 OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 	asn_TYPE_descriptor_t *td,
 	void **os_structure, void *buf_ptr, size_t size, int tag_mode) {
-	OCTET_STRING_t *st = (OCTET_STRING_t *)*os_structure;
+	asn_OCTET_STRING_specifics_t *specs = td->specifics
+				? td->specifics : &asn_DEF_OCTET_STRING_specs;
+	BIT_STRING_t *st = (BIT_STRING_t *)*os_structure;
 	ber_dec_rval_t rval;
 	asn_struct_ctx_t *ctx;
 	ssize_t consumed_myself = 0;
-	struct _stack *stck;	/* A stack structure */
+	struct _stack *stck;		/* Expectations stack structure */
 	struct _stack_el *sel = 0;	/* Stack element */
 	int tlv_constr;
-	OS_type_e type_type = (OS_type_e)(int)td->specifics;
+	OS_type_e type_variant = (OS_type_e)specs->subvariant;
 
 	ASN_DEBUG("Decoding %s as %s (frame %ld)",
 		td->name,
-		(type_type == _TT_GENERIC) ? "OCTET STRING" : "OS-SpecialCase",
+		(type_variant == _TT_GENERIC) ?
+			"OCTET STRING" : "OS-SpecialCase",
 		(long)size);
 
 	/*
 	 * Create the string if does not exist.
 	 */
 	if(st == NULL) {
-		(void *)st = *os_structure = CALLOC(1, sizeof(*st));
+		(void *)st = *os_structure = CALLOC(1, specs->struct_size);
 		if(st == NULL)
 			RETURN(RC_FAIL);
 	}
 
 	/* Restore parsing context */
-	ctx = &st->_asn_ctx;
+	ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
 
 	switch(ctx->phase) {
 	case 0:
@@ -207,10 +211,6 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 			ctx->ptr = _new_stack();
 			if(ctx->ptr) {
 				(void *)stck = ctx->ptr;
-				if(type_type == _TT_BIT_STRING) {
-					/* Number of meaningless tail bits */
-					APPEND("\0", 1);
-				}
 			} else {
 				RETURN(RC_FAIL);
 			}
@@ -219,7 +219,7 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 			 * Jump into stackless primitive decoding.
 			 */
 			_CH_PHASE(ctx, 3);
-			if(type_type == _TT_ANY && tag_mode != 1)
+			if(type_variant == _TT_ANY && tag_mode != 1)
 				APPEND(buf_ptr, rval.consumed);
 			ADVANCE(rval.consumed);
 			goto phase3;
@@ -296,7 +296,7 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 
 			ASN_DEBUG("Eat EOC; wn=%d--", sel->want_nulls);
 
-			if(type_type == _TT_ANY
+			if(type_variant == _TT_ANY
 			&& (tag_mode != 1 || sel->cont_level))
 				APPEND("\0\0", 2);
 
@@ -320,7 +320,7 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 		 * Set up expected tags,
 		 * depending on ASN.1 type being decoded.
 		 */
-		switch(type_type) {
+		switch(type_variant) {
 		case _TT_BIT_STRING:
 			/* X.690: 8.6.4.1, NOTE 2 */
 			/* Fall through */
@@ -384,7 +384,7 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 		} else {
 			sel->left = tlv_len;
 		}
-		if(type_type == _TT_ANY
+		if(type_variant == _TT_ANY
 		&& (tag_mode != 1 || sel->cont_level))
 			APPEND(buf_ptr, tlvl);
 		sel->got += tlvl;
@@ -417,16 +417,11 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 		len = ((ber_tlv_len_t)size < sel->left)
 				? (ber_tlv_len_t)size : sel->left;
 		if(len > 0) {
-			if(type_type == _TT_BIT_STRING
+			if(type_variant == _TT_BIT_STRING
 			&& sel->bits_chopped == 0) {
-				/*
-				 * Finalize the previous chunk:
-				 * strip down unused bits.
-				 */
-				st->buf[st->size-1] &= 0xff << st->buf[0];
-
+				/* Put the unused-bits-octet away */
+				st->bits_unused = *(uint8_t *)buf_ptr;
 				APPEND(((char *)buf_ptr+1), (len - 1));
-				st->buf[0] = *(uint8_t *)buf_ptr;
 				sel->bits_chopped = 1;
 			} else {
 				APPEND(buf_ptr, len);
@@ -451,12 +446,27 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 		/*
 		 * Primitive form, no stack required.
 		 */
+		assert(ctx->left >= 0);
+
 		if(size < (size_t)ctx->left) {
+			if(!size) RETURN(RC_WMORE);
+			if(type_variant == _TT_BIT_STRING && ctx->step == 0) {
+				st->bits_unused = *(uint8_t *)buf_ptr;
+				ctx->left--;
+				ADVANCE(1);
+			}
 			APPEND(buf_ptr, size);
+			assert(ctx->step);
 			ctx->left -= size;
 			ADVANCE(size);
 			RETURN(RC_WMORE);
 		} else {
+			if(type_variant == _TT_BIT_STRING
+			&& ctx->step == 0 && ctx->left) {
+				st->bits_unused = *(uint8_t *)buf_ptr;
+				ctx->left--;
+				ADVANCE(1);
+			}
 			APPEND(buf_ptr, ctx->left);
 			ADVANCE(ctx->left);
 			ctx->left = 0;
@@ -478,14 +488,15 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
 	/*
 	 * BIT STRING-specific processing.
 	 */
-	if(type_type == _TT_BIT_STRING && st->size >= 2) {
+	if(type_variant == _TT_BIT_STRING && st->size) {
 		/* Finalize BIT STRING: zero out unused bits. */
-		st->buf[st->size-1] &= 0xff << st->buf[0];
+		st->buf[st->size-1] &= 0xff << st->bits_unused;
 	}
 
 	ASN_DEBUG("Took %d bytes to encode %s: [%s]:%d",
 		consumed_myself, td->name,
-		(type_type == _TT_GENERIC) ? (char *)st->buf : "", st->size);
+		(type_variant == _TT_GENERIC) ? (char *)st->buf : "<data>",
+		st->size);
 
 
 	RETURN(RC_OK);
@@ -495,79 +506,65 @@ OCTET_STRING_decode_ber(asn_codec_ctx_t *opt_codec_ctx,
  * Encode OCTET STRING type using DER.
  */
 asn_enc_rval_t
-OCTET_STRING_encode_der(asn_TYPE_descriptor_t *td, void *ptr,
+OCTET_STRING_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_enc_rval_t erval;
-	OCTET_STRING_t *st = (OCTET_STRING_t *)ptr;
-	int add_byte = 0;
-	OS_type_e type_type = (OS_type_e)(int)td->specifics;
+	asn_enc_rval_t er;
+	asn_OCTET_STRING_specifics_t *specs = td->specifics
+				? td->specifics : &asn_DEF_OCTET_STRING_specs;
+	BIT_STRING_t *st = (BIT_STRING_t *)sptr;
+	OS_type_e type_variant = (OS_type_e)specs->subvariant;
+	int fix_last_byte = 0;
 
 	ASN_DEBUG("%s %s as OCTET STRING",
 		cb?"Estimating":"Encoding", td->name);
 
 	/*
-	 * Canonicalize BIT STRING.
+	 * Write tags.
 	 */
-	if(type_type == _TT_BIT_STRING) {
-		switch(st->size) {
-		case 0: add_byte = 1; break;
-		case 1: st->buf[0] = 0; break;
-		default:
-			/* Finalize BIT STRING: zero out unused bits. */
-			st->buf[st->size-1] &= 0xff << st->buf[0];
+	if(type_variant != _TT_ANY || tag_mode == 1) {
+		er.encoded = der_write_tags(td,
+				(type_variant == _TT_BIT_STRING) + st->size,
+			tag_mode, type_variant == _TT_ANY, tag, cb, app_key);
+		if(er.encoded == -1) {
+			er.failed_type = td;
+			er.structure_ptr = sptr;
+			return er;
 		}
+	} else {
+		/* Disallow: [<tag>] IMPLICIT ANY */
+		assert(type_variant != _TT_ANY || tag_mode != -1);
+		er.encoded = 0;
+	}
+
+	if(!cb) {
+		er.encoded += (type_variant == _TT_BIT_STRING) + st->size;
+		return er;
 	}
 
 	/*
-	 * Write tags.
+	 * Prepare to deal with the last octet of BIT STRING.
 	 */
-	if(type_type != _TT_ANY || tag_mode == 1) {
-		erval.encoded = der_write_tags(td, st->size + add_byte,
-			tag_mode, type_type == _TT_ANY, tag, cb, app_key);
-		if(erval.encoded == -1) {
-			erval.failed_type = td;
-			erval.structure_ptr = ptr;
-			return erval;
-		}
-	} else {
-		/* Disallow: [...] IMPLICIT ANY */
-		assert(type_type != _TT_ANY || tag_mode != -1);
-		erval.encoded = 0;
+	if(type_variant == _TT_BIT_STRING) {
+		uint8_t b = st->bits_unused & 0x07;
+		if(b && st->size) fix_last_byte = 1;
+		_ASN_CALLBACK(&b, 1);
+		er.encoded++;
 	}
 
-	if(cb) {
-		uint8_t zero;
-		uint8_t *buf;
-		int size;
-
-		/* BIT STRING-aware handling */
-		if(add_byte) {
-			zero = 0;
-			buf = &zero;
-			size = 1;
-		} else if(st->buf) {
-			buf = st->buf;
-			size = st->size;
-		} else {
-			assert(st->size == 0);
-			buf = 0;	/* Not used */
-			size = 0;
-		}
+	/* Invoke callback for the main part of the buffer */
+	_ASN_CALLBACK(st->buf, st->size - fix_last_byte);
 
-		if(size) {
-			if(cb(buf, size, app_key) < 0) {
-				erval.encoded = -1;
-				erval.failed_type = td;
-				erval.structure_ptr = ptr;
-				return erval;
-			}
-		}
+	/* The last octet should be stripped off the unused bits */
+	if(fix_last_byte) {
+		uint8_t b = st->buf[st->size-1] & (0xff << st->bits_unused);
+		_ASN_CALLBACK(&b, 1);
 	}
 
-	erval.encoded += st->size + add_byte;
-
-	return erval;
+	er.encoded += st->size;
+	return er;
+cb_failed:
+	_ASN_ENCODE_FAILED;
 }
 
 asn_enc_rval_t
@@ -790,7 +787,11 @@ OCTET_STRING_print_ascii(asn_TYPE_descriptor_t *td, const void *sptr,
 void
 OCTET_STRING_free(asn_TYPE_descriptor_t *td, void *sptr, int contents_only) {
 	OCTET_STRING_t *st = (OCTET_STRING_t *)sptr;
-	struct _stack *stck = (struct _stack *)st->_asn_ctx.ptr;
+	asn_OCTET_STRING_specifics_t *specs = td->specifics
+				? td->specifics : &asn_DEF_OCTET_STRING_specs;
+	asn_struct_ctx_t *ctx = (asn_struct_ctx_t *)
+					((char *)st + specs->ctx_offset);
+	struct _stack *stck = ctx->ptr;
 
 	if(!td || !st)
 		return;
@@ -860,10 +861,12 @@ OCTET_STRING_fromBuf(OCTET_STRING_t *st, const char *str, int len) {
 }
 
 OCTET_STRING_t *
-OCTET_STRING_new_fromBuf(const char *str, int len) {
+OCTET_STRING_new_fromBuf(asn_TYPE_descriptor_t *td, const char *str, int len) {
+	asn_OCTET_STRING_specifics_t *specs = td->specifics
+				? td->specifics : &asn_DEF_OCTET_STRING_specs;
 	OCTET_STRING_t *st;
 
-	(void *)st = CALLOC(1, sizeof(*st));
+	st = (OCTET_STRING_t *)CALLOC(1, specs->struct_size);
 	if(st && str && OCTET_STRING_fromBuf(st, str, len)) {
 		free(st);
 		st = NULL;
diff --git a/skeletons/OCTET_STRING.h b/skeletons/OCTET_STRING.h
index 7291585b..dd5262e8 100644
--- a/skeletons/OCTET_STRING.h
+++ b/skeletons/OCTET_STRING.h
@@ -24,9 +24,9 @@ der_type_encoder_f OCTET_STRING_encode_der;
 xer_type_encoder_f OCTET_STRING_encode_xer;
 xer_type_encoder_f OCTET_STRING_encode_xer_ascii;
 
-/***********************************
- * Some handy conversion routines. *
- ***********************************/
+/******************************
+ * Handy conversion routines. *
+ ******************************/
 
 /*
  * This function clears the previous value of the OCTET STRING (if any)
@@ -39,14 +39,29 @@ xer_type_encoder_f OCTET_STRING_encode_xer_ascii;
  */
 int OCTET_STRING_fromBuf(OCTET_STRING_t *s, const char *str, int size);
 
+/* Handy conversion from the C string into the OCTET STRING. */
+#define	OCTET_STRING_fromString(s, str)	OCTET_STRING_fromBuf(s, str, -1);
+
 /*
  * Allocate and fill the new OCTET STRING and return a pointer to the newly
  * allocated object. NULL is permitted in str: the function will just allocate
  * empty OCTET STRING.
  */
-OCTET_STRING_t *OCTET_STRING_new_fromBuf(const char *str, int size);
+OCTET_STRING_t *OCTET_STRING_new_fromBuf(asn_TYPE_descriptor_t *td,
+	const char *str, int size);
 
-/* Handy conversion from the C string into the OCTET STRING. */
-#define	OCTET_STRING_fromString(s, str)	OCTET_STRING_fromBuf(s, str, -1);
+/****************************
+ * Internally useful stuff. *
+ ****************************/
+
+typedef struct asn_OCTET_STRING_specifics_s {
+	/*
+	 * Target structure description.
+	 */
+	int struct_size;	/* Size of the structure */
+	int ctx_offset;		/* Offset of the asn_struct_ctx_t member */
+
+	int subvariant;		/* {0,1,2} for O-S, BIT STRING or ANY */
+} asn_OCTET_STRING_specifics_t;
 
 #endif	/* _OCTET_STRING_H_ */
diff --git a/skeletons/constr_TYPE.h b/skeletons/constr_TYPE.h
index 937ef10e..7e3254ed 100644
--- a/skeletons/constr_TYPE.h
+++ b/skeletons/constr_TYPE.h
@@ -133,14 +133,14 @@ typedef struct asn_TYPE_descriptor_s {
 	int (*xer_decoder);/* PLACEHOLDER */ /* Free-form XER decoder */
 	xer_type_encoder_f *xer_encoder;	/* [Canonical] XER encoder */
 
-	/*
-	 * Functions used internally. Should not be used by applications.
-	 */
-	asn_outmost_tag_f  *outmost_tag;	/* <optional, internal> */
+	/***********************************************************************
+	 * Internally useful members. Not to be used by applications directly. *
+	 **********************************************************************/
 
 	/*
 	 * Tags that are expected to occur.
 	 */
+	asn_outmost_tag_f  *outmost_tag;	/* <optional, internal> */
 	ber_tlv_tag_t *tags;	/* Effective tags sequence for this type */
 	int tags_count;		/* Number of tags which are expected */
 	ber_tlv_tag_t *all_tags;/* Every tag for BER/containment */
diff --git a/skeletons/file-dependencies b/skeletons/file-dependencies
index 9018da07..6b7ac697 100644
--- a/skeletons/file-dependencies
+++ b/skeletons/file-dependencies
@@ -7,7 +7,6 @@
 #
 
 ANY.h ANY.c
-BIT_STRING.h BIT_STRING.c
 BMPString.h BMPString.c
 BOOLEAN.h BOOLEAN.c
 ENUMERATED.h ENUMERATED.c INTEGER.h
@@ -47,6 +46,7 @@ asn_application.h
 asn_internal.h
 asn_types.h
 OCTET_STRING.h OCTET_STRING.c	# This one is used too widely
+BIT_STRING.h BIT_STRING.c	# This one is necessary for the above one
 ber_decoder.h ber_decoder.c
 ber_codec_prim.c ber_codec_prim.h
 ber_tlv_length.h ber_tlv_length.c
diff --git a/skeletons/tests/check-length.c b/skeletons/tests/check-length.c
index c01c5dd0..d76902de 100644
--- a/skeletons/tests/check-length.c
+++ b/skeletons/tests/check-length.c
@@ -40,7 +40,7 @@ check(int size) {
 	ber_dec_rval_t rval;
 	int i;
 
-	os = OCTET_STRING_new_fromBuf(0, size);
+	os = OCTET_STRING_new_fromBuf(&asn_DEF_OCTET_STRING, 0, size);
 	assert(os);
 	assert(os->size == 0);
 
@@ -69,9 +69,9 @@ check(int size) {
 	}
 
 	if(0) {
-	printf("new(%d):", size);
+	fprintf(stderr, "new(%d):", size);
 	for(i = 0; i < (buf_off<10?buf_off:10); i++)
-		printf(" %02x", buf[i]);
+		fprintf(stderr, " %02x", buf[i]);
 	printf("\n");
 	}
 
@@ -90,7 +90,7 @@ main() {
 	int i;
 
 	for(i = 0; i < 66000; i++) {
-		if(i == 4500) i = 64000;
+		if(i == 4500) i = 64000;	/* Jump */
 		check(i);
 	}