--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/util/secasn1e.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,1613 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Support for ENcoding ASN.1 data based on BER/DER (Basic/Distinguished
+ * Encoding Rules).
+ */
+
+#include "secasn1.h"
+
+typedef enum {
+    beforeHeader,
+    duringContents,
+    duringGroup,
+    duringSequence,
+    afterContents,
+    afterImplicit,
+    afterInline,
+    afterPointer,
+    afterChoice,
+    notInUse
+} sec_asn1e_parse_place;
+
+typedef enum {
+    allDone,
+    encodeError,
+    keepGoing,
+    needBytes
+} sec_asn1e_parse_status;
+
+typedef enum {
+    hdr_normal      = 0,  /* encode header normally */
+    hdr_any         = 1,  /* header already encoded in content */
+    hdr_decoder     = 2,  /* template only used by decoder. skip it. */
+    hdr_optional    = 3,  /* optional component, to be omitted */
+    hdr_placeholder = 4   /* place holder for from_buf content */
+} sec_asn1e_hdr_encoding;
+
+typedef struct sec_asn1e_state_struct {
+    SEC_ASN1EncoderContext *top;
+    const SEC_ASN1Template *theTemplate;
+    void *src;
+
+    struct sec_asn1e_state_struct *parent;	/* aka prev */
+    struct sec_asn1e_state_struct *child;	/* aka next */
+
+    sec_asn1e_parse_place place;	/* where we are in encoding process */
+
+    /*
+     * XXX explain the next fields as clearly as possible...
+     */
+    unsigned char tag_modifiers;
+    unsigned char tag_number;
+    unsigned long underlying_kind;
+
+    int depth;
+
+    PRBool isExplicit,		/* we are handling an isExplicit header */
+	   indefinite,		/* need end-of-contents */
+	   is_string,		/* encoding a simple string or an ANY */
+	   may_stream,		/* when streaming, do indefinite encoding */
+	   optional,		/* omit field if it has no contents */
+	   disallowStreaming;	/* disallow streaming in all sub-templates */	
+} sec_asn1e_state;
+
+/*
+ * An "outsider" will have an opaque pointer to this, created by calling
+ * SEC_ASN1EncoderStart().  It will be passed back in to all subsequent
+ * calls to SEC_ASN1EncoderUpdate() and related routines, and when done
+ * it is passed to SEC_ASN1EncoderFinish().
+ */
+struct sec_EncoderContext_struct {
+    PLArenaPool *our_pool;		/* for our internal allocs */
+
+    sec_asn1e_state *current;
+    sec_asn1e_parse_status status;
+
+    PRBool streaming;
+    PRBool from_buf;
+
+    SEC_ASN1NotifyProc notify_proc;	/* call before/after handling field */
+    void *notify_arg;			/* argument to notify_proc */
+    PRBool during_notify;		/* true during call to notify_proc */
+
+    SEC_ASN1WriteProc output_proc;	/* pass encoded bytes to this  */
+    void *output_arg;			/* argument to that function */
+};
+
+
+static sec_asn1e_state *
+sec_asn1e_push_state (SEC_ASN1EncoderContext *cx,
+		      const SEC_ASN1Template *theTemplate,
+		      const void *src, PRBool new_depth)
+{
+    sec_asn1e_state *state, *new_state;
+
+    state = cx->current;
+
+    new_state = (sec_asn1e_state*)PORT_ArenaZAlloc (cx->our_pool, 
+						    sizeof(*new_state));
+    if (new_state == NULL) {
+	cx->status = encodeError;
+	return NULL;
+    }
+
+    new_state->top = cx;
+    new_state->parent = state;
+    new_state->theTemplate = theTemplate;
+    new_state->place = notInUse;
+    if (src != NULL)
+	new_state->src = (char *)src + theTemplate->offset;
+
+    if (state != NULL) {
+	new_state->depth = state->depth;
+	if (new_depth)
+	    new_state->depth++;
+	state->child = new_state;
+    }
+
+    cx->current = new_state;
+    return new_state;
+}
+
+
+static void
+sec_asn1e_scrub_state (sec_asn1e_state *state)
+{
+    /*
+     * Some default "scrubbing".
+     * XXX right set of initializations?
+     */
+    state->place = beforeHeader;
+    state->indefinite = PR_FALSE;
+}
+
+
+static void
+sec_asn1e_notify_before (SEC_ASN1EncoderContext *cx, void *src, int depth)
+{
+    if (cx->notify_proc == NULL)
+	return;
+
+    cx->during_notify = PR_TRUE;
+    (* cx->notify_proc) (cx->notify_arg, PR_TRUE, src, depth);
+    cx->during_notify = PR_FALSE;
+}
+
+
+static void
+sec_asn1e_notify_after (SEC_ASN1EncoderContext *cx, void *src, int depth)
+{
+    if (cx->notify_proc == NULL)
+	return;
+
+    cx->during_notify = PR_TRUE;
+    (* cx->notify_proc) (cx->notify_arg, PR_FALSE, src, depth);
+    cx->during_notify = PR_FALSE;
+}
+
+
+static sec_asn1e_state *
+sec_asn1e_init_state_based_on_template (sec_asn1e_state *state)
+{
+    PRBool isExplicit, is_string, may_stream, optional, universal; 
+    PRBool disallowStreaming;
+    unsigned char tag_modifiers;
+    unsigned long encode_kind, under_kind;
+    unsigned long tag_number;
+    PRBool isInline = PR_FALSE;
+
+
+    encode_kind = state->theTemplate->kind;
+
+    universal = ((encode_kind & SEC_ASN1_CLASS_MASK) == SEC_ASN1_UNIVERSAL)
+		? PR_TRUE : PR_FALSE;
+
+    isExplicit = (encode_kind & SEC_ASN1_EXPLICIT) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_EXPLICIT;
+
+    optional = (encode_kind & SEC_ASN1_OPTIONAL) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_OPTIONAL;
+
+    PORT_Assert (!(isExplicit && universal));	/* bad templates */
+
+    may_stream = (encode_kind & SEC_ASN1_MAY_STREAM) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_MAY_STREAM;
+
+    disallowStreaming = (encode_kind & SEC_ASN1_NO_STREAM) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_NO_STREAM;
+
+    /* Just clear this to get it out of the way; we do not need it here */
+    encode_kind &= ~SEC_ASN1_DYNAMIC;
+
+    if( encode_kind & SEC_ASN1_CHOICE ) {
+      under_kind = SEC_ASN1_CHOICE;
+    } else if ((encode_kind & (SEC_ASN1_POINTER | SEC_ASN1_INLINE)) || 
+        (!universal && !isExplicit)) {
+	const SEC_ASN1Template *subt;
+	void *src = NULL;
+
+	PORT_Assert ((encode_kind & (SEC_ASN1_ANY | SEC_ASN1_SKIP)) == 0);
+
+	sec_asn1e_scrub_state (state);
+
+	if (encode_kind & SEC_ASN1_POINTER) {
+	    src = *(void **)state->src;
+	    state->place = afterPointer;
+
+	    if (src == NULL) {
+		/*
+		 * If this is optional, but NULL, then the field does
+		 * not need to be encoded.  In this case we are done;
+		 * we do not want to push a subtemplate.
+		 */
+		if (optional)
+		    return state;
+
+		/*
+		 * XXX this is an error; need to figure out
+		 * how to handle this
+		 */
+	    }
+	} else {
+	    src = state->src;
+	    if (encode_kind & SEC_ASN1_INLINE) {
+		/* check that there are no extraneous bits */
+		/* PORT_Assert (encode_kind == SEC_ASN1_INLINE && !optional); */
+		state->place = afterInline;
+		isInline = PR_TRUE;
+	    } else {
+		/*
+		 * Save the tag modifiers and tag number here before moving
+		 * on to the next state in case this is a member of a
+		 * SEQUENCE OF
+		 */
+		state->tag_modifiers = (unsigned char)
+		    (encode_kind & (SEC_ASN1_TAG_MASK & ~SEC_ASN1_TAGNUM_MASK));
+		state->tag_number = (unsigned char)
+		    (encode_kind & SEC_ASN1_TAGNUM_MASK);
+		
+		state->place = afterImplicit;
+		state->optional = optional;
+	    }
+	}
+
+	subt = SEC_ASN1GetSubtemplate (state->theTemplate, state->src, PR_TRUE);
+	if (isInline && optional) {
+	    /* we only handle a very limited set of optional inline cases at
+	       this time */
+	    if (PR_FALSE != SEC_ASN1IsTemplateSimple(subt)) {
+		/* we now know that the target is a SECItem*, so we can check
+		   if the source contains one */
+		SECItem* target = (SECItem*)state->src;
+		if (!target || !target->data || !target->len) {
+		    /* no valid data to encode subtemplate */
+		    return state;
+		}
+	    } else {
+		PORT_Assert(0); /* complex templates are not handled as
+				   inline optional */
+	    }
+	}
+	state = sec_asn1e_push_state (state->top, subt, src, PR_FALSE);
+	if (state == NULL)
+	    return state;
+
+	if (universal) {
+	    /*
+	     * This is a POINTER or INLINE; just init based on that
+	     * and we are done.
+	     */
+	    return sec_asn1e_init_state_based_on_template (state);
+	}
+
+	/*
+	 * This is an implicit, non-universal (meaning, application-private
+	 * or context-specific) field.  This results in a "magic" tag but
+	 * encoding based on the underlying type.  We pushed a new state
+	 * that is based on the subtemplate (the underlying type), but
+	 * now we will sort of alias it to give it some of our properties
+	 * (tag, optional status, etc.).
+	 *
+	 * NB: ALL the following flags in the subtemplate are disallowed
+	 *     and/or ignored: EXPLICIT, OPTIONAL, INNER, INLINE, POINTER.
+	 */
+
+	under_kind = state->theTemplate->kind;
+	if ((under_kind & SEC_ASN1_MAY_STREAM) && !disallowStreaming) {
+	    may_stream = PR_TRUE;
+	}
+	under_kind &= ~(SEC_ASN1_MAY_STREAM | SEC_ASN1_DYNAMIC);
+    } else {
+	under_kind = encode_kind;
+    }
+
+    /*
+     * Sanity check that there are no unwanted bits marked in under_kind.
+     * These bits were either removed above (after we recorded them) or
+     * they simply should not be found (signalling a bad/broken template).
+     * XXX is this the right set of bits to test here? (i.e. need to add
+     * or remove any?)
+     */
+#define UNEXPECTED_FLAGS \
+ (SEC_ASN1_EXPLICIT | SEC_ASN1_OPTIONAL | SEC_ASN1_SKIP | SEC_ASN1_INNER | \
+  SEC_ASN1_DYNAMIC | SEC_ASN1_MAY_STREAM | SEC_ASN1_INLINE | SEC_ASN1_POINTER)
+
+    PORT_Assert ((under_kind & UNEXPECTED_FLAGS) == 0);
+    under_kind &= ~UNEXPECTED_FLAGS;
+#undef UNEXPECTED_FLAGS
+
+    if (encode_kind & SEC_ASN1_ANY) {
+	PORT_Assert (encode_kind == under_kind);
+	tag_modifiers = 0;
+	tag_number = 0;
+	is_string = PR_TRUE;
+    } else {
+	tag_modifiers = (unsigned char)
+		(encode_kind & (SEC_ASN1_TAG_MASK & ~SEC_ASN1_TAGNUM_MASK));
+	/*
+	 * XXX This assumes only single-octet identifiers.  To handle
+	 * the HIGH TAG form we would need to do some more work, especially
+	 * in how to specify them in the template, because right now we
+	 * do not provide a way to specify more *tag* bits in encode_kind.
+	 */
+	tag_number = encode_kind & SEC_ASN1_TAGNUM_MASK;
+
+	is_string = PR_FALSE;
+	switch (under_kind & SEC_ASN1_TAGNUM_MASK) {
+	  case SEC_ASN1_SET:
+	    /*
+	     * XXX A plain old SET (as opposed to a SET OF) is not implemented.
+	     * If it ever is, remove this assert...
+	     */
+	    PORT_Assert ((under_kind & SEC_ASN1_GROUP) != 0);
+	    /* fallthru */
+	  case SEC_ASN1_SEQUENCE:
+	    tag_modifiers |= SEC_ASN1_CONSTRUCTED;
+	    break;
+	  case SEC_ASN1_BIT_STRING:
+	  case SEC_ASN1_BMP_STRING: 
+	  case SEC_ASN1_GENERALIZED_TIME:
+	  case SEC_ASN1_IA5_STRING:
+	  case SEC_ASN1_OCTET_STRING:
+	  case SEC_ASN1_PRINTABLE_STRING:
+	  case SEC_ASN1_T61_STRING:
+	  case SEC_ASN1_UNIVERSAL_STRING: 
+	  case SEC_ASN1_UTC_TIME:
+	  case SEC_ASN1_UTF8_STRING:
+	  case SEC_ASN1_VISIBLE_STRING: 
+	    /*
+	     * We do not yet know if we will be constructing the string,
+	     * so we have to wait to do this final tag modification.
+	     */
+	    is_string = PR_TRUE;
+	    break;
+	}
+    }
+
+    state->tag_modifiers = tag_modifiers;
+    state->tag_number = (unsigned char)tag_number;
+    state->underlying_kind = under_kind;
+    state->isExplicit = isExplicit;
+    state->may_stream = may_stream;
+    state->is_string = is_string;
+    state->optional = optional;
+    state->disallowStreaming = disallowStreaming;
+
+    sec_asn1e_scrub_state (state);
+
+    return state;
+}
+
+
+static void
+sec_asn1e_write_part (sec_asn1e_state *state,
+		      const char *buf, unsigned long len,
+		      SEC_ASN1EncodingPart part)
+{
+    SEC_ASN1EncoderContext *cx;
+
+    cx = state->top;
+    (* cx->output_proc) (cx->output_arg, buf, len, state->depth, part);
+}
+
+
+/*
+ * XXX This assumes only single-octet identifiers.  To handle
+ * the HIGH TAG form we would need to modify this interface and
+ * teach it to properly encode the special form.
+ */
+static void
+sec_asn1e_write_identifier_bytes (sec_asn1e_state *state, unsigned char value)
+{
+    char byte;
+
+    byte = (char) value;
+    sec_asn1e_write_part (state, &byte, 1, SEC_ASN1_Identifier);
+}
+
+int
+SEC_ASN1EncodeLength(unsigned char *buf,int value) {
+    int lenlen;
+
+    lenlen = SEC_ASN1LengthLength (value);
+    if (lenlen == 1) {
+	buf[0] = value;
+    } else {
+	int i;
+
+	i = lenlen - 1;
+	buf[0] = 0x80 | i;
+	while (i) {
+	    buf[i--] = value;
+	    value >>= 8;
+	}
+        PORT_Assert (value == 0);
+    }
+    return lenlen;
+}
+
+static void
+sec_asn1e_write_length_bytes (sec_asn1e_state *state, unsigned long value,
+			      PRBool indefinite)
+{
+    int lenlen;
+    unsigned char buf[sizeof(unsigned long) + 1];
+
+    if (indefinite) {
+	PORT_Assert (value == 0);
+	buf[0] = 0x80;
+	lenlen = 1;
+    } else {
+	lenlen = SEC_ASN1EncodeLength(buf,value);
+    }
+
+    sec_asn1e_write_part (state, (char *) buf, lenlen, SEC_ASN1_Length);
+}
+
+
+static void
+sec_asn1e_write_contents_bytes (sec_asn1e_state *state,
+				const char *buf, unsigned long len)
+{
+    sec_asn1e_write_part (state, buf, len, SEC_ASN1_Contents);
+}
+
+
+static void
+sec_asn1e_write_end_of_contents_bytes (sec_asn1e_state *state)
+{
+    const char eoc[2] = {0, 0};
+
+    sec_asn1e_write_part (state, eoc, 2, SEC_ASN1_EndOfContents);
+}
+
+static int
+sec_asn1e_which_choice
+(
+  void *src,
+  const SEC_ASN1Template *theTemplate
+)
+{
+  int rv;
+  unsigned int which = *(unsigned int *)src;
+
+  for( rv = 1, theTemplate++; theTemplate->kind != 0; rv++, theTemplate++ ) {
+    if( which == theTemplate->size ) {
+      return rv;
+    }
+  }
+
+  return 0;
+}
+
+static unsigned long
+sec_asn1e_contents_length (const SEC_ASN1Template *theTemplate, void *src,
+			   PRBool disallowStreaming, PRBool insideIndefinite,
+			   sec_asn1e_hdr_encoding *pHdrException)
+{
+    unsigned long encode_kind, underlying_kind;
+    PRBool isExplicit, optional, universal, may_stream;
+    unsigned long len;
+
+    /*
+     * This function currently calculates the length in all cases
+     * except the following: when writing out the contents of a 
+     * template that belongs to a state where it was a sub-template
+     * with the SEC_ASN1_MAY_STREAM bit set and it's parent had the
+     * optional bit set.  The information that the parent is optional
+     * and that we should return the length of 0 when that length is 
+     * present since that means the optional field is no longer present.
+     * So we add the disallowStreaming flag which is passed in when
+     * writing the contents, but for all recursive calls to 
+     * sec_asn1e_contents_length, we pass PR_FALSE, because this
+     * function correctly calculates the length for children templates
+     * from that point on.  Confused yet?  At least you didn't have
+     * to figure it out.  ;)  -javi
+     */
+    encode_kind = theTemplate->kind;
+
+    universal = ((encode_kind & SEC_ASN1_CLASS_MASK) == SEC_ASN1_UNIVERSAL)
+		? PR_TRUE : PR_FALSE;
+
+    isExplicit = (encode_kind & SEC_ASN1_EXPLICIT) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_EXPLICIT;
+
+    optional = (encode_kind & SEC_ASN1_OPTIONAL) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_OPTIONAL;
+
+    PORT_Assert (!(isExplicit && universal));	/* bad templates */
+
+    may_stream = (encode_kind & SEC_ASN1_MAY_STREAM) ? PR_TRUE : PR_FALSE;
+    encode_kind &= ~SEC_ASN1_MAY_STREAM;
+
+    /* Just clear this to get it out of the way; we do not need it here */
+    encode_kind &= ~SEC_ASN1_DYNAMIC;
+
+    if (encode_kind & SEC_ASN1_NO_STREAM) {
+	disallowStreaming = PR_TRUE;
+    }
+    encode_kind &= ~SEC_ASN1_NO_STREAM;
+
+    if (encode_kind & SEC_ASN1_CHOICE) {
+	void *src2;
+	int indx = sec_asn1e_which_choice(src, theTemplate);
+	if (0 == indx) {
+	    /* XXX set an error? "choice not found" */
+	    /* state->top->status = encodeError; */
+	    return 0;
+	}
+
+        src2 = (void *)
+	        ((char *)src - theTemplate->offset + theTemplate[indx].offset);
+
+        return sec_asn1e_contents_length(&theTemplate[indx], src2, 
+					 disallowStreaming, insideIndefinite,
+					 pHdrException);
+    }
+
+    if ((encode_kind & (SEC_ASN1_POINTER | SEC_ASN1_INLINE)) || !universal) {
+	/* XXX any bits we want to disallow (PORT_Assert against) here? */
+	theTemplate = SEC_ASN1GetSubtemplate (theTemplate, src, PR_TRUE);
+	if (encode_kind & SEC_ASN1_POINTER) {
+	    src = *(void **)src;
+	    if (src == NULL) {
+		*pHdrException = optional ? hdr_optional : hdr_normal;
+		return 0;
+	    }
+	} else if (encode_kind & SEC_ASN1_INLINE) {
+	    /* check that there are no extraneous bits */
+	    if (optional) {
+		if (PR_FALSE != SEC_ASN1IsTemplateSimple(theTemplate)) {
+		    /* we now know that the target is a SECItem*, so we can check
+		       if the source contains one */
+		    SECItem* target = (SECItem*)src;
+		    if (!target || !target->data || !target->len) {
+			/* no valid data to encode subtemplate */
+			*pHdrException = hdr_optional;
+			return 0;
+		    }
+		} else {
+		    PORT_Assert(0); /* complex templates not handled as inline
+                                       optional */
+		}
+	    }
+	}
+
+	src = (char *)src + theTemplate->offset;
+
+	/* recurse to find the length of the subtemplate */
+	len = sec_asn1e_contents_length (theTemplate, src, disallowStreaming, 
+	                                 insideIndefinite, pHdrException);
+	if (len == 0 && optional) {
+	    *pHdrException = hdr_optional;
+	} else if (isExplicit) {
+	    if (*pHdrException == hdr_any) {
+		/* *we* do not want to add in a header, 
+		** but our caller still does. 
+		*/
+		*pHdrException = hdr_normal;
+	    } else if (*pHdrException == hdr_normal) {
+		/* if the inner content exists, our length is
+		 * len(identifier) + len(length) + len(innercontent)
+		 * XXX we currently assume len(identifier) == 1;
+		 * to support a high-tag-number this would need to be smarter.
+		 */
+		len += 1 + SEC_ASN1LengthLength (len);
+	    }
+	}
+	return len;
+    }
+    underlying_kind = encode_kind;
+
+    /* This is only used in decoding; it plays no part in encoding.  */
+    if (underlying_kind & SEC_ASN1_SAVE) {
+	/* check that there are no extraneous bits */
+	PORT_Assert (underlying_kind == SEC_ASN1_SAVE);
+	*pHdrException = hdr_decoder;
+	return 0;
+    }
+
+#define UNEXPECTED_FLAGS \
+ (SEC_ASN1_EXPLICIT | SEC_ASN1_OPTIONAL | SEC_ASN1_INLINE | SEC_ASN1_POINTER |\
+  SEC_ASN1_DYNAMIC | SEC_ASN1_MAY_STREAM | SEC_ASN1_SAVE | SEC_ASN1_SKIP)
+
+    /* Having any of these bits is not expected here...  */
+    PORT_Assert ((underlying_kind & UNEXPECTED_FLAGS) == 0);
+    underlying_kind &= ~UNEXPECTED_FLAGS;
+#undef UNEXPECTED_FLAGS
+
+    if (underlying_kind & SEC_ASN1_CHOICE) {
+	void *src2;
+	int indx = sec_asn1e_which_choice(src, theTemplate);
+	if (0 == indx) {
+	    /* XXX set an error? "choice not found" */
+	    /* state->top->status = encodeError; */
+	    return 0;
+	}
+
+        src2 = (void *)
+		((char *)src - theTemplate->offset + theTemplate[indx].offset);
+        len = sec_asn1e_contents_length(&theTemplate[indx], src2, 
+	                                disallowStreaming, insideIndefinite, 
+					pHdrException);
+    } else {
+      switch (underlying_kind) {
+      case SEC_ASN1_SEQUENCE_OF:
+      case SEC_ASN1_SET_OF:
+	{
+	    const SEC_ASN1Template *tmpt;
+	    void *sub_src;
+	    unsigned long sub_len;
+	    void **group;
+
+	    len = 0;
+
+	    group = *(void ***)src;
+	    if (group == NULL)
+		break;
+
+	    tmpt = SEC_ASN1GetSubtemplate (theTemplate, src, PR_TRUE);
+
+	    for (; *group != NULL; group++) {
+		sub_src = (char *)(*group) + tmpt->offset;
+		sub_len = sec_asn1e_contents_length (tmpt, sub_src, 
+		                                     disallowStreaming,
+						     insideIndefinite,
+                                                     pHdrException);
+		len += sub_len;
+		/*
+		 * XXX The 1 below is the presumed length of the identifier;
+		 * to support a high-tag-number this would need to be smarter.
+		 */
+		if (*pHdrException == hdr_normal)
+		    len += 1 + SEC_ASN1LengthLength (sub_len);
+	    }
+	}
+	break;
+
+      case SEC_ASN1_SEQUENCE:
+      case SEC_ASN1_SET:
+	{
+	    const SEC_ASN1Template *tmpt;
+	    void *sub_src;
+	    unsigned long sub_len;
+
+	    len = 0;
+	    for (tmpt = theTemplate + 1; tmpt->kind; tmpt++) {
+		sub_src = (char *)src + tmpt->offset;
+		sub_len = sec_asn1e_contents_length (tmpt, sub_src, 
+		                                     disallowStreaming,
+						     insideIndefinite,
+                                                     pHdrException);
+		len += sub_len;
+		/*
+		 * XXX The 1 below is the presumed length of the identifier;
+		 * to support a high-tag-number this would need to be smarter.
+		 */
+		if (*pHdrException == hdr_normal)
+		    len += 1 + SEC_ASN1LengthLength (sub_len);
+	    }
+	}
+	break;
+
+      case SEC_ASN1_BIT_STRING:
+	/* convert bit length to byte */
+	len = (((SECItem *)src)->len + 7) >> 3;
+	/* bit string contents involve an extra octet */
+	if (len)
+	    len++;
+	break;
+
+      case SEC_ASN1_INTEGER:
+	/* ASN.1 INTEGERs are signed.
+	 * If the source is an unsigned integer, the encoder will need 
+	 * to handle the conversion here.
+	 */
+	{
+	    unsigned char *buf = ((SECItem *)src)->data;
+	    SECItemType integerType = ((SECItem *)src)->type;
+	    len = ((SECItem *)src)->len;
+	    while (len > 0) {
+		if (*buf != 0) {
+		    if (*buf & 0x80 && integerType == siUnsignedInteger) {
+			len++; /* leading zero needed to make number signed */
+		    }
+		    break; /* reached beginning of number */
+		}
+		if (len == 1) {
+		    break; /* the number 0 */
+		}
+		if (buf[1] & 0x80) {
+		    break; /* leading zero already present */
+		} 
+		/* extraneous leading zero, keep going */
+		buf++;
+		len--;
+	    }
+	}
+	break;
+
+      default:
+	len = ((SECItem *)src)->len;
+	break;
+      }  /* end switch */
+
+#ifndef WHAT_PROBLEM_DOES_THIS_SOLVE
+      /* if we're streaming, we may have a secitem w/len 0 as placeholder */
+      if (!len && insideIndefinite && may_stream && !disallowStreaming) {
+	  len = 1;
+      }
+#endif
+    }    /* end else */
+
+    if (len == 0 && optional)
+	*pHdrException = hdr_optional;
+    else if (underlying_kind == SEC_ASN1_ANY)
+	*pHdrException = hdr_any;
+    else 
+	*pHdrException = hdr_normal;
+
+    return len;
+}
+
+
+static void
+sec_asn1e_write_header (sec_asn1e_state *state)
+{
+    unsigned long contents_length;
+    unsigned char tag_number, tag_modifiers;
+    sec_asn1e_hdr_encoding hdrException = hdr_normal;
+    PRBool indefinite = PR_FALSE;
+
+    PORT_Assert (state->place == beforeHeader);
+
+    tag_number = state->tag_number;
+    tag_modifiers = state->tag_modifiers;
+
+    if (state->underlying_kind == SEC_ASN1_ANY) {
+	state->place = duringContents;
+	return;
+    }
+
+    if (state->underlying_kind & SEC_ASN1_CHOICE) {
+	int indx = sec_asn1e_which_choice(state->src, state->theTemplate);
+	if( 0 == indx ) {
+	    /* XXX set an error? "choice not found" */
+	    state->top->status = encodeError;
+	    return;
+	}
+	state->place = afterChoice;
+	state = sec_asn1e_push_state(state->top, &state->theTemplate[indx],
+			       (char *)state->src - state->theTemplate->offset, 
+			       PR_TRUE);
+	if (state) {
+	    /*
+	     * Do the "before" field notification.
+	     */
+	    sec_asn1e_notify_before (state->top, state->src, state->depth);
+	    state = sec_asn1e_init_state_based_on_template (state);
+	}
+	return;
+    }
+
+    /* The !isString test below is apparently intended to ensure that all 
+    ** constructed types receive indefinite length encoding.
+    */
+   indefinite = (PRBool) 
+	(state->top->streaming && state->may_stream && 
+	 (state->top->from_buf || !state->is_string));
+
+    /*
+     * If we are doing a definite-length encoding, first we have to
+     * walk the data structure to calculate the entire contents length.
+     * If we are doing an indefinite-length encoding, we still need to 
+     * know if the contents is:
+     *    optional and to be omitted, or 
+     *    an ANY (header is pre-encoded), or 
+     *    a SAVE or some other kind of template used only by the decoder.
+     * So, we call this function either way.
+     */
+    contents_length = sec_asn1e_contents_length (state->theTemplate,
+						 state->src, 
+                                                 state->disallowStreaming,
+						 indefinite,
+                                                 &hdrException);
+    /*
+     * We might be told explicitly not to put out a header.
+     * But it can also be the case, via a pushed subtemplate, that
+     * sec_asn1e_contents_length could not know that this field is
+     * really optional.  So check for that explicitly, too.
+     */
+    if (hdrException != hdr_normal || 
+	(contents_length == 0 && state->optional)) {
+	state->place = afterContents;
+	if (state->top->streaming && 
+	    state->may_stream && 
+	    state->top->from_buf) {
+	    /* we did not find an optional indefinite string, so we 
+	     * don't encode it.  However, if TakeFromBuf is on, we stop 
+	     * here anyway to give our caller a chance to intercept at the 
+	     * same point where we would stop if the field were present. 
+	     */
+	    state->top->status = needBytes;
+	}
+	return;
+    }
+
+    if (indefinite) {
+	/*
+	 * We need to put out an indefinite-length encoding.
+	 * The only universal types that can be constructed are SETs,
+	 * SEQUENCEs, and strings; so check that it is one of those,
+	 * or that it is not universal (e.g. context-specific).
+	 */
+	state->indefinite = PR_TRUE;
+	PORT_Assert ((tag_number == SEC_ASN1_SET)
+		     || (tag_number == SEC_ASN1_SEQUENCE)
+		     || ((tag_modifiers & SEC_ASN1_CLASS_MASK) != 0)
+		     || state->is_string);
+	tag_modifiers |= SEC_ASN1_CONSTRUCTED;
+	contents_length = 0;
+    }
+
+    sec_asn1e_write_identifier_bytes (state, 
+                                (unsigned char)(tag_number | tag_modifiers));
+    sec_asn1e_write_length_bytes (state, contents_length, state->indefinite);
+
+    if (contents_length == 0 && !state->indefinite) {
+	/*
+	 * If no real contents to encode, then we are done with this field.
+	 */
+	state->place = afterContents;
+	return;
+    }
+
+    /*
+     * An EXPLICIT is nothing but an outer header, which we have already
+     * written.  Now we need to do the inner header and contents.
+     */
+    if (state->isExplicit) {
+	const SEC_ASN1Template *subt =
+	      SEC_ASN1GetSubtemplate(state->theTemplate, state->src, PR_TRUE);
+	state->place = afterContents;
+	state = sec_asn1e_push_state (state->top, subt, state->src, PR_TRUE);
+	if (state != NULL)
+	    state = sec_asn1e_init_state_based_on_template (state);
+	return;
+    }
+
+    switch (state->underlying_kind) {
+      case SEC_ASN1_SET_OF:
+      case SEC_ASN1_SEQUENCE_OF:
+	/*
+	 * We need to push a child to handle each member.
+	 */
+	{
+	    void **group;
+	    const SEC_ASN1Template *subt;
+
+	    group = *(void ***)state->src;
+	    if (group == NULL || *group == NULL) {
+		/*
+		 * Group is empty; we are done.
+		 */
+		state->place = afterContents;
+		return;
+	    }
+	    state->place = duringGroup;
+	    subt = SEC_ASN1GetSubtemplate (state->theTemplate, state->src,
+					   PR_TRUE);
+	    state = sec_asn1e_push_state (state->top, subt, *group, PR_TRUE);
+	    if (state != NULL)
+		state = sec_asn1e_init_state_based_on_template (state);
+	}
+	break;
+
+      case SEC_ASN1_SEQUENCE:
+      case SEC_ASN1_SET:
+	/*
+	 * We need to push a child to handle the individual fields.
+	 */
+	state->place = duringSequence;
+	state = sec_asn1e_push_state (state->top, state->theTemplate + 1,
+				      state->src, PR_TRUE);
+	if (state != NULL) {
+	    /*
+	     * Do the "before" field notification.
+	     */
+	    sec_asn1e_notify_before (state->top, state->src, state->depth);
+	    state = sec_asn1e_init_state_based_on_template (state);
+	}
+	break;
+
+      default:
+	/*
+	 * I think we do not need to do anything else.
+	 * XXX Correct?
+	 */
+	state->place = duringContents;
+	break;
+    }
+}
+
+
+static void
+sec_asn1e_write_contents_from_buf (sec_asn1e_state *state,
+			  const char *buf, unsigned long len)
+{
+    PORT_Assert (state->place == duringContents);
+    PORT_Assert (state->top->from_buf);
+    PORT_Assert (state->may_stream && !state->disallowStreaming);
+
+    /*
+     * Probably they just turned on "take from buf", but have not
+     * yet given us any bytes.  If there is nothing in the buffer
+     * then we have nothing to do but return and wait.
+     */
+    if (buf == NULL || len == 0) {
+	state->top->status = needBytes;
+	return;
+    }
+    /*
+     * We are streaming, reading from a passed-in buffer.
+     * This means we are encoding a simple string or an ANY.
+     * For the former, we need to put out a substring, with its
+     * own identifier and length.  For an ANY, we just write it
+     * out as is (our caller is required to ensure that it
+     * is a properly encoded entity).
+     */
+    PORT_Assert (state->is_string);		/* includes ANY */
+    if (state->underlying_kind != SEC_ASN1_ANY) {
+	unsigned char identifier;
+
+	/*
+	 * Create the identifier based on underlying_kind.  We cannot
+	 * use tag_number and tag_modifiers because this can be an
+	 * implicitly encoded field.  In that case, the underlying
+	 * substrings *are* encoded with their real tag.
+	 */
+	identifier = (unsigned char)
+	                    (state->underlying_kind & SEC_ASN1_TAG_MASK);
+	/*
+	 * The underlying kind should just be a simple string; there
+	 * should be no bits like CONTEXT_SPECIFIC or CONSTRUCTED set.
+	 */
+	PORT_Assert ((identifier & SEC_ASN1_TAGNUM_MASK) == identifier);
+	/*
+	 * Write out the tag and length for the substring.
+	 */
+	sec_asn1e_write_identifier_bytes (state, identifier);
+	if (state->underlying_kind == SEC_ASN1_BIT_STRING) {
+	    char byte;
+	    /*
+	     * Assume we have a length in bytes but we need to output
+	     * a proper bit string.  This interface only works for bit
+	     * strings that are full multiples of 8.  If support for
+	     * real, variable length bit strings is needed then the
+	     * caller will have to know to pass in a bit length instead
+	     * of a byte length and then this code will have to
+	     * perform the encoding necessary (length written is length
+	     * in bytes plus 1, and the first octet of string is the
+	     * number of bits remaining between the end of the bit
+	     * string and the next byte boundary).
+	     */
+	    sec_asn1e_write_length_bytes (state, len + 1, PR_FALSE);
+	    byte = 0;
+	    sec_asn1e_write_contents_bytes (state, &byte, 1);
+	} else {
+	    sec_asn1e_write_length_bytes (state, len, PR_FALSE);
+	}
+    }
+    sec_asn1e_write_contents_bytes (state, buf, len);
+    state->top->status = needBytes;
+}
+
+static void
+sec_asn1e_write_contents (sec_asn1e_state *state)
+{
+    unsigned long len = 0;
+
+    PORT_Assert (state->place == duringContents);
+
+    switch (state->underlying_kind) {
+      case SEC_ASN1_SET:
+      case SEC_ASN1_SEQUENCE:
+	PORT_Assert (0);
+	break;
+
+      case SEC_ASN1_BIT_STRING:
+	{
+	    SECItem *item;
+	    char rem;
+
+	    item = (SECItem *)state->src;
+	    len = (item->len + 7) >> 3;
+	    rem = (unsigned char)((len << 3) - item->len); /* remaining bits */
+	    sec_asn1e_write_contents_bytes (state, &rem, 1);
+	    sec_asn1e_write_contents_bytes (state, (char *) item->data, len);
+	}
+	break;
+
+      case SEC_ASN1_BMP_STRING:
+	/* The number of bytes must be divisable by 2 */
+	if ((((SECItem *)state->src)->len) % 2) {
+	    SEC_ASN1EncoderContext *cx;
+
+	    cx = state->top;
+	    cx->status = encodeError;
+	    break;
+	}
+	/* otherwise, fall through to write the content */
+	goto process_string;
+
+      case SEC_ASN1_UNIVERSAL_STRING:
+	/* The number of bytes must be divisable by 4 */
+	if ((((SECItem *)state->src)->len) % 4) {
+	    SEC_ASN1EncoderContext *cx;
+
+	    cx = state->top;
+	    cx->status = encodeError;
+	    break;
+	}
+	/* otherwise, fall through to write the content */
+	goto process_string;
+
+      case SEC_ASN1_INTEGER:
+       /* ASN.1 INTEGERs are signed.  If the source is an unsigned
+	* integer, the encoder will need to handle the conversion here.
+	*/
+	{
+	    unsigned int blen;
+	    unsigned char *buf;
+	    SECItemType integerType;
+	    blen = ((SECItem *)state->src)->len;
+	    buf = ((SECItem *)state->src)->data;
+	    integerType = ((SECItem *)state->src)->type;
+	    while (blen > 0) {
+		if (*buf & 0x80 && integerType == siUnsignedInteger) {
+		    char zero = 0; /* write a leading 0 */
+		    sec_asn1e_write_contents_bytes(state, &zero, 1);
+		    /* and then the remaining buffer */
+		    sec_asn1e_write_contents_bytes(state, 
+						   (char *)buf, blen); 
+		    break;
+		} 
+		/* Check three possibilities:
+		 * 1.  No leading zeros, msb of MSB is not 1;
+		 * 2.  The number is zero itself;
+		 * 3.  Encoding a signed integer with a leading zero,
+		 *     keep the zero so that the number is positive.
+		 */
+		if (*buf != 0 || 
+		     blen == 1 || 
+		     (buf[1] & 0x80 && integerType != siUnsignedInteger) ) 
+		{
+		    sec_asn1e_write_contents_bytes(state, 
+						   (char *)buf, blen); 
+		    break;
+		}
+		/* byte is 0, continue */
+		buf++;
+		blen--;
+	    }
+	}
+	/* done with this content */
+	break;
+			
+process_string:			
+      default:
+	{
+	    SECItem *item;
+
+	    item = (SECItem *)state->src;
+	    sec_asn1e_write_contents_bytes (state, (char *) item->data,
+					    item->len);
+	}
+	break;
+    }
+    state->place = afterContents;
+}
+
+/*
+ * We are doing a SET OF or SEQUENCE OF, and have just finished an item.
+ */
+static void
+sec_asn1e_next_in_group (sec_asn1e_state *state)
+{
+    sec_asn1e_state *child;
+    void **group;
+    void *member;
+
+    PORT_Assert (state->place == duringGroup);
+    PORT_Assert (state->child != NULL);
+
+    child = state->child;
+
+    group = *(void ***)state->src;
+
+    /*
+     * Find placement of current item.
+     */
+    member = (char *)(state->child->src) - child->theTemplate->offset;
+    while (*group != member)
+	group++;
+
+    /*
+     * Move forward to next item.
+     */
+    group++;
+    if (*group == NULL) {
+	/*
+	 * That was our last one; we are done now.
+	 */
+	child->place = notInUse;
+	state->place = afterContents;
+	return;
+    }
+    child->src = (char *)(*group) + child->theTemplate->offset;
+
+    /*
+     * Re-"push" child.
+     */
+    sec_asn1e_scrub_state (child);
+    state->top->current = child;
+}
+
+
+/*
+ * We are moving along through a sequence; move forward by one,
+ * (detecting end-of-sequence when it happens).
+ */
+static void
+sec_asn1e_next_in_sequence (sec_asn1e_state *state)
+{
+    sec_asn1e_state *child;
+
+    PORT_Assert (state->place == duringSequence);
+    PORT_Assert (state->child != NULL);
+
+    child = state->child;
+
+    /*
+     * Do the "after" field notification.
+     */
+    sec_asn1e_notify_after (state->top, child->src, child->depth);
+
+    /*
+     * Move forward.
+     */
+    child->theTemplate++;
+    if (child->theTemplate->kind == 0) {
+	/*
+	 * We are done with this sequence.
+	 */
+	child->place = notInUse;
+	state->place = afterContents;
+	return;
+    }
+
+    /*
+     * Reset state and push.
+     */
+
+    child->src = (char *)state->src + child->theTemplate->offset;
+
+    /*
+     * Do the "before" field notification.
+     */
+    sec_asn1e_notify_before (state->top, child->src, child->depth);
+
+    state->top->current = child;
+    (void) sec_asn1e_init_state_based_on_template (child);
+}
+
+
+static void
+sec_asn1e_after_contents (sec_asn1e_state *state)
+{
+    PORT_Assert (state->place == afterContents);
+
+    if (state->indefinite)
+	sec_asn1e_write_end_of_contents_bytes (state);
+
+    /*
+     * Just make my parent be the current state.  It will then clean
+     * up after me and free me (or reuse me).
+     */
+    state->top->current = state->parent;
+}
+
+
+/*
+ * This function is called whether or not we are streaming; if we
+ * *are* streaming, our caller can also instruct us to take bytes
+ * from the passed-in buffer (at buf, for length len, which is likely
+ * bytes but could even mean bits if the current field is a bit string).
+ * If we have been so instructed, we will gobble up bytes from there
+ * (rather than from our src structure) and output them, and then
+ * we will just return, expecting to be called again -- either with
+ * more bytes or after our caller has instructed us that we are done
+ * (for now) with the buffer.
+ */
+SECStatus
+SEC_ASN1EncoderUpdate (SEC_ASN1EncoderContext *cx,
+		       const char *buf, unsigned long len)
+{
+    sec_asn1e_state *state;
+
+    if (cx->status == needBytes) {
+	cx->status = keepGoing;
+    }
+
+    while (cx->status == keepGoing) {
+	state = cx->current;
+	switch (state->place) {
+	  case beforeHeader:
+	    sec_asn1e_write_header (state);
+	    break;
+	  case duringContents:
+	    if (cx->from_buf)
+		sec_asn1e_write_contents_from_buf (state, buf, len);
+	    else
+		sec_asn1e_write_contents (state);
+	    break;
+	  case duringGroup:
+	    sec_asn1e_next_in_group (state);
+	    break;
+	  case duringSequence:
+	    sec_asn1e_next_in_sequence (state);
+	    break;
+	  case afterContents:
+	    sec_asn1e_after_contents (state);
+	    break;
+	  case afterImplicit:
+	  case afterInline:
+	  case afterPointer:
+	  case afterChoice:
+	    /*
+	     * These states are more documentation than anything.
+	     * They just need to force a pop.
+	     */
+	    PORT_Assert (!state->indefinite);
+	    state->place = afterContents;
+	    break;
+	  case notInUse:
+	  default:
+	    /* This is not an error, but rather a plain old BUG! */
+	    PORT_Assert (0);
+	    cx->status = encodeError;
+	    break;
+	}
+
+	if (cx->status == encodeError)
+	    break;
+
+	/* It might have changed, so we have to update our local copy.  */
+	state = cx->current;
+
+	/* If it is NULL, we have popped all the way to the top.  */
+	if (state == NULL) {
+	    cx->status = allDone;
+	    break;
+	}
+    }
+
+    if (cx->status == encodeError) {
+	return SECFailure;
+    }
+
+    return SECSuccess;
+}
+
+
+void
+SEC_ASN1EncoderFinish (SEC_ASN1EncoderContext *cx)
+{
+    /*
+     * XXX anything else that needs to be finished?
+     */
+
+    PORT_FreeArena (cx->our_pool, PR_FALSE);
+}
+
+
+SEC_ASN1EncoderContext *
+SEC_ASN1EncoderStart (const void *src, const SEC_ASN1Template *theTemplate,
+		      SEC_ASN1WriteProc output_proc, void *output_arg)
+{
+    PLArenaPool *our_pool;
+    SEC_ASN1EncoderContext *cx;
+
+    our_pool = PORT_NewArena (SEC_ASN1_DEFAULT_ARENA_SIZE);
+    if (our_pool == NULL)
+	return NULL;
+
+    cx = (SEC_ASN1EncoderContext*)PORT_ArenaZAlloc (our_pool, sizeof(*cx));
+    if (cx == NULL) {
+	PORT_FreeArena (our_pool, PR_FALSE);
+	return NULL;
+    }
+
+    cx->our_pool = our_pool;
+    cx->output_proc = output_proc;
+    cx->output_arg = output_arg;
+
+    cx->status = keepGoing;
+
+    if (sec_asn1e_push_state(cx, theTemplate, src, PR_FALSE) == NULL
+	|| sec_asn1e_init_state_based_on_template (cx->current) == NULL) {
+	/*
+	 * Trouble initializing (probably due to failed allocations)
+	 * requires that we just give up.
+	 */
+	PORT_FreeArena (our_pool, PR_FALSE);
+	return NULL;
+    }
+
+    return cx;
+}
+
+
+/*
+ * XXX Do we need a FilterProc, too?
+ */
+
+
+void
+SEC_ASN1EncoderSetNotifyProc (SEC_ASN1EncoderContext *cx,
+			      SEC_ASN1NotifyProc fn, void *arg)
+{
+    cx->notify_proc = fn;
+    cx->notify_arg = arg;
+}
+
+
+void
+SEC_ASN1EncoderClearNotifyProc (SEC_ASN1EncoderContext *cx)
+{
+    cx->notify_proc = NULL;
+    cx->notify_arg = NULL;	/* not necessary; just being clean */
+}
+
+void
+SEC_ASN1EncoderAbort(SEC_ASN1EncoderContext *cx, int error)
+{
+    PORT_Assert(cx);
+    PORT_SetError(error);
+    cx->status = encodeError;
+}
+
+void
+SEC_ASN1EncoderSetStreaming (SEC_ASN1EncoderContext *cx)
+{
+    /* XXX is there a way to check that we are "between" fields here? */
+
+    cx->streaming = PR_TRUE;
+}
+
+
+void
+SEC_ASN1EncoderClearStreaming (SEC_ASN1EncoderContext *cx)
+{
+    /* XXX is there a way to check that we are "between" fields here? */
+
+    cx->streaming = PR_FALSE;
+}
+
+
+void
+SEC_ASN1EncoderSetTakeFromBuf (SEC_ASN1EncoderContext *cx)
+{
+    /* 
+     * XXX is there a way to check that we are "between" fields here?  this
+     * needs to include a check for being in between groups of items in
+     * a SET_OF or SEQUENCE_OF.
+     */
+    PORT_Assert (cx->streaming);
+
+    cx->from_buf = PR_TRUE;
+}
+
+
+void
+SEC_ASN1EncoderClearTakeFromBuf (SEC_ASN1EncoderContext *cx)
+{
+    /* we should actually be taking from buf *now* */
+    PORT_Assert (cx->from_buf);
+    if (! cx->from_buf)		/* if not, just do nothing */
+	return;
+
+    cx->from_buf = PR_FALSE;
+
+    if (cx->status == needBytes) {
+	cx->status = keepGoing;
+	cx->current->place = afterContents;
+    }
+}
+
+
+SECStatus
+SEC_ASN1Encode (const void *src, const SEC_ASN1Template *theTemplate,
+		SEC_ASN1WriteProc output_proc, void *output_arg)
+{
+    SEC_ASN1EncoderContext *ecx;
+    SECStatus rv;
+
+    ecx = SEC_ASN1EncoderStart (src, theTemplate, output_proc, output_arg);
+    if (ecx == NULL)
+	return SECFailure;
+
+    rv = SEC_ASN1EncoderUpdate (ecx, NULL, 0);
+
+    SEC_ASN1EncoderFinish (ecx);
+    return rv;
+}
+
+
+/*
+ * XXX depth and data_kind are unused; is there a PC way to silence warnings?
+ * (I mean "politically correct", not anything to do with intel/win platform) 
+ */
+static void
+sec_asn1e_encode_item_count (void *arg, const char *buf, unsigned long len,
+			     int depth, SEC_ASN1EncodingPart data_kind)
+{
+    unsigned long *count;
+
+    count = (unsigned long*)arg;
+    PORT_Assert (count != NULL);
+
+    *count += len;
+}
+
+
+/* XXX depth and data_kind are unused; is there a PC way to silence warnings? */
+static void
+sec_asn1e_encode_item_store (void *arg, const char *buf, unsigned long len,
+			     int depth, SEC_ASN1EncodingPart data_kind)
+{
+    SECItem *dest;
+
+    dest = (SECItem*)arg;
+    PORT_Assert (dest != NULL);
+
+    PORT_Memcpy (dest->data + dest->len, buf, len);
+    dest->len += len;
+}
+
+
+/*
+ * Allocate an entire SECItem, or just the data part of it, to hold
+ * "len" bytes of stuff.  Allocate from the given pool, if specified,
+ * otherwise just do a vanilla PORT_Alloc.
+ *
+ * XXX This seems like a reasonable general-purpose function (for SECITEM_)?
+ */
+static SECItem *
+sec_asn1e_allocate_item (PLArenaPool *poolp, SECItem *dest, unsigned long len)
+{
+    if (poolp != NULL) {
+	void *release;
+
+	release = PORT_ArenaMark (poolp);
+	if (dest == NULL)
+	    dest = (SECItem*)PORT_ArenaAlloc (poolp, sizeof(SECItem));
+	if (dest != NULL) {
+	    dest->data = (unsigned char*)PORT_ArenaAlloc (poolp, len);
+	    if (dest->data == NULL) {
+		dest = NULL;
+	    }
+	}
+	if (dest == NULL) {
+	    /* one or both allocations failed; release everything */
+	    PORT_ArenaRelease (poolp, release);
+	} else {
+	    /* everything okay; unmark the arena */
+	    PORT_ArenaUnmark (poolp, release);
+	}
+    } else {
+	SECItem *indest;
+
+	indest = dest;
+	if (dest == NULL)
+	    dest = (SECItem*)PORT_Alloc (sizeof(SECItem));
+	if (dest != NULL) {
+	    dest->type = siBuffer;
+	    dest->data = (unsigned char*)PORT_Alloc (len);
+	    if (dest->data == NULL) {
+		if (indest == NULL)
+		    PORT_Free (dest);
+		dest = NULL;
+	    }
+	}
+    }
+
+    return dest;
+}
+
+
+SECItem *
+SEC_ASN1EncodeItem (PLArenaPool *poolp, SECItem *dest, const void *src,
+		    const SEC_ASN1Template *theTemplate)
+{
+    unsigned long encoding_length;
+    SECStatus rv;
+
+    PORT_Assert (dest == NULL || dest->data == NULL);
+
+    encoding_length = 0;
+    rv = SEC_ASN1Encode (src, theTemplate,
+			 sec_asn1e_encode_item_count, &encoding_length);
+    if (rv != SECSuccess)
+	return NULL;
+
+    dest = sec_asn1e_allocate_item (poolp, dest, encoding_length);
+    if (dest == NULL)
+	return NULL;
+
+    /* XXX necessary?  This really just checks for a bug in the allocate fn */
+    PORT_Assert (dest->data != NULL);
+    if (dest->data == NULL)
+	return NULL;
+
+    dest->len = 0;
+    (void) SEC_ASN1Encode (src, theTemplate, sec_asn1e_encode_item_store, dest);
+
+    PORT_Assert (encoding_length == dest->len);
+    return dest;
+}
+
+
+static SECItem *
+sec_asn1e_integer(PLArenaPool *poolp, SECItem *dest, unsigned long value,
+		  PRBool is_unsigned)
+{
+    unsigned long copy;
+    unsigned char sign;
+    int len = 0;
+
+    /*
+     * Determine the length of the encoded value (minimum of 1).
+     */
+    copy = value;
+    do {
+	len++;
+	sign = (unsigned char)(copy & 0x80);
+	copy >>= 8;
+    } while (copy);
+
+    /*
+     * If 'value' is non-negative, and the high bit of the last
+     * byte we counted was set, we need to add one to the length so
+     * we put a high-order zero byte in the encoding.
+     */
+    if (sign && (is_unsigned || (long)value >= 0))
+	len++;
+
+    /*
+     * Allocate the item (if necessary) and the data pointer within.
+     */
+    dest = sec_asn1e_allocate_item (poolp, dest, len);
+    if (dest == NULL)
+	return NULL;
+
+    /*
+     * Store the value, byte by byte, in the item.
+     */
+    dest->len = len;
+    while (len) {
+	dest->data[--len] = (unsigned char)value;
+	value >>= 8;
+    }
+    PORT_Assert (value == 0);
+
+    return dest;
+}
+
+
+SECItem *
+SEC_ASN1EncodeInteger(PLArenaPool *poolp, SECItem *dest, long value)
+{
+    return sec_asn1e_integer (poolp, dest, (unsigned long) value, PR_FALSE);
+}
+
+
+SECItem *
+SEC_ASN1EncodeUnsignedInteger(PLArenaPool *poolp,
+			      SECItem *dest, unsigned long value)
+{
+    return sec_asn1e_integer (poolp, dest, value, PR_TRUE);
+}