michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0:  * Utility routines to complement the ASN.1 encoding and decoding functions.
michael@0:  */
michael@0: 
michael@0: #include "secasn1.h"
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * We have a length that needs to be encoded; how many bytes will the
michael@0:  * encoding take?
michael@0:  *
michael@0:  * The rules are that 0 - 0x7f takes one byte (the length itself is the
michael@0:  * entire encoding); everything else takes one plus the number of bytes
michael@0:  * in the length.
michael@0:  */
michael@0: int
michael@0: SEC_ASN1LengthLength (unsigned long len)
michael@0: {
michael@0:     int lenlen = 1;
michael@0: 
michael@0:     if (len > 0x7f) {
michael@0: 	do {
michael@0: 	    lenlen++;
michael@0: 	    len >>= 8;
michael@0: 	} while (len);
michael@0:     }
michael@0: 
michael@0:     return lenlen;
michael@0: }
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * XXX Move over (and rewrite as appropriate) the rest of the
michael@0:  * stuff in dersubr.c!
michael@0:  */
michael@0: 
michael@0: 
michael@0: /*
michael@0:  * Find the appropriate subtemplate for the given template.
michael@0:  * This may involve calling a "chooser" function, or it may just
michael@0:  * be right there.  In either case, it is expected to *have* a
michael@0:  * subtemplate; this is asserted in debug builds (in non-debug
michael@0:  * builds, NULL will be returned).
michael@0:  *
michael@0:  * "thing" is a pointer to the structure being encoded/decoded
michael@0:  * "encoding", when true, means that we are in the process of encoding
michael@0:  *	(as opposed to in the process of decoding)
michael@0:  */
michael@0: const SEC_ASN1Template *
michael@0: SEC_ASN1GetSubtemplate (const SEC_ASN1Template *theTemplate, void *thing,
michael@0: 			PRBool encoding)
michael@0: {
michael@0:     const SEC_ASN1Template *subt = NULL;
michael@0: 
michael@0:     PORT_Assert (theTemplate->sub != NULL);
michael@0:     if (theTemplate->sub != NULL) {
michael@0: 	if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
michael@0: 	    SEC_ASN1TemplateChooserPtr chooserp;
michael@0: 
michael@0: 	    chooserp = *(SEC_ASN1TemplateChooserPtr *) theTemplate->sub;
michael@0: 	    if (chooserp) {
michael@0: 		if (thing != NULL)
michael@0: 		    thing = (char *)thing - theTemplate->offset;
michael@0: 		subt = (* chooserp)(thing, encoding);
michael@0: 	    }
michael@0: 	} else {
michael@0: 	    subt = (SEC_ASN1Template*)theTemplate->sub;
michael@0: 	}
michael@0:     }
michael@0:     return subt;
michael@0: }
michael@0: 
michael@0: PRBool SEC_ASN1IsTemplateSimple(const SEC_ASN1Template *theTemplate)
michael@0: {
michael@0:     if (!theTemplate) {
michael@0: 	return PR_TRUE; /* it doesn't get any simpler than NULL */
michael@0:     }
michael@0:     /* only templates made of one primitive type or a choice of primitive
michael@0:        types are considered simple */
michael@0:     if (! (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK))) {
michael@0: 	return PR_TRUE; /* primitive type */
michael@0:     }
michael@0:     if (!(theTemplate->kind & SEC_ASN1_CHOICE)) {
michael@0: 	return PR_FALSE; /* no choice means not simple */
michael@0:     }
michael@0:     while (++theTemplate && theTemplate->kind) {
michael@0: 	if (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK)) {
michael@0: 	    return PR_FALSE; /* complex type */
michael@0: 	}
michael@0:     }
michael@0:     return PR_TRUE; /* choice of primitive types */
michael@0: }
michael@0: