/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Netscape security libraries.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1994-2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

/*
 * Utility routines to complement the ASN.1 encoding and decoding functions.
 *
 * $Id: secasn1u.c,v 1.4 2005/04/09 05:06:34 julien.pierre.bugs%sun.com Exp $
 */

#include "secasn1.h"


/*
 * We have a length that needs to be encoded; how many bytes will the
 * encoding take?
 *
 * The rules are that 0 - 0x7f takes one byte (the length itself is the
 * entire encoding); everything else takes one plus the number of bytes
 * in the length.
 */
int
SEC_ASN1LengthLength (unsigned long len)
{
    int lenlen = 1;

    if (len > 0x7f) {
	do {
	    lenlen++;
	    len >>= 8;
	} while (len);
    }

    return lenlen;
}


/*
 * XXX Move over (and rewrite as appropriate) the rest of the
 * stuff in dersubr.c!
 */


/*
 * Find the appropriate subtemplate for the given template.
 * This may involve calling a "chooser" function, or it may just
 * be right there.  In either case, it is expected to *have* a
 * subtemplate; this is asserted in debug builds (in non-debug
 * builds, NULL will be returned).
 *
 * "thing" is a pointer to the structure being encoded/decoded
 * "encoding", when true, means that we are in the process of encoding
 *	(as opposed to in the process of decoding)
 */
const SEC_ASN1Template *
SEC_ASN1GetSubtemplate (const SEC_ASN1Template *theTemplate, void *thing,
			PRBool encoding)
{
    const SEC_ASN1Template *subt = NULL;

    PORT_Assert (theTemplate->sub != NULL);
    if (theTemplate->sub != NULL) {
	if (theTemplate->kind & SEC_ASN1_DYNAMIC) {
	    SEC_ASN1TemplateChooserPtr chooserp;

	    chooserp = *(SEC_ASN1TemplateChooserPtr *) theTemplate->sub;
	    if (chooserp) {
		if (thing != NULL)
		    thing = (char *)thing - theTemplate->offset;
		subt = (* chooserp)(thing, encoding);
	    }
	} else {
	    subt = (SEC_ASN1Template*)theTemplate->sub;
	}
    }
    return subt;
}

PRBool SEC_ASN1IsTemplateSimple(const SEC_ASN1Template *theTemplate)
{
    if (!theTemplate) {
	return PR_TRUE; /* it doesn't get any simpler than NULL */
    }
    /* only templates made of one primitive type or a choice of primitive
       types are considered simple */
    if (! (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK))) {
	return PR_TRUE; /* primitive type */
    }
    if (!theTemplate->kind & SEC_ASN1_CHOICE) {
	return PR_FALSE; /* no choice means not simple */
    }
    while (++theTemplate && theTemplate->kind) {
	if (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK)) {
	    return PR_FALSE; /* complex type */
	}
    }
    return PR_TRUE; /* choice of primitive types */
}