/* tasn_utl.c */
/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */


#include <stddef.h>
#include <string.h>
#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>
#include <openssl/err.h>

/* Utility functions for manipulating fields and offsets */

/* Add 'offset' to 'addr' */
#define offset2ptr(addr, offset) (void *)(((char *) addr) + offset)

/* Given an ASN1_ITEM CHOICE type return
 * the selector value
 */

int asn1_get_choice_selector(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	int *sel = offset2ptr(*pval, it->utype);
	return *sel;
}

/* Given an ASN1_ITEM CHOICE type set
 * the selector value, return old value.
 */

int asn1_set_choice_selector(ASN1_VALUE **pval, int value, const ASN1_ITEM *it)
{	
	int *sel, ret;
	sel = offset2ptr(*pval, it->utype);
	ret = *sel;
	*sel = value;
	return ret;
}

/* Do reference counting. The value 'op' decides what to do. 
 * if it is +1 then the count is incremented. If op is 0 count is
 * set to 1. If op is -1 count is decremented and the return value
 * is the current refrence count or 0 if no reference count exists.
 */

int asn1_do_lock(ASN1_VALUE **pval, int op, const ASN1_ITEM *it)
{
	const ASN1_AUX *aux;
	int *lck, ret;
	if(it->itype != ASN1_ITYPE_SEQUENCE) return 0;
	aux = it->funcs;
	if(!aux || !(aux->flags & ASN1_AFLG_REFCOUNT)) return 0;
	lck = offset2ptr(*pval, aux->ref_offset);
	if(op == 0) {
		*lck = 1;
		return 1;
	}
	ret = CRYPTO_add(lck, op, aux->ref_lock);
#ifdef REF_PRINT
	fprintf(stderr, "%s: Reference Count: %d\n", it->sname, *lck);
#endif
#ifdef REF_CHECK
	if(ret < 0) 
		fprintf(stderr, "%s, bad reference count\n", it->sname);
#endif
	return ret;
}

static ASN1_ENCODING *asn1_get_enc_ptr(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	const ASN1_AUX *aux;
	if(!pval || !*pval) return NULL;
	aux = it->funcs;
	if(!aux || !(aux->flags & ASN1_AFLG_ENCODING)) return NULL;
	return offset2ptr(*pval, aux->enc_offset);
}

void asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	ASN1_ENCODING *enc;
	enc = asn1_get_enc_ptr(pval, it);
	if(enc) {
		enc->enc = NULL;
		enc->len = 0;
		enc->modified = 1;
	}
}

void asn1_enc_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	ASN1_ENCODING *enc;
	enc = asn1_get_enc_ptr(pval, it);
	if(enc) {
		if(enc->enc) OPENSSL_free(enc->enc);
		enc->enc = NULL;
		enc->len = 0;
		enc->modified = 1;
	}
}

int asn1_enc_save(ASN1_VALUE **pval, unsigned char *in, int inlen, const ASN1_ITEM *it)
{
	ASN1_ENCODING *enc;
	enc = asn1_get_enc_ptr(pval, it);
	if(!enc) return 1;

	if(enc->enc) OPENSSL_free(enc->enc);
	enc->enc = OPENSSL_malloc(inlen);
	if(!enc->enc) return 0;
	memcpy(enc->enc, in, inlen);
	enc->len = inlen;
	enc->modified = 0;

	return 1;
}
		
int asn1_enc_restore(int *len, unsigned char **out, ASN1_VALUE **pval, const ASN1_ITEM *it)
{
	ASN1_ENCODING *enc;
	enc = asn1_get_enc_ptr(pval, it);
	if(!enc || enc->modified) return 0;
	if(out) {
		memcpy(*out, enc->enc, enc->len);
		*out += enc->len;
	}
	if(len) *len = enc->len;
	return 1;
}

/* Given an ASN1_TEMPLATE get a pointer to a field */
ASN1_VALUE ** asn1_get_field_ptr(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt)
{
	ASN1_VALUE **pvaltmp;
	if(tt->flags & ASN1_TFLG_COMBINE) return pval;
	pvaltmp = offset2ptr(*pval, tt->offset);
	/* NOTE for BOOLEAN types the field is just a plain
 	 * int so we can't return int **, so settle for
	 * (int *).
	 */
	return pvaltmp;
}

/* Handle ANY DEFINED BY template, find the selector, look up
 * the relevant ASN1_TEMPLATE in the table and return it.
 */

const ASN1_TEMPLATE *asn1_do_adb(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt, int nullerr)
{
	const ASN1_ADB *adb;
	const ASN1_ADB_TABLE *atbl;
	long selector;
	ASN1_VALUE **sfld;
	int i;
	if(!(tt->flags & ASN1_TFLG_ADB_MASK)) return tt;

	/* Else ANY DEFINED BY ... get the table */
	adb = ASN1_ADB_ptr(tt->item);

	/* Get the selector field */
	sfld = offset2ptr(*pval, adb->offset);

	/* Check if NULL */
	if(!sfld) {
		if(!adb->null_tt) goto err;
		return adb->null_tt;
	}

	/* Convert type to a long:
	 * NB: don't check for NID_undef here because it
	 * might be a legitimate value in the table
	 */
	if(tt->flags & ASN1_TFLG_ADB_OID) 
		selector = OBJ_obj2nid((ASN1_OBJECT *)*sfld);
	else 
		selector = ASN1_INTEGER_get((ASN1_INTEGER *)*sfld);

	/* Try to find matching entry in table
	 * Maybe should check application types first to
	 * allow application override? Might also be useful
	 * to have a flag which indicates table is sorted and
	 * we can do a binary search. For now stick to a
	 * linear search.
	 */

	for(atbl = adb->tbl, i = 0; i < adb->tblcount; i++, atbl++)
		if(atbl->value == selector) return &atbl->tt;

	/* FIXME: need to search application table too */

	/* No match, return default type */
	if(!adb->default_tt) goto err;		
	return adb->default_tt;
	
	err:
	/* FIXME: should log the value or OID of unsupported type */
	if(nullerr) ASN1err(ASN1_F_ASN1_DO_ADB, ASN1_R_UNSUPPORTED_ANY_DEFINED_BY_TYPE);
	return NULL;
}