/* crypto/bn/bn_ctx.c *//* Written by Ulf Moeller for the OpenSSL project. *//* ==================================================================== * Copyright (c) 1998-2000 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 *    openssl-core@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). * */#ifndef BN_CTX_DEBUG# undef NDEBUG			/* avoid conflicting definitions */# define NDEBUG#endif#include <stdio.h>#include <assert.h>#include "cryptlib.h"#include "bn.h"#include "workaround.h"BN_CTX *BN_CTX_new(void){    BN_CTX *ret;    ret = (BN_CTX *) Our_malloc(sizeof(BN_CTX));    if (ret == NULL) {	BNerr(BN_F_BN_CTX_NEW, ERR_R_MALLOC_FAILURE);	return (NULL);    }    BN_CTX_init(ret);    ret->flags = BN_FLG_MALLOCED;    return (ret);}void BN_CTX_init(BN_CTX * ctx){    int i;    ctx->tos = 0;    ctx->flags = 0;    ctx->depth = 0;    ctx->too_many = 0;    for (i = 0; i < BN_CTX_NUM; i++)	BN_init(&(ctx->bn[i]));}void BN_CTX_free(BN_CTX * ctx){    int i;    if (ctx == NULL)	return;    assert(ctx->depth == 0);    for (i = 0; i < BN_CTX_NUM; i++)	BN_clear_free(&(ctx->bn[i]));    if (ctx->flags & BN_FLG_MALLOCED)	OPENSSL_free(ctx);}void BN_CTX_start(BN_CTX * ctx){    if (ctx->depth < BN_CTX_NUM_POS)	ctx->pos[ctx->depth] = ctx->tos;    ctx->depth++;}BIGNUM *BN_CTX_get(BN_CTX * ctx){    if (ctx->depth > BN_CTX_NUM_POS || ctx->tos >= BN_CTX_NUM) {	if (!ctx->too_many) {	    BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);	    /* disable error code until BN_CTX_end is called: */	    ctx->too_many = 1;	}	return NULL;    }    return (&(ctx->bn[ctx->tos++]));}void BN_CTX_end(BN_CTX * ctx){    if (ctx == NULL)	return;    assert(ctx->depth > 0);    if (ctx->depth == 0)	/* should never happen, but we can tolerate it if not in	 * debug mode (could be a 'goto err' in the calling function	 * before BN_CTX_start was reached) */	BN_CTX_start(ctx);    ctx->too_many = 0;    ctx->depth--;    if (ctx->depth < BN_CTX_NUM_POS)	ctx->tos = ctx->pos[ctx->depth];}