From 9b141126d4b6f0636bc047e81b846c193ae26611 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ulf=20M=C3=B6ller?= <ulf@openssl.org>
Date: Sat, 5 Feb 2000 14:17:32 +0000
Subject: New functions BN_CTX_start(), BN_CTX_get(), BN_CTX_end() to access
 temporary BIGNUMs. BN_CTX still uses a fixed number of BIGNUMs, but the
 BN_CTX implementation could now easily be changed.

---
 crypto/bn/bn_ctx.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 crypto/bn/bn_ctx.c

(limited to 'crypto/bn/bn_ctx.c')

diff --git a/crypto/bn/bn_ctx.c b/crypto/bn/bn_ctx.c
new file mode 100644
index 0000000000..8b079e237f
--- /dev/null
+++ b/crypto/bn/bn_ctx.c
@@ -0,0 +1,123 @@
+/* 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).
+ *
+ */
+
+#include <stdio.h>
+#include <assert.h>
+#include "cryptlib.h"
+#include <openssl/bn.h>
+
+
+BN_CTX *BN_CTX_new(void)
+	{
+	BN_CTX *ret;
+
+	ret=(BN_CTX *)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;
+	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)
+		Free(ctx);
+	}
+
+void BN_CTX_start(BN_CTX *ctx)
+	{
+	ctx->pos[ctx->depth++] = ctx->tos;
+	}
+
+BIGNUM *BN_CTX_get(BN_CTX *ctx)
+	{
+	if (ctx->tos >= BN_CTX_NUM)
+		{
+		BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
+		return NULL;
+		}
+	return (&(ctx->bn[ctx->tos++]));
+	}
+
+void BN_CTX_end(BN_CTX *ctx)
+	{
+	if (ctx == NULL) return;
+	assert(ctx->depth > 0);
+	ctx->depth--;
+	ctx->tos = ctx->pos[ctx->depth];
+	}
-- 
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