--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ssl/libcrypto/src/crypto/bn/bn_recp.c	Fri Jun 04 16:20:51 2010 +0100
@@ -0,0 +1,234 @@
+/* crypto/bn/bn_recp.c */
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
+ * All rights reserved.
+ *
+ * This package is an SSL implementation written
+ * by Eric Young (eay@cryptsoft.com).
+ * The implementation was written so as to conform with Netscapes SSL.
+ * 
+ * This library is free for commercial and non-commercial use as long as
+ * the following conditions are aheared to.  The following conditions
+ * apply to all code found in this distribution, be it the RC4, RSA,
+ * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
+ * included with this distribution is covered by the same copyright terms
+ * except that the holder is Tim Hudson (tjh@cryptsoft.com).
+ * 
+ * Copyright remains Eric Young's, and as such any Copyright notices in
+ * the code are not to be removed.
+ * If this package is used in a product, Eric Young should be given attribution
+ * as the author of the parts of the library used.
+ * This can be in the form of a textual message at program startup or
+ * in documentation (online or textual) provided with the package.
+ * 
+ * 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 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 acknowledgement:
+ *    "This product includes cryptographic software written by
+ *     Eric Young (eay@cryptsoft.com)"
+ *    The word 'cryptographic' can be left out if the rouines from the library
+ *    being used are not cryptographic related :-).
+ * 4. If you include any Windows specific code (or a derivative thereof) from 
+ *    the apps directory (application code) you must include an acknowledgement:
+ *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
+ * 
+ * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
+ * ANY EXPRESS 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 AUTHOR OR 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.
+ * 
+ * The licence and distribution terms for any publically available version or
+ * derivative of this code cannot be changed.  i.e. this code cannot simply be
+ * copied and put under another distribution licence
+ * [including the GNU Public Licence.]
+ */
+
+#include <stdio.h>
+#include "cryptlib.h"
+#include "bn_lcl.h"
+
+EXPORT_C void BN_RECP_CTX_init(BN_RECP_CTX *recp)
+	{
+	BN_init(&(recp->N));
+	BN_init(&(recp->Nr));
+	recp->num_bits=0;
+	recp->flags=0;
+	}
+
+EXPORT_C BN_RECP_CTX *BN_RECP_CTX_new(void)
+	{
+	BN_RECP_CTX *ret;
+
+	if ((ret=(BN_RECP_CTX *)OPENSSL_malloc(sizeof(BN_RECP_CTX))) == NULL)
+		return(NULL);
+
+	BN_RECP_CTX_init(ret);
+	ret->flags=BN_FLG_MALLOCED;
+	return(ret);
+	}
+
+EXPORT_C void BN_RECP_CTX_free(BN_RECP_CTX *recp)
+	{
+	if(recp == NULL)
+	    return;
+
+	BN_free(&(recp->N));
+	BN_free(&(recp->Nr));
+	if (recp->flags & BN_FLG_MALLOCED)
+		OPENSSL_free(recp);
+	}
+
+EXPORT_C int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
+	{
+	if (!BN_copy(&(recp->N),d)) return 0;
+	BN_zero(&(recp->Nr));
+	recp->num_bits=BN_num_bits(d);
+	recp->shift=0;
+	return(1);
+	}
+
+EXPORT_C int BN_mod_mul_reciprocal(BIGNUM *r, const BIGNUM *x, const BIGNUM *y,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
+	{
+	int ret=0;
+	BIGNUM *a;
+	const BIGNUM *ca;
+
+	BN_CTX_start(ctx);
+	if ((a = BN_CTX_get(ctx)) == NULL) goto err;
+	if (y != NULL)
+		{
+		if (x == y)
+			{ if (!BN_sqr(a,x,ctx)) goto err; }
+		else
+			{ if (!BN_mul(a,x,y,ctx)) goto err; }
+		ca = a;
+		}
+	else
+		ca=x; /* Just do the mod */
+
+	ret = BN_div_recp(NULL,r,ca,recp,ctx);
+err:
+	BN_CTX_end(ctx);
+	bn_check_top(r);
+	return(ret);
+	}
+
+EXPORT_C int BN_div_recp(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m,
+	BN_RECP_CTX *recp, BN_CTX *ctx)
+	{
+	int i,j,ret=0;
+	BIGNUM *a,*b,*d,*r;
+
+	BN_CTX_start(ctx);
+	a=BN_CTX_get(ctx);
+	b=BN_CTX_get(ctx);
+	if (dv != NULL)
+		d=dv;
+	else
+		d=BN_CTX_get(ctx);
+	if (rem != NULL)
+		r=rem;
+	else
+		r=BN_CTX_get(ctx);
+	if (a == NULL || b == NULL || d == NULL || r == NULL) goto err;
+
+	if (BN_ucmp(m,&(recp->N)) < 0)
+		{
+		BN_zero(d);
+		if (!BN_copy(r,m)) return 0;
+		BN_CTX_end(ctx);
+		return(1);
+		}
+
+	/* We want the remainder
+	 * Given input of ABCDEF / ab
+	 * we need multiply ABCDEF by 3 digests of the reciprocal of ab
+	 *
+	 */
+
+	/* i := max(BN_num_bits(m), 2*BN_num_bits(N)) */
+	i=BN_num_bits(m);
+	j=recp->num_bits<<1;
+	if (j>i) i=j;
+
+	/* Nr := round(2^i / N) */
+	if (i != recp->shift)
+		recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
+			i,ctx); /* BN_reciprocal returns i, or -1 for an error */
+	if (recp->shift == -1) goto err;
+
+	/* d := |round(round(m / 2^BN_num_bits(N)) * recp->Nr / 2^(i - BN_num_bits(N)))|
+	 *    = |round(round(m / 2^BN_num_bits(N)) * round(2^i / N) / 2^(i - BN_num_bits(N)))|
+	 *   <= |(m / 2^BN_num_bits(N)) * (2^i / N) * (2^BN_num_bits(N) / 2^i)|
+	 *    = |m/N|
+	 */
+	if (!BN_rshift(a,m,recp->num_bits)) goto err;
+	if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err;
+	if (!BN_rshift(d,b,i-recp->num_bits)) goto err;
+	d->neg=0;
+
+	if (!BN_mul(b,&(recp->N),d,ctx)) goto err;
+	if (!BN_usub(r,m,b)) goto err;
+	r->neg=0;
+
+#if 1
+	j=0;
+	while (BN_ucmp(r,&(recp->N)) >= 0)
+		{
+		if (j++ > 2)
+			{
+			BNerr(BN_F_BN_DIV_RECP,BN_R_BAD_RECIPROCAL);
+			goto err;
+			}
+		if (!BN_usub(r,r,&(recp->N))) goto err;
+		if (!BN_add_word(d,1)) goto err;
+		}
+#endif
+
+	r->neg=BN_is_zero(r)?0:m->neg;
+	d->neg=m->neg^recp->N.neg;
+	ret=1;
+err:
+	BN_CTX_end(ctx);
+	bn_check_top(dv);
+	bn_check_top(rem);
+	return(ret);
+	} 
+
+/* len is the expected size of the result
+ * We actually calculate with an extra word of precision, so
+ * we can do faster division if the remainder is not required.
+ */
+/* r := 2^len / m */
+EXPORT_C int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx)
+	{
+	int ret= -1;
+	BIGNUM *t;
+
+	BN_CTX_start(ctx);
+	if((t = BN_CTX_get(ctx)) == NULL) goto err;
+
+	if (!BN_set_bit(t,len)) goto err;
+
+	if (!BN_div(r,NULL,t,m,ctx)) goto err;
+
+	ret=len;
+err:
+	bn_check_top(r);
+	BN_CTX_end(ctx);
+	return(ret);
+	}