--- /dev/null
+/* crypto/bn/bn_word.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"
+
+BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
+ {
+#ifndef BN_LLONG
+ BN_ULONG ret=0;
+#else
+ BN_ULLONG ret=0;
+#endif
+ int i;
+
+ if (w == 0)
+ return (BN_ULONG)-1;
+
+ bn_check_top(a);
+ w&=BN_MASK2;
+ for (i=a->top-1; i>=0; i--)
+ {
+#ifndef BN_LLONG
+ ret=((ret<<BN_BITS4)|((a->d[i]>>BN_BITS4)&BN_MASK2l))%w;
+ ret=((ret<<BN_BITS4)|(a->d[i]&BN_MASK2l))%w;
+#else
+ ret=(BN_ULLONG)(((ret<<(BN_ULLONG)BN_BITS2)|a->d[i])%
+ (BN_ULLONG)w);
+#endif
+ }
+ return((BN_ULONG)ret);
+ }
+
+BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
+ {
+ BN_ULONG ret = 0;
+ int i, j;
+
+ bn_check_top(a);
+ w &= BN_MASK2;
+
+ if (!w)
+ /* actually this an error (division by zero) */
+ return (BN_ULONG)-1;
+ if (a->top == 0)
+ return 0;
+
+ /* normalize input (so bn_div_words doesn't complain) */
+ j = BN_BITS2 - BN_num_bits_word(w);
+ w <<= j;
+ if (!BN_lshift(a, a, j))
+ return (BN_ULONG)-1;
+
+ for (i=a->top-1; i>=0; i--)
+ {
+ BN_ULONG l,d;
+
+ l=a->d[i];
+ d=bn_div_words(ret,l,w);
+ ret=(l-((d*w)&BN_MASK2))&BN_MASK2;
+ a->d[i]=d;
+ }
+ if ((a->top > 0) && (a->d[a->top-1] == 0))
+ a->top--;
+ ret >>= j;
+ bn_check_top(a);
+ return(ret);
+ }
+
+int BN_add_word(BIGNUM *a, BN_ULONG w)
+ {
+ BN_ULONG l;
+ int i;
+
+ bn_check_top(a);
+ w &= BN_MASK2;
+
+ /* degenerate case: w is zero */
+ if (!w) return 1;
+ /* degenerate case: a is zero */
+ if(BN_is_zero(a)) return BN_set_word(a, w);
+ /* handle 'a' when negative */
+ if (a->neg)
+ {
+ a->neg=0;
+ i=BN_sub_word(a,w);
+ if (!BN_is_zero(a))
+ a->neg=!(a->neg);
+ return(i);
+ }
+ for (i=0;w!=0 && i<a->top;i++)
+ {
+ a->d[i] = l = (a->d[i]+w)&BN_MASK2;
+ w = (w>l)?1:0;
+ }
+ if (w && i==a->top)
+ {
+ if (bn_wexpand(a,a->top+1) == NULL) return 0;
+ a->top++;
+ a->d[i]=w;
+ }
+ bn_check_top(a);
+ return(1);
+ }
+
+int BN_sub_word(BIGNUM *a, BN_ULONG w)
+ {
+ int i;
+
+ bn_check_top(a);
+ w &= BN_MASK2;
+
+ /* degenerate case: w is zero */
+ if (!w) return 1;
+ /* degenerate case: a is zero */
+ if(BN_is_zero(a))
+ {
+ i = BN_set_word(a,w);
+ if (i != 0)
+ BN_set_negative(a, 1);
+ return i;
+ }
+ /* handle 'a' when negative */
+ if (a->neg)
+ {
+ a->neg=0;
+ i=BN_add_word(a,w);
+ a->neg=1;
+ return(i);
+ }
+
+ if ((a->top == 1) && (a->d[0] < w))
+ {
+ a->d[0]=w-a->d[0];
+ a->neg=1;
+ return(1);
+ }
+ i=0;
+ for (;;)
+ {
+ if (a->d[i] >= w)
+ {
+ a->d[i]-=w;
+ break;
+ }
+ else
+ {
+ a->d[i]=(a->d[i]-w)&BN_MASK2;
+ i++;
+ w=1;
+ }
+ }
+ if ((a->d[i] == 0) && (i == (a->top-1)))
+ a->top--;
+ bn_check_top(a);
+ return(1);
+ }
+
+int BN_mul_word(BIGNUM *a, BN_ULONG w)
+ {
+ BN_ULONG ll;
+
+ bn_check_top(a);
+ w&=BN_MASK2;
+ if (a->top)
+ {
+ if (w == 0)
+ BN_zero(a);
+ else
+ {
+ ll=bn_mul_words(a->d,a->d,a->top,w);
+ if (ll)
+ {
+ if (bn_wexpand(a,a->top+1) == NULL) return(0);
+ a->d[a->top++]=ll;
+ }
+ }
+ }
+ bn_check_top(a);
+ return(1);
+ }
+
projects / cassiopeia.git / blobdiff