diff options
Diffstat (limited to 'openssl/crypto/bn/bn_shift.c')
| -rw-r--r-- | openssl/crypto/bn/bn_shift.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/openssl/crypto/bn/bn_shift.c b/openssl/crypto/bn/bn_shift.c new file mode 100644 index 00000000..c4d301af --- /dev/null +++ b/openssl/crypto/bn/bn_shift.c @@ -0,0 +1,220 @@ +/* crypto/bn/bn_shift.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" + +int BN_lshift1(BIGNUM *r, const BIGNUM *a) + { + register BN_ULONG *ap,*rp,t,c; + int i; + + bn_check_top(r); + bn_check_top(a); + + if (r != a) + { + r->neg=a->neg; + if (bn_wexpand(r,a->top+1) == NULL) return(0); + r->top=a->top; + } + else + { + if (bn_wexpand(r,a->top+1) == NULL) return(0); + } + ap=a->d; + rp=r->d; + c=0; + for (i=0; i<a->top; i++) + { + t= *(ap++); + *(rp++)=((t<<1)|c)&BN_MASK2; + c=(t & BN_TBIT)?1:0; + } + if (c) + { + *rp=1; + r->top++; + } + bn_check_top(r); + return(1); + } + +int BN_rshift1(BIGNUM *r, const BIGNUM *a) + { + BN_ULONG *ap,*rp,t,c; + int i; + + bn_check_top(r); + bn_check_top(a); + + if (BN_is_zero(a)) + { + BN_zero(r); + return(1); + } + if (a != r) + { + if (bn_wexpand(r,a->top) == NULL) return(0); + r->top=a->top; + r->neg=a->neg; + } + ap=a->d; + rp=r->d; + c=0; + for (i=a->top-1; i>=0; i--) + { + t=ap[i]; + rp[i]=((t>>1)&BN_MASK2)|c; + c=(t&1)?BN_TBIT:0; + } + bn_correct_top(r); + bn_check_top(r); + return(1); + } + +int BN_lshift(BIGNUM *r, const BIGNUM *a, int n) + { + int i,nw,lb,rb; + BN_ULONG *t,*f; + BN_ULONG l; + + bn_check_top(r); + bn_check_top(a); + + r->neg=a->neg; + nw=n/BN_BITS2; + if (bn_wexpand(r,a->top+nw+1) == NULL) return(0); + lb=n%BN_BITS2; + rb=BN_BITS2-lb; + f=a->d; + t=r->d; + t[a->top+nw]=0; + if (lb == 0) + for (i=a->top-1; i>=0; i--) + t[nw+i]=f[i]; + else + for (i=a->top-1; i>=0; i--) + { + l=f[i]; + t[nw+i+1]|=(l>>rb)&BN_MASK2; + t[nw+i]=(l<<lb)&BN_MASK2; + } + memset(t,0,nw*sizeof(t[0])); +/* for (i=0; i<nw; i++) + t[i]=0;*/ + r->top=a->top+nw+1; + bn_correct_top(r); + bn_check_top(r); + return(1); + } + +int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) + { + int i,j,nw,lb,rb; + BN_ULONG *t,*f; + BN_ULONG l,tmp; + + bn_check_top(r); + bn_check_top(a); + + nw=n/BN_BITS2; + rb=n%BN_BITS2; + lb=BN_BITS2-rb; + if (nw >= a->top || a->top == 0) + { + BN_zero(r); + return(1); + } + if (r != a) + { + r->neg=a->neg; + if (bn_wexpand(r,a->top-nw+1) == NULL) return(0); + } + else + { + if (n == 0) + return 1; /* or the copying loop will go berserk */ + } + + f= &(a->d[nw]); + t=r->d; + j=a->top-nw; + r->top=j; + + if (rb == 0) + { + for (i=j; i != 0; i--) + *(t++)= *(f++); + } + else + { + l= *(f++); + for (i=j-1; i != 0; i--) + { + tmp =(l>>rb)&BN_MASK2; + l= *(f++); + *(t++) =(tmp|(l<<lb))&BN_MASK2; + } + *(t++) =(l>>rb)&BN_MASK2; + } + bn_correct_top(r); + bn_check_top(r); + return(1); + } |