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2754597013
openssl/crypto/bn/bn_lib.c
Geoff Thorpe 2754597013 A general spring-cleaning (in autumn) to fix up signed/unsigned warnings. 
I have tried to convert 'len' type variable declarations to unsigned as a
means to address these warnings when appropriate, but when in doubt I have
used casts in the comparisons instead. The better solution (that would get
us all lynched by API users) would be to go through and convert all the
function prototypes and structure definitions to use unsigned variables
except when signed is necessary. The proliferation of (signed) "int" for
strictly non-negative uses is unfortunate.
2003-10-29 20:24:15 +00:00

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/* crypto/bn/bn_lib.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.]
*/
#ifndef BN_DEBUG
# undef NDEBUG /* avoid conflicting definitions */
# define NDEBUG
#endif
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include "cryptlib.h"
#include "bn_lcl.h"
const char *BN_version="Big Number" OPENSSL_VERSION_PTEXT;
/* For a 32 bit machine
* 2 - 4 == 128
* 3 - 8 == 256
* 4 - 16 == 512
* 5 - 32 == 1024
* 6 - 64 == 2048
* 7 - 128 == 4096
* 8 - 256 == 8192
*/
static int bn_limit_bits=0;
static int bn_limit_num=8; /* (1<<bn_limit_bits) */
static int bn_limit_bits_low=0;
static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
static int bn_limit_bits_high=0;
static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
static int bn_limit_bits_mont=0;
static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
void BN_set_params(int mult, int high, int low, int mont)
{
if (mult >= 0)
{
if (mult > (int)(sizeof(int)*8)-1)
mult=sizeof(int)*8-1;
bn_limit_bits=mult;
bn_limit_num=1<<mult;
}
if (high >= 0)
{
if (high > (int)(sizeof(int)*8)-1)
high=sizeof(int)*8-1;
bn_limit_bits_high=high;
bn_limit_num_high=1<<high;
}
if (low >= 0)
{
if (low > (int)(sizeof(int)*8)-1)
low=sizeof(int)*8-1;
bn_limit_bits_low=low;
bn_limit_num_low=1<<low;
}
if (mont >= 0)
{
if (mont > (int)(sizeof(int)*8)-1)
mont=sizeof(int)*8-1;
bn_limit_bits_mont=mont;
bn_limit_num_mont=1<<mont;
}
}
int BN_get_params(int which)
{
if (which == 0) return(bn_limit_bits);
else if (which == 1) return(bn_limit_bits_high);
else if (which == 2) return(bn_limit_bits_low);
else if (which == 3) return(bn_limit_bits_mont);
else return(0);
}
const BIGNUM *BN_value_one(void)
{
static BN_ULONG data_one=1L;
static BIGNUM const_one={&data_one,1,1,0};
return(&const_one);
}
char *BN_options(void)
{
static int init=0;
static char data[16];
if (!init)
{
init++;
#ifdef BN_LLONG
sprintf(data,"bn(%d,%d)",(int)sizeof(BN_ULLONG)*8,
(int)sizeof(BN_ULONG)*8);
#else
sprintf(data,"bn(%d,%d)",(int)sizeof(BN_ULONG)*8,
(int)sizeof(BN_ULONG)*8);
#endif
}
return(data);
}
int BN_num_bits_word(BN_ULONG l)
{
static const char bits[256]={
0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
};
#if defined(SIXTY_FOUR_BIT_LONG)
if (l & 0xffffffff00000000L)
{
if (l & 0xffff000000000000L)
{
if (l & 0xff00000000000000L)
{
return(bits[(int)(l>>56)]+56);
}
else return(bits[(int)(l>>48)]+48);
}
else
{
if (l & 0x0000ff0000000000L)
{
return(bits[(int)(l>>40)]+40);
}
else return(bits[(int)(l>>32)]+32);
}
}
else
#else
#ifdef SIXTY_FOUR_BIT
if (l & 0xffffffff00000000LL)
{
if (l & 0xffff000000000000LL)
{
if (l & 0xff00000000000000LL)
{
return(bits[(int)(l>>56)]+56);
}
else return(bits[(int)(l>>48)]+48);
}
else
{
if (l & 0x0000ff0000000000LL)
{
return(bits[(int)(l>>40)]+40);
}
else return(bits[(int)(l>>32)]+32);
}
}
else
#endif
#endif
{
#if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
if (l & 0xffff0000L)
{
if (l & 0xff000000L)
return(bits[(int)(l>>24L)]+24);
else return(bits[(int)(l>>16L)]+16);
}
else
#endif
{
#if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
if (l & 0xff00L)
return(bits[(int)(l>>8)]+8);
else
#endif
return(bits[(int)(l )] );
}
}
}
int BN_num_bits(const BIGNUM *a)
{
BN_ULONG l;
int i;
bn_check_top(a);
if (a->top == 0) return(0);
l=a->d[a->top-1];
assert(l != 0);
i=(a->top-1)*BN_BITS2;
return(i+BN_num_bits_word(l));
}
void BN_clear_free(BIGNUM *a)
{
int i;
if (a == NULL) return;
if (a->d != NULL)
{
OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
OPENSSL_free(a->d);
}
i=BN_get_flags(a,BN_FLG_MALLOCED);
OPENSSL_cleanse(a,sizeof(BIGNUM));
if (i)
OPENSSL_free(a);
}
void BN_free(BIGNUM *a)
{
if (a == NULL) return;
if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
OPENSSL_free(a->d);
a->flags|=BN_FLG_FREE; /* REMOVE? */
if (a->flags & BN_FLG_MALLOCED)
OPENSSL_free(a);
}
void BN_init(BIGNUM *a)
{
memset(a,0,sizeof(BIGNUM));
}
BIGNUM *BN_new(void)
{
BIGNUM *ret;
if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
{
BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
return(NULL);
}
ret->flags=BN_FLG_MALLOCED;
ret->top=0;
ret->neg=0;
ret->dmax=0;
ret->d=NULL;
return(ret);
}
/* This is used both by bn_expand2() and bn_dup_expand() */
/* The caller MUST check that words > b->dmax before calling this */
static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
{
BN_ULONG *A,*a = NULL;
const BN_ULONG *B;
int i;
if (words > (INT_MAX/(4*BN_BITS2)))
{
BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
return NULL;
}
bn_check_top(b);
if (BN_get_flags(b,BN_FLG_STATIC_DATA))
{
BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
return(NULL);
}
a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*(words+1));
if (A == NULL)
{
BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
return(NULL);
}
#if 1
B=b->d;
/* Check if the previous number needs to be copied */
if (B != NULL)
{
for (i=b->top>>2; i>0; i--,A+=4,B+=4)
{
/*
* The fact that the loop is unrolled
* 4-wise is a tribute to Intel. It's
* the one that doesn't have enough
* registers to accomodate more data.
* I'd unroll it 8-wise otherwise:-)
*
* <appro@fy.chalmers.se>
*/
BN_ULONG a0,a1,a2,a3;
a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
}
switch (b->top&3)
{
case 3: A[2]=B[2];
case 2: A[1]=B[1];
case 1: A[0]=B[0];
case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
* the switch table by doing a=top&3; a--; goto jump_table[a];
* which fails for top== 0 */
;
}
}
#else
memset(A,0,sizeof(BN_ULONG)*(words+1));
memcpy(A,b->d,sizeof(b->d[0])*b->top);
#endif
return(a);
}
/* This is an internal function that can be used instead of bn_expand2()
* when there is a need to copy BIGNUMs instead of only expanding the
* data part, while still expanding them.
* Especially useful when needing to expand BIGNUMs that are declared
* 'const' and should therefore not be changed.
* The reason to use this instead of a BN_dup() followed by a bn_expand2()
* is memory allocation overhead. A BN_dup() followed by a bn_expand2()
* will allocate new memory for the BIGNUM data twice, and free it once,
* while bn_dup_expand() makes sure allocation is made only once.
*/
BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
{
BIGNUM *r = NULL;
/* This function does not work if
* words <= b->dmax && top < words
* because BN_dup() does not preserve 'dmax'!
* (But bn_dup_expand() is not used anywhere yet.)
*/
if (words > b->dmax)
{
BN_ULONG *a = bn_expand_internal(b, words);
if (a)
{
r = BN_new();
if (r)
{
r->top = b->top;
r->dmax = words;
r->neg = b->neg;
r->d = a;
}
else
{
/* r == NULL, BN_new failure */
OPENSSL_free(a);
}
}
/* If a == NULL, there was an error in allocation in
bn_expand_internal(), and NULL should be returned */
}
else
{
r = BN_dup(b);
}
return r;
}
/* This is an internal function that should not be used in applications.
* It ensures that 'b' has enough room for a 'words' word number
* and initialises any unused part of b->d with leading zeros.
* It is mostly used by the various BIGNUM routines. If there is an error,
* NULL is returned. If not, 'b' is returned. */
BIGNUM *bn_expand2(BIGNUM *b, int words)
{
BN_ULONG *A;
int i;
if (words > b->dmax)
{
BN_ULONG *a = bn_expand_internal(b, words);
if (a)
{
if (b->d)
OPENSSL_free(b->d);
b->d=a;
b->dmax=words;
}
else
b = NULL;
}
/* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
if ((b != NULL) && (b->top < b->dmax))
{
A = &(b->d[b->top]);
for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
{
A[0]=0; A[1]=0; A[2]=0; A[3]=0;
A[4]=0; A[5]=0; A[6]=0; A[7]=0;
}
for (i=(b->dmax - b->top)&7; i>0; i--,A++)
A[0]=0;
assert(A == &(b->d[b->dmax]));
}
return b;
}
BIGNUM *BN_dup(const BIGNUM *a)
{
BIGNUM *r, *t;
if (a == NULL) return NULL;
bn_check_top(a);
t = BN_new();
if (t == NULL) return(NULL);
r = BN_copy(t, a);
/* now r == t || r == NULL */
if (r == NULL)
BN_free(t);
return r;
}
BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
{
int i;
BN_ULONG *A;
const BN_ULONG *B;
bn_check_top(b);
if (a == b) return(a);
if (bn_wexpand(a,b->top) == NULL) return(NULL);
#if 1
A=a->d;
B=b->d;
for (i=b->top>>2; i>0; i--,A+=4,B+=4)
{
BN_ULONG a0,a1,a2,a3;
a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
}
switch (b->top&3)
{
case 3: A[2]=B[2];
case 2: A[1]=B[1];
case 1: A[0]=B[0];
case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
}
#else
memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
#endif
/* memset(&(a->d[b->top]),0,sizeof(a->d[0])*(a->max-b->top));*/
a->top=b->top;
if ((a->top == 0) && (a->d != NULL))
a->d[0]=0;
a->neg=b->neg;
return(a);
}
BIGNUM *BN_ncopy(BIGNUM *a, const BIGNUM *b, size_t n)
{
int i, min;
BN_ULONG *A;
const BN_ULONG *B;
bn_check_top(b);
if (a == b)
return a;
min = (b->top < (int)n)? b->top: (int)n;
if (!min)
{
BN_zero(a);
return a;
}
if (bn_wexpand(a, min) == NULL)
return NULL;
A=a->d;
B=b->d;
for (i=min>>2; i>0; i--, A+=4, B+=4)
{
BN_ULONG a0,a1,a2,a3;
a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
}
switch (min&3)
{
case 3: A[2]=B[2];
case 2: A[1]=B[1];
case 1: A[0]=B[0];
case 0: ;
}
a->top = min;
a->neg = b->neg;
bn_fix_top(a);
return(a);
}
void BN_swap(BIGNUM *a, BIGNUM *b)
{
int flags_old_a, flags_old_b;
BN_ULONG *tmp_d;
int tmp_top, tmp_dmax, tmp_neg;
flags_old_a = a->flags;
flags_old_b = b->flags;
tmp_d = a->d;
tmp_top = a->top;
tmp_dmax = a->dmax;
tmp_neg = a->neg;
a->d = b->d;
a->top = b->top;
a->dmax = b->dmax;
a->neg = b->neg;
b->d = tmp_d;
b->top = tmp_top;
b->dmax = tmp_dmax;
b->neg = tmp_neg;
a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
}
void BN_clear(BIGNUM *a)
{
if (a->d != NULL)
memset(a->d,0,a->dmax*sizeof(a->d[0]));
a->top=0;
a->neg=0;
}
BN_ULONG BN_get_word(const BIGNUM *a)
{
int i,n;
BN_ULONG ret=0;
n=BN_num_bytes(a);
if (n > (int)sizeof(BN_ULONG))
return(BN_MASK2);
for (i=a->top-1; i>=0; i--)
{
#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
ret<<=BN_BITS4; /* stops the compiler complaining */
ret<<=BN_BITS4;
#else
ret=0;
#endif
ret|=a->d[i];
}
return(ret);
}
int BN_set_word(BIGNUM *a, BN_ULONG w)
{
int i,n;
if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
n=sizeof(BN_ULONG)/BN_BYTES;
a->neg=0;
a->top=0;
a->d[0]=(BN_ULONG)w&BN_MASK2;
if (a->d[0] != 0) a->top=1;
for (i=1; i<n; i++)
{
/* the following is done instead of
* w>>=BN_BITS2 so compilers don't complain
* on builds where sizeof(long) == BN_TYPES */
#ifndef SIXTY_FOUR_BIT /* the data item > unsigned long */
w>>=BN_BITS4;
w>>=BN_BITS4;
#else
w=0;
#endif
a->d[i]=(BN_ULONG)w&BN_MASK2;
if (a->d[i] != 0) a->top=i+1;
}
return(1);
}
BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
{
unsigned int i,m;
unsigned int n;
BN_ULONG l;
if (ret == NULL) ret=BN_new();
if (ret == NULL) return(NULL);
l=0;
n=len;
if (n == 0)
{
ret->top=0;
return(ret);
}
if (bn_expand(ret,(int)(n+2)*8) == NULL)
return(NULL);
i=((n-1)/BN_BYTES)+1;
m=((n-1)%(BN_BYTES));
ret->top=i;
ret->neg=0;
while (n-- > 0)
{
l=(l<<8L)| *(s++);
if (m-- == 0)
{
ret->d[--i]=l;
l=0;
m=BN_BYTES-1;
}
}
/* need to call this due to clear byte at top if avoiding
* having the top bit set (-ve number) */
bn_fix_top(ret);
return(ret);
}
/* ignore negative */
int BN_bn2bin(const BIGNUM *a, unsigned char *to)
{
int n,i;
BN_ULONG l;
n=i=BN_num_bytes(a);
while (i-- > 0)
{
l=a->d[i/BN_BYTES];
*(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
}
return(n);
}
int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
{
int i;
BN_ULONG t1,t2,*ap,*bp;
bn_check_top(a);
bn_check_top(b);
i=a->top-b->top;
if (i != 0) return(i);
ap=a->d;
bp=b->d;
for (i=a->top-1; i>=0; i--)
{
t1= ap[i];
t2= bp[i];
if (t1 != t2)
return(t1 > t2?1:-1);
}
return(0);
}
int BN_cmp(const BIGNUM *a, const BIGNUM *b)
{
int i;
int gt,lt;
BN_ULONG t1,t2;
if ((a == NULL) || (b == NULL))
{
if (a != NULL)
return(-1);
else if (b != NULL)
return(1);
else
return(0);
}
bn_check_top(a);
bn_check_top(b);
if (a->neg != b->neg)
{
if (a->neg)
return(-1);
else return(1);
}
if (a->neg == 0)
{ gt=1; lt= -1; }
else { gt= -1; lt=1; }
if (a->top > b->top) return(gt);
if (a->top < b->top) return(lt);
for (i=a->top-1; i>=0; i--)
{
t1=a->d[i];
t2=b->d[i];
if (t1 > t2) return(gt);
if (t1 < t2) return(lt);
}
return(0);
}
int BN_set_bit(BIGNUM *a, int n)
{
int i,j,k;
i=n/BN_BITS2;
j=n%BN_BITS2;
if (a->top <= i)
{
if (bn_wexpand(a,i+1) == NULL) return(0);
for(k=a->top; k<i+1; k++)
a->d[k]=0;
a->top=i+1;
}
a->d[i]|=(((BN_ULONG)1)<<j);
return(1);
}
int BN_clear_bit(BIGNUM *a, int n)
{
int i,j;
i=n/BN_BITS2;
j=n%BN_BITS2;
if (a->top <= i) return(0);
a->d[i]&=(~(((BN_ULONG)1)<<j));
bn_fix_top(a);
return(1);
}
int BN_is_bit_set(const BIGNUM *a, int n)
{
int i,j;
if (n < 0) return(0);
i=n/BN_BITS2;
j=n%BN_BITS2;
if (a->top <= i) return(0);
return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
}
int BN_mask_bits(BIGNUM *a, int n)
{
int b,w;
w=n/BN_BITS2;
b=n%BN_BITS2;
if (w >= a->top) return(0);
if (b == 0)
a->top=w;
else
{
a->top=w+1;
a->d[w]&= ~(BN_MASK2<<b);
}
bn_fix_top(a);
return(1);
}
int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
{
int i;
BN_ULONG aa,bb;
aa=a[n-1];
bb=b[n-1];
if (aa != bb) return((aa > bb)?1:-1);
for (i=n-2; i>=0; i--)
{
aa=a[i];
bb=b[i];
if (aa != bb) return((aa > bb)?1:-1);
}
return(0);
}
/* Here follows a specialised variants of bn_cmp_words(). It has the
property of performing the operation on arrays of different sizes.
The sizes of those arrays is expressed through cl, which is the
common length ( basicall, min(len(a),len(b)) ), and dl, which is the
delta between the two lengths, calculated as len(a)-len(b).
All lengths are the number of BN_ULONGs... */
int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
int cl, int dl)
{
int n,i;
n = cl-1;
if (dl < 0)
{
for (i=dl; i<0; i++)
{
if (b[n-i] != 0)
return -1; /* a < b */
}
}
if (dl > 0)
{
for (i=dl; i>0; i--)
{
if (a[n+i] != 0)
return 1; /* a > b */
}
}
return bn_cmp_words(a,b,cl);
}
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