Commit 79ba545c authored by Andy Polyakov's avatar Andy Polyakov
Browse files

bn_shift.c: minimize reallocations, which allows BN_FLG_STATIC_DATA to 

be shifted in specific cases.
parent 993adc05

crypto/bn/bn_shift.c

+15 −12
Original line number Diff line number Diff line
@@ -99,7 +99,7 @@ int BN_lshift1(BIGNUM *r, const BIGNUM *a) 
int BN_rshift1(BIGNUM *r, const BIGNUM *a)

	{

	BN_ULONG *ap,*rp,t,c;

	int i;

	int i,j;



	bn_check_top(r);

	bn_check_top(a);
@@ -109,22 +109,25 @@ int BN_rshift1(BIGNUM *r, const BIGNUM *a) 
		BN_zero(r);

		return(1);

		}

	i = a->top;

	ap= a->d;

	j = i-(ap[i-1]==1);

	if (a != r)

		{

		if (bn_wexpand(r,a->top) == NULL) return(0);

		r->top=a->top;

		if (bn_wexpand(r,j) == NULL) return(0);

		r->neg=a->neg;

		}

	ap=a->d;

	rp=r->d;

	c=0;

	for (i=a->top-1; i>=0; i--)

	t=ap[--i];

	c=(t&1)?BN_TBIT:0;

	if (t>>=1) rp[i]=t;

	while (i>0)

		{

		t=ap[i];

		t=ap[--i];

		rp[i]=((t>>1)&BN_MASK2)|c;

		c=(t&1)?BN_TBIT:0;

		}

	bn_correct_top(r);

	r->top=j;

	bn_check_top(r);

	return(1);

	}
@@ -182,10 +185,11 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) 
		BN_zero(r);

		return(1);

		}

	i = (BN_num_bits(a)-n+(BN_BITS2-1))/BN_BITS2;

	if (r != a)

		{

		r->neg=a->neg;

		if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);

		if (bn_wexpand(r,i) == NULL) return(0);

		}

	else

		{
@@ -196,7 +200,7 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) 
	f= &(a->d[nw]);

	t=r->d;

	j=a->top-nw;

	r->top=j;

	r->top=i;



	if (rb == 0)

		{
@@ -212,9 +216,8 @@ int BN_rshift(BIGNUM *r, const BIGNUM *a, int n) 
			l= *(f++);

			*(t++) =(tmp|(l<<lb))&BN_MASK2;

			}

		*(t++) =(l>>rb)&BN_MASK2;

		if ((l = (l>>rb)&BN_MASK2)) *(t) = l;

		}

	bn_correct_top(r);

	bn_check_top(r);

	return(1);

	}