diff options
Diffstat (limited to 'openssl-1.1.0h/crypto/bn/bn_shift.c')
| -rw-r--r-- | openssl-1.1.0h/crypto/bn/bn_shift.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/openssl-1.1.0h/crypto/bn/bn_shift.c b/openssl-1.1.0h/crypto/bn/bn_shift.c new file mode 100644 index 0000000..6a1eec8 --- /dev/null +++ b/openssl-1.1.0h/crypto/bn/bn_shift.c @@ -0,0 +1,175 @@ +/* + * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the OpenSSL license (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#include "internal/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, j; + + bn_check_top(r); + bn_check_top(a); + + if (BN_is_zero(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, j) == NULL) + return (0); + r->neg = a->neg; + } + rp = r->d; + t = ap[--i]; + c = (t & 1) ? BN_TBIT : 0; + if (t >>= 1) + rp[i] = t; + while (i > 0) { + t = ap[--i]; + rp[i] = ((t >> 1) & BN_MASK2) | c; + c = (t & 1) ? BN_TBIT : 0; + } + r->top = j; + if (!r->top) + r->neg = 0; /* don't allow negative zero */ + 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); + + if (n < 0) { + BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT); + return 0; + } + + nw = n / BN_BITS2; + if (bn_wexpand(r, a->top + nw + 1) == NULL) + return (0); + r->neg = a->neg; + 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, sizeof(*t) * nw); + 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); + + if (n < 0) { + BNerr(BN_F_BN_RSHIFT, BN_R_INVALID_SHIFT); + return 0; + } + + nw = n / BN_BITS2; + rb = n % BN_BITS2; + lb = BN_BITS2 - rb; + if (nw >= a->top || a->top == 0) { + BN_zero(r); + return (1); + } + i = (BN_num_bits(a) - n + (BN_BITS2 - 1)) / BN_BITS2; + if (r != a) { + if (bn_wexpand(r, i) == NULL) + return (0); + r->neg = a->neg; + } 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 = i; + + 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; + } + if ((l = (l >> rb) & BN_MASK2)) + *(t) = l; + } + if (!r->top) + r->neg = 0; /* don't allow negative zero */ + bn_check_top(r); + return (1); +} |