Imported OpenSSL 1.1.1a

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;
+}