Built motion from commit 6a09e18b.|2.6.11

[motion2.git] / legacy-libs / grpc-cloned / deps / grpc / third_party / boringssl / crypto / fipsmodule / bn / jacobi.c

diff --git a/legacy-libs/grpc-cloned/deps/grpc/third_party/boringssl/crypto/fipsmodule/bn/jacobi.c b/legacy-libs/grpc-cloned/deps/grpc/third_party/boringssl/crypto/fipsmodule/bn/jacobi.c
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+/* ====================================================================
+ * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com). */
+
+#include <openssl/bn.h>
+
+#include <openssl/err.h>
+
+#include "internal.h"
+
+
+// least significant word
+#define BN_lsw(n) (((n)->width == 0) ? (BN_ULONG) 0 : (n)->d[0])
+
+int bn_jacobi(const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) {
+  // In 'tab', only odd-indexed entries are relevant:
+  // For any odd BIGNUM n,
+  //     tab[BN_lsw(n) & 7]
+  // is $(-1)^{(n^2-1)/8}$ (using TeX notation).
+  // Note that the sign of n does not matter.
+  static const int tab[8] = {0, 1, 0, -1, 0, -1, 0, 1};
+
+  // The Jacobi symbol is only defined for odd modulus.
+  if (!BN_is_odd(b)) {
+    OPENSSL_PUT_ERROR(BN, BN_R_CALLED_WITH_EVEN_MODULUS);
+    return -2;
+  }
+
+  // Require b be positive.
+  if (BN_is_negative(b)) {
+    OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
+    return -2;
+  }
+
+  int ret = -2;
+  BN_CTX_start(ctx);
+  BIGNUM *A = BN_CTX_get(ctx);
+  BIGNUM *B = BN_CTX_get(ctx);
+  if (B == NULL) {
+    goto end;
+  }
+
+  if (!BN_copy(A, a) ||
+      !BN_copy(B, b)) {
+    goto end;
+  }
+
+  // Adapted from logic to compute the Kronecker symbol, originally implemented
+  // according to Henri Cohen, "A Course in Computational Algebraic Number
+  // Theory" (algorithm 1.4.10).
+
+  ret = 1;
+
+  while (1) {
+    // Cohen's step 3:
+
+    // B is positive and odd
+    if (BN_is_zero(A)) {
+      ret = BN_is_one(B) ? ret : 0;
+      goto end;
+    }
+
+    // now A is non-zero
+    int i = 0;
+    while (!BN_is_bit_set(A, i)) {
+      i++;
+    }
+    if (!BN_rshift(A, A, i)) {
+      ret = -2;
+      goto end;
+    }
+    if (i & 1) {
+      // i is odd
+      // multiply 'ret' by  $(-1)^{(B^2-1)/8}$
+      ret = ret * tab[BN_lsw(B) & 7];
+    }
+
+    // Cohen's step 4:
+    // multiply 'ret' by  $(-1)^{(A-1)(B-1)/4}$
+    if ((A->neg ? ~BN_lsw(A) : BN_lsw(A)) & BN_lsw(B) & 2) {
+      ret = -ret;
+    }
+
+    // (A, B) := (B mod |A|, |A|)
+    if (!BN_nnmod(B, B, A, ctx)) {
+      ret = -2;
+      goto end;
+    }
+    BIGNUM *tmp = A;
+    A = B;
+    B = tmp;
+    tmp->neg = 0;
+  }
+
+end:
+  BN_CTX_end(ctx);
+  return ret;
+}