Merge math.mp.Integer changes from the crypto branch

source/tanya/math/package.d

@@ -3,10 +3,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /**
- * Copyright: Eugene Wissner 2016.
+ * Copyright: Eugene Wissner 2016-2017.
  * License: $(LINK2 https://www.mozilla.org/en-US/MPL/2.0/,
  *                  Mozilla Public License, v. 2.0).
- * Authors: $(LINK2 mailto:belka@caraus.de, Eugene Wissner)
+ * Authors: $(LINK2 mailto:info@caraus.de, Eugene Wissner)
  */
 module tanya.math;
 
@@ -79,7 +79,7 @@ body
 }
 
 /// Ditto.
-I pow(I)(in auto ref I x, in auto ref I y, in auto ref I z)
+I pow(I)(const auto ref I x, const auto ref I y, const auto ref I z)
     if (is(I == Integer))
 in
 {
@@ -88,8 +88,8 @@ in
 body
 {
     size_t i = y.length;
-	auto tmp2 = Integer(x.allocator), tmp1 = Integer(x, x.allocator);
+    auto tmp1 = Integer(x, x.allocator);
-	Integer result = Integer(x.allocator);
+    auto result = Integer(x.allocator);
 
     if (x.length == 0 && i != 0)
     {
@@ -109,7 +109,7 @@ body
                 result *= tmp1;
                 result %= z;
             }
-			tmp2 = tmp1;
+            auto tmp2 = tmp1;
             tmp1 *= tmp2;
             tmp1 %= z;
         }
@@ -134,15 +134,15 @@ pure nothrow @safe @nogc unittest
 ///
 unittest
 {
-	assert(cast(long) pow(Integer(3), Integer(5), Integer(7)) == 5);
+    assert(pow(Integer(3), Integer(5), Integer(7)) == 5);
-	assert(cast(long) pow(Integer(2), Integer(2), Integer(1)) == 0);
+    assert(pow(Integer(2), Integer(2), Integer(1)) == 0);
-	assert(cast(long) pow(Integer(3), Integer(3), Integer(3)) == 0);
+    assert(pow(Integer(3), Integer(3), Integer(3)) == 0);
-	assert(cast(long) pow(Integer(7), Integer(4), Integer(2)) == 1);
+    assert(pow(Integer(7), Integer(4), Integer(2)) == 1);
-	assert(cast(long) pow(Integer(53), Integer(0), Integer(2)) == 1);
+    assert(pow(Integer(53), Integer(0), Integer(2)) == 1);
-	assert(cast(long) pow(Integer(53), Integer(1), Integer(3)) == 2);
+    assert(pow(Integer(53), Integer(1), Integer(3)) == 2);
-	assert(cast(long) pow(Integer(53), Integer(2), Integer(5)) == 4);
+    assert(pow(Integer(53), Integer(2), Integer(5)) == 4);
-	assert(cast(long) pow(Integer(0), Integer(0), Integer(5)) == 1);
+    assert(pow(Integer(0), Integer(0), Integer(5)) == 1);
-	assert(cast(long) pow(Integer(0), Integer(5), Integer(5)) == 0);
+    assert(pow(Integer(0), Integer(5), Integer(5)) == 0);
 }
 
 /**
@@ -170,3 +170,31 @@ unittest
 
     known.each!((ref x) => assert(isPseudoprime(x)));
 }
+
+/**
+ * Params:
+ *  I = Value type.
+ *  x = Value.
+ *
+ * Returns: The absolute value of a number.
+ */
+I abs(I : Integer)(const auto ref I x)
+{
+    auto result = Integer(x, x.allocator);
+    result.sign = Sign.positive;
+    return result;
+}
+
+/// Ditto.
+I abs(I : Integer)(I x)
+{
+    x.sign = Sign.positive;
+    return x;
+}
+
+/// Ditto.
+I abs(I)(const I x)
+    if (isIntegral!I)
+{
+    return x >= 0 ? x : -x;
+}