Improve Vector constructor for C++11

[libs/math.git] / source / linal / vector.h

diff --git a/source/linal/vector.h b/source/linal/vector.h
index 152c26e66482e943e5837c5ddecc54fc9e7c2fde..31597d4282410e2606590eaea2faa6d3c22c2cd9 100644 (file)
--- a/source/linal/vector.h
+++ b/source/linal/vector.h
@@ -3,6 +3,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <ostream>
 
 namespace Msp {
 namespace LinAl {
@@ -78,9 +79,19 @@ public:
 
        Vector();
        Vector(const T *);
+
+       /** Constructs a vector from an array of interleaved values.  Intended for
+       use by Matrix row accessor. */
+       Vector(const T *, unsigned);
+
+#if __cplusplus >= 201103L
+       template<typename... Args>
+       Vector(T, Args...);
+#else
        Vector(T, T);
        Vector(T, T, T);
        Vector(T, T, T, T);
+#endif
        template<typename U>
        Vector(const Vector<U, N> &);
 
@@ -113,6 +124,25 @@ inline Vector<T, N>::Vector(const T *d)
                (*this)[i] = d[i];
 }
 
+template<typename T, unsigned N>
+inline Vector<T, N>::Vector(const T *d, unsigned stride)
+{
+       for(unsigned i=0; i<N; ++i)
+               (*this)[i] = d[i*stride];
+}
+
+#if __cplusplus >= 201103L
+template<typename T, unsigned N>
+template<typename... Args>
+inline Vector<T, N>::Vector(T x_, Args... v)
+{
+       static_assert(1+sizeof...(v)==N, "Incorrect number of arguments in Vector constructor");
+       (*this)[0] = x_;
+       unsigned i = 1;
+       for(auto c: std::initializer_list<T> { static_cast<T>(v)... })
+               (*this)[i++] = c;
+}
+#else
 /* The compiler won't instantiate these unless they are used.  Trying to use
 them on the wrong class results in an error. */
 template<typename T, unsigned N>
@@ -138,6 +168,7 @@ inline Vector<T, N>::Vector(T x_, T y_, T z_, T w_)
        this->VectorComponents<T, 4>::z = z_;
        this->VectorComponents<T, 4>::w = w_;
 }
+#endif
 
 template<typename T, unsigned N>
 template<typename U>
@@ -161,9 +192,9 @@ template<typename T, unsigned N>
 inline Vector<T, N+1> compose(T s, const Vector<T, N> &v)
 {
        Vector<T, N+1> r;
+       r[0] = s;
        for(unsigned i=0; i<N; ++i)
-               r[i] = v[i];
-       r[N] = s;
+               r[i+1] = v[i];
        return r;
 }
 
@@ -313,6 +344,20 @@ inline Vector<T, 3> cross(const Vector<T, 3> &v1, const Vector<T, 3> &v2)
        return Vector<T, 3>(v1.y*v2.z-v1.z*v2.y, v1.z*v2.x-v1.x*v2.z, v1.x*v2.y-v1.y*v2.x);
 }
 
+template<typename T, unsigned N>
+inline std::ostream &operator<<(std::ostream &s, const Vector<T, N> &v)
+{
+       s << "Vector" << N << '(';
+       for(unsigned i=0; i<N; ++i)
+       {
+               if(i)
+                       s << ", ";
+               s << v[i];
+       }
+       s << ')';
+       return s;
+}
+
 } // namespace LinAl
 } // namespace Msp