* fix a couple of warnings (patch from Armin Berres)

* allow Map to map null data

Eigen/src/Core/IO.h

@@ -6,12 +6,12 @@
 //
 // Eigen is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Lesser General Public
-// License as published by the Free Software Foundation; either 
+// License as published by the Free Software Foundation; either
 // version 3 of the License, or (at your option) any later version.
 //
 // Alternatively, you can redistribute it and/or
 // modify it under the terms of the GNU General Public License as
-// published by the Free Software Foundation; either version 2 of 
+// published by the Free Software Foundation; either version 2 of
 // the License, or (at your option) any later version.
 //
 // Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
@@ -19,7 +19,7 @@
 // FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
 // GNU General Public License for more details.
 //
-// You should have received a copy of the GNU Lesser General Public 
+// You should have received a copy of the GNU Lesser General Public
 // License and a copy of the GNU General Public License along with
 // Eigen. If not, see <http://www.gnu.org/licenses/>.
 
@@ -58,7 +58,7 @@ struct IOFormat
     coeffSeparator(_coeffSeparator), precision(_precision), flags(_flags)
   {
     rowSpacer = "";
-    int i=matSuffix.length()-1;
+    int i = int(matSuffix.length())-1;
     while (i>=0 && matSuffix[i]!='\n')
     {
       rowSpacer += ' ';
@@ -81,7 +81,7 @@ struct IOFormat
   * This class represents an expression with stream operators controlled by a given IOFormat.
   * It is the return type of MatrixBase::format()
   * and most of the time this is the only way it is used.
-  * 
+  *
   * See class IOFormat for some examples.
   *
   * \sa MatrixBase::format(), class IOFormat
@@ -135,7 +135,7 @@ std::ostream & ei_print_matrix(std::ostream & s, const MatrixBase<Derived> & _m,
         std::stringstream sstr;
         sstr.precision(fmt.precision);
         sstr << m.coeff(i,j);
-        width = std::max<int>(width, sstr.str().length());
+        width = std::max<int>(width, int(sstr.str().length()));
       }
   }
   s.precision(fmt.precision);

Eigen/src/Core/MapBase.h

@@ -53,7 +53,7 @@ template<typename Derived> class MapBase
       ColsAtCompileTime = ei_traits<Derived>::ColsAtCompileTime,
       SizeAtCompileTime = Base::SizeAtCompileTime
     };
-    
+
     typedef typename ei_traits<Derived>::AlignedDerivedType AlignedDerivedType;
     typedef typename ei_traits<Derived>::Scalar Scalar;
     typedef typename Base::PacketScalar PacketScalar;
@@ -83,7 +83,7 @@ template<typename Derived> class MapBase
       else // column-major
         return const_cast<Scalar*>(m_data)[row + col * stride()];
     }
-    
+
     inline const Scalar coeff(int index) const
     {
       ei_assert(Derived::IsVectorAtCompileTime || (ei_traits<Derived>::Flags & LinearAccessBit));
@@ -138,28 +138,29 @@ template<typename Derived> class MapBase
               m_cols(ColsAtCompileTime == Dynamic ? size : ColsAtCompileTime)
     {
       EIGEN_STATIC_ASSERT_VECTOR_ONLY(Derived)
-      ei_assert(size > 0);
+      ei_assert(size > 0 || data == 0);
       ei_assert(SizeAtCompileTime == Dynamic || SizeAtCompileTime == size);
     }
 
     inline MapBase(const Scalar* data, int rows, int cols)
             : m_data(data), m_rows(rows), m_cols(cols)
     {
-      ei_assert(rows > 0 && (RowsAtCompileTime == Dynamic || RowsAtCompileTime == rows)
+      ei_assert( (data == 0)
-             && cols > 0 && (ColsAtCompileTime == Dynamic || ColsAtCompileTime == cols));
+              || (   rows > 0 && (RowsAtCompileTime == Dynamic || RowsAtCompileTime == rows)
+                  && cols > 0 && (ColsAtCompileTime == Dynamic || ColsAtCompileTime == cols)));
     }
 
     template<typename OtherDerived>
     Derived& operator+=(const MatrixBase<OtherDerived>& other)
     { return derived() = forceAligned() + other; }
-    
+
     template<typename OtherDerived>
     Derived& operator-=(const MatrixBase<OtherDerived>& other)
     { return derived() = forceAligned() - other; }
 
     Derived& operator*=(const Scalar& other)
     { return derived() = forceAligned() * other; }
-    
+
     Derived& operator/=(const Scalar& other)
     { return derived() = forceAligned() / other; }
 

Eigen/src/Core/MathFunctions.h

@@ -51,7 +51,7 @@ inline int ei_sin(int)  { ei_assert(false); return 0; }
 inline int ei_cos(int)  { ei_assert(false); return 0; }
 
 #if EIGEN_GNUC_AT_LEAST(4,3)
-inline int ei_pow(int x, int y) { return std::pow(x, y); }
+inline int ei_pow(int x, int y) { return int(std::pow(x, y)); }
 #else
 inline int ei_pow(int x, int y) { return int(std::pow(double(x), y)); }
 #endif
@@ -103,7 +103,7 @@ template<> inline float ei_random(float a, float b)
   } while(i==0);
   return i/256.f;
 #else
-  return a + (b-a) * std::rand() / RAND_MAX;
+  return a + (b-a) * float(std::rand()) / float(RAND_MAX);
 #endif
 }
 template<> inline float ei_random()
@@ -254,7 +254,7 @@ inline long double ei_pow(long double x, long double y)  { return std::pow(x, y)
 
 template<> inline long double ei_random(long double a, long double b)
 {
-  return ei_random<double>(a,b);
+  return static_cast<long double>(ei_random<double>(a,b));
 }
 template<> inline long double ei_random()
 {