readDMAT for vectors of vectors

Former-commit-id: ecc6ddfdd3d3bacaf86ef2a082901347ac99cd9c

include/igl/readDMAT.cpp

@@ -5,38 +5,54 @@
 
 #include <Eigen/Dense>
 
-template <class Mat>
-IGL_INLINE bool igl::readDMAT(const std::string file_name, Mat & W)
+// Static helper method reads the first to elements in the given file
+// Inputs:
+//   fp  file pointer of .dmat file that was just opened
+// Outputs:
+//   num_rows  number of rows
+//   num_cols number of columns
+// Returns true on success, false on failure
+static inline bool readDMAT_read_header(FILE * fp, int & num_rows, int & num_cols)
 {
-  FILE * fp = fopen(file_name.c_str(),"r");
-  if(fp == NULL)
-  {
-    fprintf(stderr,"IOError: readDMAT() could not open %s...\n",file_name.c_str());
-    return false; 
-  }
   // first line contains number of rows and number of columns
-  int num_cols, num_rows;
   int res = fscanf(fp,"%d %d\n",&num_cols,&num_rows);
   if(res != 2)
   {
-    fclose(fp);
     fprintf(stderr,"IOError: readDMAT() first row should be [num cols] [num rows]...\n");
     return false;
   }
-
   // check that number of columns and rows are sane
   if(num_cols < 0)
   {
-    fclose(fp);
     fprintf(stderr,"IOError: readDMAT() number of columns %d < 0\n",num_cols);
     return false;
   }
   if(num_rows < 0)
   {
-    fclose(fp);
     fprintf(stderr,"IOError: readDMAT() number of rows %d < 0\n",num_rows);
     return false;
   }
+  return true;
+}
+
+#ifndef IGL_NO_EIGEN
+template <typename DerivedW>
+IGL_INLINE bool igl::readDMAT(const std::string file_name,
+  Eigen::PlainObjectBase<DerivedW> & W)
+{
+  FILE * fp = fopen(file_name.c_str(),"r");
+  if(fp == NULL)
+  {
+    fprintf(stderr,"IOError: readDMAT() could not open %s...\n",file_name.c_str());
+    return false; 
+  }
+  int num_rows,num_cols;
+  bool head_success = readDMAT_read_header(fp,num_rows,num_cols);
+  if(!head_success)
+  {
+    fclose(fp);
+    return false;
+  }
 
   // Resize output to fit matrix
   W.resize(num_rows,num_cols);
@@ -47,7 +63,55 @@ IGL_INLINE bool igl::readDMAT(const std::string file_name, Mat & W)
     // loop over rows (down columns) quickly
     for(int i = 0;i < num_rows;i++)
     {
-      if(fscanf(fp," %lg",&W(i,j)) != 1)
+      double d;
+      if(fscanf(fp," %lg",&d) != 1)
+      {
+        fclose(fp);
+        fprintf(
+          stderr,
+          "IOError: readDMAT() bad format after reading %d entries\n",
+          j*num_rows + i);
+        return false;
+      }
+      W(i,j) = d;
+    }
+  }
+
+  fclose(fp);
+  return true;
+}
+#endif
+
+template <typename Scalar>
+IGL_INLINE bool igl::readDMAT(
+  const std::string file_name, 
+  std::vector<std::vector<Scalar> > & W)
+{
+  FILE * fp = fopen(file_name.c_str(),"r");
+  if(fp == NULL)
+  {
+    fprintf(stderr,"IOError: readDMAT() could not open %s...\n",file_name.c_str());
+    return false; 
+  }
+  int num_rows,num_cols;
+  bool head_success = readDMAT_read_header(fp,num_rows,num_cols);
+  if(!head_success)
+  {
+    fclose(fp);
+    return false;
+  }
+
+  // Resize for output
+  W.resize(num_rows,typename std::vector<Scalar>(num_cols));
+
+  // Loop over columns slowly
+  for(int j = 0;j < num_cols;j++)
+  {
+    // loop over rows (down columns) quickly
+    for(int i = 0;i < num_rows;i++)
+    {
+      double d;
+      if(fscanf(fp," %lg",&d) != 1)
       {
         fclose(fp);
         fprintf(
@@ -56,13 +120,15 @@ IGL_INLINE bool igl::readDMAT(const std::string file_name, Mat & W)
           j*num_rows + i);
         return false;
       }
+      W[i][j] = (Scalar)d;
     }
   }
+
   fclose(fp);
   return true;
 }
 
 #ifndef IGL_HEADER_ONLY
 // Explicit template specialization
-template bool igl::readDMAT<Eigen::Matrix<double, -1, -1, 0, -1, -1> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Eigen::Matrix<double, -1, -1, 0, -1, -1> &);
+template bool igl::readDMAT<Eigen::Matrix<double, -1, -1, 0, -1, -1> >(std::basic_string<char, std::char_traits<char>, std::allocator<char> >, Eigen::PlainObjectBase<Eigen::Matrix<double, -1, -1, 0, -1, -1> >&);
 #endif

include/igl/readDMAT.h

@@ -13,6 +13,10 @@
 //   3 2
 //   1 4 2 5 3 6
 #include <string>
+#include <vector>
+#ifndef IGL_NO_EIGEN
+#  include <Eigen/Core>
+#endif
 namespace igl
 {
   // Read a matrix from an ascii dmat file
@@ -23,8 +27,16 @@ namespace igl
   //   W  eigen matrix containing read-in coefficients
   // Returns true on success, false on error
   //
-  template <class Mat>
-  IGL_INLINE bool readDMAT(const std::string file_name, Mat & W);
+#ifndef IGL_NO_EIGEN
+  template <typename DerivedW>
+  IGL_INLINE bool readDMAT(const std::string file_name, 
+    Eigen::PlainObjectBase<DerivedW> & W);
+#endif
+  // Wrapper for vector of vectors
+  template <typename Scalar>
+  IGL_INLINE bool readDMAT(
+    const std::string file_name, 
+    std::vector<std::vector<Scalar> > & W);
 }
 
 #ifdef IGL_HEADER_ONLY