better error messages

readLib/source/Interface.boost.cc

@@ -21,6 +21,7 @@ namespace corsika_data {
 
   struct DataFile {
     std::ifstream file_in_;
+    std::string file_name_;
     boost::iostreams::filtering_istream in_;
     DataFile() {}
     ~DataFile() {}
@@ -34,10 +35,12 @@ namespace corsika_data {
       auto i1 = s.find_first_not_of(" \t\r\n"); // trimm right
       auto i2 = s.find_first_of(" \t\r\n", i1); // trimm left
       std::string trimmed(s.substr(i1, i2 - i1));
+      file_name_ = trimmed;
       file_in_.open(trimmed, ios_base::in | ios_base::binary);
       if (!file_in_ || !file_in_.good()) {
-        std::cerr << std::string("Cannot open file: \'") + trimmed << "\'" << std::endl;
-        throw std::runtime_error(std::string("Cannot open file: ") + trimmed);
+        std::cerr << std::string("Cannot open file: \'") + file_name_ << "\'"
+                  << std::endl;
+        throw std::runtime_error(std::string("Cannot open file: ") + file_name_);
       }
       if (trimmed.rfind(".bz2") == trimmed.length() - 4)
         in_.push(boost::iostreams::bzip2_decompressor());
@@ -48,20 +51,27 @@ namespace corsika_data {
       for (int i = 0; i < length; i++) {
         in_ >> data[i];
         if (!in_.good()) {
-          throw std::runtime_error(std::string("Cannot FillArray i=") +
-                                   std::to_string(i));
+          throw std::runtime_error(std::string("Cannot FillArray i/length=") +
+                                   std::to_string(i) + "/" + std::to_string(length) +
+                                   " in file " + file_name_);
         }
       }
     }
     double ReadNextNumber() {
       double data;
       in_ >> data;
-      if (!in_.good()) { throw std::runtime_error(std::string("Cannot ReadNextNumber")); }
+      if (!in_.good()) {
+        throw std::runtime_error(
+            std::string("Cannot ReadNextNumber in file " + file_name_));
+      }
       return data;
     }
     int ReadNextText(std::string& data) {
       std::getline(in_, data, ' ');
-      if (!in_.good()) { throw std::runtime_error(std::string("Cannot ReadNextText")); }
+      if (!in_.good()) {
+        throw std::runtime_error(
+            std::string("Cannot ReadNextText in file " + file_name_));
+      }
       return 0;
     }
   };