check file attributes before reading

[todo]

tan/src/reader/reader.cpp

Lines 19 to 24 in 12ad011

 // TODO: check file attributes before reading 
 _filename = filename; 
 std::ifstream ifs(filename); 
 // read the whole file at once 
 std::string content((std::istreambuf_iterator<char>(ifs)), (std::istreambuf_iterator<char>())); 
 // count the number of lines 

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This issue was generated by todo based on a TODO comment in 12ad011 when #6 was merged. cc @tjysdsg.

[Jiyang (Mark) Tang]

Since ifstream will throw if it cannot open a file, there is no need to check beforehand.