Fix a existing c++ application that parses a specific file type

I have an application that is used to parse a specific file type, the application still works with the files it was written to parse, but recently there were some changes on the new files whihc the current application errors out with: Exception thrown at 0x00007FFDE9FC3C58 in [login to view URL]: Microsoft C++ exception: [rethrow] at memory location 0x0000000000000000. Unhandled exception at 0x00007FFDE9FC3C58 in [login to view URL]: Microsoft C++ exception: [rethrow] at memory location 0x0000000000000000. when it reached the follwing code: size_t charsRead = 0; while (readPosition() < size() && charsRead < p_Size) { ++charsRead; char lC = read<char>(); if (lC == 0) break; out += lC; } _readPos += p_Size - charsRead; } charRead is an __int64