fast-cpp-csv-parser | fast-cpp-csv-parser | Parser library

The libary provides two classes:. Note that everything is contained in the io namespace. The constructor takes a file name and optionally a data source. If no data source is provided the function tries to open the file with the given name and throws an error::can_not_open_file exception on failure. If a data source is provided then the file name is only used to format error messages. In that case you can essentially put any string there. Using a string that describes the data source results in more informative error messages. some_string_type can be a std::string or a char*. If the data source is a std::FILE* then the library will take care of calling std::fclose. If it is a std::istream then the stream is not closed by the library. For best performance open the streams in binary mode. However using text mode also works. ByteSourceBase provides an interface that you can use to implement further data sources. The read function should fill the provided buffer with at most size bytes from the data source. It should return the number of bytes actually written to the buffer. If data source has run out of bytes (because for example an end of file was reached) then the function should return 0. If a fatal error occures then you can throw an exception. Note that the function can be called both from the main and the worker thread. However, it is guarenteed that they do not call the function at the same time. Lines are read by calling the next_line function. It returns a pointer to a null terminated C-string that contains the line. If the end of file is reached a null pointer is returned. The newline character is not included in the string. You may modify the string as long as you do not write past the null terminator. The string stays valid until the destructor is called or until next_line is called again. Windows and *nix newlines are handled transparently. UTF-8 BOMs are automatically ignored and missing newlines at the end of the file are no problem. Important: There is a limit of 2^24-1 characters per line. If this limit is exceeded a error::line_length_limit_exceeded exception is thrown. Looping over all the lines in a file can be done in the following way. The remaining functions are mainly used used to format error messages. The file line indicates the current position in the file, i.e., after the first next_line call it is 1 and after the second 2. Before the first call it is 0. The file name is truncated as internally C-strings are used to avoid std::bad_alloc exceptions during error reporting. Note: It is not possible to exchange the line termination character. CSVReader uses policies. These are classes with only static members to allow core functionality to be exchanged in an efficient way. The column_count template parameter indicates how many columns you want to read from the CSV file. This must not necessarily coincide with the actual number of columns in the file. The three policies govern various aspects of the parsing. The trim policy indicates what characters should be ignored at the begin and the end of every column. The default ignores spaces and tabs. This makes sure that. is interpreted in the same way as. The trim_chars can take any number of template parameters. For example trim_chars<' ', '\t', '_'> is also valid. If no character should be trimmed use trim_chars<>.