Back-end utility functions

The following functions can be used in your validator and assimilator code:

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int get_output_file_path(RESULT const&, std::string&);

Returns the path of a result's output file (parses result.xml_doc_out and computes the file's position in the hierarchical directory structure).

int get_output_file_paths(RESULT const&, vector<string>&);

Same, for multiple output files.

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int try_fopen(char* path, FILE*& f, char* mode);

Open a file, distinguishing between recoverable and nonrecoverable errors. Returns zero on success. Returns ERR_FOPEN if the directory is present but not the file (this is considered a nonrecoverable error). Returns ERR_OPENDIR if the directory is not there (this is generally a recoverable error, like NFS mount failure).

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double median_mean_credit(vector<RESULT> const& results);

Given a vector of N correct results, computes a canonical credit as follows:

• if N==1, return that result's claimed credit
• if N==2, return min of claimed credits
• if N>2, toss out high and low claimed credit, and return the average of the rest.