EIC code displayed by LXR master/​include/​root/​ROOT/​RCsvDS.hxx	Source navigation Diff markup Identifier search General search
	Version: master test Revert   Change

File indexing completed on 2025-09-18 09:32:02

 // Author: Enric Tejedor CERN  10/2017
 
 /*************************************************************************
  * Copyright (C) 1995-2022, Rene Brun and Fons Rademakers.               *
  * All rights reserved.                                                  *
  *                                                                       *
  * For the licensing terms see $ROOTSYS/LICENSE.                         *
  * For the list of contributors see $ROOTSYS/README/CREDITS.             *
  *************************************************************************/
 
 #ifndef ROOT_RCSVTDS
 #define ROOT_RCSVTDS
 
 #include "ROOT/RDataFrame.hxx"
 #include "ROOT/RDataSource.hxx"
 
 #include <cstdint>
 #include <deque>
 #include <list>
 #include <unordered_map>
 #include <set>
 #include <memory>
 #include <vector>
 
 #include <TRegexp.h>
 
 namespace ROOT {
 
 namespace Internal {
 class RRawFile;
 }
 
 namespace RDF {
 
 class RCsvDS final : public ROOT::RDF::RDataSource {
 public:
    /// Options that control how the CSV file is parsed
    struct ROptions {
       /// The first line describes the columns. The names are used as RDF column names
       /// unless fColumnNames is not empty, in which case it replaces the given names.
       /// If both, fHeaders is false and fColumnNames is empty, generic column names Col1.n.Col$n$ are used.
       bool fHeaders = true;
       char fDelimiter = ',';             ///< Column delimiter character
       bool fLeftTrim = false;            ///< Leading whitespaces are removed
       bool fRightTrim = false;           ///< Trailing whitespaces are removed
       bool fSkipBlankLines = true;       ///< Ignore empty lines (after trimming, if trimming is enabled)
       std::int64_t fSkipFirstNLines = 0; ///< Ignore the first N lines of the file
       std::int64_t fSkipLastNLines = 0;  ///< Ignore the last N lines of the file
       std::int64_t fLinesChunkSize = -1; ///< Number of lines to read, -1 to read all
       /// Character indicating that the remainder of the line should be ignored, if different from '\0'.
       /// If it is the first character of the line (after trimming), the line is ignored altogether.
       /// Note that the comment character must not be part of the data, e.g. in strings.
       char fComment = '\0';
       /// Impose column names. This can be used if a header is missing or if the header has unparsable or
       /// unwanted column names. If this list is not empty, it must contain exactly as many elements as
       /// the number of columns in the CSV file.
       std::vector<std::string> fColumnNames;
       /// Specify custom column types, accepts an unordered map with keys being column name, values being type alias
       /// ('O' for boolean, 'D' for double, 'L' for Long64_t, 'T' for std::string)
       std::unordered_map<std::string, char> fColumnTypes;
    };
 
 private:
    // Possible values are D, O, L, T. This is possible only because we treat double, bool, Long64_t and string
    using ColType_t = char;
    static const std::unordered_map<ColType_t, std::string> fgColTypeMap;
 
    // Regular expressions for type inference
    static const TRegexp fgIntRegex, fgDoubleRegex1, fgDoubleRegex2, fgDoubleRegex3, fgTrueRegex, fgFalseRegex;
 
    ROptions fOptions;
    std::uint64_t fDataPos = 0;
    std::int64_t fDataLineNumber = 0;
    std::int64_t fLineNumber = 0;     // used to skip the last lines
    std::int64_t fMaxLineNumber = -1; // set to non-negative if fOptions.fSkipLastNLines is set
    std::unique_ptr<ROOT::Internal::RRawFile> fCsvFile;
    ULong64_t fEntryRangesRequested = 0ULL;
    ULong64_t fProcessedLines = 0ULL; // marks the progress of the consumption of the csv lines
    std::vector<std::string> fHeaders; // the column names
    std::unordered_map<std::string, ColType_t> fColTypes;
    std::set<std::string> fColContainingEmpty; // store columns which had empty entry
    std::list<ColType_t> fColTypesList; // column types, order is the same as fHeaders, values the same as fColTypes
    std::vector<std::vector<void *>> fColAddresses;         // fColAddresses[column][slot] (same ordering as fHeaders)
    std::vector<Record_t> fRecords;                         // fRecords[entry][column] (same ordering as fHeaders)
    std::vector<std::vector<double>> fDoubleEvtValues;      // one per column per slot
    std::vector<std::vector<Long64_t>> fLong64EvtValues;    // one per column per slot
    std::vector<std::vector<std::string>> fStringEvtValues; // one per column per slot
    // This must be a deque to avoid the specialisation vector<bool>. This would not
    // work given that the pointer to the boolean in that case cannot be taken
    std::vector<std::deque<bool>> fBoolEvtValues; // one per column per slot
 
    void Construct();
 
    bool Readln(std::string &line);
    void RewindToData();
    void FillHeaders(const std::string &);
    void FillRecord(const std::string &, Record_t &);
    void GenerateHeaders(size_t);
    std::vector<void *> GetColumnReadersImpl(std::string_view, const std::type_info &) final;
    void ValidateColTypes(std::vector<std::string> &) const;
    void InferColTypes(std::vector<std::string> &);
    void InferType(const std::string &, unsigned int);
    std::vector<std::string> ParseColumns(const std::string &);
    size_t ParseValue(const std::string &, std::vector<std::string> &, size_t);
    ColType_t GetType(std::string_view colName) const;
    void FreeRecords();
 
 protected:
    std::string AsString() final;
 
 public:
    RCsvDS(std::string_view fileName, const ROptions &options);
    RCsvDS(std::string_view fileName, bool readHeaders = true, char delimiter = ',', Long64_t linesChunkSize = -1LL,
           std::unordered_map<std::string, char> &&colTypes = {});
    // Rule of five
    RCsvDS(const RCsvDS &) = delete;
    RCsvDS &operator=(const RCsvDS &) = delete;
    RCsvDS(RCsvDS &&) = delete;
    RCsvDS &operator=(RCsvDS &&) = delete;
    ~RCsvDS() final;
 
    void Finalize() final;
    std::size_t GetNFiles() const final { return 1; }
    const std::vector<std::string> &GetColumnNames() const final;
    std::vector<std::pair<ULong64_t, ULong64_t>> GetEntryRanges() final;
    std::string GetTypeName(std::string_view colName) const final;
    bool HasColumn(std::string_view colName) const final;
    bool SetEntry(unsigned int slot, ULong64_t entry) final;
    void SetNSlots(unsigned int nSlots) final;
    std::string GetLabel() final;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////
 /// \brief Factory method to create a CSV RDataFrame.
 /// \param[in] fileName Path of the CSV file.
 /// \param[in] options File parsing settings.
 RDataFrame FromCSV(std::string_view fileName, const RCsvDS::ROptions &options);
 
 ////////////////////////////////////////////////////////////////////////////////////////////////
 /// \brief Factory method to create a CSV RDataFrame.
 /// \param[in] fileName Path of the CSV file.
 /// \param[in] readHeaders `true` if the CSV file contains headers as first row, `false` otherwise
 ///                        (default `true`).
 /// \param[in] delimiter Delimiter character (default ',').
 /// \param[in] linesChunkSize bunch of lines to read, use -1 to read all
 /// \param[in] colTypes Allow user to specify custom column types, accepts an unordered map with keys being
 ///                      column type, values being type alias ('O' for boolean, 'D' for double, 'L' for
 ///                      Long64_t, 'T' for std::string)
 RDataFrame FromCSV(std::string_view fileName, bool readHeaders = true, char delimiter = ',',
                    Long64_t linesChunkSize = -1LL, std::unordered_map<std::string, char> &&colTypes = {});
 
 } // ns RDF
 
 } // ns ROOT
 
 #endif

This page was automatically generated by the 2.3.7 LXR engine. The LXR team