FBB::CSV4180(3bobcat)
CSV4180 convertor
(libbobcat-dev_6.06.02)
2005-2024
NAME
FBB::CSV4180 - Converter for comma separated values
SYNOPSIS
    #include <bobcat/csv>
Linking option: -lbobcat
DESCRIPTION
Objects of the class CSV4180 can be used to convert series of comma
separated values to the individual separated values (also called `fields'
below). The class implements RFC 4180
(cf. https://www.ietf.org/rfc/rfc4180.txt, section 2).
According to RFC 4180 lines contain comma separated values: comma separated
values on one line are processed together, as a series of values. The final
comma separated value on a line is not ended by a comma.
Comma separated values may be surrounded by double quotes. However, they
must be surrounded by double quotes in these cases:
    
    -  if the values contain commas;
    
-  if the values contain double quotes (in which case the double quote
        is `escaped' by doubling it, e.g., "a "" double quote");
    
-  if the values extend over multiple lines. E.g.,
        
"First line
second line"
    
Comma separated values may be empty: the following line defines three
empty comma separated values:
        
,,
        
    The first empty value starts at the beginning of the line, and continues
up to the first comma; the second empty value starts beyond the first comma
and continues up to the second comma; the third empty value starts beyond the
second comma, and continues up to the end of the line. If the line ends in
blank space characters then the third value isn't empty, but contains those
blank space characters.
By default, values are interpreted as strings. The CSV4180 class also
offers facilities to ignore specific fields, or to ensure that they can be
converted to integral or floating point values. The second constructor (below)
expects a std::string argument defining how to interpret fields. Options
are:
    
    -  I:  the field must be convertible to an integral value;
    
-  D:  the field must be convertible to a floating point value;
    
-  S:  the field is a string: it is used as-is;
    
-  X:  the field is omitted from the final set of comma separated
        values. I.e., if a line contains three comma separated values, and the
        specification "SXS" is used then this results in two comma
        separated values: the first and third value of three comma separated
        values encountered on lines.
    
-  -:  synonym of X.
    
In addition, field specifications may contain blank spaces, which are
ignored.
When processing comma separated values the first line may be considered a
header line. X specifications also apply to header lines, but
otherwise they merely consist of S-type fields. In addition, when
processing multiple input lines all non-header lines are made available in a
vector of vectors of fields, whereas the header line itself can be accessed
via a dedicated member (header()).
NAMESPACE
    FBB
    All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
INHERITS FROM
    -
CONSTRUCTORS
    
    -  explicit CSV4180(size_t nFields = 0, bool header = false,
                    char fieldSep = ','):
 The first parameter specifies the number of fields that must be
        present on input lines. When using the default value the number of
        fields encountered on the first line determines the number of fields
        that must be present on subsequent lines. If the second parameter is
        true then the first line is interpreted as the header line. The
        third parameter specifies the character separating the fields. By
        default it's a comma, but sometimes (not part of the RFC) a semicolon
        is used. By specifying fieldSep any character other than a comma
        can be used as field separator.
 
-  explicit CSV4180(std::string const &specs, bool header = false,
                    char fieldSep = ','):
 The first parameter defines the number and types of the comma separated
        values on input lines. Specifications can be
            
            -  D: the field must be convertible to a floating point
                value;
            
-  I: the field must be convertible to an integral value;
            
-  S: the field is left as-is, and can be retrieved as a
                std::string.
            
-  X or -: the field is ignored and is not stored inside
                the CSV4180 object.
            
-  blank space characters are ignored.
            
 
 An exception is thrown when encountering other than the abovementioned
        characters are encountered.
If I or D fields cannot be properly converted, or if a line
        contains too few or too many comma separated values the input stream's
        fail status is set.
 
The last two parameters are interpreted as the last two parameters of
        the previous constructor.
 
 
Copy and move constructors (and assignment operators) are available.
OVERLOADED OPERATORS
    
    -  std::istream &operator>>(std::istream &in, CSV4180 &csv):
 One line of text is extracted from in and processed by the csv
        object. The csv object may or may not already contain converted
        comma separated values. When empty, the first line is processed
        according to the specifications provided to the csv object at
        construction time. Otherwise, the comma separated values on extracted
        lines must match the number and types of the fields, as specified by
        the csv object. When input lines do not match these specifications
        in's fail status is set.
MEMBER FUNCTIONS
    
    -  void clear(size_t nFields = 0):
 The internally stored data (referred to by the data, header, and
        lastLine members) are erased. By default, the required number of
        CSV fields is reset to 0, but can be set to a specific value by
        specifying a value for its nFields parameter.
 
-  std::vector<std::vector<std::string>> const &data() const:
 A reference to the vector of vectors of fields stored inside the
        CSV4180 object is returned. The vector returned by data does
        not contain the header line. If a header line was requested it can be
        retrieved from the header() member.
 
-  std::vector<std::string> const &header() const:
 If the constructor's header parameter was specified as true
        then this member returns the fields encountered on the first line that
        was processed by the read1 member. Otherwise, header returns
        a reference to an empty vector.
 
-  std::string const &lastLine() const:
 A reference to the last line that was successfully extracted from the
        input stream by the read1 member is returned. So once the lines
        containing the comma separated values have been processed, the next
        line on the input stream can be obtained from this member.
 
-  size_t nValues() const:
 After successfully calling read1 for the first time this member
        returns the required number of comma separated values that must be
        encountered on subsequent input lines.
 
-  size_t read(std::istream &in, size_t nLines = 0):
 By default, all lines of in are read and are processed by the
        read1 member. By specifying a non-zero value for the nLines
        parameter the specified number of lines is read from in.
        Reading stops once in's status is not good. When nLines is
        specified as zero, then in's status flags are cleared. The number
        of successfully processed lines is returned.
 
-  std::istream &read1(std::istream &in):
 One line is read from in and is parsed for its comma separated
        values. If parsing fails, in's fail status is set. After
        successfully calling read1 for the first time all subsequent lines
        read by read1 must have the same number of comma separated values
        as encountered when calling read1 for the first time. The parsed
        fields are stored in a vector of std::string objects, and that
        vector is added to the vector of vectors of strings that is returned
        by the data member.
 
-  std::vector<std::vector<std::string>> release():
 The vector of vectors of fields stored inside the CSV4180 object is
        returned. After calling release the internally stored vector of
        fields is empty.  The vector returned by data does not contain the
        header line. If a header line was requested it can be retrieved from
        the header() member. Note that this member does not reset the
        number of expected fields for subsequently processed CSV-lines. If
        that's what you want, call clear after calling release.
 
EXAMPLE
    
#include <iostream>
#include <bobcat/csv4180>
using namespace std;
using namespace FBB;
int main(int argc, char **argv)
{
    CSV4180 csv;                    // this processes 'input'
    size_t nLines = csv.read(cin);
    cerr << nLines << " lines were read\n";
    if (not csv.header().empty())
    {
        cerr << "header: " << '\n';
        for (auto const &field: csv.header())
            cerr << "   `" << field << "'\n";
    }
    cerr << "# CSV values: " << csv.nValues() << '\n';
    for (auto const &line: csv.data())
    {
        cerr << "Line:\n";
        for (auto const &entry: line)
            cerr << "   `" << entry << "'\n";
    }
}
FILES
    bobcat/csv - defines the class interface
SEE ALSO
    bobcat(7)
BUGS
    None Reported.
BOBCAT PROJECT FILES
    -  https://fbb-git.gitlab.io/bobcat/: gitlab project page;
    
-  bobcat_6.06.02-x.dsc: detached signature;
    
-  bobcat_6.06.02-x.tar.gz: source archive;
    
-  bobcat_6.06.02-x_i386.changes: change log;
    
-  libbobcat1_6.06.02-x_*.deb: debian package containing the
            libraries;
    
-  libbobcat1-dev_6.06.02-x_*.deb: debian package containing the
            libraries, headers and manual pages;
    
BOBCAT
    Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.
COPYRIGHT
    This is free software, distributed under the terms of the
    GNU General Public License (GPL).
AUTHOR
    Frank B. Brokken (f.b.brokken@rug.nl).