FBB::Table(3bobcat)

Construct text tables
(libbobcat-dev_6.04.00)

2005-2023

NAME

SYNOPSIS

DESCRIPTION

FBB::Tablebuf objects are std::streambuf objects that can be used to create tables. The tables are filled either column-wise or row-wise. Many of the table's characteristics may be fine-tuned by a separate FBB::TableSupport object, described in a separate man-page (TableSupport(3bobcat)). When no FBB::TableSupport object is used, a plain row-wise or column-wise table is constructed which can be inserted into a std::ostream. Displaying a table (e.g., at the standard output stream) involves the following steps:

• Optionally, a TableSupport object is created;
• A Tablebuf object is created (maybe passing it a TableSupport object);
• The Tablebuf object is used to initialize a std::ostream
• The elements of the table are filled by inserting information into that std::ostream
• The Tablebuf itself contains the formatted table and may itself be inserted into a std::ostream like std::cout.

Tables defined by TableBuf consist of a (number of element dependent) number of rows and a fixed number of columns, the latter value is specified at construction time. Columns and rows are normally addressed using index values (starting at 0). Before the leftmost column, between the columns and beyond the last column separators are defined. By default the separators are empty, but each separator may be given a (fixed) width or content. The separator before column col is addressed as separator col, the rightmost separator is addressed as separator nColummns.

Likewise, rows can be separated from each other using separators. These separating rows are also empty by default. The row-separator before row row is addressed as row-separator row. The row-separator following the final row is addressed as row-separator nRows, where nRows is the value returned by the nRows member function.

Non-default (i.e., non-empty) separators are defined using FBB::TableSupport objects (cf. tablesupport(3bobcat)).

TableBuf's sister-class Table can be used to insert elements into a table in a more direct way. With TableBuf field separators are used to switch to the next table-element, and (with row-wise filled tables) a row separator can be used to switch to the next row when it's only partially defined. Instead, with Table objects each new insertion defines another table element, and no wrapping std::ostream object is required.

NAMESPACE

INHERITS FROM

std::streambuf - allowing TableBuf objects to be wrapped in std::ostream objects.

FBB::TableBase - This class implements common elements of the table implementation (the FBB::TableBuf class is also derived from TableBase). The TableBase class is not intended to be used otherwise, and no separate man-page is provided. All facilities provided by Table inherited from TableBase are described in this man-page.

ENUMERATIONS

enum FillDirection
This enumeration has two values:

• ROWWISE:
  When this value is specified at construction time, elements are added row-wise to the table. I.e., the second element inserted into the Table will be found in the second column of the first row.
• COLUMNWISE:
  When this value is specified at construction time, elements are added column-wise to the table. I.e., the second element will be found in the second row of the first column.

enum WidthType
This enumeration holds two values:

• COLUMNWIDTH:
  This value may be specified when the columns should be allowed variable widths. In this case each column will be as wide as its widest element. This is the default WidthType used by Table objects.
• EQUALWIDTH:
  This value may be specified when all the table's columns should have equal width (i.e., equal to the width of the widest table element),

CONSTRUCTORS

• Tablebuf(size_t nColumns, Table::FillDirection direction, Table::WidthType widthType = Table::COLUMNWIDTH):
  The table's number of columns, the fill directions and the column width-type must be provided. The number of rows is implied by the combination of this parameter and the number of elements that is actually inserted into the Table object. The direction parameter specifies the way new elements are added to the Table object: row-wise or column-wise. Finally, the widthType parameter is used to specify the way the width of the table's columns is determined. Each column either defines its own width or all columns have equal widths.
• TableBuf(TableSupport &tableSupport, Table::FillDirection direction, Table::WidthType widthType = Table::COLUMNWIDTH):
  This constructor operates identically to the previous constructor, but expects an additional reference to a TableSupport object. A TableSupport object offers additional formatting features used by the table defining elements like horizontal lines between rows, additional separators, etc, etc. The TableSupport object is passed as a non-const reference as the Table object must be able to manipulate its data. See tablesuppport(3bobcat) for more information about TableSupport.

Copy and move constructors (and assignment operators) are not available.

OVERLOADED OPERATORS

• std::ostream &operator<<(std::ostream &out, TableBuf &tablebuf):
  This operator inserts a TableBuf into a std::ostream object. Note that the TableBuf object inserted into out is a non-const object, as the table may have to be completed by adding empty elements for missing ones. The out stream should not be equal to the std::ostream object that is used to wrap in a TableBuf object.
• TableBuf &operator<<(TableBuf &obj, Align const &align):
  This operator is used to change the default alignment of either a column or an element. It is a wrapper around the member setAlign() (see below for its description). By default, all elements are right-aligned. See align(3bobcat) for more information about the Align class. Unlike the insertion operators available for Table type objects, the insertion operator for TableBuf objects is only used to define column or cell-alignment.

MEMBER FUNCTIONS

• void clear():
  The content of the table are erased. All existing elements are removed, and the table will be empty.
• size_t nRows():
  The currently available number of rows in the table is returned. Its value is only defined after calling def().
• TableBuf &setAlign(Align const &align):
  The alignment type of either a column or an element of the TableBuf object is defined using setAlign. The standard alignments std::left, std::right and std::internal may be specified, but in addition the alignment FBB::center may be used if elements should be centered into their column. A construction like

  tab << Align(2, FBB::center)
  

  requests centering of all elements in the table's column having index value 2 (i.e., the table's 3rd column), whereas a construction like

  tab << Align(2, 3, FBB::center)
  

  requests centering of element [2][3]. It is the responsibility of the programmer to ensure that such elements exist. By default, all elements are right-aligned.
• TableBuf &def():
  After inserting elements into a TableBuf object its number of elements may or may not be an integral multiple of the number of columns specified at construction time. To `complete' a TableBuf object to a rectangular object, for which all column widths and alignments have been determined def may be called. It is automatically called by operator<<(ostream, TableBuf). In other situations it may be called explicitly to force the insertion of another row in a table using ROWWISE insertions. With COLUMNWISE insertions its working is complex, since new elements added to a COLUMNWISE filled table will reshuffle its elements over the table's columns.
• setFieldSeparator(char fs):
  The default field separator is the `backspace' (\b) character. After inserting a field separator the next table element will be defined. Inserting two field separators inserts an table empty element and starts the definition of the next element. This field separator character can be redefined by this function. Calling setFieldSeparator without argument disables the use of a field separator character, and only leaves the use of the fs manipulator to switch to the next field.
• setRowSeparator(char rs):
  The default row separator is the newline character (\n). After inserting a row separator the next element to enter into the table will be the leftmost element of the next row. Inserting two row separators adds an empty row to the table. Calling setRowSeparator without argument disables the use of a row separator character, and only leaves the use of the rs manipulator to switch to the next field.

MANPULATORS

• Table &def(Table &table):
  This manipulator can be inserted into a a TableBuf's wrapping ostream to call the table's def() member.
• FBB::fs:
  This manipulator can be inserted into a TableBuf's wrapping ostream to switch to the next field of the table. It is an alternative to using the field separator character.
• FBB::rs:
  This manipulator can be inserted into a TableBuf's wrapping ostream to switch to the next row of the table. It is an alternative to using the row separator character.

EXAMPLE

#include <iostream>
#include <ostream>
#include <string>
#include <algorithm>
#include <iterator>

#include <bobcat/tablebuf>
#include <bobcat/tablelines>

using namespace std;
using namespace FBB;

int main()
{
    TableLines tablelines;

    tablelines << 0;            // set separator widths
    for (size_t sep = 0; sep != 8; ++sep)
        tablelines << 3;


    TableBuf tab(tablelines, 8, TableBuf::ROWWISE);

    ostream out(&tab);

    copy(istream_iterator<string>(cin), istream_iterator<string>(),
            ostream_iterator<string>(out, "\b"));

    cout << tab << '\n';            // complete the table and insert
}

FILES

SEE ALSO

BUGS

BOBCAT PROJECT FILES

• https://fbb-git.gitlab.io/bobcat/: gitlab project page;
• bobcat_6.04.00-x.dsc: detached signature;
• bobcat_6.04.00-x.tar.gz: source archive;
• bobcat_6.04.00-x_i386.changes: change log;
• libbobcat1_6.04.00-x_*.deb: debian package containing the libraries;
• libbobcat1-dev_6.04.00-x_*.deb: debian package containing the libraries, headers and manual pages;

BOBCAT

COPYRIGHT

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