Provided by: libbobcat-dev_5.11.01-1_amd64 
NAME
FBB::OFoldBuf - Folds long lines written to ostream
SYNOPSIS
#include <bobcat/ofoldbuf>
Linking option: -lbobcat
DESCRIPTION
FBB::OFoldBuf is a specialization of FBB::OFilterBuf folding long lines written to an
std::ostream object. The OFoldBuf writes the (folded) lines to a second ostream (the
destination stream which is either used by or opened by the OFoldBuf object).
Internally the OFoldBuf defines its actions using a little finite state automation
distinguishing three states (INDENT, WS and NON_WS) and three character categories (\n,
other white space characters (space), and non-space characters). The nine combinations
resulting from these two sets are discussed below.
OFoldBuf objects will never fold lines in the middle of series of non-blank characters
(called a `word’ below) but will always break a line at a white space character. The
resulting lines will always appear to the right of a configurable left margin and to the
left of a configurable right margin. There is a somewhat pathological exception to this:
if a word is too long to fit in between the margins then the word will exceed the right
hand margin.
The indentation used for the left margins is configurable to either blanks (the default)
or tabs. When tabs are used the width of a tab character is configurable, using a default
of 8 positions in the destination stream.
What follows is a description of the Finite State Automaton (FSA) defining what happens
when various character types appear at its three states. The phrase `... is written’ means
that the described information is written to the ostream used or opened by the OFoldBuf
object. OFoldBuf’s initial state is INDENT:
State char. description
───────────────────────────────────────────────────────────────────────
INDENT \n a new line character is written
space the indentation is set;
the space character is added to the indentation;
next state: WS
non-ws the character is added to the currently stored word;
next state: NON_WS
───────────────────────────────────────────────────────────────────────
WS \n a new line character is written;
stored white-space is erased;
next state: INDENT
space white space character is added to the currently
stored space characters;
non-ws the character is added to the currently stored word;
next state: NON_WS
───────────────────────────────────────────────────────────────────────
NON_WS \n stored white space and word are written;
a new line is written;
next state: INDENT
space stored white space and word are written;
white space character is added to the currently
stored space characters;
next state: WS
non-ws the character is added to the currently stored word;
───────────────────────────────────────────────────────────────────────
NAMESPACE
FBB
All constructors, members, operators and manipulators, mentioned in this man-page, are
defined in the namespace FBB.
INHERITS FROM
FBB::OFilterBuf
ENUMERATION
The enumeration TabsOrBlanks is used to select tabs or blanks when writing the
indentation. The default is blanks. When tabs are selected the display width of tabs
characters can be configured as well (using the default of 8 positions for each
tab-character). The enumeration has two values:
o BLANKS:
The default, indicating that the left margin is specified and written as a number
of blanks;
o TABS:
Indicating that the left margin is specified and written as a number of
tab-characters.
The enumeration TrailingBlanks is used to configure the OFoldBuf object with respect to
any trailing blanks that may appear on the final line. These trailing blanks can appear on
the final line it it is not properly terminated with a newline character but instead ends
in white space. By default these white space characters are ignored, but they may be kept
as well. The enumeration has two values:
o IGNORE_TRAILING_BLANKS:
This indicates that trailing blanks appearing at the final line if it is not
terminated by a newline should not be written to the destination std::ostream. This
is the default used by OFoldBuf objects.
o KEEP_TRAILING_BLANKS:
This indicates that trailing blanks at the final line if it is not terminated by a
newline should be written to the destination std::ostream
CONSTRUCTORS
o OFoldBuf(size_t leftIndent = 0, size_t rightMargin = 80, TabsOrBlanks tob = BLANKS,
TrailingBlanks tb = IGNORE_TRAILING_BLANKS):
This constructor initializes an OFoldBuf object but does not associate it with a
destination stream. It can also be used as the default constructor.
o OFoldBuf(char const *fname, size_t leftIndent = 0, size_t rightMargin = 80,
TabsOrBlanks tob = BLANKS, TrailingBlanks tb = IGNORE_TRAILING_BLANKS):
This constructor initializes an OFoldBuf object and opens (using std::ios::out) the
destination stream using the name specified as its fname argument.
o OFoldBuf(std::ostream &stream, size_t leftIndent = 0, size_t rightMargin = 80,
TabsOrBlanks tob = BLANKS, TrailingBlanks tb = IGNORE_TRAILING_BLANKS):
This constructor initializes an OFoldBuf object and uses as its destination stream
the std::ostream stream.
The destructor writes any buffered information to the destination stream and will then
flush the destination stream.
Copy and move constructors (and assignment operators) are not available.
MEMBER FUNCTIONS
All members of FBB::OFilterBuf, in particular its out() and reset members are available,
as FBB::OFoldBuf inherits from this class.
o void setMargins(size_t leftMargin, size_t rightMargin):
This member can be used to modify the left- and right folding margins. Note that
the left margin may also be modified using the FBB::lm and FBB::mlm manipulators.
o void setTrailingBlanks(TrailingBlanks tb):
This member can be used to modify the currently used TrailingBlanks parameter.
o void useBlanks():
This member can be used to select blanks to be used when inserting left margins.
o void useTabs(size_t tabWidth = 8):
This member can be used to select tab-characters to be used when inserting left
margins. The second parameter is used to specify the display width of a
tab-character.
STATIC MEMBER FUNCTIONS
o size_t leftMargin(std::ostreambuf const *buffer):
This member returns the current left margin setting of the OFoldBuf object passed
to it as its argument. The member defines a std::streambuf parameter which is down
cast to an OFoldBuf and an FBB::Exception exception is thrown if that cast fails.
o size_t rightMargin(std::ostreambuf const *buffer):
This member returns the current right margin setting of the OFoldBuf object passed
to it as its argument. The member’s parameter is down cast in the same way as
leftMargin()’s argument: an FBB::Exception exception is thrown if that cast fails.
EXAMPLE
#include <iostream>
#include <ostream>
#include <string>
#include <bobcat/ofoldbuf>
using namespace std;
using namespace FBB;
int main()
{
OFoldBuf fb(cout, 4, 40);
ostream out(&fb);
out << lm(4);
string line;
while (getline(cin, line))
out << line << ’\n’;
}
FILES
bobcat/ofoldbuf - defines the class interface
SEE ALSO
bobcat(7), lm(3bobcat), mlm(3bobcat), ofilterbuf(3bobcat), ofoldstream(3bobcat)
BUGS
None Reported.
BOBCAT PROJECT FILES
o https://fbb-git.gitlab.io/bobcat/: gitlab project page;
o bobcat_5.11.01-x.dsc: detached signature;
o bobcat_5.11.01-x.tar.gz: source archive;
o bobcat_5.11.01-x_i386.changes: change log;
o libbobcat1_5.11.01-x_*.deb: debian package containing the libraries;
o libbobcat1-dev_5.11.01-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).