ConfigFile objects read standard unix-style configuration
files. Lines are stored with initial white-space (blanks and tabs) removed.
If a line ends in \, then the next line (initial white-space removed) is
appended to the current line.
Information at and beyond the first # on individual lines is removed
if the rmComment flag is set to true. In that case, lines containing
only blanks and tabs are not stored. Also, if the comment character # is
prefixed by a backslash (i.e., \#) it is not considered comment, but an
intentional # character. In the retrieved configuration information it
appears as a single # character. If the configuration file should contain
\# write \\#, this results in replacing \# by #, leaving
\#.
All non-empty lines of the configuration file (when comment is ignored comment
is not considered to be line-content) are stored in the ConfigFile object.
When line indices should be stored the (0-based) line indices of lines will be
available as well.
At construction time comment handling (keep comment / remove comment),
case-sensitive searching (sensitive / insensitive) and index storage (store /
don't store) can be specified.
It can't be modified using the open member, but overloaded assignment is
supported and comment and letter case handling can be modified by set-members.
NAMESPACE
FBB
All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace FBB.
INHERITS FROM
-
ENUMERATIONS
The following enumerations are defined by the class ConfigFile:
Comment:
This enumeration has two values: ConfigFile::KeepComment is used to indicate that comment on
lines must be kept; ConfigFile::RemoveComment is used to indicate that comment on
lines must be removed;
SearchCasing:
This enumeration also has two values: ConfigFile::SearchCaseSensitive is used to do case sensitive
searches for targets; ConfigFile::SearchCaseInsensitive is used to do case
insensitive searches for targets.
Indices:
This enumeration also has two values: ConfigFile::IgnoreIndices when used, the line numbers of the
original configuration file will not be made available; ConfigFile::StoreIndices when used, the line numbers of the
original configuration file will be made available;
TYPES
The following types are defined by the class ConfigFile:
const_iterator:
a const_iterator is an iterator pointing to a
line (std::string) of the configuration file;
const_RE_iterator: a const_RE_iterator is an iterator pointing to
lines matching a regular expression. It supports the following operations:
const_RE_iterator &operator++(): the prefix increment operator
increments the iterator to point to the next line in the configuration file
matching the iterator's regular expression;
std::string const &operator*(): the dereferencing operator
returns the line of the configuration file the iterator refers to;
std::string const *operator->(): the pointer operator returns the
address of the line of the configuration file the iterator refers to;
const_RE_iterators can be compared for (in)equality and they can be
copy-constructed; const_RE_iterator objects are returned by the
ConfigFile::beginRE, ConfigFile::endRE and ConfigFile::beginEndRE
members and cannot otherwise be constructed.
When two const_RE_iterator objects are subtracted the
number of lines matching their regular expression is returned. E.g., (see
below for a description of the functions used in the next example):
ConfigFile cf(...)
auto iters = cf.beginEndRE("^hello");
cout << "There are " << (iters.second - iters.first) <<
" lines starting with hello\n";
The two const_RE_iterator objects should refer to the same regular
expression. The provided example illustrates how this is realized using
beginEndRE.
FBB::Pattern is used to perform the regular expression pattern
matching.
CONSTRUCTORS
ConfigFile(Comment cType = KeepComment, SearchCasing sType =
SearchCaseSensitive, Indices iType = IgnoreIndices):
This constructor is used to create an empty ConfigFile
object. It is not associated with an input stream: the open member can
be used for that. The parameters can be used to specify specific handling of
comment, letter-casing and storage of line numbers in the original
configuration file.
ConfigFile(std::string const &fname, Comment cType = KeepComment,
SearchCasing sType = SearchCaseSensitive,
Indices iType = IgnoreIndices):
This constructor is used to create a ConfigFile object, which
is filled with the information from a file whose name is provided as the
constructor's first argument. The other parameters are used as described with
the first constructor. It throws an FBB::Errno exception if the file
could not be opened.
The copy and move constructors are available.
OVERLOADED OPERATORS
std::string const &operator[](size_t idx) const:
This member returns the (0-based) idx-th line of the configuration
file.
The overloaded assignment and move assignment operators are available.
MEMBER FUNCTIONS
ConfigFile::const_iterator begin() const:
This member returns a const_iterator to the first line of the
configuration file.
ConfigFile::const_RE_iterator beginRE(std::string const &target) const:
Deprecated. Use beginEndRE instead.
ConfigFile::const_iterator end() const:
This member returns a const_iterator pointing beyond the last line
of the configuration file.
ConfigFile::const_RE_iterator endRE() const:
Deprecated. Use BeginEndRE instead.
std::pair<ConfigFile::const_RE_iterator, ConfigFile::const_RE_iterator>
beginEndRE(std::string const &target) const:
A pair of const_RE_iterators is returned. The first
field of the pair is a const iterator to the first element (i.e.,
line) of the ConfigFile object in which the regular expression target
is found.
The second field is a const iterator marking the end of the
series of lines started at the the first line matching the regular expression
specified by target.
If the RemoveComment flag was specified, then comment-text is not
searched. The iterator returned in the pair's first field can be
incremented until the iteratr returned in the pair's second field is
reached; all iterators (unequal the iterator in second) point to lines
matching the specified regular expression.
The iterator's increment operator searches the next line matching the
specified regular expression.
Although the difference between two const_RE_iterators can be computed
it is a relatively expensive operation. The difference is obtained by
performing repeated regular expression matchings rather than the mere
algebraic subtraction of pointer values. If the difference cannot be computed
UINT_MAX is returned.
This member also interprets the SearchCasing flag.
ConfigFile::const_iterator find(std::string const &target) const:
This member returns an iterator to the first element (i.e., line) of
the FBB::ConfigFile object in which target is found. Note that
target may appear anywhere within a line. If the RemoveComment flag
was specified, then comment-text is not searched. Use the end member to
determine the end-iterator. It is not guaranteed that all lines between the
returned iterator and end will also contain target. This member also
interprets the SearchCasing flag.
std::string findKey(std::string const &keyPattern,
size_t count = 1) const:
This member can be used to retrieve information from lines having the
general pattern `keyPattern value'. Initial and trailing white space on
lines are ignored. keyPattern itself should not contain initial or
trailing white space. At least one white space character must appear between
keyPattern and value. If at least count lines were found matching
keyPattern value then this member returns the first sequence of non white
space characters following keyPattern after matching count lines
matching keyPattern value (i.e., `value' is returned). If value is
empty or if fewer than count lines match keyPattern an empty string is
returned. An FBB::Errno exception is thrown if count equals 0.
std::string findKeyTail(std::string const &keyPattern,
size_t count = 1) const:
This member can be used to retrieve information from lines having the
general pattern `keyPattern value', merely followed by white
space. Initial and trailing white space on lines are ignored. keyPattern
itself should not contain initial or trailing white space. At least one white
space character must appear between keyPattern and value. If at least
count lines were found matching keyPattern value then this member
returns the information beyond keyPattern after matching count lines
matching keyPattern (i.e., `value' is returned). This function differs
from findKey in that all information trailing keyPattern is returned
in value. If value is empty or if fewer than count lines match
keyPattern an empty string is returned. An FBB::Errno exception is
thrown if count equals 0.
ConfigFile::const_iterator findRE(std::string const &target) const:
This member returns an iterator to the first line of the
ConfigFile object matching the regular expression target. After
calling this function beginRE will return an iterator to the same line and
endRE returns the end-iterator for lines matching target. If the
RemoveComment flag was specified, then comment-text is not searched. The
inherited end member can be used to determine the end-iterator. It is not
guaranteed that all lines between the returned iterator and end will also
contain target. If that is required, the members beginRE and endRE
can be used. This member also interprets the SearchCasing flag.
size_t index(size_t idx):
This function should only be used when the parameter StoreIndices
was specified at construction time. In that case it will return the original
0-based line index in the configuration file associated with the
idxth (0-based) index in the current Configuration object.
size_t index(const_iterator const &iter):
This function should only be used when the parameter StoreIndices
was specified at construction time. In that case it will return the original
0-based line index in the configuration file associated with the configuration
line in the current Configuration object pointed to by iter. This may
also be an (incremented version of the) iterator returned by the member
findRE or beginRE, as long as the iterator's value is within the half
open range beginRE to endRE.
void open(std::string const &fname):
This member will read the configuration file having name fname.
It will redefine the current contents of the ConfigFile object,
destroying any information previously stored in it. The configuation file is
read according to the latest setting of the comment-flag. It will throw an
FBB::Errno exception if the file could not be opened.
This member clears previously available information and reinitializes the
object with information read from the new file.
void setCommentHandling(Comment type):
This member can be used to change the comment-handling type originally
set by the constructor, or set by earlier calls of this function. When called
it won't affect the current contents of the ConfigFile object, but
new calls of its open member will read the configuation file according
to the last setting of the comment flag.
void setSearchCasing(SearchCasing type):
This member can be used to change the handling of the letter-casing
originally set by the constructor, or set by earlier calls of this
function. When called it won't affect the current contents of the
ConfigFile object, but new calls of its open member will read
the configuation file according to the last setting of the letter-casing flag.
size_t size() const:
This member returns the number of lines in the configuration file.
EXAMPLE
Assume the configuration file is called config.rc and contains the
following lines:
# this is ignored
noline: this one too
line: this is found
this is not a line containing line: at the beginning of the line
line: this one is
line: what about this one? \
it's extending over multiple lines
and there may, of course, be more lines in this file
The following program may be compiled and run as a.out config.rc:
#include <iostream>
#include <iterator>
#include <algorithm>
#include <string>
#include <bobcat/configfile>
using namespace std;
using namespace FBB;
int main(int argc, char **argv)
{
ConfigFile cf(argv[1]);
cout << *cf.find("this one") << endl; // find text within a line
// find all lines matching
// `^line:'
copy(cf.beginRE("^line:"), cf.endRE(),
ostream_iterator<string>(cout, "\n"));
}
Producing the output:
noline: this one too
line: this is found
line: this one is
line: what about this one? it's extending over multiple lines