Configuration files
The basics
ConfigFileC reads configuration files in a format similar to that
used by make. In its simplest form a files consists of a number of
lines of the form '(variable) = (value)'. Comments start with '#',
every thing between the '#' and the new line is ignored. Variable
names are case sensitive and must not contain spaces or
punctuation other than an underscore '_'. The value is taken as
the first non space character after the '=' sign until the end of
the line. Lines may be continued with a backslash '\'. Values may
be enclosed with double quotes, special characters (such as '#'
and '\n') will not be interpreted inside the quoted text. If you
wish to include quotes in your text the can be escaped with '\'
and backslashes with '\\'.
Typically a configuration file would contain something like the following:
# My program setup.
Threshold = 1.2
MaxRegions = 4 # Typically set to 3.
InputFile = "windmill.cif"
The 'ConfigFileC' class deals entirely with strings. If you ask
for an undefined variable an empty string is given. The code to
read and process this file would look something like:
ConfigFileC cfg("setup.conf");
RealT threshold = cfg["Threshold"].RealValue();
StringC filename = cfg["InputFile"];
IntT maxRegions = cfg["MaxRegions"].IntValue();
Sections
The following examples shows how to declare a section in your
config file. The contents of a section are exactly as before, and
may be defined recursively.
Filter1 {
Gamma = 1.2
Alpha = 0.4
}
You can access sections with the 'Section(..)' method. If the section
exists it will return the a ConfigFileC which can then be used to
access the configuration information it contains.
ConfigFileC cfg("setup.conf");
ConfigFileC cfg_filt1 = cfg.Section("Filter1");
if(cfg_filt1.IsValid()) { // Check that section has been found.
RealT gamma = cfg_filt1["Gamma"].RealValue();
RealT alpha = cfg_filt1["Alpha"].RealValue();
}
Normal classes: