OLSRd commons library
Copyright (c) 2004-2011 the olsr.org team
Cleaned up and extracted into this form by Henning Rogge in 2011

The OLSRd commons library is a collection of helper functions
that are used through the whole OSLRd for list/tree handling,
string management and other things.

=================================
    OLSRd commons template API
=================================

The template API contains a simple template engine, that allow the
user to define several values for key, which are then inserted into
a template pattern and appended to an autobuf.
 
The template engine looks for a series of keys, each beginning and
ending with a '%'. The user has to supply a string for each of the keys,
that contains the corresponding value. The engine then replace each of
the keys in the provided template pattern with the value, and appends
the result to the autobuf.

The user has to call the function abuf_template_init() first, which
analyzes the template pattern, compares it to the array of keys and
stores the result in an array of intergers. The array must have at
least 3 times as many entries as the number of keys in the template
pattern.

After this the function abuf_templatef() appends to combination of
template pattern and values to the autobuf.

Pseudocode:

char *keys[2] = {
    "key1", "key2"
};

{
    char *pattern = "print %key1%, %key2%";
    char *values[2];
    int buffer[30];
    int indexCount;
    
    values[0] = "value for key 1";
    values[1] = "second value";
    
    indexCount = abuf_template_init(keys, ARRAYSIZE(keys), pattern,
        buffer, ARRAYSIZE(buffer));
    
    if (indexCount >= 0) {
        abuf_templatef(autobuf, pattern, values, buffer, indexCount);
    }
}