uludev / skvconf

A simple key-value configuration language

skvconf

Simple key-value configuration language written in C

Compiling from source

Dependencies

• meson
• A C compiler (e.g. gcc)
• flex
• bison

Build Instructions

1. meson setup build .
2. meson compile -C build
3. meson install -C build (optional)

If you use meson in your project you can also use skvconf through a subproject.

Tests

If you wish to contribute (for whatever reason) or just check wether the API behaves correctly use meson test -C build. When contributing add test cases that check your expected behavior.

Basic Usage

skvconf is simple. Both in it's language and API. A basic example looks like this:

#include <skvconf.h>
#include <stdio.h>

int main(void) {
    skvconf_elm_t *conf;
    skvconf_parse_file("test.conf", &conf);
    skvconf_elm_t *elm = skvconf_find_element(conf, "test.value", NULL);
    if (!elm) {
        printf("undefined\n");
        return 1;
    }
    if (elm->type != SKVCONF_TYPE_STR) {
        printf("wrong type!\n");
        return 1;
    }
    printf("test.value: %s\n", elm->val.str);
    skvconf_elm_destroy(conf);
    return 0;
}

Your main interactions are going to be with three functions:

• skvconf_parse_file
• skvconf_find_element
• skvconf_elm_destroy All of them are made available through the skvconf.h header, which also includes a few other headers automatically.

The definition for an skvconf_elm_t can be found in skvconf_types.h:

typedef struct skvconf_elm {
    skvconf_type_t type;
    union {
        int num;
        char *str;
        bool boolean;
    } val;
    char *id;
    struct skvconf_elm *next;
    struct skvconf_elm *child;
} skvconf_elm_t;

the type is simply an enum specifying the type of the object:

typedef enum {
    SKVCONF_TYPE_NUM,
    SKVCONF_TYPE_STR,
    SKVCONF_TYPE_BOOLEAN,
    SKVCONF_TYPE_GROUP,
} skvconf_type_t;

Depending on the type of the object you can access the corresponding member of the union val in an element.

Notes

• You can't use skvconf_find_element to find a group element
• If a single key has been defined with multiple values, the last one is used, regardless of type (this is due to the find function exiting after finding the first element that matches and the parser returning the elements in reverse order).

Configuration file syntax

A configuration file has a very basic syntax:

a = 3
b = "abc"
c = true
d {
    e = false
}

It is made up of key-value pairs as well as groups, which are basically namespaces. In this example, a, b and c are simply key-value pairs accessible by their respective names. d is a group which means it cannot be found by the skvconf_find_element function and e is another key-value pair which is accessible as d.e. You can also have nested groups.