rodb

Rodb is a zero fragmentation micro database read-only access library. The primary goal of rodb is to provide access to compiled config files in memory restricted applications, like games. A very common problem in games is finding an efficient and convenient way to store and access large number of different config files, like level description, gameplay settings, effect configurations and many others.

Rodb uses YAML as a source format. YAML files are converted to a binary blob optimized for fairly efficient in-memory access. The blob is later loaded into a single contiguous block of memory with only one read operation.

Rodb supports a limited subset of YAML types: UTF-8 strings, 32-bit integers, single precision floats and booleans. Values of any of these types can be put into arrays and maps (only string keys are allowed in maps). There's no restriction on nesting of these data structures.

Since arrays can contain values of any types and lengths, they are implemented with an additional table of offsets to elements. The access to elements is O(1). Maps store their keys in a sorted array of strings, which allows for O(logN) access.

Please note that rodb is not designed to provide access to gigabytes of data or to churn millions of transaction per second. Its focus is simplicity and minimal memory fragmentation. Some performance is sacrificed to achieve these goals.

Config Example

# World properties
world:
    layers:
        - ground
        - road
        - cracks

# Ball properties
ball:
    # Physics
    radius: 37.5
    start_position: {x: 160, y: -50}
    start_speed: 200

# Game settings
game:
    start_level: levels/woodbridge.rodb
    debug: true
    allowed_levels: [1, 2, levels/woodbridge.rodb, 7, 12, [100, 101, 102]]

For complete example please check the example directory.

Usage Example

// Load database into memory. The file is not needed after this point.
rodb::Database db("config.rodb");
rodb::Value root = db.root();

// Access some data
float x = root["ball"]["start_position"]["x"];
float y = root["ball"]["start_position"]["y"];

// Iterate over layers
rodb::Value layers = root["world"]["layers"];
for (size_t i = 0; i < layers.size(); ++i)
{
    // Do something with each layer
    print_layer(layers[i]);
}

For complete example please check the example directory.

License

The code is licensed under the terms of MIT License.