frisb/fdboost

(function() {
  var EncodingNamespace;

  module.exports = EncodingNamespace = (function() {

    /**
     * Creates a new EncodingNamespace instance
     * @class
     * @property {object} typeCodes Type codes dictionary.
     * @return {EncodingNamespace} an EncodingNamespace instance.
     */
    function EncodingNamespace(fdb) {
      this.fdb = fdb;
      this.adapters = require('./adapters')(this);
    }


    /**
     * Encode value to buffer
     * @method
     * @param {string} [prefix] String identifier.
     * @param {(undefined|string|integer|double|boolean|null|date|array|object)} value Value to encode.
     * @return {Buffer} Buffer
     */

    EncodingNamespace.prototype.encode = function(value, prefix) {
      var TypedAdapter, adapter, startPos, typeCode;
      if (value === '\xff') {
        return value;
      }
      startPos = 1;
      typeCode = this.adapters.types.get(value);
      TypedAdapter = this.adapters.get(typeCode);
      if (prefix) {
        startPos += prefix.length;
        adapter = new TypedAdapter(value, startPos);
        adapter.data.write(prefix, 0, startPos, 'ascii');
      } else {
        adapter = new TypedAdapter(value, startPos);
      }
      adapter.data.writeUInt8(typeCode, startPos - 1);
      return adapter.data;
    };


    /**
     * Decode value from buffer
     * @method
     * @param {Buffer} buffer Buffer to decode.
     * @param {string} [prefix] String identifier.
     * @return {(undefined|string|integer|double|boolean|null|date|array|object)} Value
     */

    EncodingNamespace.prototype.decode = function(buffer, prefix) {
      var TypedAdapter, adapter, startPos, typeCode;
      if (!buffer) {
        return null;
      }
      startPos = 0;
      if (prefix) {
        if (buffer.toString('ascii', 0, prefix.length) === prefix) {
          startPos = prefix.length;
        } else {
          throw new Error("Invalid prefix \"" + prefix + "\".");
        }
      }
      typeCode = buffer.readUInt8(startPos);
      TypedAdapter = this.adapters.get(typeCode);
      adapter = new TypedAdapter(buffer, startPos + 1);
      return adapter.value;
    };

    return EncodingNamespace;

  })();

  module.exports = function(fdb) {
    return fdb.encoding = new EncodingNamespace(fdb);
  };

}).call(this);