18.4.3 DREI-BASE Package

The buffer protocol has been designed to be reasonably efficient with a variety of different implementation strategies (single gap buffer or sequence of independent lines). It contains (and should only contain) the absolute minimum of functionality that can be implemented efficiently independently of strategy. However, this minimum of functionality is not always convenient.

The purpose of the DREI-BASE package is to implement additional functionality on top of the buffer protocol, in a way that does not depend on how the buffer protocol was implemented. Thus, the DREI-BASE package should remain intact across different implementation strategies of the buffer protocol.

Achieving portability of the DREI-BASE package is not terribly hard as long as only buffer protocol functions are used. What is slightly harder is to be sure to maximize efficiency across several implementation strategies. The next section discusses such considerations and gives guidelines to implementers of additional functionality.

Implementers of the buffer protocol may use the contents of the next section to make sure they respect the efficiency considerations that are expected by the DREI-BASE package.

• Efficiency Considerations