Introduction

  CIFLIB [1] is a class library that was developed by the Nucleic Acid Database (NDB) Project [2] to provide an application interface to Crystallographic Information File (CIF) [3,4,5,6] data. CIFLIB is designed to completely encapulsate all I/O operations and integrity checking on CIF dictionaries and data files from a calling application. CIFLIB performs the following functions:

• reads and writes CIF format data files and dictionaries.
• provides read and write access for individual data items.
• performs detailed integrity checks on CIF data and dictionaries as defined by the Dictionary Description Language (DDL) 2.1 [7,8,9,10].
• provides utility methods for navigating a CIF schema
• provides a stable callable interface in C, C⁺⁺ and FORTRAN.

Figure 1 illustrates how this software library facilitates using CIF as an interchange format in the automated data processing scheme used by the NDB. As the figure illustrates, CIFLIB provides complete access to the DDL, CIF dictionaries and CIF data files. This library can be used to build wrappers and filters around existing applications which need to access CIF data. Because CIFLIB provides complete access to the dictionary schema, the library can be conveniently used as an in-memory database or as a loader for an external database.

This is the first in a series of documents that will present the features of CIFLIB. In this document, the C language application interface [11] for CIFLIB is described.

 

Figure 1:  Functional diagram of CIFLIB