Representation of Multiple Markup Language Files that Differ in Structure and Content in One File for the Production of New Markup Language Files

摘要

A method and apparatus for representing two or more related markup language source files in a single delta file is provided. The markup language source files are represented in such a way that the delta file is easily processed to produce one or more merged combinations of the source files. The method and apparatus ensure that any one of the original files can be extracted from the delta file and the delta file remains a valid delta file for any remaining source files. The method and apparatus is adapted to enable the sources files to be aligned with respect to structurally significant elements and textual content so as to reduce repetitions in the delta file of common content. The method and apparatus are suited for use, but not exclusively, with XML documents and files.

主权项

1. A method of representing differences between two or more markup language source files in one markup language delta file, the method comprising the steps of:
a) creating a delta file with a root element of the same type as the root element of one or more of the source files where element of the same type means an element with the same name and namespace; b) identifying structurally significant elements in the two or more source files and determining a preferred alignment, constrained by document order, of the two or more source files, the preferred alignment of the two or more source files being determined with respect to structurally significant elements and textual content; c) determining which subtrees in the source files are common to two or more of the source files with respect to the preferred alignment; d) recording in the delta file common subtrees as equal; and e) recording in the delta file according to the preferred alignment information about the contents of the two or more source files which is not common to all the source files such that each element in the source files will have the same type as the corresponding one or more elements in the delta file and will have at least corresponding ancestor elements of the same type up to and including the root element, and any text node or element directly or indirectly within an element in a source file will have a corresponding text node or element contained directly or indirectly within the corresponding element in the delta file,whereby the preferred alignment reduces repetition in the delta file of common content structured differently in different source files.