Late Detection of ZIP Items Unfit for Streaming Consumption

Several substantial conditions that represent a package unfit for streaming consumption may be detected mid-processing by a streaming package implementer. These include:

• A duplicate ZIP item name is detected the moment the second ZIP item with that name is encountered. Duplicate ZIP item names are not allowed. [M3.3]

• In interleaved packages, an incomplete sequence of ZIP items is detected when the last ZIP item is received. Because one of the interleaved pieces is missing, the entire sequence of ZIP items cannot be mapped to a part and is therefore invalid. [M2.16]

• An inconsistency between the local ZIP item headers and the ZIP central directory file headers is detected at the end of package consumption, when the central directory is processed.

• A ZIP item that is not a file, according to the file attributes in the ZIP central directory, is detected at the end of package consumption, when the central directory is processed. Only a ZIP item that is a file shall be mapped to a part in a valid package.

When any of these conditions are detected, the streaming package implementer shall generate an error, regardless of any processing that has already taken place. Package implementers shall not generate a package containing any of these conditions when generating a package intended for streaming consumption. [M3.13]