DocumentID: ECMA-376/Part2/9.2.5
Title: ECMA-376, Part2: 9.2.5 ZIP Package Limitations
Extracted-From: ECMA-376 Office Open XML File Formats, 1st Edition / December 2006
Warning: Coverted to HTML format by a script known to have bugs

• Next: 9.2.6 Mapping Part Content Type
• Up: 9.2 Mapping to a ZIP Archive
• Table of contents: Table of contents
• Previous: 9.2.4 Mapping ZIP Item Names to Part Names

9.2.5 ZIP Package Limitations

The package implementer shall map all ZIP items to parts except MS-DOSZIP items, as defined in the ZIP specification, that are not MS-DOS files. [M3.7]

[Note: The ZIP specification specifies that ZIP items recognized as MS-DOS files are those with a "version made by" field and an "external file attributes" field in the "file header" record in the central directory that have a value of 0. end note]

In ZIP archives, the package implementer shall not exceed 65,535 bytes for the combined length of the item name, Extra field, and Comment fields. [M3.8] Accordingly, part names stored in ZIP archives are limited to 65,535 characters, subtracting the size of the Extra and Comment fields.

Package implementers should restrict part naming to accommodate file system limitations when naming parts to be stored as ZIP items. [S3.1]

[Example:

Examples of these limitations are:

• On Windows file systems, the asterisk ("*") and colon (":") are not valid, so parts named with this character will not unzip successfully.
• On Windows file systems, many programs can handle only file names that are less than 256 characters including the full path; parts with longer names might not behave properly once unzipped.
• On Unix file systems, the semicolon (";") has a special meaning, so parts with this character might not be processed as expected.

end example]

ZIP-based packages shall not include encryption as described in the ZIP specification. Package implementers shall enforce this restriction. [M3.9]