The single-part and multi-part archives

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Archive management functions

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WLanguage procedure

The single-part and multi-part archives

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The single-part and multi-part archives

Overview

Two types of archives are available:

single-part archive.
multi-part archive.

Only the single-part archives are available.

Versions 17 and later

This feature is now available for iPhone/iPad applications.

New in version 17

This feature is now available for iPhone/iPad applications.

Single-part archive

A single-part archive appears like a single file whose type is ".WDZ", ".ZIP", ".CAB" or ".7z": an archive file groups all the compressed files.

The archive occupies the necessary space to contain all the compressed files.

Example: Your program must save several large files. Your program can create an archive containing all the files to save. This archive will increase the available disk space.

Multi-part archive

Overview

A multi-file archive contains several files (or sub-archives) of identical size. The size of each sub-archive is defined when creating the multi-file archive.

The first sub-archive is a file whose type is ".WDZ", ".ZIP" or "7z". The following sub-archives are files numbered from 1 to N via their extension.

For the archives in WINDEV format (WDZ), the sub-archives have the following extensions: ".001", ".002", ..., ".NNN".

For the archives in ZIP format, the sub-archives have the following extensions: ".Z01", ".Z02", ..., ".ZNN".

Remark: The archives in".CAB" format are necessarily single-part archives.

Principle

To create a multi-part archive:

Create an archive (zipCreate).
Add files to this archive. The added files are automatically compressed (zipAddFile, zipAddDirectory).
Split this archive into several sub-archives (zipSplit). The sub-archives have the same size. You define the size of the sub-archives.

Once the multi-file archive is created, the sub-archives can be stored on different media (diskette, CD, ...).

The sub-archives can be merged (zipMerge): the archive becomes a single-part archive.

Remark: All these operations can also be performed via WDZip.

Caution: Single-part and multi-part archives

Some archiving features can only be used on the single-part archives (adding files, deleting files, creating a self-extracting executable, ...). To perform these operations on a multi-part archive, all you have to do is merge the sub-archives (zipMerge) to get a single-part archive.

From a multi-part archive, you only have the ability to:

Merge the different parts (zipMerge),
Get information about the archive and about the files found in the archive (zipExtractPath, zipInfoFile, zipListFile, ...),
Extract the files (zipExtractFile, zipExtractAll).

Examples

Storage on diskettes

Your program must store a large amount of data on diskettes. Your program can create an archive containing the requested data. Once created, this archive can be divided into several parts. These volumes have the size of a diskette (1.44 MB). All you have to do is copy these different parts on the diskettes.

Related Examples:

Complete examples (WINDEV): WD Zip

[ + ] This example presents the use of archiving WLanguage functions with compression.
The following topics are presented in this example:
1/ How to create an archive?
2/ How to compress and uncompress files?
3/ How to manage Drag&Drop from the file explorer of Windows to a TreeView control?
Summary of the example supplied with WINDEV:
This example allows you to create and read compressed archives in WDZ, ZIP, CAB and RAR format (in read-only). This feature can be very useful to manage the automatic backups. Furthermore, the example allows you to create multi-volume archives.