Microsoft KB Archive/174866

= PRB: CAB SDK Headers Contain Incorrect CB_MAX_DISK Value =

Article ID: 174866

Article Last Modified on 5/11/2006

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APPLIES TO


 * Microsoft Internet Client Software Development Kit 4.0
 * Microsoft Internet Client Software Development Kit 4.01

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This article was previously published under Q174866



SYMPTOMS
When compressing data using Fci.lib from the Cabinet (CAB) SDK, a new cabinet file is started after about 134 MB of data has been compressed.



CAUSE
Fci.h contains an incorrect definition for CB_MAX_DISK. The value is defined as 0x7FFFFFFL (134,217,727) instead of 0x7FFFFFFFL (2,147,483,647) as it should be. CB_MAX_DISK is also defined incorrectly in this way in Fdi.h.



RESOLUTION
Redefine CB_MAX_DISK to the correct value of 0x7FFFFFFFL:
 * 1) define CB_MAX_DISK 0x7FFFFFFFL



MORE INFORMATION
Specifying a value of 0 for disk size (cb value in CCAB struct) resets the value to CB_MAX_DISK. However, CB_MAX_DISK is defined incorrectly as 0x7FFFFFFL or 134,217,727. It should be 0x7FFFFFFFL, or 2,147,483,647. Data compression proceeds to about 134 Mb, then it switches to a new cabinet. The desired result of a larger cabinet (CAB) can be obtained by explicitly supplying the correct larger value.

Note that a CAB can normally contain at most 65,500 or so files. There is no code in FCI to avoid exceeding this value, so the user application may have to enforce it.

Also note that unless a CAB will be randomly extracted, cbFolderThresh should be explicitly set to a very large value. If the CAB will be randomly extracted, values between 100 K and 1 Mb would be appropriate.

