File corruption can occur when closing file

[gwlucastrig]

There is a bug in the way that GvrsFile writes out the free-space list when authoring a data file. This bug may lead to a corrupt output file.

Free space records are variable-length records that represent unused sections of a GVRS file. They occur in applications that are using data compression and performing multiple changes to tiles in the GVRS data file. Non-compressed tile records have fixed sizes. But the size of compressed records can change based on their content. Therefore, situations occur when the space that was previously used to store a tile is no longer large enough. The old space is put on the free list. New space is allocated.

The free space information needs to be preserved when a file is closed so that it can be re-used if the file is opened for future data-writing operations. Unfortunately, a bug occurred in the logic that writes this information.

The bug would not occur when the optional checksums were enabled. It only occurred when checksums were shut off.

[gwlucastrig]

Bug is now fixed. Thank you for your patience in this matter.