On Thu, Nov 01, 2012 at 11:52:21AM +0000, commits@source.squeak.org wrote:

David T. Lewis uploaded a new version of ImageFormat to project VM Maker: http://source.squeak.org/VMMaker/ImageFormat-dtl.14.mcz

==================== Summary ====================

Name: ImageFormat-dtl.14 Author: dtl Time: 1 November 2012, 7:52:14.48 am UUID: 76bad473-3b56-48fa-8fa7-80d8c7afc523 Ancestors: ImageFormat-dtl.13

Add updates to ImageFormat to report #availableBits and bitAssignments.

Add ImageFileHeader and CogImageFileHeader with tests in ImageFileHeaderTest.

The purpose of ImageFileHeader is to document the current formats of Cog and interpreter image file headers, and to provide a convenient way to inspect the data values an image file header.

To explore the file header of an image file:

| fs | fs := (FileStream readOnlyFileNamed: Smalltalk imageName) binary. ([CogImageFileHeader readFrom: fs] ensure: [fs close]) explore

The image file header is the 64 (or 128) bytes immediately preceding the object memory contents in an image file. The ImageFileHeader classes provide a way to inspect the contents of an image header, displaying the image format type and the values of the data fields in the header.

ImageFormat is a stand alone package in the VMMaker repository that can be loaded into any image without requiring VMMaker.

Example attached.

Dave