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• A ShellSort with a twist Revised and even faster (7 March 2009)

A ShellSort with a twist Revised and even faster (7 March 2009)

This shell algorithm is founded on a very solid performer that was originally developed by vb2themax, and optimized further by several very talented coders, before I twisted a little more out of it in this hybrid version.
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This latest version employs a clever SAFEARRAY substitution technique to trick VB into thinking the four-byte string pointers in the string array are just VB longs in a native VB long array, and is now much faster.
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Also uses valid addition and subtraction of unsigned long integers to guarantee safe arithmetic operations on memory address pointers.
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Includes both Shell and ShellHyb algorithms with indexed versions in 25kb class and demo project.
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Update 21 June 2008 inspired by comments from Roger Gilchrist. Improved indexed sorting support routine to better exploit fast re-sorting performance, and added much needed index sorting documentation.
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Obscure Bug Fix 7 March 09. I documented they 'can sort sub-sets of the array data' but with the indexed versions if you do an error *could* occur without this very small change.

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