Re: Good hash for pointers

On 5/23/2024 5:32 PM, Chris M. Thomasson wrote:

On 5/23/2024 4:11 AM, Malcolm McLean wrote:

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What is a good hash function for pointers to use in portable ANSI C?
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The pointers are nodes of a tree, which are read only, and I want to associate read/write data with them. So potentially a lage number of pointers,and they might be consecutively ordered if they are taken from an array, or they might be returned from repeared calls to malloc() with small allocations. Obviously I have no control over pointer size or internal representation.
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I kind of remember an old one for 32-bit pointers. It was something like multiply by a prime and shift to the right by 7 or 8. Shit, I think. It was way back on comp.programming.threads.

 There was an old paper from microsoft that had a pointer hash. It was used to index into a table of locks. I need to find it.