Copyright 2018 andriniaina

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hash an object multiple times superfast without doing reflection each time (experimental)

Farmhash.Sharp.HashObject

High performance generic memberwise GetHashCode() :

• internally uses Farmhash.Sharp for a superfast hashing function
• maintains a cache of expression tree => the Reflection is done only once per type => a magnitude times faster than using reflection

This library could have been written using functional programming an yielding debuggable dynamically built functions, but i am convinced that using Expression trees gives the greatest performance and avoids unnecessary type casts.

Supports :

• all primitive types
• Objects and nested objects (except circular references)
• IEnumerable<>
• IDictionary<>
• enums

Todo:

• expose a predicate to filter properties (eg. public properties only, or a filter by name)
• plugin architecture to handle more custom types

Performance on my machine (Athlon X4-860k)

object count	time with expression tree cache	no cache
1	<1ms	<1ms
1000	1ms	800ms
10000	16ms	~8000ms (500x slower)