[Zlib-devel] Causality question

[John Reiser]

> One of the things I am noticing, and that makes me wonder, is
> something that appears to violate causality:
> 
> Emitting match for pos 1703, length 6 from 1699
> 
> e.g. deflate_slow emits a match that appears to go into the "future".

Think "ripple" (overlapping) matches where a byte-by-byte copy from
smallest index to larger generates enough of the future before it is
copied even farther into the future.

Example: "banana".  Match at position= 3, previous position= 1
(delta position= 2), length= 3.  "banana"[3] is "in the future"
but is copied from "banana"[1] before being copied to "banana"[5].

The most common example is the output of memset(ptr,0,n) with
n >= (1+ MIN_MATCH).

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