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fe26328a19
this speeds up the system.sets time from ~0.2 to ~0.06 in release mode. This is still slower than intsets and tables (which both are ~0.01). This assumes that most sets will be sparse. fixes #10617
29 lines
817 B
Nim
29 lines
817 B
Nim
#
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#
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# Nim's Runtime Library
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# (c) Copyright 2012 Andreas Rumpf
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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# set handling
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type
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NimSet = array[0..4*2048-1, uint8]
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proc countBits32(n: int32): int {.compilerproc.} =
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var v = n
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v = v -% ((v shr 1'i32) and 0x55555555'i32)
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v = (v and 0x33333333'i32) +% ((v shr 2'i32) and 0x33333333'i32)
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result = ((v +% (v shr 4'i32) and 0xF0F0F0F'i32) *% 0x1010101'i32) shr 24'i32
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proc countBits64(n: int64): int {.compilerproc.} =
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result = countBits32(toU32(n and 0xffffffff'i64)) +
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countBits32(toU32(n shr 32'i64))
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proc cardSet(s: NimSet, len: int): int {.compilerproc, inline.} =
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for i in 0..<len:
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if likely(s[i] == 0): continue
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inc(result, countBits32(int32(s[i])))
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