mirror of
https://github.com/featurebasedb/featurebase.git
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08659c350b
This commit moves the computation of the intersection count to the `roaring` package so that no allocations are required. The implementation operates at the roaring container level and has specialized functions for array-array, array-bitmap, and bitmap-bitmap container pairs.
59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
package roaring
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func hasAsm() bool
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func BSFQ(memory uint64) int
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func POPCNTQ(memory uint64) int
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// bit population count, take from
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// https://code.google.com/p/go/issues/detail?id=4988#c11
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// credit: https://code.google.com/u/arnehormann/
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func popcntGo(x uint64) (n uint64) {
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x -= (x >> 1) & 0x5555555555555555
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x = (x>>2)&0x3333333333333333 + x&0x3333333333333333
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x += x >> 4
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x &= 0x0f0f0f0f0f0f0f0f
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x *= 0x0101010101010101
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return x >> 56
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}
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func popcntSliceGo(s []uint64) uint64 {
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cnt := uint64(0)
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for _, x := range s {
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cnt += popcntGo(x)
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}
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return cnt
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}
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func popcntMaskSliceGo(s, m []uint64) uint64 {
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cnt := uint64(0)
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for i := range s {
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cnt += popcntGo(s[i] &^ m[i])
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}
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return cnt
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}
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func popcntAndSliceGo(s, m []uint64) uint64 {
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cnt := uint64(0)
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for i := range s {
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cnt += popcntGo(s[i] & m[i])
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}
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return cnt
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}
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func popcntOrSliceGo(s, m []uint64) uint64 {
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cnt := uint64(0)
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for i := range s {
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cnt += popcntGo(s[i] | m[i])
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}
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return cnt
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}
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func popcntXorSliceGo(s, m []uint64) uint64 {
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cnt := uint64(0)
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for i := range s {
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cnt += popcntGo(s[i] ^ m[i])
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}
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return cnt
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}
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