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Merge pull request #528 from slingamn/bitset_again

fix #527
This commit is contained in:
Daniel Oaks 2019-05-28 11:41:45 +10:00 committed by GitHub
commit ed85dd519f
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GPG Key ID: 4AEE18F83AFDEB23
6 changed files with 60 additions and 38 deletions

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@ -204,8 +204,8 @@ package caps
numCapabs = len(CAPDEFS)
bitsetLen = numCapabs // 64
if numCapabs % 64 > 0:
bitsetLen = numCapabs // 32
if numCapabs % 32 > 0:
bitsetLen += 1
print ("""
const (

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@ -11,7 +11,7 @@ import (
)
// Set holds a set of enabled capabilities.
type Set [bitsetLen]uint64
type Set [bitsetLen]uint32
// NewSet returns a new Set, with the given capabilities enabled.
func NewSet(capabs ...Capability) *Set {

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@ -7,7 +7,6 @@ package modes
import (
"strings"
"sync/atomic"
"github.com/oragono/oragono/irc/utils"
)
@ -318,12 +317,13 @@ func ParseChannelModeChanges(params ...string) (ModeChanges, map[rune]bool) {
}
// ModeSet holds a set of modes.
type ModeSet [1]uint64
type ModeSet [2]uint32
// valid modes go from 65 ('A') to 122 ('z'), making at most 58 possible values;
// subtract 65 from the mode value and use that bit of the uint64 to represent it
// subtract 65 from the mode value and use that bit of the uint32 to represent it
const (
minMode = 65 // 'A'
minMode = 65 // 'A'
maxMode = 122 // 'z'
)
// returns a pointer to a new ModeSet
@ -357,11 +357,10 @@ func (set *ModeSet) AllModes() (result []Mode) {
return
}
block := atomic.LoadUint64(&set[0])
var i uint
for i = 0; i < 64; i++ {
if block&(1<<i) != 0 {
result = append(result, Mode(minMode+i))
var i Mode
for i = minMode; i <= maxMode; i++ {
if set.HasMode(i) {
result = append(result, i)
}
}
return

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@ -77,6 +77,16 @@ func TestSetMode(t *testing.T) {
}
}
func TestModeString(t *testing.T) {
set := NewModeSet()
set.SetMode('A', true)
set.SetMode('z', true)
if modeString := set.String(); !(modeString == "Az" || modeString == "Za") {
t.Errorf("unexpected modestring: %s", modeString)
}
}
func TestNilReceivers(t *testing.T) {
set := NewModeSet()
set = nil
@ -113,3 +123,16 @@ func TestHighestChannelUserMode(t *testing.T) {
t.Errorf("nil modeset should have the zero mode as highest channel-user mode")
}
}
func BenchmarkModeString(b *testing.B) {
set := NewModeSet()
set.SetMode('A', true)
set.SetMode('N', true)
set.SetMode('b', true)
set.SetMode('i', true)
set.SetMode('x', true)
b.ResetTimer()
for i := 0; i < b.N; i++ {
_ = set.String()
}
}

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@ -5,28 +5,28 @@ package utils
import "sync/atomic"
// Library functions for lock-free bitsets, typically (constant-sized) arrays of uint64.
// Library functions for lock-free bitsets, typically (constant-sized) arrays of uint32.
// For examples of use, see caps.Set and modes.ModeSet; the array has to be converted to a
// slice to use these functions.
// BitsetGet returns whether a given bit of the bitset is set.
func BitsetGet(set []uint64, position uint) bool {
idx := position / 64
bit := position % 64
block := atomic.LoadUint64(&set[idx])
func BitsetGet(set []uint32, position uint) bool {
idx := position / 32
bit := position % 32
block := atomic.LoadUint32(&set[idx])
return (block & (1 << bit)) != 0
}
// BitsetSet sets a given bit of the bitset to 0 or 1, returning whether it changed.
func BitsetSet(set []uint64, position uint, on bool) (changed bool) {
idx := position / 64
bit := position % 64
func BitsetSet(set []uint32, position uint, on bool) (changed bool) {
idx := position / 32
bit := position % 32
addr := &set[idx]
var mask uint64
var mask uint32
mask = 1 << bit
for {
current := atomic.LoadUint64(addr)
var desired uint64
current := atomic.LoadUint32(addr)
var desired uint32
if on {
desired = current | mask
} else {
@ -34,7 +34,7 @@ func BitsetSet(set []uint64, position uint, on bool) (changed bool) {
}
if current == desired {
return false
} else if atomic.CompareAndSwapUint64(addr, current, desired) {
} else if atomic.CompareAndSwapUint32(addr, current, desired) {
return true
}
}
@ -44,9 +44,9 @@ func BitsetSet(set []uint64, position uint, on bool) (changed bool) {
// This has false positives under concurrent modification (i.e., it can return true
// even though w.r.t. the sequence of atomic modifications, there was no point at
// which the bitset was completely empty), but that's not how we're using this method.
func BitsetEmpty(set []uint64) (empty bool) {
func BitsetEmpty(set []uint32) (empty bool) {
for i := 0; i < len(set); i++ {
if atomic.LoadUint64(&set[i]) != 0 {
if atomic.LoadUint32(&set[i]) != 0 {
return false
}
}
@ -56,14 +56,14 @@ func BitsetEmpty(set []uint64) (empty bool) {
// BitsetUnion modifies `set` to be the union of `set` and `other`.
// This has race conditions in that we don't necessarily get a single
// consistent view of `other` across word boundaries.
func BitsetUnion(set []uint64, other []uint64) {
func BitsetUnion(set []uint32, other []uint32) {
for i := 0; i < len(set); i++ {
for {
ourAddr := &set[i]
ourBlock := atomic.LoadUint64(ourAddr)
otherBlock := atomic.LoadUint64(&other[i])
ourBlock := atomic.LoadUint32(ourAddr)
otherBlock := atomic.LoadUint32(&other[i])
newBlock := ourBlock | otherBlock
if atomic.CompareAndSwapUint64(ourAddr, ourBlock, newBlock) {
if atomic.CompareAndSwapUint32(ourAddr, ourBlock, newBlock) {
break
}
}
@ -72,23 +72,23 @@ func BitsetUnion(set []uint64, other []uint64) {
// BitsetCopy copies the contents of `other` over `set`.
// Similar caveats about race conditions as with `BitsetUnion` apply.
func BitsetCopy(set []uint64, other []uint64) {
func BitsetCopy(set []uint32, other []uint32) {
for i := 0; i < len(set); i++ {
data := atomic.LoadUint64(&other[i])
atomic.StoreUint64(&set[i], data)
data := atomic.LoadUint32(&other[i])
atomic.StoreUint32(&set[i], data)
}
}
// BitsetSubtract modifies `set` to subtract the contents of `other`.
// Similar caveats about race conditions as with `BitsetUnion` apply.
func BitsetSubtract(set []uint64, other []uint64) {
func BitsetSubtract(set []uint32, other []uint32) {
for i := 0; i < len(set); i++ {
for {
ourAddr := &set[i]
ourBlock := atomic.LoadUint64(ourAddr)
otherBlock := atomic.LoadUint64(&other[i])
ourBlock := atomic.LoadUint32(ourAddr)
otherBlock := atomic.LoadUint32(&other[i])
newBlock := ourBlock & (^otherBlock)
if atomic.CompareAndSwapUint64(ourAddr, ourBlock, newBlock) {
if atomic.CompareAndSwapUint32(ourAddr, ourBlock, newBlock) {
break
}
}

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@ -5,7 +5,7 @@ package utils
import "testing"
type testBitset [2]uint64
type testBitset [4]uint32
func TestSets(t *testing.T) {
var t1 testBitset