Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Replace extendSetMaybe by extendSet and bring the checks at the calling point (for performance) #106

Merged
merged 2 commits into from
Jul 21, 2022
Merged

Replace extendSetMaybe by extendSet and bring the checks at the calling point (for performance) #106

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
8b8b79b
The 'extendMaybe' function is seemingly *not* inlined in Go. Yet it
lemire Jul 21, 2022
e8e2dee
Merge branch 'master' into dlemire/avoiding_calls_to_extend_maybe
lemire Jul 21, 2022
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 28 additions & 25 deletions bitset.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -151,24 +151,22 @@ func (b *BitSet) Len() uint {
return b.length
}

// extendSetMaybe adds additional words to incorporate new bits if needed
func (b *BitSet) extendSetMaybe(i uint) {
if i >= b.length { // if we need more bits, make 'em
if i >= Cap() {
panic("You are exceeding the capacity")
}
nsize := wordsNeeded(i + 1)
if b.set == nil {
b.set = make([]uint64, nsize)
} else if cap(b.set) >= nsize {
b.set = b.set[:nsize] // fast resize
} else if len(b.set) < nsize {
newset := make([]uint64, nsize, 2*nsize) // increase capacity 2x
copy(newset, b.set)
b.set = newset
}
b.length = i + 1
// extendSet adds additional words to incorporate new bits if needed
func (b *BitSet) extendSet(i uint) {
if i >= Cap() {
panic("You are exceeding the capacity")
}
nsize := wordsNeeded(i + 1)
if b.set == nil {
b.set = make([]uint64, nsize)
} else if cap(b.set) >= nsize {
b.set = b.set[:nsize] // fast resize
} else if len(b.set) < nsize {
newset := make([]uint64, nsize, 2*nsize) // increase capacity 2x
copy(newset, b.set)
b.set = newset
}
b.length = i + 1
}

// Test whether bit i is set.
Expand All @@ -186,7 +184,9 @@ func (b *BitSet) Test(i uint) bool {
// may lead to a memory shortage and a panic: the caller is responsible
// for providing sensible parameters in line with their memory capacity.
func (b *BitSet) Set(i uint) *BitSet {
b.extendSetMaybe(i)
if i >= b.length { // if we need more bits, make 'em
b.extendSet(i)
}
b.set[i>>log2WordSize] |= 1 << wordsIndex(i)
return b
}
Expand Down Expand Up @@ -234,8 +234,9 @@ func (b *BitSet) FlipRange(start, end uint) *BitSet {
if start >= end {
return b
}

b.extendSetMaybe(end - 1)
if end-1 >= b.length { // if we need more bits, make 'em
b.extendSet(end - 1)
}
var startWord uint = start >> log2WordSize
var endWord uint = end >> log2WordSize
b.set[startWord] ^= ^(^uint64(0) << wordsIndex(start))
Expand Down Expand Up @@ -713,7 +714,9 @@ func (b *BitSet) InPlaceIntersection(compare *BitSet) {
b.set[i] = 0
}
if compare.length > 0 {
b.extendSetMaybe(compare.length - 1)
if compare.length-1 >= b.length {
b.extendSet(compare.length - 1)
}
}
}

Expand Down Expand Up @@ -752,8 +755,8 @@ func (b *BitSet) InPlaceUnion(compare *BitSet) {
if l > int(b.wordCount()) {
l = int(b.wordCount())
}
if compare.length > 0 {
b.extendSetMaybe(compare.length - 1)
if compare.length > 0 && compare.length-1 >= b.length {
b.extendSet(compare.length - 1)
}
for i := 0; i < l; i++ {
b.set[i] |= compare.set[i]
Expand Down Expand Up @@ -800,8 +803,8 @@ func (b *BitSet) InPlaceSymmetricDifference(compare *BitSet) {
if l > int(b.wordCount()) {
l = int(b.wordCount())
}
if compare.length > 0 {
b.extendSetMaybe(compare.length - 1)
if compare.length > 0 && compare.length-1 >= b.length {
b.extendSet(compare.length - 1)
}
for i := 0; i < l; i++ {
b.set[i] ^= compare.set[i]
Expand Down