mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-04 14:46:57 -05:00
86e2789960
* update github.com/PuerkitoBio/goquery * update github.com/alecthomas/chroma * update github.com/blevesearch/bleve/v2 * update github.com/caddyserver/certmagic * update github.com/go-enry/go-enry/v2 * update github.com/go-git/go-billy/v5 * update github.com/go-git/go-git/v5 * update github.com/go-redis/redis/v8 * update github.com/go-testfixtures/testfixtures/v3 * update github.com/jaytaylor/html2text * update github.com/json-iterator/go * update github.com/klauspost/compress * update github.com/markbates/goth * update github.com/mattn/go-isatty * update github.com/mholt/archiver/v3 * update github.com/microcosm-cc/bluemonday * update github.com/minio/minio-go/v7 * update github.com/prometheus/client_golang * update github.com/unrolled/render * update github.com/xanzy/go-gitlab * update github.com/yuin/goldmark * update github.com/yuin/goldmark-highlighting Co-authored-by: techknowlogick <techknowlogick@gitea.io>
94 lines
3.3 KiB
Markdown
Vendored
94 lines
3.3 KiB
Markdown
Vendored
# bitset
|
|
|
|
*Go language library to map between non-negative integers and boolean values*
|
|
|
|
[](https://github.com/willf/bitset/actions?query=workflow%3ATest)
|
|
[](https://goreportcard.com/report/github.com/willf/bitset)
|
|
[](https://pkg.go.dev/github.com/bits-and-blooms/bitset?tab=doc)
|
|
|
|
|
|
## Description
|
|
|
|
Package bitset implements bitsets, a mapping between non-negative integers and boolean values.
|
|
It should be more efficient than map[uint] bool.
|
|
|
|
It provides methods for setting, clearing, flipping, and testing individual integers.
|
|
|
|
But it also provides set intersection, union, difference, complement, and symmetric operations, as well as tests to check whether any, all, or no bits are set, and querying a bitset's current length and number of positive bits.
|
|
|
|
BitSets are expanded to the size of the largest set bit; the memory allocation is approximately Max bits, where Max is the largest set bit. BitSets are never shrunk. On creation, a hint can be given for the number of bits that will be used.
|
|
|
|
Many of the methods, including Set, Clear, and Flip, return a BitSet pointer, which allows for chaining.
|
|
|
|
### Example use:
|
|
|
|
```go
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"math/rand"
|
|
|
|
"github.com/bits-and-blooms/bitset"
|
|
)
|
|
|
|
func main() {
|
|
fmt.Printf("Hello from BitSet!\n")
|
|
var b bitset.BitSet
|
|
// play some Go Fish
|
|
for i := 0; i < 100; i++ {
|
|
card1 := uint(rand.Intn(52))
|
|
card2 := uint(rand.Intn(52))
|
|
b.Set(card1)
|
|
if b.Test(card2) {
|
|
fmt.Println("Go Fish!")
|
|
}
|
|
b.Clear(card1)
|
|
}
|
|
|
|
// Chaining
|
|
b.Set(10).Set(11)
|
|
|
|
for i, e := b.NextSet(0); e; i, e = b.NextSet(i + 1) {
|
|
fmt.Println("The following bit is set:", i)
|
|
}
|
|
if b.Intersection(bitset.New(100).Set(10)).Count() == 1 {
|
|
fmt.Println("Intersection works.")
|
|
} else {
|
|
fmt.Println("Intersection doesn't work???")
|
|
}
|
|
}
|
|
```
|
|
|
|
As an alternative to BitSets, one should check out the 'big' package, which provides a (less set-theoretical) view of bitsets.
|
|
|
|
Package documentation is at: https://pkg.go.dev/github.com/bits-and-blooms/bitset?tab=doc
|
|
|
|
## Memory Usage
|
|
|
|
The memory usage of a bitset using N bits is at least N/8 bytes. The number of bits in a bitset is at least as large as one plus the greatest bit index you have accessed. Thus it is possible to run out of memory while using a bitset. If you have lots of bits, you might prefer compressed bitsets, like the [Roaring bitmaps](http://roaringbitmap.org) and its [Go implementation](https://github.com/RoaringBitmap/roaring).
|
|
|
|
## Implementation Note
|
|
|
|
Go 1.9 introduced a native `math/bits` library. We provide backward compatibility to Go 1.7, which might be removed.
|
|
|
|
It is possible that a later version will match the `math/bits` return signature for counts (which is `int`, rather than our library's `unit64`). If so, the version will be bumped.
|
|
|
|
## Installation
|
|
|
|
```bash
|
|
go get github.com/bits-and-blooms/bitset
|
|
```
|
|
|
|
## Contributing
|
|
|
|
If you wish to contribute to this project, please branch and issue a pull request against master ("[GitHub Flow](https://guides.github.com/introduction/flow/)")
|
|
|
|
## Running all tests
|
|
|
|
Before committing the code, please check if it passes tests, has adequate coverage, etc.
|
|
```bash
|
|
go test
|
|
go test -cover
|
|
```
|