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// Package bloomfilter is face-meltingly fast, thread-safe,
// marshalable, unionable, probability- and
// optimal-size-calculating Bloom filter in go
//
// https://github.com/steakknife/bloomfilter
//
// Copyright © 2014, 2015, 2018 Barry Allard
//
// MIT license
//
package v2
import (
"compress/gzip"
_ "encoding/gob" // make sure gob is available
"encoding/json"
"errors"
"io"
"os"
)
// ReadFrom r and overwrite f with new Bloom filter data
func (f *Filter) ReadFrom(r io.Reader) (n int64, err error) {
f2, n, err := ReadFrom(r)
if err != nil {
return -1, err
}
f.lock.Lock()
defer f.lock.Unlock()
f.m = f2.m
f.n = f2.n
f.bits = f2.bits
f.keys = f2.keys
return n, nil
}
// ReadFrom Reader r into a lossless-compressed Bloom filter f
func ReadFrom(r io.Reader) (f *Filter, n int64, err error) {
f = new(Filter)
rawR, err := gzip.NewReader(r)
if err != nil {
return nil, -1, err
}
defer rawR.Close()
n, err = f.UnmarshalFromReader(rawR)
if err != nil {
return nil, -1, err
}
return f, n, nil
}
// ReadFile from filename into a lossless-compressed Bloom Filter f
// Suggested file extension: .bf.gz
func ReadFile(filename string) (f *Filter, n int64, err error) {
r, err := os.Open(filename)
if err != nil {
return nil, -1, err
}
defer r.Close()
return ReadFrom(r)
}
// WriteTo a Writer w from lossless-compressed Bloom Filter f
func (f *Filter) WriteTo(w io.Writer) (n int64, err error) {
f.lock.RLock()
defer f.lock.RUnlock()
rawW := gzip.NewWriter(w)
defer rawW.Close()
intN, _, err := f.MarshallToWriter(rawW)
//intN, _, err := f.MarshallToWriter(w)
n = int64(intN)
return n, err
}
// WriteFile filename from a a lossless-compressed Bloom Filter f
// Suggested file extension: .bf.gz
func (f *Filter) WriteFile(filename string) (n int64, err error) {
w, err := os.Create(filename)
if err != nil {
return -1, err
}
defer w.Close()
return f.WriteTo(w)
}
type jsonType struct {
Version string `json:"version"`
Bits []uint64 `json:"bits"`
Keys []uint64 `json:"keys"`
M uint64 `json:"m"`
N uint64 `json:"n"`
}
func (f *Filter) MarshalJSON() ([]byte, error) {
return json.Marshal(&jsonType{
string(version),
f.bits,
f.keys,
f.m,
f.n,
})
}
func (f *Filter) UnmarshalJSON(data []byte) error {
var j jsonType
if err := json.Unmarshal(data, &j); err != nil {
return err
}
if j.Version != string(version) {
return errors.New("incompatible version")
}
f.bits = j.Bits
f.keys = j.Keys
f.n = j.N
f.m = j.M
return nil
}
// GobDecode conforms to interface gob.GobDecoder
func (f *Filter) GobDecode(data []byte) error {
return f.UnmarshalBinary(data)
}
// GobEncode conforms to interface gob.GobEncoder
func (f *Filter) GobEncode() ([]byte, error) {
return f.MarshalBinary()
}
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