forkjo/vendor/github.com/RoaringBitmap/roaring/serialization.go

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2018-05-19 14:49:46 +02:00
package roaring
import (
"encoding/binary"
"errors"
"fmt"
"io"
"github.com/tinylib/msgp/msgp"
)
// writeTo for runContainer16 follows this
// spec: https://github.com/RoaringBitmap/RoaringFormatSpec
//
func (b *runContainer16) writeTo(stream io.Writer) (int, error) {
buf := make([]byte, 2+4*len(b.iv))
binary.LittleEndian.PutUint16(buf[0:], uint16(len(b.iv)))
for i, v := range b.iv {
binary.LittleEndian.PutUint16(buf[2+i*4:], v.start)
binary.LittleEndian.PutUint16(buf[2+2+i*4:], v.length)
}
return stream.Write(buf)
}
func (b *runContainer32) writeToMsgpack(stream io.Writer) (int, error) {
bts, err := b.MarshalMsg(nil)
if err != nil {
return 0, err
}
return stream.Write(bts)
}
func (b *runContainer16) writeToMsgpack(stream io.Writer) (int, error) {
bts, err := b.MarshalMsg(nil)
if err != nil {
return 0, err
}
return stream.Write(bts)
}
func (b *runContainer32) readFromMsgpack(stream io.Reader) (int, error) {
err := msgp.Decode(stream, b)
return 0, err
}
func (b *runContainer16) readFromMsgpack(stream io.Reader) (int, error) {
err := msgp.Decode(stream, b)
return 0, err
}
var errCorruptedStream = errors.New("insufficient/odd number of stored bytes, corrupted stream detected")
func (b *runContainer16) readFrom(stream io.Reader) (int, error) {
b.iv = b.iv[:0]
b.card = 0
var numRuns uint16
err := binary.Read(stream, binary.LittleEndian, &numRuns)
if err != nil {
return 0, err
}
nr := int(numRuns)
encRun := make([]uint16, 2*nr)
by := make([]byte, 4*nr)
err = binary.Read(stream, binary.LittleEndian, &by)
if err != nil {
return 0, err
}
for i := range encRun {
if len(by) < 2 {
return 0, errCorruptedStream
}
encRun[i] = binary.LittleEndian.Uint16(by)
by = by[2:]
}
for i := 0; i < nr; i++ {
if i > 0 && b.iv[i-1].last() >= encRun[i*2] {
return 0, fmt.Errorf("error: stored runContainer had runs that were not in sorted order!! (b.iv[i-1=%v].last = %v >= encRun[i=%v] = %v)", i-1, b.iv[i-1].last(), i, encRun[i*2])
}
b.iv = append(b.iv, interval16{start: encRun[i*2], length: encRun[i*2+1]})
b.card += int64(encRun[i*2+1]) + 1
}
return 0, err
}