/usr/share/gocode/src/github.com/influxdata/influxdb/tsdb/engine/tsm1/encoding.go is in golang-github-influxdb-influxdb-dev 1.0.2+dfsg1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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import (
"encoding/binary"
"fmt"
"time"
"github.com/influxdata/influxdb/influxql"
"github.com/influxdata/influxdb/tsdb"
)
const (
// BlockFloat64 designates a block encodes float64 values
BlockFloat64 = byte(0)
// BlockInteger designates a block encodes int64 values
BlockInteger = byte(1)
// BlockBoolean designates a block encodes boolean values
BlockBoolean = byte(2)
// BlockString designates a block encodes string values
BlockString = byte(3)
// encodedBlockHeaderSize is the size of the header for an encoded block. There is one
// byte encoding the type of the block.
encodedBlockHeaderSize = 1
)
type Value interface {
UnixNano() int64
Value() interface{}
Size() int
String() string
internalOnly()
}
func NewValue(t int64, value interface{}) Value {
switch v := value.(type) {
case int64:
return &IntegerValue{unixnano: t, value: v}
case float64:
return &FloatValue{unixnano: t, value: v}
case bool:
return &BooleanValue{unixnano: t, value: v}
case string:
return &StringValue{unixnano: t, value: v}
}
return &EmptyValue{}
}
type EmptyValue struct {
}
func (e *EmptyValue) UnixNano() int64 { return tsdb.EOF }
func (e *EmptyValue) Value() interface{} { return nil }
func (e *EmptyValue) Size() int { return 0 }
func (e *EmptyValue) String() string { return "" }
func (_ *EmptyValue) internalOnly() {}
func (_ *StringValue) internalOnly() {}
func (_ *IntegerValue) internalOnly() {}
func (_ *BooleanValue) internalOnly() {}
func (_ *FloatValue) internalOnly() {}
// Encode converts the values to a byte slice. If there are no values,
// this function panics.
func (a Values) Encode(buf []byte) ([]byte, error) {
if len(a) == 0 {
panic("unable to encode block type")
}
switch a[0].(type) {
case *FloatValue:
return encodeFloatBlock(buf, a)
case *IntegerValue:
return encodeIntegerBlock(buf, a)
case *BooleanValue:
return encodeBooleanBlock(buf, a)
case *StringValue:
return encodeStringBlock(buf, a)
}
return nil, fmt.Errorf("unsupported value type %T", a[0])
}
// InfluxQLType returns the influxql.DataType the values map to.
func (a Values) InfluxQLType() (influxql.DataType, error) {
if len(a) == 0 {
return influxql.Unknown, fmt.Errorf("no values to infer type")
}
switch a[0].(type) {
case *FloatValue:
return influxql.Float, nil
case *IntegerValue:
return influxql.Integer, nil
case *BooleanValue:
return influxql.Boolean, nil
case *StringValue:
return influxql.String, nil
}
return influxql.Unknown, fmt.Errorf("unsupported value type %T", a[0])
}
// BlockType returns the type of value encoded in a block or an error
// if the block type is unknown.
func BlockType(block []byte) (byte, error) {
blockType := block[0]
switch blockType {
case BlockFloat64, BlockInteger, BlockBoolean, BlockString:
return blockType, nil
default:
return 0, fmt.Errorf("unknown block type: %d", blockType)
}
}
func BlockCount(block []byte) int {
if len(block) <= encodedBlockHeaderSize {
panic(fmt.Sprintf("count of short block: got %v, exp %v", len(block), encodedBlockHeaderSize))
}
// first byte is the block type
tb, _, err := unpackBlock(block[1:])
if err != nil {
panic(fmt.Sprintf("BlockCount: error unpacking block: %s", err.Error()))
}
return CountTimestamps(tb)
}
// DecodeBlock takes a byte array and will decode into values of the appropriate type
// based on the block.
func DecodeBlock(block []byte, vals []Value) ([]Value, error) {
if len(block) <= encodedBlockHeaderSize {
panic(fmt.Sprintf("decode of short block: got %v, exp %v", len(block), encodedBlockHeaderSize))
}
blockType, err := BlockType(block)
if err != nil {
return nil, err
}
switch blockType {
case BlockFloat64:
var buf []FloatValue
decoded, err := DecodeFloatBlock(block, &TimeDecoder{}, &FloatDecoder{}, &buf)
if len(vals) < len(decoded) {
vals = make([]Value, len(decoded))
}
for i := range decoded {
vals[i] = &decoded[i]
}
return vals[:len(decoded)], err
case BlockInteger:
var buf []IntegerValue
decoded, err := DecodeIntegerBlock(block, &TimeDecoder{}, &IntegerDecoder{}, &buf)
if len(vals) < len(decoded) {
vals = make([]Value, len(decoded))
}
for i := range decoded {
vals[i] = &decoded[i]
}
return vals[:len(decoded)], err
case BlockBoolean:
var buf []BooleanValue
decoded, err := DecodeBooleanBlock(block, &TimeDecoder{}, &BooleanDecoder{}, &buf)
if len(vals) < len(decoded) {
vals = make([]Value, len(decoded))
}
for i := range decoded {
vals[i] = &decoded[i]
}
return vals[:len(decoded)], err
case BlockString:
var buf []StringValue
decoded, err := DecodeStringBlock(block, &TimeDecoder{}, &StringDecoder{}, &buf)
if len(vals) < len(decoded) {
vals = make([]Value, len(decoded))
}
for i := range decoded {
vals[i] = &decoded[i]
}
return vals[:len(decoded)], err
default:
panic(fmt.Sprintf("unknown block type: %d", blockType))
}
}
type FloatValue struct {
unixnano int64
value float64
}
func (f *FloatValue) UnixNano() int64 {
return f.unixnano
}
func (f *FloatValue) Value() interface{} {
return f.value
}
func (f *FloatValue) Size() int {
return 16
}
func (f *FloatValue) String() string {
return fmt.Sprintf("%v %v", time.Unix(0, f.unixnano), f.value)
}
func encodeFloatBlock(buf []byte, values []Value) ([]byte, error) {
if len(values) == 0 {
return nil, nil
}
// A float block is encoded using different compression strategies
// for timestamps and values.
// Encode values using Gorilla float compression
venc := NewFloatEncoder()
// Encode timestamps using an adaptive encoder that uses delta-encoding,
// frame-or-reference and run length encoding.
tsenc := NewTimeEncoder()
for _, v := range values {
tsenc.Write(v.UnixNano())
venc.Push(v.(*FloatValue).value)
}
venc.Finish()
// Encoded timestamp values
tb, err := tsenc.Bytes()
if err != nil {
return nil, err
}
// Encoded float values
vb, err := venc.Bytes()
if err != nil {
return nil, err
}
// Prepend the first timestamp of the block in the first 8 bytes and the block
// in the next byte, followed by the block
block := packBlockHeader(BlockFloat64)
block = append(block, packBlock(tb, vb)...)
return block, nil
}
func DecodeFloatBlock(block []byte, tdec *TimeDecoder, vdec *FloatDecoder, a *[]FloatValue) ([]FloatValue, error) {
// Block type is the next block, make sure we actually have a float block
blockType := block[0]
if blockType != BlockFloat64 {
return nil, fmt.Errorf("invalid block type: exp %d, got %d", BlockFloat64, blockType)
}
block = block[1:]
tb, vb, err := unpackBlock(block)
if err != nil {
return nil, err
}
// Setup our timestamp and value decoders
tdec.Init(tb)
if err := vdec.SetBytes(vb); err != nil {
return nil, err
}
// Decode both a timestamp and value
i := 0
for tdec.Next() && vdec.Next() {
ts := tdec.Read()
v := vdec.Values()
if i < len(*a) {
elem := &(*a)[i]
elem.unixnano = ts
elem.value = v
} else {
*a = append(*a, FloatValue{ts, v})
}
i++
}
// Did timestamp decoding have an error?
if tdec.Error() != nil {
return nil, tdec.Error()
}
// Did float decoding have an error?
if vdec.Error() != nil {
return nil, vdec.Error()
}
return (*a)[:i], nil
}
type BooleanValue struct {
unixnano int64
value bool
}
func (b *BooleanValue) Size() int {
return 9
}
func (b *BooleanValue) UnixNano() int64 {
return b.unixnano
}
func (b *BooleanValue) Value() interface{} {
return b.value
}
func (f *BooleanValue) String() string {
return fmt.Sprintf("%v %v", time.Unix(0, f.unixnano), f.Value())
}
func encodeBooleanBlock(buf []byte, values []Value) ([]byte, error) {
if len(values) == 0 {
return nil, nil
}
// A boolean block is encoded using different compression strategies
// for timestamps and values.
// Encode values using Gorilla float compression
venc := NewBooleanEncoder()
// Encode timestamps using an adaptive encoder
tsenc := NewTimeEncoder()
for _, v := range values {
tsenc.Write(v.UnixNano())
venc.Write(v.(*BooleanValue).value)
}
// Encoded timestamp values
tb, err := tsenc.Bytes()
if err != nil {
return nil, err
}
// Encoded float values
vb, err := venc.Bytes()
if err != nil {
return nil, err
}
// Prepend the first timestamp of the block in the first 8 bytes and the block
// in the next byte, followed by the block
block := packBlockHeader(BlockBoolean)
block = append(block, packBlock(tb, vb)...)
return block, nil
}
func DecodeBooleanBlock(block []byte, tdec *TimeDecoder, vdec *BooleanDecoder, a *[]BooleanValue) ([]BooleanValue, error) {
// Block type is the next block, make sure we actually have a float block
blockType := block[0]
if blockType != BlockBoolean {
return nil, fmt.Errorf("invalid block type: exp %d, got %d", BlockBoolean, blockType)
}
block = block[1:]
tb, vb, err := unpackBlock(block)
if err != nil {
return nil, err
}
// Setup our timestamp and value decoders
tdec.Init(tb)
vdec.SetBytes(vb)
// Decode both a timestamp and value
i := 0
for tdec.Next() && vdec.Next() {
ts := tdec.Read()
v := vdec.Read()
if i < len(*a) {
elem := &(*a)[i]
elem.unixnano = ts
elem.value = v
} else {
*a = append(*a, BooleanValue{ts, v})
}
i++
}
// Did timestamp decoding have an error?
if tdec.Error() != nil {
return nil, tdec.Error()
}
// Did boolean decoding have an error?
if vdec.Error() != nil {
return nil, vdec.Error()
}
return (*a)[:i], nil
}
type IntegerValue struct {
unixnano int64
value int64
}
func (v *IntegerValue) Value() interface{} {
return v.value
}
func (v *IntegerValue) UnixNano() int64 {
return v.unixnano
}
func (v *IntegerValue) Size() int {
return 16
}
func (f *IntegerValue) String() string {
return fmt.Sprintf("%v %v", time.Unix(0, f.unixnano), f.Value())
}
func encodeIntegerBlock(buf []byte, values []Value) ([]byte, error) {
tsEnc := NewTimeEncoder()
vEnc := NewIntegerEncoder()
for _, v := range values {
tsEnc.Write(v.UnixNano())
vEnc.Write(v.(*IntegerValue).value)
}
// Encoded timestamp values
tb, err := tsEnc.Bytes()
if err != nil {
return nil, err
}
// Encoded int64 values
vb, err := vEnc.Bytes()
if err != nil {
return nil, err
}
// Prepend the first timestamp of the block in the first 8 bytes
block := packBlockHeader(BlockInteger)
return append(block, packBlock(tb, vb)...), nil
}
func DecodeIntegerBlock(block []byte, tdec *TimeDecoder, vdec *IntegerDecoder, a *[]IntegerValue) ([]IntegerValue, error) {
blockType := block[0]
if blockType != BlockInteger {
return nil, fmt.Errorf("invalid block type: exp %d, got %d", BlockInteger, blockType)
}
block = block[1:]
// The first 8 bytes is the minimum timestamp of the block
tb, vb, err := unpackBlock(block)
if err != nil {
return nil, err
}
// Setup our timestamp and value decoders
tdec.Init(tb)
vdec.SetBytes(vb)
// Decode both a timestamp and value
i := 0
for tdec.Next() && vdec.Next() {
ts := tdec.Read()
v := vdec.Read()
if i < len(*a) {
elem := &(*a)[i]
elem.unixnano = ts
elem.value = v
} else {
*a = append(*a, IntegerValue{ts, v})
}
i++
}
// Did timestamp decoding have an error?
if tdec.Error() != nil {
return nil, tdec.Error()
}
// Did int64 decoding have an error?
if vdec.Error() != nil {
return nil, vdec.Error()
}
return (*a)[:i], nil
}
type StringValue struct {
unixnano int64
value string
}
func (v *StringValue) Value() interface{} {
return v.value
}
func (v *StringValue) UnixNano() int64 {
return v.unixnano
}
func (v *StringValue) Size() int {
return 8 + len(v.value)
}
func (f *StringValue) String() string {
return fmt.Sprintf("%v %v", time.Unix(0, f.unixnano), f.Value())
}
func encodeStringBlock(buf []byte, values []Value) ([]byte, error) {
tsEnc := NewTimeEncoder()
vEnc := NewStringEncoder()
for _, v := range values {
tsEnc.Write(v.UnixNano())
vEnc.Write(v.(*StringValue).value)
}
// Encoded timestamp values
tb, err := tsEnc.Bytes()
if err != nil {
return nil, err
}
// Encoded string values
vb, err := vEnc.Bytes()
if err != nil {
return nil, err
}
// Prepend the first timestamp of the block in the first 8 bytes
block := packBlockHeader(BlockString)
return append(block, packBlock(tb, vb)...), nil
}
func DecodeStringBlock(block []byte, tdec *TimeDecoder, vdec *StringDecoder, a *[]StringValue) ([]StringValue, error) {
blockType := block[0]
if blockType != BlockString {
return nil, fmt.Errorf("invalid block type: exp %d, got %d", BlockString, blockType)
}
block = block[1:]
// The first 8 bytes is the minimum timestamp of the block
tb, vb, err := unpackBlock(block)
if err != nil {
return nil, err
}
// Setup our timestamp and value decoders
tdec.Init(tb)
if err := vdec.SetBytes(vb); err != nil {
return nil, err
}
// Decode both a timestamp and value
i := 0
for tdec.Next() && vdec.Next() {
ts := tdec.Read()
v := vdec.Read()
if i < len(*a) {
elem := &(*a)[i]
elem.unixnano = ts
elem.value = v
} else {
*a = append(*a, StringValue{ts, v})
}
i++
}
// Did timestamp decoding have an error?
if tdec.Error() != nil {
return nil, tdec.Error()
}
// Did string decoding have an error?
if vdec.Error() != nil {
return nil, vdec.Error()
}
return (*a)[:i], nil
}
func packBlockHeader(blockType byte) []byte {
return []byte{blockType}
}
func packBlock(ts []byte, values []byte) []byte {
// We encode the length of the timestamp block using a variable byte encoding.
// This allows small byte slices to take up 1 byte while larger ones use 2 or more.
b := make([]byte, 10)
i := binary.PutUvarint(b, uint64(len(ts)))
// block is <len timestamp bytes>, <ts bytes>, <value bytes>
block := append(b[:i], ts...)
// We don't encode the value length because we know it's the rest of the block after
// the timestamp block.
return append(block, values...)
}
func unpackBlock(buf []byte) (ts, values []byte, err error) {
// Unpack the timestamp block length
tsLen, i := binary.Uvarint(buf)
if i <= 0 {
err = fmt.Errorf("unpackBlock: unable to read timestamp block length")
return
}
// Unpack the timestamp bytes
tsIdx := int(i) + int(tsLen)
if tsIdx > len(buf) {
err = fmt.Errorf("unpackBlock: not enough data for timestamp")
return
}
ts = buf[int(i):tsIdx]
// Unpack the value bytes
values = buf[tsIdx:]
return
}
// ZigZagEncode converts a int64 to a uint64 by zig zagging negative and positive values
// across even and odd numbers. Eg. [0,-1,1,-2] becomes [0, 1, 2, 3]
func ZigZagEncode(x int64) uint64 {
return uint64(uint64(x<<1) ^ uint64((int64(x) >> 63)))
}
// ZigZagDecode converts a previously zigzag encoded uint64 back to a int64
func ZigZagDecode(v uint64) int64 {
return int64((v >> 1) ^ uint64((int64(v&1)<<63)>>63))
}
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