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encode.go
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encode.go
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package lsmtree
import (
"encoding/binary"
)
func encodePut(key []byte, value []byte) []byte {
encodedKeyLen := encodeLen(len(key))
encodedValueLen := encodeLen(len(value))
len := len(encodedKeyLen) + len(key) + len(encodedValueLen) + len(value)
data := make([]byte, 0, len)
encodedLen := encodeLen(len)
data = append(data, encodedLen...)
data = append(data, encodedKeyLen...)
data = append(data, key...)
data = append(data, encodedValueLen...)
data = append(data, value...)
return data
}
func encodeLen(len int) []byte {
var encoded [8]byte
binary.LittleEndian.PutUint64(encoded[:], uint64(len))
return encoded[:]
}
func decodeLen(encoded []byte) int {
return int(binary.LittleEndian.Uint64(encoded))
}
func decode(encoded []byte) ([]byte, []byte, bool) {
keyLen := decodeLen(encoded[0:8])
key := encoded[8 : 8+keyLen]
keyPartLen := 8 + keyLen
if keyPartLen+1 == len(encoded) {
return key, nil, true
}
valueLenStart := 8 + keyLen
value := encoded[valueLenStart+8:]
return key, value, false
}
func encodeDelete(key []byte) []byte {
encodedKeyLen := encodeLen(len(key))
len := len(encodedKeyLen) + len(key) + 1
data := make([]byte, 0, len)
encodedLen := encodeLen(len)
data = append(data, encodedLen...)
data = append(data, encodedKeyLen...)
data = append(data, key...)
// mark deletion
data = append(data, 0)
return data
}