ceremonyclient/pebble/sstable/compression_cgo.go

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2024-01-03 07:31:42 +00:00
// Copyright 2021 The LevelDB-Go and Pebble Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
//go:build cgo
// +build cgo
package sstable
import (
"bytes"
"github.com/DataDog/zstd"
)
// decodeZstd decompresses b with the Zstandard algorithm.
// It reuses the preallocated capacity of decodedBuf if it is sufficient.
// On success, it returns the decoded byte slice.
func decodeZstd(decodedBuf, b []byte) ([]byte, error) {
return zstd.Decompress(decodedBuf, b)
}
// encodeZstd compresses b with the Zstandard algorithm at default compression
// level (level 3). It reuses the preallocated capacity of compressedBuf if it
// is sufficient. The subslice `compressedBuf[:varIntLen]` should already encode
// the length of `b` before calling encodeZstd. It returns the encoded byte
// slice, including the `compressedBuf[:varIntLen]` prefix.
func encodeZstd(compressedBuf []byte, varIntLen int, b []byte) []byte {
buf := bytes.NewBuffer(compressedBuf[:varIntLen])
writer := zstd.NewWriterLevel(buf, 3)
writer.Write(b)
writer.Close()
return buf.Bytes()
}