[WIP] Initial commit

vendor/github.com/cockroachdb/pebble/sstable/compression_nocgo.go

@@ -0,0 +1,30 @@
+// 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 "github.com/klauspost/compress/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) {
+	decoder, _ := zstd.NewReader(nil)
+	defer decoder.Close()
+	return decoder.DecodeAll(b, decodedBuf[:0])
+}
+
+// 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 {
+	encoder, _ := zstd.NewWriter(nil)
+	defer encoder.Close()
+	return encoder.EncodeAll(b, compressedBuf[:varIntLen])
+}