| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package compress |
| |
| import ( |
| "io" |
| "sync" |
| |
| "github.com/apache/arrow/go/v9/parquet/internal/debug" |
| "github.com/klauspost/compress/zstd" |
| ) |
| |
| type zstdCodec struct{} |
| |
| type zstdcloser struct { |
| *zstd.Decoder |
| } |
| |
| var ( |
| enc *zstd.Encoder |
| dec *zstd.Decoder |
| initEncoder sync.Once |
| initDecoder sync.Once |
| ) |
| |
| func getencoder() *zstd.Encoder { |
| initEncoder.Do(func() { |
| enc, _ = zstd.NewWriter(nil, zstd.WithZeroFrames(true)) |
| }) |
| return enc |
| } |
| |
| func getdecoder() *zstd.Decoder { |
| initDecoder.Do(func() { |
| dec, _ = zstd.NewReader(nil) |
| }) |
| return dec |
| } |
| |
| func (zstdCodec) Decode(dst, src []byte) []byte { |
| dst, err := getdecoder().DecodeAll(src, dst[:0]) |
| if err != nil { |
| panic(err) |
| } |
| return dst |
| } |
| |
| func (z *zstdcloser) Close() error { |
| z.Decoder.Close() |
| return nil |
| } |
| |
| func (zstdCodec) NewReader(r io.Reader) io.ReadCloser { |
| ret, _ := zstd.NewReader(r) |
| return &zstdcloser{ret} |
| } |
| |
| func (zstdCodec) NewWriter(w io.Writer) io.WriteCloser { |
| ret, _ := zstd.NewWriter(w) |
| return ret |
| } |
| |
| func (zstdCodec) NewWriterLevel(w io.Writer, level int) (io.WriteCloser, error) { |
| var compressLevel zstd.EncoderLevel |
| if level == DefaultCompressionLevel { |
| compressLevel = zstd.SpeedDefault |
| } else { |
| compressLevel = zstd.EncoderLevelFromZstd(level) |
| } |
| return zstd.NewWriter(w, zstd.WithEncoderLevel(compressLevel)) |
| } |
| |
| func (z zstdCodec) Encode(dst, src []byte) []byte { |
| return getencoder().EncodeAll(src, dst[:0]) |
| } |
| |
| func (z zstdCodec) EncodeLevel(dst, src []byte, level int) []byte { |
| compressLevel := zstd.EncoderLevelFromZstd(level) |
| if level == DefaultCompressionLevel { |
| compressLevel = zstd.SpeedDefault |
| } |
| enc, _ := zstd.NewWriter(nil, zstd.WithZeroFrames(true), zstd.WithEncoderLevel(compressLevel)) |
| return enc.EncodeAll(src, dst[:0]) |
| } |
| |
| // from zstd.h, ZSTD_COMPRESSBOUND |
| func (zstdCodec) CompressBound(len int64) int64 { |
| debug.Assert(len > 0, "len for zstd CompressBound should be > 0") |
| extra := ((128 << 10) - len) >> 11 |
| if len >= (128 << 10) { |
| extra = 0 |
| } |
| return len + (len >> 8) + extra |
| } |
| |
| func init() { |
| codecs[Codecs.Zstd] = zstdCodec{} |
| } |