228 lines
6.2 KiB
Go
228 lines
6.2 KiB
Go
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// Copyright 2018 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package compressio
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import (
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"bytes"
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"compress/flate"
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"encoding/base64"
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"fmt"
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"io"
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"math/rand"
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"runtime"
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"testing"
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"time"
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)
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type harness interface {
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Errorf(format string, v ...interface{})
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Fatalf(format string, v ...interface{})
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Logf(format string, v ...interface{})
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}
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func initTest(t harness, size int) []byte {
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// Set number of processes to number of CPUs.
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runtime.GOMAXPROCS(runtime.NumCPU())
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// Construct synthetic data. We do this by encoding random data with
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// base64. This gives a high level of entropy, but still quite a bit of
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// structure, to give reasonable compression ratios (~75%).
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var buf bytes.Buffer
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bufW := base64.NewEncoder(base64.RawStdEncoding, &buf)
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bufR := rand.New(rand.NewSource(0))
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if _, err := io.CopyN(bufW, bufR, int64(size)); err != nil {
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t.Fatalf("unable to seed random data: %v", err)
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}
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return buf.Bytes()
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}
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type testOpts struct {
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Name string
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Data []byte
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NewWriter func(*bytes.Buffer) (io.Writer, error)
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NewReader func(*bytes.Buffer) (io.Reader, error)
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PreCompress func()
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PostCompress func()
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PreDecompress func()
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PostDecompress func()
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CompressIters int
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DecompressIters int
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}
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func doTest(t harness, opts testOpts) {
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// Compress.
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var compressed bytes.Buffer
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compressionStartTime := time.Now()
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if opts.PreCompress != nil {
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opts.PreCompress()
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}
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if opts.CompressIters <= 0 {
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opts.CompressIters = 1
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}
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for i := 0; i < opts.CompressIters; i++ {
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compressed.Reset()
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w, err := opts.NewWriter(&compressed)
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if err != nil {
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t.Errorf("%s: NewWriter got err %v, expected nil", opts.Name, err)
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}
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if _, err := io.Copy(w, bytes.NewBuffer(opts.Data)); err != nil {
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t.Errorf("%s: compress got err %v, expected nil", opts.Name, err)
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return
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}
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closer, ok := w.(io.Closer)
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if ok {
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if err := closer.Close(); err != nil {
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t.Errorf("%s: got err %v, expected nil", opts.Name, err)
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return
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}
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}
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}
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if opts.PostCompress != nil {
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opts.PostCompress()
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}
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compressionTime := time.Since(compressionStartTime)
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compressionRatio := float32(compressed.Len()) / float32(len(opts.Data))
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// Decompress.
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var decompressed bytes.Buffer
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decompressionStartTime := time.Now()
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if opts.PreDecompress != nil {
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opts.PreDecompress()
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}
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if opts.DecompressIters <= 0 {
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opts.DecompressIters = 1
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}
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for i := 0; i < opts.DecompressIters; i++ {
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decompressed.Reset()
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r, err := opts.NewReader(bytes.NewBuffer(compressed.Bytes()))
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if err != nil {
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t.Errorf("%s: NewReader got err %v, expected nil", opts.Name, err)
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return
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}
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if _, err := io.Copy(&decompressed, r); err != nil {
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t.Errorf("%s: decompress got err %v, expected nil", opts.Name, err)
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return
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}
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}
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if opts.PostDecompress != nil {
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opts.PostDecompress()
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}
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decompressionTime := time.Since(decompressionStartTime)
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// Verify.
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if decompressed.Len() != len(opts.Data) {
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t.Errorf("%s: got %d bytes, expected %d", opts.Name, decompressed.Len(), len(opts.Data))
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}
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if !bytes.Equal(opts.Data, decompressed.Bytes()) {
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t.Errorf("%s: got mismatch, expected match", opts.Name)
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if len(opts.Data) < 32 { // Don't flood the logs.
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t.Errorf("got %v, expected %v", decompressed.Bytes(), opts.Data)
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}
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}
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t.Logf("%s: compression time %v, ratio %2.2f, decompression time %v",
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opts.Name, compressionTime, compressionRatio, decompressionTime)
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}
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func TestCompress(t *testing.T) {
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var (
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data = initTest(t, 10*1024*1024)
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data0 = data[:0]
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data1 = data[:1]
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data2 = data[:11]
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data3 = data[:16]
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data4 = data[:]
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)
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for _, data := range [][]byte{data0, data1, data2, data3, data4} {
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for _, blockSize := range []uint32{1, 4, 1024, 4 * 1024, 16 * 1024} {
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// Skip annoying tests; they just take too long.
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if blockSize <= 16 && len(data) > 16 {
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continue
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}
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// Do the compress test.
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doTest(t, testOpts{
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Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), blockSize),
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Data: data,
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NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
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return NewWriter(b, blockSize, flate.BestCompression)
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},
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NewReader: func(b *bytes.Buffer) (io.Reader, error) {
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return NewReader(b)
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},
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})
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}
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// Do the vanilla test.
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doTest(t, testOpts{
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Name: fmt.Sprintf("len(data)=%d, vanilla flate", len(data)),
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Data: data,
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NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
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return flate.NewWriter(b, flate.BestCompression)
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},
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NewReader: func(b *bytes.Buffer) (io.Reader, error) {
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return flate.NewReader(b), nil
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},
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})
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}
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}
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const (
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// benchBlockSize is the blockSize for benchmarks.
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benchBlockSize = 32 * 1024
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// benchDataSize is the amount of data for benchmarks.
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benchDataSize = 10 * 1024 * 1024
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)
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func BenchmarkCompress(b *testing.B) {
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b.StopTimer()
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b.SetBytes(benchDataSize)
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data := initTest(b, benchDataSize)
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doTest(b, testOpts{
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Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), benchBlockSize),
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Data: data,
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PreCompress: b.StartTimer,
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PostCompress: b.StopTimer,
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NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
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return NewWriter(b, benchBlockSize, flate.BestCompression)
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},
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NewReader: func(b *bytes.Buffer) (io.Reader, error) {
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return NewReader(b)
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},
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CompressIters: b.N,
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})
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}
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func BenchmarkDecompress(b *testing.B) {
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b.StopTimer()
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b.SetBytes(benchDataSize)
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data := initTest(b, benchDataSize)
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doTest(b, testOpts{
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Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), benchBlockSize),
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Data: data,
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PreDecompress: b.StartTimer,
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PostDecompress: b.StopTimer,
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NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
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return NewWriter(b, benchBlockSize, flate.BestCompression)
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},
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NewReader: func(b *bytes.Buffer) (io.Reader, error) {
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return NewReader(b)
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},
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DecompressIters: b.N,
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})
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}
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