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// Copyright 2018 Google Inc.
//
// Licensed 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 compressio
import (
"bytes"
"compress/flate"
"encoding/base64"
"fmt"
"io"
"math/rand"
"runtime"
"testing"
"time"
)
type harness interface {
Errorf(format string, v ...interface{})
Fatalf(format string, v ...interface{})
Logf(format string, v ...interface{})
}
func initTest(t harness, size int) []byte {
// Set number of processes to number of CPUs.
runtime.GOMAXPROCS(runtime.NumCPU())
// Construct synthetic data. We do this by encoding random data with
// base64. This gives a high level of entropy, but still quite a bit of
// structure, to give reasonable compression ratios (~75%).
var buf bytes.Buffer
bufW := base64.NewEncoder(base64.RawStdEncoding, &buf)
bufR := rand.New(rand.NewSource(0))
if _, err := io.CopyN(bufW, bufR, int64(size)); err != nil {
t.Fatalf("unable to seed random data: %v", err)
}
return buf.Bytes()
}
type testOpts struct {
Name string
Data []byte
NewWriter func(*bytes.Buffer) (io.Writer, error)
NewReader func(*bytes.Buffer) (io.Reader, error)
PreCompress func()
PostCompress func()
PreDecompress func()
PostDecompress func()
CompressIters int
DecompressIters int
}
func doTest(t harness, opts testOpts) {
// Compress.
var compressed bytes.Buffer
compressionStartTime := time.Now()
if opts.PreCompress != nil {
opts.PreCompress()
}
if opts.CompressIters <= 0 {
opts.CompressIters = 1
}
for i := 0; i < opts.CompressIters; i++ {
compressed.Reset()
w, err := opts.NewWriter(&compressed)
if err != nil {
t.Errorf("%s: NewWriter got err %v, expected nil", opts.Name, err)
}
if _, err := io.Copy(w, bytes.NewBuffer(opts.Data)); err != nil {
t.Errorf("%s: compress got err %v, expected nil", opts.Name, err)
return
}
closer, ok := w.(io.Closer)
if ok {
if err := closer.Close(); err != nil {
t.Errorf("%s: got err %v, expected nil", opts.Name, err)
return
}
}
}
if opts.PostCompress != nil {
opts.PostCompress()
}
compressionTime := time.Since(compressionStartTime)
compressionRatio := float32(compressed.Len()) / float32(len(opts.Data))
// Decompress.
var decompressed bytes.Buffer
decompressionStartTime := time.Now()
if opts.PreDecompress != nil {
opts.PreDecompress()
}
if opts.DecompressIters <= 0 {
opts.DecompressIters = 1
}
for i := 0; i < opts.DecompressIters; i++ {
decompressed.Reset()
r, err := opts.NewReader(bytes.NewBuffer(compressed.Bytes()))
if err != nil {
t.Errorf("%s: NewReader got err %v, expected nil", opts.Name, err)
return
}
if _, err := io.Copy(&decompressed, r); err != nil {
t.Errorf("%s: decompress got err %v, expected nil", opts.Name, err)
return
}
}
if opts.PostDecompress != nil {
opts.PostDecompress()
}
decompressionTime := time.Since(decompressionStartTime)
// Verify.
if decompressed.Len() != len(opts.Data) {
t.Errorf("%s: got %d bytes, expected %d", opts.Name, decompressed.Len(), len(opts.Data))
}
if !bytes.Equal(opts.Data, decompressed.Bytes()) {
t.Errorf("%s: got mismatch, expected match", opts.Name)
if len(opts.Data) < 32 { // Don't flood the logs.
t.Errorf("got %v, expected %v", decompressed.Bytes(), opts.Data)
}
}
t.Logf("%s: compression time %v, ratio %2.2f, decompression time %v",
opts.Name, compressionTime, compressionRatio, decompressionTime)
}
func TestCompress(t *testing.T) {
var (
data = initTest(t, 10*1024*1024)
data0 = data[:0]
data1 = data[:1]
data2 = data[:11]
data3 = data[:16]
data4 = data[:]
)
for _, data := range [][]byte{data0, data1, data2, data3, data4} {
for _, blockSize := range []uint32{1, 4, 1024, 4 * 1024, 16 * 1024} {
// Skip annoying tests; they just take too long.
if blockSize <= 16 && len(data) > 16 {
continue
}
// Do the compress test.
doTest(t, testOpts{
Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), blockSize),
Data: data,
NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
return NewWriter(b, blockSize, flate.BestCompression)
},
NewReader: func(b *bytes.Buffer) (io.Reader, error) {
return NewReader(b)
},
})
}
// Do the vanilla test.
doTest(t, testOpts{
Name: fmt.Sprintf("len(data)=%d, vanilla flate", len(data)),
Data: data,
NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
return flate.NewWriter(b, flate.BestCompression)
},
NewReader: func(b *bytes.Buffer) (io.Reader, error) {
return flate.NewReader(b), nil
},
})
}
}
const (
// benchBlockSize is the blockSize for benchmarks.
benchBlockSize = 32 * 1024
// benchDataSize is the amount of data for benchmarks.
benchDataSize = 10 * 1024 * 1024
)
func BenchmarkCompress(b *testing.B) {
b.StopTimer()
b.SetBytes(benchDataSize)
data := initTest(b, benchDataSize)
doTest(b, testOpts{
Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), benchBlockSize),
Data: data,
PreCompress: b.StartTimer,
PostCompress: b.StopTimer,
NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
return NewWriter(b, benchBlockSize, flate.BestCompression)
},
NewReader: func(b *bytes.Buffer) (io.Reader, error) {
return NewReader(b)
},
CompressIters: b.N,
})
}
func BenchmarkDecompress(b *testing.B) {
b.StopTimer()
b.SetBytes(benchDataSize)
data := initTest(b, benchDataSize)
doTest(b, testOpts{
Name: fmt.Sprintf("len(data)=%d, blockSize=%d", len(data), benchBlockSize),
Data: data,
PreDecompress: b.StartTimer,
PostDecompress: b.StopTimer,
NewWriter: func(b *bytes.Buffer) (io.Writer, error) {
return NewWriter(b, benchBlockSize, flate.BestCompression)
},
NewReader: func(b *bytes.Buffer) (io.Reader, error) {
return NewReader(b)
},
DecompressIters: b.N,
})
}
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