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// Copyright 2015, Joe Tsai. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
package bzip2
import (
"bytes"
"errors"
"flag"
"io"
"os/exec"
"strings"
"testing"
"github.com/dsnet/compress/internal/testutil"
)
var zcheck = flag.Bool("zcheck", false, "verify test vectors with C bzip2 library")
func cmdCompress(input []byte) ([]byte, error) { return cmdExec(input, "-z") }
func cmdDecompress(input []byte) ([]byte, error) { return cmdExec(input, "-d") }
// cmdExec executes the bzip2 tool, passing the input in as stdin.
// It returns the stdout and an error.
func cmdExec(input []byte, args ...string) ([]byte, error) {
var bo, be bytes.Buffer
cmd := exec.Command("bzip2", args...)
cmd.Stdin = bytes.NewReader(input)
cmd.Stdout = &bo
cmd.Stderr = &be
err := cmd.Run()
ss := strings.Split(strings.TrimSpace(be.String()), "\n")
if len(ss) > 0 && ss[len(ss)-1] != "" {
// Assume any stderr indicates an error and last line is the message.
return nil, errors.New(ss[len(ss)-1])
}
return bo.Bytes(), err
}
var testdata = []struct {
name string
data []byte
ratio float64 // The minimum expected ratio (uncompressed / compressed)
}{
{"Nil", nil, 0},
{"Binary", testutil.MustLoadFile("../testdata/binary.bin"), 5.68},
{"Digits", testutil.MustLoadFile("../testdata/digits.txt"), 2.22},
{"Huffman", testutil.MustLoadFile("../testdata/huffman.txt"), 1.24},
{"Random", testutil.MustLoadFile("../testdata/random.bin"), 0.98},
{"Repeats", testutil.MustLoadFile("../testdata/repeats.bin"), 3.93},
{"Twain", testutil.MustLoadFile("../testdata/twain.txt"), 2.99},
{"Zeros", testutil.MustLoadFile("../testdata/zeros.bin"), 5825.0},
}
var levels = []struct {
name string
level int
}{
{"Speed", BestSpeed},
{"Default", DefaultCompression},
{"Compression", BestCompression},
}
var sizes = []struct {
name string
size int
}{
{"1e4", 1e4},
{"1e5", 1e5},
{"1e6", 1e6},
}
func TestRoundTrip(t *testing.T) {
for _, v := range testdata {
v := v
t.Run(v.name, func(t *testing.T) {
t.Parallel()
var buf1, buf2 bytes.Buffer
// Compress the input.
wr, err := NewWriter(&buf1, nil)
if err != nil {
t.Errorf("NewWriter() = (_, %v), want (_, nil)", err)
}
n, err := io.Copy(wr, bytes.NewReader(v.data))
if n != int64(len(v.data)) || err != nil {
t.Errorf("Copy() = (%d, %v), want (%d, nil)", n, err, len(v.data))
}
if err := wr.Close(); err != nil {
t.Errorf("Close() = %v, want nil", err)
}
// Verify that the compression ratio is within expected bounds.
ratio := float64(len(v.data)) / float64(buf1.Len())
if ratio < v.ratio {
t.Errorf("poor compression ratio: %0.2f < %0.2f", ratio, v.ratio)
}
// Verify that the C library can decompress the output of Writer and
// that the Reader can decompress the output of the C library.
if *zcheck {
zd, err := cmdDecompress(buf1.Bytes())
if err != nil {
t.Errorf("unexpected cmdDecompress error: %v", err)
}
if got, want, ok := testutil.BytesCompare(zd, v.data); !ok {
t.Errorf("output data mismatch:\ngot %s\nwant %s", got, want)
}
zc, err := cmdCompress(v.data)
if err != nil {
t.Errorf("unexpected cmdCompress error: %v", err)
}
zratio := float64(len(v.data)) / float64(len(zc))
if ratio < 0.9*zratio {
t.Errorf("poor compression ratio: %0.2f < %0.2f", ratio, 0.9*zratio)
}
buf1.Reset()
buf1.Write(zc) // Use output of C library for Reader test
}
// Decompress the output.
rd, err := NewReader(&buf1, nil)
if err != nil {
t.Errorf("NewReader() = (_, %v), want (_, nil)", err)
}
n, err = io.Copy(&buf2, rd)
if n != int64(len(v.data)) || err != nil {
t.Errorf("Copy() = (%d, %v), want (%d, nil)", n, err, len(v.data))
}
if err := rd.Close(); err != nil {
t.Errorf("Close() = %v, want nil", err)
}
if got, want, ok := testutil.BytesCompare(buf2.Bytes(), v.data); !ok {
t.Errorf("output data mismatch:\ngot %s\nwant %s", got, want)
}
})
}
}
func runBenchmarks(b *testing.B, f func(b *testing.B, buf []byte, lvl int)) {
for _, td := range testdata {
if len(td.data) == 0 {
continue
}
if testing.Short() && !(td.name == "Twain" || td.name == "Digits") {
continue
}
for _, tl := range levels {
for _, ts := range sizes {
buf := testutil.ResizeData(td.data, ts.size)
b.Run(td.name+"/"+tl.name+"/"+ts.name, func(b *testing.B) {
f(b, buf, tl.level)
})
}
}
}
}
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