internal/compress: Import flate and such from klauspost/compress

1 files changed, 108 insertions, 0 deletions

diff --git a/internal/compress/flate/reader_test.go b/internal/compress/flate/reader_test.go
new file mode 100644
index 00000000..6eedfb9b
--- /dev/null
+++ b/internal/compress/flate/reader_test.go
@@ -0,0 +1,108 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package flate
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func TestNlitOutOfRange(t *testing.T) {
+	// Trying to decode this bogus flate data, which has a Huffman table
+	// with nlit=288, should not panic.
+	io.Copy(io.Discard, NewReader(strings.NewReader(
+		"\xfc\xfe\x36\xe7\x5e\x1c\xef\xb3\x55\x58\x77\xb6\x56\xb5\x43\xf4"+
+			"\x6f\xf2\xd2\xe6\x3d\x99\xa0\x85\x8c\x48\xeb\xf8\xda\x83\x04\x2a"+
+			"\x75\xc4\xf8\x0f\x12\x11\xb9\xb4\x4b\x09\xa0\xbe\x8b\x91\x4c")))
+}
+
+const (
+	digits = iota
+	twain
+	random
+)
+
+var testfiles = []string{
+	// Digits is the digits of the irrational number e. Its decimal representation
+	// does not repeat, but there are only 10 possible digits, so it should be
+	// reasonably compressible.
+	digits: "../testdata/e.txt",
+	// Twain is Project Gutenberg's edition of Mark Twain's classic English novel.
+	twain: "../testdata/Mark.Twain-Tom.Sawyer.txt",
+	// Random bytes
+	random: "../testdata/sharnd.out",
+}
+
+func benchmarkDecode(b *testing.B, testfile, level, n int) {
+	b.ReportAllocs()
+	b.StopTimer()
+	b.SetBytes(int64(n))
+	buf0, err := os.ReadFile(testfiles[testfile])
+	if err != nil {
+		b.Fatal(err)
+	}
+	if len(buf0) == 0 {
+		b.Fatalf("test file %q has no data", testfiles[testfile])
+	}
+	compressed := new(bytes.Buffer)
+	w, err := NewWriter(compressed, level)
+	if err != nil {
+		b.Fatal(err)
+	}
+	for i := 0; i < n; i += len(buf0) {
+		if len(buf0) > n-i {
+			buf0 = buf0[:n-i]
+		}
+		io.Copy(w, bytes.NewReader(buf0))
+	}
+	w.Close()
+	buf1 := compressed.Bytes()
+	buf0, compressed, w = nil, nil, nil
+	r := NewReader(bytes.NewReader(buf1))
+	res := r.(Resetter)
+	runtime.GC()
+	b.StartTimer()
+
+	for i := 0; i < b.N; i++ {
+		_ = res.Reset(bytes.NewReader(buf1), nil)
+		_, _ = io.Copy(io.Discard, r)
+	}
+}
+
+// These short names are so that gofmt doesn't break the BenchmarkXxx function
+// bodies below over multiple lines.
+const (
+	constant = ConstantCompression
+	speed    = BestSpeed
+	default_ = DefaultCompression
+	compress = BestCompression
+	oneK     = -1024
+)
+
+func BenchmarkDecodeDigitsSpeed1e4(b *testing.B)    { benchmarkDecode(b, digits, speed, 1e4) }
+func BenchmarkDecodeDigitsSpeed1e5(b *testing.B)    { benchmarkDecode(b, digits, speed, 1e5) }
+func BenchmarkDecodeDigitsSpeed1e6(b *testing.B)    { benchmarkDecode(b, digits, speed, 1e6) }
+func BenchmarkDecodeDigitsDefault1e4(b *testing.B)  { benchmarkDecode(b, digits, default_, 1e4) }
+func BenchmarkDecodeDigitsDefault1e5(b *testing.B)  { benchmarkDecode(b, digits, default_, 1e5) }
+func BenchmarkDecodeDigitsDefault1e6(b *testing.B)  { benchmarkDecode(b, digits, default_, 1e6) }
+func BenchmarkDecodeDigitsCompress1e4(b *testing.B) { benchmarkDecode(b, digits, compress, 1e4) }
+func BenchmarkDecodeDigitsCompress1e5(b *testing.B) { benchmarkDecode(b, digits, compress, 1e5) }
+func BenchmarkDecodeDigitsCompress1e6(b *testing.B) { benchmarkDecode(b, digits, compress, 1e6) }
+func BenchmarkDecodeTwainSpeed1e4(b *testing.B)     { benchmarkDecode(b, twain, speed, 1e4) }
+func BenchmarkDecodeTwainSpeed1e5(b *testing.B)     { benchmarkDecode(b, twain, speed, 1e5) }
+func BenchmarkDecodeTwainSpeed1e6(b *testing.B)     { benchmarkDecode(b, twain, speed, 1e6) }
+func BenchmarkDecodeTwainDefault1e4(b *testing.B)   { benchmarkDecode(b, twain, default_, 1e4) }
+func BenchmarkDecodeTwainDefault1e5(b *testing.B)   { benchmarkDecode(b, twain, default_, 1e5) }
+func BenchmarkDecodeTwainDefault1e6(b *testing.B)   { benchmarkDecode(b, twain, default_, 1e6) }
+func BenchmarkDecodeTwainCompress1e4(b *testing.B)  { benchmarkDecode(b, twain, compress, 1e4) }
+func BenchmarkDecodeTwainCompress1e5(b *testing.B)  { benchmarkDecode(b, twain, compress, 1e5) }
+func BenchmarkDecodeTwainCompress1e6(b *testing.B)  { benchmarkDecode(b, twain, compress, 1e6) }
+func BenchmarkDecodeRandomSpeed1e4(b *testing.B)    { benchmarkDecode(b, random, speed, 1e4) }
+func BenchmarkDecodeRandomSpeed1e5(b *testing.B)    { benchmarkDecode(b, random, speed, 1e5) }
+func BenchmarkDecodeRandomSpeed1e6(b *testing.B)    { benchmarkDecode(b, random, speed, 1e6) }