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

1 files changed, 193 insertions, 0 deletions

diff --git a/internal/compress/zlib/reader_test.go b/internal/compress/zlib/reader_test.go
new file mode 100644
index 00000000..9b534b1e
--- /dev/null
+++ b/internal/compress/zlib/reader_test.go
@@ -0,0 +1,193 @@
+// Copyright 2009 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 zlib
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"testing"
+)
+
+type zlibTest struct {
+	desc       string
+	raw        string
+	compressed []byte
+	dict       []byte
+	err        error
+}
+
+// Compare-to-golden test data was generated by the ZLIB example program at
+// https://www.zlib.net/zpipe.c
+
+var zlibTests = []zlibTest{
+	{
+		"truncated empty",
+		"",
+		[]byte{},
+		nil,
+		io.ErrUnexpectedEOF,
+	},
+	{
+		"truncated dict",
+		"",
+		[]byte{0x78, 0xbb},
+		[]byte{0x00},
+		io.ErrUnexpectedEOF,
+	},
+	{
+		"truncated checksum",
+		"",
+		[]byte{0x78, 0xbb, 0x00, 0x01, 0x00, 0x01, 0xca, 0x48,
+			0xcd, 0xc9, 0xc9, 0xd7, 0x51, 0x28, 0xcf, 0x2f,
+			0xca, 0x49, 0x01, 0x04, 0x00, 0x00, 0xff, 0xff,
+		},
+		[]byte{0x00},
+		io.ErrUnexpectedEOF,
+	},
+	{
+		"empty",
+		"",
+		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01},
+		nil,
+		nil,
+	},
+	{
+		"goodbye",
+		"goodbye, world",
+		[]byte{
+			0x78, 0x9c, 0x4b, 0xcf, 0xcf, 0x4f, 0x49, 0xaa,
+			0x4c, 0xd5, 0x51, 0x28, 0xcf, 0x2f, 0xca, 0x49,
+			0x01, 0x00, 0x28, 0xa5, 0x05, 0x5e,
+		},
+		nil,
+		nil,
+	},
+	{
+		"bad header (CINFO)",
+		"",
+		[]byte{0x88, 0x98, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01},
+		nil,
+		ErrHeader,
+	},
+	{
+		"bad header (FCHECK)",
+		"",
+		[]byte{0x78, 0x9f, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01},
+		nil,
+		ErrHeader,
+	},
+	{
+		"bad checksum",
+		"",
+		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0xff},
+		nil,
+		ErrChecksum,
+	},
+	{
+		"not enough data",
+		"",
+		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00},
+		nil,
+		io.ErrUnexpectedEOF,
+	},
+	{
+		"excess data is silently ignored",
+		"",
+		[]byte{
+			0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01,
+			0x78, 0x9c, 0xff,
+		},
+		nil,
+		nil,
+	},
+	{
+		"dictionary",
+		"Hello, World!\n",
+		[]byte{
+			0x78, 0xbb, 0x1c, 0x32, 0x04, 0x27, 0xf3, 0x00,
+			0xb1, 0x75, 0x20, 0x1c, 0x45, 0x2e, 0x00, 0x24,
+			0x12, 0x04, 0x74,
+		},
+		[]byte{
+			0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x0a,
+		},
+		nil,
+	},
+	{
+		"wrong dictionary",
+		"",
+		[]byte{
+			0x78, 0xbb, 0x1c, 0x32, 0x04, 0x27, 0xf3, 0x00,
+			0xb1, 0x75, 0x20, 0x1c, 0x45, 0x2e, 0x00, 0x24,
+			0x12, 0x04, 0x74,
+		},
+		[]byte{
+			0x48, 0x65, 0x6c, 0x6c,
+		},
+		ErrDictionary,
+	},
+	{
+		"truncated zlib stream amid raw-block",
+		"hello",
+		[]byte{
+			0x78, 0x9c, 0x00, 0x0c, 0x00, 0xf3, 0xff, 0x68, 0x65, 0x6c, 0x6c, 0x6f,
+		},
+		nil,
+		io.ErrUnexpectedEOF,
+	},
+	{
+		"truncated zlib stream amid fixed-block",
+		"He",
+		[]byte{
+			0x78, 0x9c, 0xf2, 0x48, 0xcd,
+		},
+		nil,
+		io.ErrUnexpectedEOF,
+	},
+}
+
+func TestDecompressor(t *testing.T) {
+	b := new(bytes.Buffer)
+	for _, tt := range zlibTests {
+		in := bytes.NewReader(tt.compressed)
+
+		zr, err := NewReaderDict(in, tt.dict)
+		if err != nil {
+			if !errors.Is(err, tt.err) {
+				t.Errorf("%s: NewReader: %s", tt.desc, err)
+			}
+
+			continue
+		}
+		defer zr.Close()
+
+		// Read and verify correctness of data.
+		b.Reset()
+
+		n, err := io.Copy(b, zr)
+		if err != nil {
+			if !errors.Is(err, tt.err) {
+				t.Errorf("%s: io.Copy: %v want %v", tt.desc, err, tt.err)
+			}
+
+			continue
+		}
+
+		s := b.String()
+		if s != tt.raw {
+			t.Errorf("%s: got %d-byte %q want %d-byte %q", tt.desc, n, s, len(tt.raw), tt.raw)
+		}
+
+		// Check for sticky errors.
+		if n, err := zr.Read([]byte{0}); n != 0 || !errors.Is(err, io.EOF) {
+			t.Errorf("%s: Read() = (%d, %v), want (0, io.EOF)", tt.desc, n, err)
+		}
+
+		if err := zr.Close(); err != nil {
+			t.Errorf("%s: Close() = %v, want nil", tt.desc, err)
+		}
+	}
+}