common/bitutil: fix decompression corner cases; fuzz, test & bench

common/bitutil/compress_fuzz.go

@@ -0,0 +1,56 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build gofuzz
+
+package bitutil
+
+import "bytes"
+
+// Fuzz implements a go-fuzz fuzzer method to test various compression method
+// invocations.
+func Fuzz(data []byte) int {
+	if len(data) == 0 {
+		return -1
+	}
+	if data[0]%2 == 0 {
+		return fuzzCompress(data[1:])
+	}
+	return fuzzDecompress(data[1:])
+}
+
+// fuzzCompress implements a go-fuzz fuzzer method to test the bit compression and
+// decompression algorithm.
+func fuzzCompress(data []byte) int {
+	proc, _ := DecompressBytes(CompressBytes(data), len(data))
+	if !bytes.Equal(data, proc) {
+		panic("content mismatch")
+	}
+	return 0
+}
+
+// fuzzDecompress implements a go-fuzz fuzzer method to test the bit decompression
+// and recompression algorithm.
+func fuzzDecompress(data []byte) int {
+	blob, err := DecompressBytes(data, 1024)
+	if err != nil {
+		return 0
+	}
+	if comp := CompressBytes(blob); !bytes.Equal(comp, data) {
+		panic("content mismatch")
+	}
+	return 0
+}