vendor: Add dependencies for discosrv

vendor/github.com/cznic/zappy/encode.go

@@ -0,0 +1,37 @@
+// Copyright 2014 The zappy Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the SNAPPY-GO-LICENSE file.
+
+package zappy
+
+import (
+	"encoding/binary"
+)
+
+// We limit how far copy back-references can go, the same as the snappy C++
+// code.
+const maxOffset = 1 << 20
+
+// emitCopy writes a copy chunk and returns the number of bytes written.
+func emitCopy(dst []byte, offset, length int) (n int) {
+	n = binary.PutVarint(dst, int64(-length))
+	n += binary.PutUvarint(dst[n:], uint64(offset))
+	return
+}
+
+// emitLiteral writes a literal chunk and returns the number of bytes written.
+func emitLiteral(dst, lit []byte) (n int) {
+	n = binary.PutVarint(dst, int64(len(lit)-1))
+	n += copy(dst[n:], lit)
+	return
+}
+
+// MaxEncodedLen returns the maximum length of a zappy block, given its
+// uncompressed length.
+func MaxEncodedLen(srcLen int) int {
+	return 10 + srcLen
+}