Add brotli compressor

This commit is for the encoder for brotli compression format.
Brotli is a generic byte-level compression algorithm.

brotli/enc/command.h

@@ -0,0 +1,45 @@
+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// This class models a sequence of literals and a backward reference copy.
+
+#ifndef BROTLI_ENC_COMMAND_H_
+#define BROTLI_ENC_COMMAND_H_
+
+#include <stdint.h>
+
+namespace brotli {
+
+// Command holds a sequence of literals and a backward reference copy.
+class Command {
+ public:
+  Command() : insert_length_(0), copy_length_(0),
+              copy_distance_(0), distance_code_(0),
+              distance_prefix_(0), command_prefix_(0),
+              distance_extra_bits_(0), distance_extra_bits_value_(0) {}
+
+  uint32_t insert_length_;
+  uint32_t copy_length_;
+  uint32_t copy_distance_;
+  // Values <= 16 are short codes, values > 16 are distances shifted by 16.
+  uint32_t distance_code_;
+  uint16_t distance_prefix_;
+  uint16_t command_prefix_;
+  int distance_extra_bits_;
+  uint32_t distance_extra_bits_value_;
+};
+
+}  // namespace brotli
+
+#endif  // BROTLI_ENC_COMMAND_H_