1/*
2 * Copyright 2018-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <memory.h>
20
21#include <folly/Memory.h>
22#include <folly/Portability.h>
23#include <folly/compression/Compression.h>
24
25#if FOLLY_HAVE_LIBZSTD
26
27#ifndef ZSTD_STATIC_LINKING_ONLY
28#define ZSTD_STATIC_LINKING_ONLY
29#endif
30#include <zstd.h>
31
32namespace folly {
33namespace io {
34namespace zstd {
35
36/**
37 * Interface for zstd-specific codec initialization.
38 */
39class Options {
40 public:
41 /* Create an Options struct with the default options for the given `level`.
42 * NOTE: This is the zstd level, COMPRESSION_LEVEL_DEFAULT and such aren't
43 * supported, since zstd supports negative compression levels.
44 */
45 explicit Options(int level);
46
47 /**
48 * Set the compression `param` to `value`.
49 * See the zstd documentation for ZSTD_CCtx_setParameter() for details, this
50 * is just a thin wrapper.
51 */
52 void set(ZSTD_cParameter param, unsigned value);
53
54 /**
55 * Set the maximum allowed window size during decompression.
56 * `maxWindowSize == 0` means don't set the maximum window size.
57 * zstd's current default limit is 2^27.
58 * See the zstd documentation for ZSTD_DCtx_setMaxWindowSize() for details.
59 */
60 void setMaxWindowSize(size_t maxWindowSize) {
61 maxWindowSize_ = maxWindowSize;
62 }
63
64 /// Get a reference to the ZSTD_CCtx_params.
65 ZSTD_CCtx_params const* params() const {
66 return params_.get();
67 }
68
69 /// Get the compression level.
70 int level() const {
71 return level_;
72 }
73
74 /// Get the maximum window size.
75 size_t maxWindowSize() const {
76 return maxWindowSize_;
77 }
78
79 private:
80 static void freeCCtxParams(ZSTD_CCtx_params* params);
81 std::unique_ptr<
82 ZSTD_CCtx_params,
83 folly::static_function_deleter<ZSTD_CCtx_params, &freeCCtxParams>>
84 params_;
85 size_t maxWindowSize_{0};
86 int level_;
87};
88
89/// Get a zstd Codec with the given options.
90std::unique_ptr<Codec> getCodec(Options options);
91/// Get a zstd StreamCodec with the given options.
92std::unique_ptr<StreamCodec> getStreamCodec(Options options);
93
94} // namespace zstd
95} // namespace io
96} // namespace folly
97
98#endif
99