1//===-- llvm/Support/Compression.h ---Compression----------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file contains basic functions for compression/decompression.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_SUPPORT_COMPRESSION_H
14#define LLVM_SUPPORT_COMPRESSION_H
15
16#include "llvm/ADT/ArrayRef.h"
17#include "llvm/Support/DataTypes.h"
18
19namespace llvm {
20template <typename T> class SmallVectorImpl;
21class Error;
22
23// None indicates no compression. The other members are a subset of
24// compression::Format, which is used for compressed debug sections in some
25// object file formats (e.g. ELF). This is a separate class as we may add new
26// compression::Format members for non-debugging purposes.
27enum class DebugCompressionType {
28 None, ///< No compression
29 Zlib, ///< zlib
30 Zstd, ///< Zstandard
31};
32
33namespace compression {
34namespace zlib {
35
36constexpr int NoCompression = 0;
37constexpr int BestSpeedCompression = 1;
38constexpr int DefaultCompression = 6;
39constexpr int BestSizeCompression = 9;
40
41bool isAvailable();
42
43void compress(ArrayRef<uint8_t> Input,
44 SmallVectorImpl<uint8_t> &CompressedBuffer,
45 int Level = DefaultCompression);
46
47Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
48 size_t &UncompressedSize);
49
50Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
51 size_t UncompressedSize);
52
53} // End of namespace zlib
54
55namespace zstd {
56
57constexpr int NoCompression = -5;
58constexpr int BestSpeedCompression = 1;
59constexpr int DefaultCompression = 5;
60constexpr int BestSizeCompression = 12;
61
62bool isAvailable();
63
64void compress(ArrayRef<uint8_t> Input,
65 SmallVectorImpl<uint8_t> &CompressedBuffer,
66 int Level = DefaultCompression);
67
68Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
69 size_t &UncompressedSize);
70
71Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
72 size_t UncompressedSize);
73
74} // End of namespace zstd
75
76enum class Format {
77 Zlib,
78 Zstd,
79};
80
81inline Format formatFor(DebugCompressionType Type) {
82 switch (Type) {
83 case DebugCompressionType::None:
84 llvm_unreachable("not a compression type");
85 case DebugCompressionType::Zlib:
86 return Format::Zlib;
87 case DebugCompressionType::Zstd:
88 return Format::Zstd;
89 }
90 llvm_unreachable("");
91}
92
93struct Params {
94 constexpr Params(Format F)
95 : format(F), level(F == Format::Zlib ? zlib::DefaultCompression
96 : zstd::DefaultCompression) {}
97 Params(DebugCompressionType Type) : Params(formatFor(Type)) {}
98
99 Format format;
100 int level;
101 // This may support multi-threading for zstd in the future. Note that
102 // different threads may produce different output, so be careful if certain
103 // output determinism is desired.
104};
105
106// Return nullptr if LLVM was built with support (LLVM_ENABLE_ZLIB,
107// LLVM_ENABLE_ZSTD) for the specified compression format; otherwise
108// return a string literal describing the reason.
109const char *getReasonIfUnsupported(Format F);
110
111// Compress Input with the specified format P.Format. If Level is -1, use
112// *::DefaultCompression for the format.
113void compress(Params P, ArrayRef<uint8_t> Input,
114 SmallVectorImpl<uint8_t> &Output);
115
116// Decompress Input. The uncompressed size must be available.
117Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
118 uint8_t *Output, size_t UncompressedSize);
119Error decompress(Format F, ArrayRef<uint8_t> Input,
120 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);
121Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
122 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);
123
124} // End of namespace compression
125
126} // End of namespace llvm
127
128#endif
129

source code of include/llvm-17/llvm/Support/Compression.h