llvm/llvm/include/llvm/Support/Compression.h

//===-- llvm/Support/Compression.h ---Compression----------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains basic functions for compression/decompression.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_COMPRESSION_H
#define LLVM_SUPPORT_COMPRESSION_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/DataTypes.h"

namespace llvm {
template <typename T> class SmallVectorImpl;
class Error;

// None indicates no compression. The other members are a subset of
// compression::Format, which is used for compressed debug sections in some
// object file formats (e.g. ELF). This is a separate class as we may add new
// compression::Format members for non-debugging purposes.
enum class DebugCompressionType { … };

namespace compression {
namespace zlib {

constexpr int NoCompression = …;
constexpr int BestSpeedCompression = …;
constexpr int DefaultCompression = …;
constexpr int BestSizeCompression = …;

bool isAvailable();

void compress(ArrayRef<uint8_t> Input,
              SmallVectorImpl<uint8_t> &CompressedBuffer,
              int Level = DefaultCompression);

Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
                 size_t &UncompressedSize);

Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
                 size_t UncompressedSize);

} // End of namespace zlib

namespace zstd {

constexpr int NoCompression = …;
constexpr int BestSpeedCompression = …;
constexpr int DefaultCompression = …;
constexpr int BestSizeCompression = …;

bool isAvailable();

void compress(ArrayRef<uint8_t> Input,
              SmallVectorImpl<uint8_t> &CompressedBuffer,
              int Level = DefaultCompression, bool EnableLdm = false);

Error decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
                 size_t &UncompressedSize);

Error decompress(ArrayRef<uint8_t> Input, SmallVectorImpl<uint8_t> &Output,
                 size_t UncompressedSize);

} // End of namespace zstd

enum class Format { … };

inline Format formatFor(DebugCompressionType Type) { … }

struct Params { … };

// Return nullptr if LLVM was built with support (LLVM_ENABLE_ZLIB,
// LLVM_ENABLE_ZSTD) for the specified compression format; otherwise
// return a string literal describing the reason.
const char *getReasonIfUnsupported(Format F);

// Compress Input with the specified format P.Format. If Level is -1, use
// *::DefaultCompression for the format.
void compress(Params P, ArrayRef<uint8_t> Input,
              SmallVectorImpl<uint8_t> &Output);

// Decompress Input. The uncompressed size must be available.
Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
                 uint8_t *Output, size_t UncompressedSize);
Error decompress(Format F, ArrayRef<uint8_t> Input,
                 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);
Error decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
                 SmallVectorImpl<uint8_t> &Output, size_t UncompressedSize);

} // End of namespace compression

} // End of namespace llvm

#endif