Compression.cpp | Explore in Territory

//===--- Compression.cpp - Compression implementation ---------------------===//
//
// 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 implements compression functions.
//
//===----------------------------------------------------------------------===//

#include "llvm/Support/Compression.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Config/config.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#if LLVM_ENABLE_ZLIB
#include <zlib.h>
#endif
#if LLVM_ENABLE_ZSTD
#include <zstd.h>
#endif

usingnamespacellvm;
usingnamespacellvm::compression;

const char *compression::getReasonIfUnsupported(compression::Format F) { … }

void compression::compress(Params P, ArrayRef<uint8_t> Input,
                           SmallVectorImpl<uint8_t> &Output) { … }

Error compression::decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
                              uint8_t *Output, size_t UncompressedSize) { … }

Error compression::decompress(compression::Format F, ArrayRef<uint8_t> Input,
                              SmallVectorImpl<uint8_t> &Output,
                              size_t UncompressedSize) { … }

Error compression::decompress(DebugCompressionType T, ArrayRef<uint8_t> Input,
                              SmallVectorImpl<uint8_t> &Output,
                              size_t UncompressedSize) { … }

#if LLVM_ENABLE_ZLIB

static StringRef convertZlibCodeToString(int Code) { … }

bool zlib::isAvailable() { … }

void zlib::compress(ArrayRef<uint8_t> Input,
                    SmallVectorImpl<uint8_t> &CompressedBuffer, int Level) { … }

Error zlib::decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
                       size_t &UncompressedSize) { … }

Error zlib::decompress(ArrayRef<uint8_t> Input,
                       SmallVectorImpl<uint8_t> &Output,
                       size_t UncompressedSize) { … }

#else
bool zlib::isAvailable() { return false; }
void zlib::compress(ArrayRef<uint8_t> Input,
                    SmallVectorImpl<uint8_t> &CompressedBuffer, int Level) {
  llvm_unreachable("zlib::compress is unavailable");
}
Error zlib::decompress(ArrayRef<uint8_t> Input, uint8_t *UncompressedBuffer,
                       size_t &UncompressedSize) {
  llvm_unreachable("zlib::decompress is unavailable");
}
Error zlib::decompress(ArrayRef<uint8_t> Input,
                       SmallVectorImpl<uint8_t> &UncompressedBuffer,
                       size_t UncompressedSize) {
  llvm_unreachable("zlib::decompress is unavailable");
}
#endif

#if LLVM_ENABLE_ZSTD

bool zstd::isAvailable() { return true; }

#include <zstd.h> // Ensure ZSTD library is included

void zstd::compress(ArrayRef<uint8_t> Input,
                    SmallVectorImpl<uint8_t> &CompressedBuffer, int Level,
                    bool EnableLdm) {
  ZSTD_CCtx *Cctx = ZSTD_createCCtx();
  if (!Cctx)
    report_bad_alloc_error("Failed to create ZSTD_CCtx");

  if (ZSTD_isError(ZSTD_CCtx_setParameter(
          Cctx, ZSTD_c_enableLongDistanceMatching, EnableLdm ? 1 : 0))) {
    ZSTD_freeCCtx(Cctx);
    report_bad_alloc_error("Failed to set ZSTD_c_enableLongDistanceMatching");
  }

  if (ZSTD_isError(
          ZSTD_CCtx_setParameter(Cctx, ZSTD_c_compressionLevel, Level))) {
    ZSTD_freeCCtx(Cctx);
    report_bad_alloc_error("Failed to set ZSTD_c_compressionLevel");
  }

  unsigned long CompressedBufferSize = ZSTD_compressBound(Input.size());
  CompressedBuffer.resize_for_overwrite(CompressedBufferSize);

  size_t const CompressedSize =
      ZSTD_compress2(Cctx, CompressedBuffer.data(), CompressedBufferSize,
                     Input.data(), Input.size());

  ZSTD_freeCCtx(Cctx);

  if (ZSTD_isError(CompressedSize))
    report_bad_alloc_error("Compression failed");

  __msan_unpoison(CompressedBuffer.data(), CompressedSize);
  if (CompressedSize < CompressedBuffer.size())
    CompressedBuffer.truncate(CompressedSize);
}

Error zstd::decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
                       size_t &UncompressedSize) {
  const size_t Res = ::ZSTD_decompress(
      Output, UncompressedSize, (const uint8_t *)Input.data(), Input.size());
  UncompressedSize = Res;
  // Tell MemorySanitizer that zstd output buffer is fully initialized.
  // This avoids a false report when running LLVM with uninstrumented ZLib.
  __msan_unpoison(Output, UncompressedSize);
  return ZSTD_isError(Res) ? make_error<StringError>(ZSTD_getErrorName(Res),
                                                     inconvertibleErrorCode())
                           : Error::success();
}

Error zstd::decompress(ArrayRef<uint8_t> Input,
                       SmallVectorImpl<uint8_t> &Output,
                       size_t UncompressedSize) {
  Output.resize_for_overwrite(UncompressedSize);
  Error E = zstd::decompress(Input, Output.data(), UncompressedSize);
  if (UncompressedSize < Output.size())
    Output.truncate(UncompressedSize);
  return E;
}

#else
bool zstd::isAvailable() { … }
void zstd::compress(ArrayRef<uint8_t> Input,
                    SmallVectorImpl<uint8_t> &CompressedBuffer, int Level,
                    bool EnableLdm) { … }
Error zstd::decompress(ArrayRef<uint8_t> Input, uint8_t *Output,
                       size_t &UncompressedSize) { … }
Error zstd::decompress(ArrayRef<uint8_t> Input,
                       SmallVectorImpl<uint8_t> &Output,
                       size_t UncompressedSize) { … }
#endif
llvm/llvm/lib/Support/Compression.cpp
