forked from OSchip/llvm-project
105 lines
3.8 KiB
C++
105 lines
3.8 KiB
C++
//===--- Compression.cpp - Compression implementation ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements compression functions.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/Compression.h"
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#include "llvm/ADT/OwningPtr.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Config/config.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/MemoryBuffer.h"
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#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
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#include <zlib.h>
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#endif
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using namespace llvm;
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#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
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static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
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switch (Level) {
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case zlib::NoCompression: return 0;
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case zlib::BestSpeedCompression: return 1;
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case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
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case zlib::BestSizeCompression: return 9;
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}
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llvm_unreachable("Invalid zlib::CompressionLevel!");
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}
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static zlib::Status encodeZlibReturnValue(int ReturnValue) {
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switch (ReturnValue) {
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case Z_OK: return zlib::StatusOK;
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case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
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case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
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case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
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case Z_DATA_ERROR: return zlib::StatusInvalidData;
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default: llvm_unreachable("unknown zlib return status!");
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}
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}
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bool zlib::isAvailable() { return true; }
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zlib::Status zlib::compress(StringRef InputBuffer,
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OwningPtr<MemoryBuffer> &CompressedBuffer,
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CompressionLevel Level) {
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unsigned long CompressedSize = ::compressBound(InputBuffer.size());
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OwningArrayPtr<char> TmpBuffer(new char[CompressedSize]);
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int CLevel = encodeZlibCompressionLevel(Level);
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Status Res = encodeZlibReturnValue(::compress2(
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(Bytef *)TmpBuffer.get(), &CompressedSize,
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(const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
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if (Res == StatusOK) {
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CompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
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StringRef(TmpBuffer.get(), CompressedSize)));
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// Tell MSan that memory initialized by zlib is valid.
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__msan_unpoison(CompressedBuffer->getBufferStart(), CompressedSize);
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}
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return Res;
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}
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zlib::Status zlib::uncompress(StringRef InputBuffer,
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OwningPtr<MemoryBuffer> &UncompressedBuffer,
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size_t UncompressedSize) {
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OwningArrayPtr<char> TmpBuffer(new char[UncompressedSize]);
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Status Res = encodeZlibReturnValue(
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::uncompress((Bytef *)TmpBuffer.get(), (uLongf *)&UncompressedSize,
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(const Bytef *)InputBuffer.data(), InputBuffer.size()));
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if (Res == StatusOK) {
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UncompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
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StringRef(TmpBuffer.get(), UncompressedSize)));
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// Tell MSan that memory initialized by zlib is valid.
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__msan_unpoison(UncompressedBuffer->getBufferStart(), UncompressedSize);
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}
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return Res;
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}
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uint32_t zlib::crc32(StringRef Buffer) {
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return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
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}
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#else
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bool zlib::isAvailable() { return false; }
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zlib::Status zlib::compress(StringRef InputBuffer,
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OwningPtr<MemoryBuffer> &CompressedBuffer,
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CompressionLevel Level) {
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return zlib::StatusUnsupported;
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}
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zlib::Status zlib::uncompress(StringRef InputBuffer,
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OwningPtr<MemoryBuffer> &UncompressedBuffer,
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size_t UncompressedSize) {
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return zlib::StatusUnsupported;
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}
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uint32_t zlib::crc32(StringRef Buffer) {
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llvm_unreachable("zlib::crc32 is unavailable");
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}
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#endif
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