llvm-6502/lib/Support/Compression.cpp
Alexey Samsonov ef7aefc53b Expose CRC-32 implementation from zlib
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188380 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-14 16:03:29 +00:00

105 lines
3.8 KiB
C++

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