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Compression.cpp
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1 //===--- Compression.cpp - Compression implementation ---------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements compression functions.
11 //
12 //===----------------------------------------------------------------------===//
13 
15 #include "llvm/ADT/OwningPtr.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/Config/config.h"
18 #include "llvm/Support/Compiler.h"
21 #if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
22 #include <zlib.h>
23 #endif
24 
25 using namespace llvm;
26 
27 #if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
29  switch (Level) {
30  case zlib::NoCompression: return 0;
31  case zlib::BestSpeedCompression: return 1;
32  case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
33  case zlib::BestSizeCompression: return 9;
34  }
35  llvm_unreachable("Invalid zlib::CompressionLevel!");
36 }
37 
38 static zlib::Status encodeZlibReturnValue(int ReturnValue) {
39  switch (ReturnValue) {
40  case Z_OK: return zlib::StatusOK;
41  case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
42  case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
43  case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
44  case Z_DATA_ERROR: return zlib::StatusInvalidData;
45  default: llvm_unreachable("unknown zlib return status!");
46  }
47 }
48 
49 bool zlib::isAvailable() { return true; }
51  OwningPtr<MemoryBuffer> &CompressedBuffer,
53  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
54  OwningArrayPtr<char> TmpBuffer(new char[CompressedSize]);
55  int CLevel = encodeZlibCompressionLevel(Level);
56  Status Res = encodeZlibReturnValue(::compress2(
57  (Bytef *)TmpBuffer.get(), &CompressedSize,
58  (const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
59  if (Res == StatusOK) {
60  CompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
61  StringRef(TmpBuffer.get(), CompressedSize)));
62  // Tell MSan that memory initialized by zlib is valid.
63  __msan_unpoison(CompressedBuffer->getBufferStart(), CompressedSize);
64  }
65  return Res;
66 }
67 
69  OwningPtr<MemoryBuffer> &UncompressedBuffer,
70  size_t UncompressedSize) {
71  OwningArrayPtr<char> TmpBuffer(new char[UncompressedSize]);
73  ::uncompress((Bytef *)TmpBuffer.get(), (uLongf *)&UncompressedSize,
74  (const Bytef *)InputBuffer.data(), InputBuffer.size()));
75  if (Res == StatusOK) {
76  UncompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
77  StringRef(TmpBuffer.get(), UncompressedSize)));
78  // Tell MSan that memory initialized by zlib is valid.
79  __msan_unpoison(UncompressedBuffer->getBufferStart(), UncompressedSize);
80  }
81  return Res;
82 }
83 
84 uint32_t zlib::crc32(StringRef Buffer) {
85  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
86 }
87 
88 #else
89 bool zlib::isAvailable() { return false; }
91  OwningPtr<MemoryBuffer> &CompressedBuffer,
94 }
96  OwningPtr<MemoryBuffer> &UncompressedBuffer,
97  size_t UncompressedSize) {
99 }
100 uint32_t zlib::crc32(StringRef Buffer) {
101  llvm_unreachable("zlib::crc32 is unavailable");
102 }
103 #endif
104 
static int encodeZlibCompressionLevel(zlib::CompressionLevel Level)
Definition: Compression.cpp:28
size_t size() const
size - Get the string size.
Definition: StringRef.h:113
const char * getBufferStart() const
Definition: MemoryBuffer.h:51
static zlib::Status encodeZlibReturnValue(int ReturnValue)
Definition: Compression.cpp:38
Status compress(StringRef InputBuffer, OwningPtr< MemoryBuffer > &CompressedBuffer, CompressionLevel Level=DefaultCompression)
Definition: Compression.cpp:50
#define llvm_unreachable(msg)
const char * data() const
Definition: StringRef.h:107
T * get() const
Definition: OwningPtr.h:135
bool isAvailable()
Definition: Compression.cpp:49
void reset(T *P=0)
Definition: OwningPtr.h:51
static MemoryBuffer * getMemBufferCopy(StringRef InputData, StringRef BufferName="")
#define __msan_unpoison(p, size)
Definition: Compiler.h:342
uint32_t crc32(StringRef Buffer)
Definition: Compression.cpp:84
Status uncompress(StringRef InputBuffer, OwningPtr< MemoryBuffer > &UncompressedBuffer, size_t UncompressedSize)
Definition: Compression.cpp:68