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
14#include "llvm/Support/Compression.h"
15#include "llvm/ADT/SmallVector.h"
16#include "llvm/ADT/StringRef.h"
17#include "llvm/Config/config.h"
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/ErrorHandling.h"
20#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
21#include <zlib.h>
22#endif
23
24using namespace llvm;
25
26#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
27static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
28  switch (Level) {
29    case zlib::NoCompression: return 0;
30    case zlib::BestSpeedCompression: return 1;
31    case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
32    case zlib::BestSizeCompression: return 9;
33  }
34  llvm_unreachable("Invalid zlib::CompressionLevel!");
35}
36
37static zlib::Status encodeZlibReturnValue(int ReturnValue) {
38  switch (ReturnValue) {
39    case Z_OK: return zlib::StatusOK;
40    case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
41    case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
42    case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
43    case Z_DATA_ERROR: return zlib::StatusInvalidData;
44    default: llvm_unreachable("unknown zlib return status!");
45  }
46}
47
48bool zlib::isAvailable() { return true; }
49zlib::Status zlib::compress(StringRef InputBuffer,
50                            SmallVectorImpl<char> &CompressedBuffer,
51                            CompressionLevel Level) {
52  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
53  CompressedBuffer.resize(CompressedSize);
54  int CLevel = encodeZlibCompressionLevel(Level);
55  Status Res = encodeZlibReturnValue(::compress2(
56      (Bytef *)CompressedBuffer.data(), &CompressedSize,
57      (const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
58  // Tell MemorySanitizer that zlib output buffer is fully initialized.
59  // This avoids a false report when running LLVM with uninstrumented ZLib.
60  __msan_unpoison(CompressedBuffer.data(), CompressedSize);
61  CompressedBuffer.resize(CompressedSize);
62  return Res;
63}
64
65zlib::Status zlib::uncompress(StringRef InputBuffer,
66                              SmallVectorImpl<char> &UncompressedBuffer,
67                              size_t UncompressedSize) {
68  UncompressedBuffer.resize(UncompressedSize);
69  Status Res = encodeZlibReturnValue(::uncompress(
70      (Bytef *)UncompressedBuffer.data(), (uLongf *)&UncompressedSize,
71      (const Bytef *)InputBuffer.data(), InputBuffer.size()));
72  // Tell MemorySanitizer that zlib output buffer is fully initialized.
73  // This avoids a false report when running LLVM with uninstrumented ZLib.
74  __msan_unpoison(UncompressedBuffer.data(), UncompressedSize);
75  UncompressedBuffer.resize(UncompressedSize);
76  return Res;
77}
78
79uint32_t zlib::crc32(StringRef Buffer) {
80  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
81}
82
83#else
84bool zlib::isAvailable() { return false; }
85zlib::Status zlib::compress(StringRef InputBuffer,
86                            SmallVectorImpl<char> &CompressedBuffer,
87                            CompressionLevel Level) {
88  return zlib::StatusUnsupported;
89}
90zlib::Status zlib::uncompress(StringRef InputBuffer,
91                              SmallVectorImpl<char> &UncompressedBuffer,
92                              size_t UncompressedSize) {
93  return zlib::StatusUnsupported;
94}
95uint32_t zlib::crc32(StringRef Buffer) {
96  llvm_unreachable("zlib::crc32 is unavailable");
97}
98#endif
99
100