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