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 24 using namespace llvm; 25 26 #if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ 27 static 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 37 static 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 48 bool zlib::isAvailable() { return true; } 49 zlib::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 65 zlib::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 79 uint32_t zlib::crc32(StringRef Buffer) { 80 return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size()); 81 } 82 83 #else 84 bool zlib::isAvailable() { return false; } 85 zlib::Status zlib::compress(StringRef InputBuffer, 86 SmallVectorImpl<char> &CompressedBuffer, 87 CompressionLevel Level) { 88 return zlib::StatusUnsupported; 89 } 90 zlib::Status zlib::uncompress(StringRef InputBuffer, 91 SmallVectorImpl<char> &UncompressedBuffer, 92 size_t UncompressedSize) { 93 return zlib::StatusUnsupported; 94 } 95 uint32_t zlib::crc32(StringRef Buffer) { 96 llvm_unreachable("zlib::crc32 is unavailable"); 97 } 98 #endif 99 100
