lib/Support/Compression.cpp

   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/Error.h"
  20 #include "llvm/Support/ErrorHandling.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
  28 static Error createError(StringRef Err) {
  29   return make_error<StringError>(Err, inconvertibleErrorCode());
  30 }
  31
  32 static StringRef convertZlibCodeToString(int Code) {
  33   switch (Code) {
  34   case Z_MEM_ERROR:
  35     return "zlib error: Z_MEM_ERROR";
  36   case Z_BUF_ERROR:
  37     return "zlib error: Z_BUF_ERROR";
  38   case Z_STREAM_ERROR:
  39     return "zlib error: Z_STREAM_ERROR";
  40   case Z_DATA_ERROR:
  41     return "zlib error: Z_DATA_ERROR";
  42   case Z_OK:
  43   default:
  44     llvm_unreachable("unknown or unexpected zlib status code");
  45   }
  46 }
  47
  48 bool zlib::isAvailable() { return true; }
  49
  50 Error zlib::compress(StringRef InputBuffer,
  51                      SmallVectorImpl<char> &CompressedBuffer, int Level) {
  52   unsigned long CompressedSize = ::compressBound(InputBuffer.size());
  53   CompressedBuffer.reserve(CompressedSize);
  54   int Res =
  55       ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
  56                   (const Bytef *)InputBuffer.data(), InputBuffer.size(), Level);
  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.set_size(CompressedSize);
  61   return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
  62 }
  63
  64 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
  65                        size_t &UncompressedSize) {
  66   int Res =
  67       ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
  68                    (const Bytef *)InputBuffer.data(), InputBuffer.size());
  69   // Tell MemorySanitizer that zlib output buffer is fully initialized.
  70   // This avoids a false report when running LLVM with uninstrumented ZLib.
  71   __msan_unpoison(UncompressedBuffer, UncompressedSize);
  72   return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
  73 }
  74
  75 Error zlib::uncompress(StringRef InputBuffer,
  76                        SmallVectorImpl<char> &UncompressedBuffer,
  77                        size_t UncompressedSize) {
  78   UncompressedBuffer.resize(UncompressedSize);
  79   Error E =
  80       uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
  81   UncompressedBuffer.resize(UncompressedSize);
  82   return E;
  83 }
  84
  85 uint32_t zlib::crc32(StringRef Buffer) {
  86   return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
  87 }
  88
  89 #else
  90 bool zlib::isAvailable() { return false; }
  91 Error zlib::compress(StringRef InputBuffer,
  92                      SmallVectorImpl<char> &CompressedBuffer, int Level) {
  93   llvm_unreachable("zlib::compress is unavailable");
  94 }
  95 Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
  96                        size_t &UncompressedSize) {
  97   llvm_unreachable("zlib::uncompress is unavailable");
  98 }
  99 Error zlib::uncompress(StringRef InputBuffer,
 100                        SmallVectorImpl<char> &UncompressedBuffer,
 101                        size_t UncompressedSize) {
 102   llvm_unreachable("zlib::uncompress is unavailable");
 103 }
 104 uint32_t zlib::crc32(StringRef Buffer) {
 105   llvm_unreachable("zlib::crc32 is unavailable");
 106 }
 107 #endif