Imported Upstream version 5.18.0.161

Former-commit-id: 4db48158d3a35497b8f118ab21b5f08ac3d86d98

external/llvm/lib/Support/Compression.cpp

@@ -0,0 +1,121 @@
+//===--- Compression.cpp - Compression implementation ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements compression functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Compression.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
+#include <zlib.h>
+#endif
+
+using namespace llvm;
+
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+static Error createError(StringRef Err) {
+  return make_error<StringError>(Err, inconvertibleErrorCode());
+}
+
+static int encodeZlibCompressionLevel(zlib::CompressionLevel Level) {
+  switch (Level) {
+    case zlib::NoCompression: return 0;
+    case zlib::BestSpeedCompression: return 1;
+    case zlib::DefaultCompression: return Z_DEFAULT_COMPRESSION;
+    case zlib::BestSizeCompression: return 9;
+  }
+  llvm_unreachable("Invalid zlib::CompressionLevel!");
+}
+
+static StringRef convertZlibCodeToString(int Code) {
+  switch (Code) {
+  case Z_MEM_ERROR:
+    return "zlib error: Z_MEM_ERROR";
+  case Z_BUF_ERROR:
+    return "zlib error: Z_BUF_ERROR";
+  case Z_STREAM_ERROR:
+    return "zlib error: Z_STREAM_ERROR";
+  case Z_DATA_ERROR:
+    return "zlib error: Z_DATA_ERROR";
+  case Z_OK:
+  default:
+    llvm_unreachable("unknown or unexpected zlib status code");
+  }
+}
+
+bool zlib::isAvailable() { return true; }
+
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer,
+                     CompressionLevel Level) {
+  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
+  CompressedBuffer.resize(CompressedSize);
+  int CLevel = encodeZlibCompressionLevel(Level);
+  int Res = ::compress2((Bytef *)CompressedBuffer.data(), &CompressedSize,
+                        (const Bytef *)InputBuffer.data(), InputBuffer.size(),
+                        CLevel);
+  // Tell MemorySanitizer that zlib output buffer is fully initialized.
+  // This avoids a false report when running LLVM with uninstrumented ZLib.
+  __msan_unpoison(CompressedBuffer.data(), CompressedSize);
+  CompressedBuffer.resize(CompressedSize);
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
+}
+
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  int Res =
+      ::uncompress((Bytef *)UncompressedBuffer, (uLongf *)&UncompressedSize,
+                   (const Bytef *)InputBuffer.data(), InputBuffer.size());
+  // Tell MemorySanitizer that zlib output buffer is fully initialized.
+  // This avoids a false report when running LLVM with uninstrumented ZLib.
+  __msan_unpoison(UncompressedBuffer, UncompressedSize);
+  return Res ? createError(convertZlibCodeToString(Res)) : Error::success();
+}
+
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
+  UncompressedBuffer.resize(UncompressedSize);
+  Error E =
+      uncompress(InputBuffer, UncompressedBuffer.data(), UncompressedSize);
+  UncompressedBuffer.resize(UncompressedSize);
+  return E;
+}
+
+uint32_t zlib::crc32(StringRef Buffer) {
+  return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
+}
+
+#else
+bool zlib::isAvailable() { return false; }
+Error zlib::compress(StringRef InputBuffer,
+                     SmallVectorImpl<char> &CompressedBuffer,
+                     CompressionLevel Level) {
+  llvm_unreachable("zlib::compress is unavailable");
+}
+Error zlib::uncompress(StringRef InputBuffer, char *UncompressedBuffer,
+                       size_t &UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
+}
+Error zlib::uncompress(StringRef InputBuffer,
+                       SmallVectorImpl<char> &UncompressedBuffer,
+                       size_t UncompressedSize) {
+  llvm_unreachable("zlib::uncompress is unavailable");
+}
+uint32_t zlib::crc32(StringRef Buffer) {
+  llvm_unreachable("zlib::crc32 is unavailable");
+}
+#endif
+