Add basic zlib support to LLVM. This would allow to use compression/uncompression in selected LLVM tools.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180083 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 89 insertions, 0 deletions

diff --git a/lib/Support/Compression.cpp b/lib/Support/Compression.cpp
new file mode 100644
index 0000000000..d0adf79ec7
--- /dev/null
+++ b/lib/Support/Compression.cpp
@@ -0,0 +1,89 @@
+//===--- 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/OwningPtr.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MemoryBuffer.h"
+#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
+#include <zlib.h>
+#endif
+
+using namespace llvm;
+
+#if LLVM_ENABLE_ZLIB == 1
+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;
+  }
+}
+
+static zlib::Status encodeZlibReturnValue(int ReturnValue) {
+  switch (ReturnValue) {
+    case Z_OK: return zlib::StatusOK;
+    case Z_MEM_ERROR: return zlib::StatusOutOfMemory;
+    case Z_BUF_ERROR: return zlib::StatusBufferTooShort;
+    case Z_STREAM_ERROR: return zlib::StatusInvalidArg;
+    case Z_DATA_ERROR: return zlib::StatusInvalidData;
+    default: llvm_unreachable("unknown zlib return status!");
+  }
+}
+
+bool zlib::isAvailable() { return true; }
+zlib::Status zlib::compress(StringRef InputBuffer,
+                            OwningPtr<MemoryBuffer> &CompressedBuffer,
+                            CompressionLevel Level) {
+  unsigned long CompressedSize = ::compressBound(InputBuffer.size());
+  OwningArrayPtr<char> TmpBuffer(new char[CompressedSize]);
+  int CLevel = encodeZlibCompressionLevel(Level);
+  Status Res = encodeZlibReturnValue(::compress2(
+      (Bytef *)TmpBuffer.get(), &CompressedSize,
+      (const Bytef *)InputBuffer.data(), InputBuffer.size(), CLevel));
+  if (Res == StatusOK)
+    CompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
+        StringRef(TmpBuffer.get(), CompressedSize)));
+  return Res;
+}
+
+zlib::Status zlib::uncompress(StringRef InputBuffer,
+                              OwningPtr<MemoryBuffer> &UncompressedBuffer,
+                              size_t UncompressedSize) {
+  OwningArrayPtr<char> TmpBuffer(new char[UncompressedSize]);
+  Status Res = encodeZlibReturnValue(
+      ::uncompress((Bytef *)TmpBuffer.get(), (uLongf *)&UncompressedSize,
+                   (const Bytef *)InputBuffer.data(), InputBuffer.size()));
+  if (Res == StatusOK)
+    UncompressedBuffer.reset(MemoryBuffer::getMemBufferCopy(
+        StringRef(TmpBuffer.get(), UncompressedSize)));
+  return Res;
+}
+
+#else
+bool zlib::isAvailable() { return false; }
+zlib::Status zlib::compress(StringRef InputBuffer,
+                            OwningPtr<MemoryBuffer> &CompressedBuffer,
+                            CompressionLevel Level) {
+  return zlib::StatusUnsupported;
+}
+zlib::Status zlib::uncompress(StringRef InputBuffer,
+                              OwningPtr<MemoryBuffer> &UncompressedBuffer,
+                              size_t UncompressedSize) {
+  return zlib::StatusUnsupported;
+}
+#endif
+