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
diff --git a/unittests/Support/CompressionTest.cpp b/unittests/Support/CompressionTest.cpp
new file mode 100644
index 0000000..aad7ed0
--- /dev/null
+++ b/unittests/Support/CompressionTest.cpp
@@ -0,0 +1,68 @@
+//===- llvm/unittest/Support/CompressionTest.cpp - Compression tests ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements unit tests for the 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/MemoryBuffer.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+#if LLVM_ENABLE_ZLIB == 1
+
+void TestZlibCompression(StringRef Input, zlib::CompressionLevel Level) {
+  OwningPtr<MemoryBuffer> Compressed;
+  OwningPtr<MemoryBuffer> Uncompressed;
+  EXPECT_EQ(zlib::StatusOK, zlib::compress(Input, Compressed, Level));
+  // Check that uncompressed buffer is the same as original.
+  EXPECT_EQ(zlib::StatusOK, zlib::uncompress(Compressed->getBuffer(),
+                                             Uncompressed, Input.size()));
+  EXPECT_EQ(Input.size(), Uncompressed->getBufferSize());
+  EXPECT_EQ(0,
+            memcmp(Input.data(), Uncompressed->getBufferStart(), Input.size()));
+  if (Input.size() > 0) {
+    // Uncompression fails if expected length is too short.
+    EXPECT_EQ(zlib::StatusBufferTooShort,
+              zlib::uncompress(Compressed->getBuffer(), Uncompressed,
+                               Input.size() - 1));
+  }
+}
+
+TEST(CompressionTest, Zlib) {
+  TestZlibCompression("", zlib::DefaultCompression);
+
+  TestZlibCompression("hello, world!", zlib::NoCompression);
+  TestZlibCompression("hello, world!", zlib::BestSizeCompression);
+  TestZlibCompression("hello, world!", zlib::BestSpeedCompression);
+  TestZlibCompression("hello, world!", zlib::DefaultCompression);
+
+  const size_t kSize = 1024;
+  char BinaryData[kSize];
+  for (size_t i = 0; i < kSize; ++i) {
+    BinaryData[i] = i & 255;
+  }
+  StringRef BinaryDataStr(BinaryData, kSize);
+
+  TestZlibCompression(BinaryDataStr, zlib::NoCompression);
+  TestZlibCompression(BinaryDataStr, zlib::BestSizeCompression);
+  TestZlibCompression(BinaryDataStr, zlib::BestSpeedCompression);
+  TestZlibCompression(BinaryDataStr, zlib::DefaultCompression);
+}
+
+#endif
+
+}